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Document:	Guide to VAX/VMS Disk and Magnetic Tape Operations
Order Number:	AI-Y506B-TE
Revision:
Pages:	206
Original Filename:	http://bitsavers.org/pdf/dec/vax/vms/4.4/AI-Y506B-TE_VMS_4.4_Disk_and_Tape_Operations_198604.pdf

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Guide to VAX/VMS Disk and Magnetic
Tape Operations
Order Number: Al-Y506B-TE

April 1986
This guide describes formats and procedures for using disk and magnetic tapes
on Version 4.4 of the VAX/VMS operating system. The tasks described in this
guide are oriented toward the use of private media.

Revision/Update Information:

This revised manual supersedes Guide
to VAX/VMS Disk and Magnetic Tape
Operations, Version 4.0.

Software Version:

VAX/VMS Version 4.4

digital equipment corporation
maynard, massachusetts

April 1986
The information in this document is subject to change without notice and should
not be construed as a commitment by Digital Equipment Corporation. Digital
Equipment Corporation assumes no responsibility for any errors that may appear
in this document.
The software described in this document is furnished under a license and may be
used or copied only in accordance with the terms of such license.
No responsibility is assumed for the use or reliability of software on equipment
that is not supplied by Digital Equipment Corporation or its affiliated companies.
Copyright © 1986 by Digital Equipment Corporation
All Rights Reserved • Printed in U.S.A.
The postpaid READER'S COMMENTS form on the last page of this document
requests the user's critical evaluation to assist in preparing future documentation.
The following are trademarks of Digital Equipment Corporation:
DEC
DEC/CMS
DEC/MMS
DECnet
DECsystem-10
DECSYSTEM-20
DECUS
DECwriter

DIBOL
EduSystem
IAS
MASSBUS
PDP
PDT
RSTS
RSX

UNIBUS
VAX
VAXcluster
VMS
VT

~D~DD~D
ZK-2833

HOW TO ORDER ADDITIONAL DOCUMENTATION
DIRECT MAIL ORDERS
USA 8t PUERTO Rico*

CANADA

INTERNATIONAL

Digital Equipment Corporation
P.O. Box CS2008
Nashua, New Hampshire
03061

Digital Equipment
of Canada Ltd.
100 Herzberg Road
Kanata, Ontario K2K 2A6
Attn: Direct Order Desk

Digital Equipment Corporation
PSG Business Manager
c/o Digital's local subsidiary
or approved distributor

In Continental USA and Puerto Rico call 800-258-1710.
In New Hampshire, Alaska, and Hawaii call 603-884-6660.
In Canada call 800-267-6215.
*Any prepaid order from Puerto Rico must be placed with the local Digital subsidiary (809-754-7575).
Internal orders should be placed through the Software Distribution Center (SOC), Digital Equipment
Corporation, Westminster, Massachusetts 01473.
This document was prepared using an in-house documentation production system. All page
composition and make-up was performed by TeX. the typesetting system developed by
Donald E. Knuth at Stanford University. TeX is a registered trademark of the American Mathematical
Society.

Contents
PREFACE

xiii

PART I DISK AND MAGNETIC TAPE CONCEPTS
INTRODUCTION TO DISK AND MAGNETIC TAPE MEDIA

1-1

1.1

THE HISTORY OF FILE STORAGE MEDIA

1-1

1.2

BASIC DISK CONCEPTS

1-2

1.3

BASIC MAGNETIC TAPE CONCEPTS

1-7

1.4

HOW TO IDENTIFY ROUTINE OPERATIONS

1-9

1.5

USING COMMAND PROCEDURES TO PERFORM ROUTINE
OPERATIONS

1-9

DISK AND MAGNETIC TAPE PROTECTION

2-1

DATA PROTECTION
2.1.1 UIC-Based Protection
2.1.2 ACL-Based Protection
2.1.3 VAX/VMS ANSI-Labeled Magnetic Tape Accessibility
Protection

2-1
2-2
2-4

VOLUME-LEVEL PROTECTION
2.2.1 Disk Volume Protection
2.2.2 Magnetic Tape Volume Protection
2.2.2.1
Protection for VAX/VMS Magnetic Tapes• 2-7
2.2.2.2
Protection for Interchange Environments• 2-8

2-6
2-6

CHAPTER 1

CHAPTER 2

2.1

2.2

2-5

2-7

iii

Contents

FILE-LEVEL PROTECTION
2.3.1
Disk File Protection
2.3.2 Directory File Protection
2.3.3 Magnetic Tape File Protection

2.3

2-8
2-9
2-11
2-13

PART II DISK AND MAGNETIC TAPE OPERATIONS
CHAPTER 3

PREPARING DISK AND MAGNETIC TAPE VOLUMES FOR
PRIVATE USE

3-1

3.1

SETTING UP A PRIVATE VOLUME

3-1

3.2

ALLOCATING A DRIVE TO YOUR PROCESS
3.2.1 Allocating a Disk Drive
3.2.2 Allocating a Magnetic Tape Drive

3-2
3-2
3-3

3.3

INITIALIZING A VOLUME
3.3.1
Initializing a Disk Volume
3.3.2 Initializing a Magnetic Tape Volume

3-4
3-6
3-6

3.4

MOUNTING A VOLUME
3-8
3.4.1
Mounting a Disk Volume
3-10
3.4.2 Mounting a Disk Volume Set
3-11
3.4.2. 1
Creating a Disk Volume Set from New Volumes • 3-12
3.4.2.2
Creating a Disk Volume Set from an Existing
Volume• 3-13
3.4.2.3
Adding Volumes to a Disk Volume Set• 3-14
3.4.3 Mounting a Magnetic Tape Volume
3-15
3.4.3.1
Mounting an ANSI-Labeled Volume • 3-15
3.4.3.2
Using MOUNT Command Qualifiers • 3-16
3.4.4 Mounting a Magnetic Tape Volume Set
3-19
3.4.4.1
Creating a Magnetic Tape Volume Set• 3-20
3.4.4.2
Mounting Continuation Volumes in a Volume Set• 3-21

3.5

DISMOUNTING A VOLUME

3-23

Contents

3.6

DEALLOCATING DRIVES

3.7

USING COMMAND PROCEDURES TO SET UP DISKS AND
MAGNETIC TAPES
3. 7 .1 Designing Command Procedures to Set Up Disk
Volumes
3. 7 .2 Designing Command Procedures to Set up Magnetic Tape
Volumes

3-28

MANIPULATING FILES ON DISKS AND MAGNETIC TAPES

4-1

4.1

USING DCL TO MANIPULATE FILES

4-1

4.2

USING DCL TO RETRIEVE FILE INFORMATION
4.2.1 Retrieving Directory Information
4.2.2 Retrieving Device Information
4.2.3 Retrieving Magnetic Tape Device Information
4.2.4 Retrieving Disk File Protection Information
4.2.5 Retrieving Disk Quota Information

4-2
4-3
4-4
4-7
4-8

4.3

USING DCL TO MODIFY FILE CHARACTERISTICS
4.3.1 Modifying ACL Characteristics
4.3.2 Modifying Directory Characteristics
4.3.3 Modifying Disk File Characteristics
4.3.4 Modifying Magnetic Tape Device Characteristics
4.3.5 Modifying File Protection Characteristics
4.3.6 Modifying Volume Characteristics

4-10
4-10
4-11
4-12
4-12
4-13
4-15

4.4

USING DCL TO ACCESS FILES
4.4.1 Accessing Disk Files for Read and Write Operations
4.4. 1 . 1
Reading Files from a Disk Volume • 4-16
4.4.1.2
Writing Files to a Disk Volume• 4-17
4.4.1.3
Writing Files from Disk Volumes to Magnetic Tape
Volumes • 4-18

4-15
4-16

CHAPTER 4

3-25

3-26
3-27

4-9

Contents

4.4.2

Accessing Magnetic Tape Files for Read and Write
Operations
4-19
4.4.2.1
Locating ANSI-Labeled Magnetic Tape Files for READ or
WRITE Access • 4-20
4.4.2.2
Reading Files on Magnetic Tape Volumes• 4-22
4.4.2.3
Writing to Files on Magnetic Tape Volumes• 4-23

COMMAND PROCEDURES FOR ACCESSING FOREIGN
VOLUMES

4.5

CHAPTER 5

4-24

TRANSFERRING DISK AND MAGNETIC TAPE INFORMATION 5-1

5.1

TRANSFERRING INFORMATION WITHIN AND ACROSS OPERATING
SYSTEMS
5-1

5.2

USING THE COPY COMMAND TO TRANSFER INFORMATION
5-2
5.2.1 Copying Files from Disk Volumes
5-2
5.2.2 Copying Files from Magnetic Tape Volumes
5-3
5.2.3 Copying Files to and from Non-File-Structured Volumes
5-6
5.2.3.1
Copying Files to a Non-File-Structured Volume• 5-6
5.2.3.2
Copying Files from a Non-File-Structured Volume• 5-7

5.3

USING THE CONVERT UTILITY TO TRANSFER INFORMATION

5-8

5.4

USING THE EXCHANGE UTILITY TO TRANSFER INFORMATION
5.4.1 Invoking and Terminating the Exchange Utility
5.4.2 Using EXCHANGE at DCL Command Level

5-10
5-11
5-12

5.5

USING COMMAND PROCEDURES TO TRANSFER
INFORMATION
5.5.1 Using a Command Procedure to Copy Files
5.5.2 Using a Command Procedure to Exchange Information _

5-12
5-13
5-15

Contents

CHAPTER 6

MAINTAINING DATA INTEGRITY ON DISK AND MAGNETIC
TAPE VOLUMES
6-1

6.1

USING BACKUP TO MAINTAIN DATA INTEGRITY

6-2

6.2

CHOOSING BACKUP OPERATIONS
6.2.1 Deciding What to Baok Up
6.2.2 Deciding How to Back Up Files or Volumes
6.2.2.1
Copying Files• 6-4
6.2.2.2
Saving Files• 6-5
6.2.2.3
Restoring Files • 6-5
6.2.2.4
Comparing Files• 6-5
6.2.2.5
Listing Files • 6-5
6.2.3 Invoking the VAX/VMS Backup Utility

6-3
6-3
6-4

6.3

USING BACKUP MEDIA
6.3.1 Using BACKUP with Magnetic Tape
6.3.2 Using BACKUP with Files-11 Disk Volumes
6.3.3 Using BACKUP with Sequential Disk Volumes
6.3.4 Remote Files-11 Save Sets
6.3.5 Rotating Backup Sets

6-6
6-7
6-7
6-8
6-9
6-9

6.4

PERFORMING BACKUP TASKS
6-10
6.4.1 Copying Disk Files, Directories, and Volumes
6-11
6.4. 1. 1
Copying Single Files with BACKUP • 6-11
6.4. 1.2
Copying Multiple Files with BACKUP • 6-11
6.4. 1.3
Copying an Entire Directory Tree with BACKUP • 6-12
6.4. 1.4
Copying a Disk Volume to a Disk with BACKUP • 6-12
6.4.1.5
Copying a Disk Volume Set to a Disk with BACKUP• 6-13
6.4.2 Saving Disk Files, Directories, and Volumes to Magnetic
Tape
6-13
6.4.2.1
Saving Disk Files to Magnetic Tape• 6-14
6.4.2.2
Saving Directories to Magnetic Tape• 6-14
6.4.2.3
Saving a Directory Tree to Magnetic Tape• 6-15
6.4.2.4
Saving Disk Volumes to Magnetic Tape• 6-15
6.4.2.5
Saving Unstructured Disk Volumes to Magnetic
Tape• 6-15
6.4.3 Saving Disk Files, Directories, and Volumes to Disks _
6-16
6.4.3. 1
Writing Save Sets on File-Structured Disk Volumes • 6-16
6.4.3.2
Writing Save Sets on Sequential Disk Volumes • 6-16
6.4.3.3
Writing Multivolume Sequential Disk Save Sets• 6-17

6-6

vii

Contents

6.4.4

Backing Up Full Volumes and Volume Sets
6.4.4.1
Backing Up a Disk Volume Set When Drives are
Limited • 6-19
6.4.5 Performing Selective Backups
6.4.6 Protecting a BACKUP Save Set
6.4.7 R~storing Disk Files, Directories, and Volumes from Save
Sets
6.4.7.1
Restoring Disk Files from Save Sets on Magnetic
Tape• 6-23
6.4.7.2
Restoring Disk Files from Save Sets on Sequential
Disk• 6-24
6.4.7.3
Restoring Disk Files from Save Sets on Multiple
Volumes• 6-25
6.4.8 Restoring Entire Disk Volumes
6.4.8.1
Changing Volume Initialization Parameters Before
Restoring• 6-26
6.4.9 Listing the Contents of a BACKUP Save Set
6.4.10 Comparing Files with BACKUP

6-26
6-27

6.5

USING BACKUP JOURNAL FILES

6-28

6.6

USING COMMAND PROCEDURES TO PERFORM BACKUP
OPERATIONS

6-30

CHAPTER 7

7.1

6-18

6-20
6-22
6-23

6-25

HANDLING OPERATOR-ORIENTED DISK AND MAGNETIC TAPE
FUNCTIONS
7-1
USING THE OPERATOR TERMINAL TO HANDLE USER
REQUESTS

7-1

7.2

HANDLING USER REQUESTS FOR MOUNTING VOLUMES
7-3
7 .2.1 Requests for Mounting Disks and Single Magnetic Tape
Volumes
7-4
7.2.2 Requests for Mounting Magnetic Tape Volume Sets _
7-5
7.2.2.1
Mounting Volume Sets with Automatic Switching• 7-5
7 .2.2.2
Mounting Volume Sets without Automatic Switching • 7-6

7.3

HANDLING REQUESTS FROM THE BACKUP UTILITY
7.3.1 Writing to a Save Set
7.3.2 Reading from a Save Set

viii

7-8
7-8
7-9

Contents

7 .3.3
7.4

APPENDIX A
A.1

Recovering from an Error

7-9

HANDLING MOUNT VERIFICATION TASKS
7 .4.1 Mount Verification for Offline Devices
7.4.2 Mount Verification for Write-Locked Devices
7.4.3 Canceling Mount Verification
7 .4.4 Dismounting a Volume to Abort Mount Verification

7-11
7-11
7-13
7-14
7-14

VAX/VMS DISK FILES AND VOLUMES

A-1

FILES-11 DISK STRUCTURE
A.1 .1 Index File
A.1 .2 Storage Bit Map File
A.1.3 Bad Block File
A.1 .4 Master File Directory
A.1.5 Core Image File
A.1.6 Volume Set List File
A. 1 . 7 Continuation File
A.1 .8 Backup Log File
A.1.9 Pending Bad Block Log File
A.1.10 Files-11 On-Disk Structure Level 1 Versus Structure
Level 2

A-1
A-2
A-2
A-3
A-3
A-3
A-3
A-3
A-4
A-4

APPENDIX B VAX/VMS ANSI-LABELED MAGNETIC TAPE

A-4

B-1

B.1

LOGICAL FORMAT OF ANSI-LABELED VOLUMES

B-1

B.2

VAX/VMS MAGNETIC TAPE ANCILLARY CONTROL PROCESS
(MTAACP)

B-1

BASIC COMPONENTS OF THE VAX/VMS ANSI-LABELED
FORMAT
B.3.1 Beginning-of-Tape and End-of-Tape Markers
B.3.2 Tape Marks
B.3.3 Labels

B-2
B-2
B-2
B-4

VOLUME AND FILE CONFIGURATIONS

B-4

B.3

B.4

Contents

Single File/Single Volume Configuration
Single File/Multivolume Configuration
Multifile/Single Volume Configuration
Multifile/Multivolume Configuration

B-6
B-7
B-8
B-9

VOLUME LABELS
B.5.1 VOL 1 Label
B.5.1. 1
Volume Identifier Field • B-10
B.5.1.2
Accessibility Field• B-10
B.5.1.3
Implementation Identifier Field• B-10
B.5.1.4
Owner Identifier Field• B-10
B.5.2 VOL2 Label
B.5.2.1
Volume-Owner Field • B-11

B-9
B-9

B.4.1
B.4.2
B.4.3
B.4.4
B.5

HEADER LABELS
B.6.1 HDR1
B.6.1.1
File Identifier Field • B-12
B.6.1.2
File-Set Identifier Field • B-13
File Section Number and File Sequence Number
B.6.1.3
Fields • B-13
B.6.1.4
Generation Number and Generation-Version Number
Fields • B-14
B.6.1.5
Creation Date and Expiration Date Fields • B-14
Accessibility Field • B-15
B.6.1.6
B.6.1.7
Implementation Identifier Fie1d • B-15
B.6.2 HDR2 LABEL
B.6.2.1
Record Format Field • B-15
B.6.2.2
Block Length Field • B-17
B.6.2.3
Record Length Field • B-17
B.6.2.4
Implementation-Dependent Field • B-18
B.6.2.5
Buffer-Offset Length Field • B-18
B.6.3 HDR3 LABEL
B.6.4 HDR4 Label

B.6

B.7

TRAILER LABELS

B-10

B-11
B-11

B-15

B-19
B-19
B-19

Contents

INDEX

FIGURES
1-3

1-1
1-2

File Extents
Files-11 On-Disk Structure Hierarchy

1-3
1-4
2-1

Tracks and Cylinders
lnterrecord Gaps
Illustrating User Categories with a UIC of [100,100]

B-1

Basic Layout of a VAX/VMS ANSI-Labeled Volume

2-3
B-3

B-2

Single File/Single Volume Configuration

B-6

B-3
B-4

Single File/Multivolume Configuration
Multifile/Single Volume Configuration

B-7

B-5
B-6

Multifile/Multivolume Configuration
Blocked Fixed-Length Records

B-7

Variable-Length Records

1-4
1-5
1-8

B-8
B-9
8-16
8-17

TABLES
A-1
B-1

VAX/VMS Reserved Files
Labels and Components Supported by VAX/VMS

A-1

8-5

Preface
The Guide to VAX/VMS Disk and Magnetic Tape Operations describes some
of the routine tasks that are performed on private disk and magnetic tape
media.

Intended Audience
This guide is intended for all users, from the VAX operator to the VAX/VMS
system manager. The only prerequisite is that Introduction to VAX/VMS be
read first.
The Guide to VAX/VMS Disk and Magnetic Tape Operations is not a guide to
system management. Although the system manager may use it as an aid in
certain types of operations, this manual is designed primarily for the private
user of disk and magnetic tape.
If you are a novice user, you can use this guide as.: stepping stone to a
basic understanding of disk and magnetic tape operations. Experienced
users unfamiliar with DIGITAL software can use it to gain familiarity with
DIGITAL terms and techniques. Experienced DIGITAL users should find the
guide useful because it describes in detail most of the disk and magnetic tape
operations routinely performed on the VAX/VMS operating system.

Structure of This Document
Information in this guide is organized in four major sections:
•

PART I describes basic disk and magnetic tape concepts. It also describes
the protection schemes that apply to disk and magnetic tape media.

•

PART II describes tasks that are frequently performed on private disk
and magnetic tape media. The chapters in Part II include examples of
command procedures designed to simplify the use of routine disk and
magnetic tape operations.

•

APPENDIX A describes the Files-11 On-Disk Structure for VAX/VMS
disk files and volumes.

•

APPENDIX B describes formats and components for VAX/VMS magnetic
tape volumes and files.

xiii

Preface

Associated Documents
The tasks described in this guide employ various VAX/VMS utilities and
DCL commands. Detailed descriptions of the utilities and commands
are provided in the VAX/VMS Utilities volumes and the VAX/VMS DCL
Dictionary.
The Guide to VAX/VMS Software Installation provides instructions for
procedures used in system installation.
The VAX/VMS System Manager's Reference Manual provides task-oriented
instructions for maintaining public files and volumes; these instructions
include steps for bootstrapping and running standalone BACKUP.
The Guide to VAXclusters provides information for maintaining public files
and volumes in a VAXcluster environment.
The Guide to VAX/VMS System Security describes security features available
through the VAX/VMS operating system; see this guide for more information
on data protection.
The VAX/VMS Volume Shadowing Manual (not part of the VAX/VMS
document set) describes how to mount, dismount, and maintain volumes
using the volume shadowing option.

Conventions Used in This Document
Convention

Meaning
A symbol with a one- to six-character
abbreviation indicates that you press a key
on the terminal, for example, IRETI.
The phrase CTRL/x indicates that you
must press the key labeled CTRL while you
simultaneously press another key, for example,
CTRL/C, CTRL/Y CTRL/0.
I

$SHOW TIME
05-JUN-1986 11 :55:22

xiv

Command examples show all output lines or
prompting characters that the system prints
or displays in black letters. All user-entered
commands are shown in red letters.

Preface

Convention

Meaning

$TYPE MYFILE.DAT

Vertical series of periods, or ellipsis, mean
either that not all the data that the system
would display in response to the particular
command is shown or that not all the data a
user would enter is shown.

file-spec, ...

Horizontal ellipsis indicates that additional
parameters, values, or information can be
entered.

[logical-name]

Square brackets indicate that the enclosed item
is optional. (Square brackets are not, however,
optional in the syntax of a directory name in a
file specification or in the syntax of a substring
specification in an assignment statement.)

quotation marks
apostrophes

The term quotation marks is used to refer
to double quotation marks (" ). The term
apostrophe ( ' ) is used to refer to a single
quotation mark.

PART I DISK AND MAGNETIC TAPE CONCEPTS

Introduction to Disk and Magnetic Tape
Media
This chapter provides an introduction to storage media and describes
basic disk and magnetic tape concepts. It also mentions the importance
of identifying routine disk and magnetic tape operations, and the advantage
of using command procedures to perform them.

1.1

The History of File Storage Media
As technology has progressed, so has the volume of information that must be
saved. Business and industrial concerns, for instance, have compiled many
types of data files about a wide range of subjects. For a long time, all these
data files were stored efficiently on paper in desk drawers and filing cabinets.
But, as these paper files grew, it often took longer to locate the needed data
than to create it in the first place. Storing all of a company's data files on
paper became impractical.
As the need for saving data increased, the need also arose for a better
medium to store and retrieve data quickly, reliably, and economically. The
computer and computerized filing systems provide such storage media.
At first, computerized files consisted of collections of punched cards. Cards
provide a convenient means of grouping related pieces of information.
This information might represent, for example, a business event, such as a
purchase or sale of office furniture. Or, in the engineering environment, the
information could represent variable equations and data constants related
to stress analysis. This information, grouped on a single card, represents a
record of that event. Records of similar events, grouped together, constitute
a file.
As a storage medium, cards have certain advantages. They are easy to
add, delete, or rearrange. However, cards become worn, require physical
handling, and are bulky. Cards are also relatively slow to process because
they allow only sequential file access. Sequential access means that the
search for a record starts at the beginning of the file and proceeds in order
through each record. At times, when the needed record (or group of records)
is near the end of the file, the search wastes computer processing time.
The introduction of magnetic tape as a storage medium eliminated some of
the disadvantages of cards. Magnetic tape provides both a storage medium
and a means for inputfoutput (1/0), and its uses have grown along with the
needs of the user. Magnetic tape offers virtually unlimited storage. It
1-1

Introduction to Disk and Magnetic Tape Media

requires much less storage space than a card file with a comparable amount
of data. However, magnetic tape is limited as a storage medium because, like
a card file, it allows only sequential file access.
In contrast to magnetic tape, disk storage allows direct· file access. Direct
access means that the computer can locate the desired record without first
searching the records that precede it in the file. The time needed to access
the record is independent of the record's location in the file.

1.2

Basic Disk Concepts
VAX/VMS disk files reside on Files-11 On-Disk Structure volumes. The
term Files-11 On-Disk Structure refers to the logical structure given to the
disk: a hierarchical organization of files, their data, and the directories
needed to gain access to them. The VAX/VMS file system implements the
disk structure and provides access control to the files located on the disk.
This section describes the Files-11 On-Disk Structure levels and defines the
terminology related to it. (The term Files-11 used alone always refers to
Files-11 On-Disk Structure levels.)
The smallest addressable unit of information on a disk is a block. Files-11
On-Disk Structures define a block to consist of 512 8-bit bytes. Blocks can be
treated as units for transfer between a Files-11 disk volume and memory.
Blocks are logically grouped into a cluster, which is the basic unit by which
disk space is allocated. The system manager or operator determines the
number of blocks in a cluster when a given disk, known as a volume, is
first prepared for use (initialized). Cluster sizes from 1 to 65,535 blocks are
allowed, but the smaller cluster sizes in the range are more practical. In
general, a disk with a relatively small number of blocks is given a smaller
cluster size, while larger disks are given larger cluster sizes to minimize the
overhead for disk space allocation.
Contiguous clusters allocated to a particular file have been given the name
extent. An extent can contain all or part of a file. If enough contiguous
area is available on the disk, the entire file is allocated as a single extent.
Sometimes, however, not enough contiguous area is available to contain
the entire file, or, when you create a file initially, you may not wish to
reserve the entire required amount of space. When the file is eventually
extended, it is unlikely that the adjacent clusters will still be unallocated. If
the adjacent clusters are already allocated to another file, the extension will
not occur contiguously. Whether the clusters are contiguous or not, the file
is divided into two or more parts, and each part is an extent. Thus, a file can
consist of multiple extents located in separate areas on the disk, as shown in
Figure 1-1.

1-2

Introduction to Disk and Magnetic Tape Media

Figure 1-1

File Extents
Single extent for file A

ZK-738-82

Figure 1-2 shows the hierarchy of blocks, clusters, extents, and files in the
Files-11 On-Disk Structure.

1-3

Introduction to Disk and Magnetic Tape Media

Figure 1-2 Files-11 On-Disk Structure Hierarchy

File

Extent3

You can exercise as little or as much control as you want over the allocation
of space on a Files-11 disk file. For example, you can specify the number
of blocks to be allocated, and even give the exact location for the blocks on
the volume. On the other hand, you can allow VAX Record Management
Services (RMS) to handle all disk space allocation details automatically.
If you wish, you can specify the size of the initial space allocation and the
size to be used by RMS each time the file is extended. If you find that a
file needs less space than is allocated to it, you can specify that the unused
clusters are to be deallocated from the file. These clusters will then be
available for allocation to other files on the volume.

When a large amount of file storage space is needed, you can combine
several Files-11 volumes into what is called a volume set. A volume set,
although composed of several physical volumes, has the appearance of one
large volume. The different extents of a file can be located on different
volumes in the volume set. In general, you need not specify a particular
volume in the set to locate a file or create a new one, although it is possible
(and sometimes desirable for performance reasons) to specify a particular
volume to be used for a certain allocation request.
The smallest unit discernible to the Files-11 structure is the sector; for most
Files-11 disks, a sector is equivalent to a block, which is 512 bytes. Other
basic terms related to disk structure are track and cylinder. A track is the
collection of sectors (or blocks on Files-11 structures) at a single radius on
one recording surface of a disk. It is accessible to a given read/write head
position on the disk device. A cylinder consists of all tracks at the same
radius on all recording surfaces of a disk.
1-4

Introduction to Disk and Magnetic Tape Media

Because access to any of the blocks in a given cylinder does not require
any movement of the disk's read/write heads, it is generally advantageous
to keep related data blocks in the same cylinder. For this reason, when
choosing a cluster size for a large-capacity disk, a system manager will often
select a cluster size that divides evenly into the cylinder size.
Figure 1-3 is a graphic representation of tracks and cylinders.
Figure 1-3 Tracks and Cylinders

r--- ------1
I A track is comprised of

I the area at a single radius I
on one recording surface.
1
L _ _ _ _ _ _ _ _ _J1

r---------,I

I A cylinder consists of

these tracks in the same

I radius on all the recording I
c~~s.:..__
.J

- - __

Recording occurs on both
surfaces of each platter. The
extreme top and bottom
surfaces of some disk models
are not used for recording.

ZK-740-82

A record is a collection of logically related data that a program treats as a
processing unit. A record can be the same size as a block, smaller than a
block, or even larger than a block. Therefore, a block can contain one record,
multiple records, or only part of a record. The remainder of this section
contains a brief explanation of some basic elements of the Files-11 structure.

1-5

Introduction to Disk and Magnetic Tape Media

A Files-11 structure resides on a volume, which is a physical medium, such
as a disk pack. A Files-11 volume is an ordered set of 512-byte blocks. The
blocks are numbered consecutively from 0 ton; the value of n depends on
the size of the disk.
Each Files-11 volume has an index file, which is created when the volume
is initialized. (You cannot use a disk as a Files-11 disk until it has been
initialized with the INITIALIZE command.) The index file contains the
following information:
•

Bootstrap block

•

Home block

•

File headers

The bootstrap block contains the bootstrap program and is physically
the first block on the volume. All Files-11 volumes have an area for this
bootstrap block even if the operating system does not require a bootstrap
block. If the volume is not the operating system volume, the bootstrap block
area contains a program other than the bootstrap program. This program
displays a message on the system console indicating that the volume is not
the operating system volume, but a volume containing only user files.
The home block is normally the next block after the bootstrap block; it
identifies the disk as a Files-11 volume. If for some reason the home block
cannot be read (physically unusable), an alternative block will be selected for
use as the home block. This block provides specific information about the
volume and default values for files on the volume. Among the items in the
home block are the following:
•

The volume name

•

Information to locate the remainder of the index file

•

The maximum number of files that can be present on the volume at any
one time

•

The user identification code (UIC) of the owner of the volume

•

Volume protection information (specifies which users can read and/or
write the entire volume)

Files-11 volumes contain several copies of the home block to ensure against
accidental destruction of this information and the consequent loss of access
to other files on the volume.

1-6

Introduction to Disk and Magnetic Tape Media

The bulk of the index file consists of file headers; each file header describes
one file on the volume. File headers contain information such as the owner
UIC, protection, creation date, and creation time. Most important, the file
header contains a list of extents that make up the file, describing where
the file is physically located on the volume. If a file has a large number
of extents, multiple file headers are used to describe them. A file identifier
number is associated with each file header.
When you create a file, you normally specify a file name to RMS, which
assigns this name to the file on a Files-11 volume. RMS places the file name
and file identifier associated with the newly created file in a directory, which
contains an entry defining the location for each file. When you access the
file, you supply the file name, which supplies a path to the file identifier
through the directory entry. The file identifier, in tum, points to the location
of the file header, which contains a listing of the extent or extents that locate
the actual data.

1.3

Basic Magnetic Tape Concepts
The file storage system for magnetic tapes on VAX/VMS is based on the
standard magnetic tape structure as defined by the American National
Standard X3.27 - 1978. This standard will be referred to as the ANSI
standard throughout this guide.
Magnetic tape data is organized sequentially; the data records and files are
organized in the order in which they are written.
On VAX/VMS, characters of data on magnetic tape are measured in bytes
per inch (bpi). This measurement is called density. (The ANSI standard
uses characters per inch (cpi), which is equivalent to the bpi convention used
by VAX/VMS.) A 1600 bpi tape can accommodate 1600 characters of data,
using an inch of recording space.
Even though a magnetic tape may have a density of 1600 bpi, there are
not always 1600 characters on every inch of tape because of the interrecord
gap (IRG). The IRG is an interval of blank space between data records; it is
created automatically when records are written to the magnetic tape. The
IRG is a breakpoint on the magnetic tape, which allows the magnetic tape
unit to decelerate, and stop if necessary, after a record operation and then
accelerate to working speed before the next record operation.
Each IRG is approximately 0.6 inch in length. Writing an SO-character record
at 1600 bpi requires 0.05 inch of space. Therefore, the IRG requires 12 times
more space than the data, wasting valuable storage space. RMS can reduce
the size of this wasted space by using record blocking. This technique groups
individual records into a block and places the IRG after the block rather than
after each record.

1-7

Introduction to Disk and Magnetic Tape Media

Note that a block on disk is different from a block on magnetic tape. On
disk, a block is fixed at a size of 512 bytes; on magnetic tape, the size of a
blockis determined by the user. However, record blocking requires more
buffer space to be allocated for your program, which increases RMS memory
requirements. The greater the number of records in a block, the greater
the buffer size requirements. You must determine the point at which the
benefits of record blocking cease. This determination should be based on the
configuration of your computer system.
The following example shows how space can be saved by record blocking.
Assume that a 1600-bpi magnetic tape contains 10 records that are not
grouped into a block. Each record is 160 characters long (0.1 inch at 1600
bpi) with a 0.6 inch IRG after each record. This uses 7 inches of tape.
However, placing the same 10 records into one block uses only 1.6 inches
of tape (1 inch for the data records and 0.6-inch for the IRG). Figure 1-4
illustrates this example of record blocking.
Figure 1-4 lnterrecord Gaps
WITHOUT RECORD BLOCKING
Record

Record

1.11.

...

I RG

l,l.l.tl
..!.1.:

IR G

~.l.:.i.i.t.l

Record

!
I RG

:.1.'1_l.,i1.,1

I RG 'l..:.ll.. I RG
l'=··

lllllll

IRG

I RG

WITH RECORD BLOCKING
Al I 10 records
(

~---,

-1RGI
ZK-741-82

Record blocking also increases the efficiency of the flow of data into the
computer. For example, 10 unblocked records require 10 separate physical
transfers, while 10 records placed into a single block require only 1 physical
transfer. Moreover, a shorter length of magnetic tape is traversed for the
same amount of data; thus the operation is completed in less time.

1-8

Introduction to Disk and Magnetic Tape Media

Data on magnetic tape is also organized into files. When you create a file
on magnetic tape, the magnetic tape file system writes a set of header labels
on the tape immediately preceding the data blocks. These labels contain
information such as the user-supplied file name, creation date, and expiration
date. Additional labels, called trailer labels, are also written following the
file. To access a file on magnetic tape by the file name, the file system
searches the tape for the header label set that contains the specified file
name.
When the data blocks of a file or related files do not physically fit on one
volume (a reel of magnetic tape), the file is continued on another volume.
This is a multivolume file. The volumes in a multivolume file constitute a
volume set. When access is made to a file on a volume set, all volumes in
the set are searched.

1.4

How to Identify Routine Operations
Many of the operations that you perform on disk and magnetic tape media
are routine in nature. You will find it worthwhile to take the time to identify
those tasks that you routinely perform at your particular site. Once you have
isolated those tasks, you can design command procedures to assist you in
performing them.
If you are a system manager or an operator, for example, you must frequently
perform data integrity tasks such as backing up media. You could enter all
of the commands, parameters, and qualifiers required to back up your media
each time that you perform the backup operation. Or, you could write a
single command procedure (containing that set of commands, qualifiers, and
parameters) that, when executed, would also perform the backup operation.

1.5

Using Command Procedures to Perform Routine Operations
In order to familiarize yourself with the syntax used to design and execute
command procedures, see the Guide to Using DCL and Command Procedures

on VAX/VMS.
Each of the chapters in Part II of this guide describes a routine type of disk
and magnetic tape operation. With the exception of Chapter 7, each of these
chapters contains examples of command procedures that are designed to ease
the performance of routine disk and magnetic tape operations.
Chapter 7 specifically describes operator-oriented disk and magnetic tape
functions.

1-9

Disk and Magnetic Tape Protection

This chapter describes the types of data protection that the VAX/VMS
operating system provides for disks and magnetic tapes. In particular, the
chapter focuses on disk and magnetic tape protection at the volume level and
at the file level.

2. 1

Data Protection
The VAX/VMS operating system protects data on disk and magnetic tape
volumes to ensure against accidental or unauthorized access. A volume is the
entity that exists when a medium is mounted on a device. For example, disk
packs and reels of magnetic tape are called volumes when they are mounted
on disk and magnetic tape drives.
VAX/VMS systems support the protection of data on disk and magnetic
tape media at the volume and file levels. At the volume level, the system
provides protection for both disks and magnetic tapes. At the file level,
the system provides protection for individual disk files, directory files that
reside on disk volumes, and magnetic tape files. However, distinct file-level
protection for magnetic tape files is limited to one special case, which is
described in Section 2.3.3.
In addition to protecting the data on mounted volumes, the system
also provides device-level protection. Note, however, that this chapter
is primarily concerned with how to protect data residing on disk and
magnetic tape media. It does not describe how to set device protection. For
information on setting device protection characteristics, see the descriptions
of the DCL commands INITIALIZE, MOUNT, and SET VOLUME in the
VAX/VMS DCL Dictionary.

On VAX/VMS, data residing on disk and magnetic tape volumes can be
protected by one or more of the following:
•

user identification codes (UICs)

•

access control lists (ACLs)

•

ANSI-standard accessibility

2-1

Disk and Magnetic Tape Protection

2.1.1

UIC-Based Protection
UIC-based protection is supported for disk and magnetic tape volumes and
individual files on disk volumes, including directories. UIC-based protection
is determined by an owner's user identification code (UIC) and a protection
code. The owner UIC is normally the UIC of the user who created the file or
volume. The protection code indicates who is allowed access and for what
purposes.
UIC formats can contain alphanumeric characters or they can consist
entirely of octal numbers. For example, [VMS,USER) and [360,030) are
both legitimate UIC formats.
When a user attempts to access a file or volume, the user's UIC is compared
to the owner UIC of the file or volume. Depending on the relationship of the
UICs, the user falls into one or more of the following categories:
•

SYSTEM - all users who have system privilege (SYSPRV) or low group
numbers, usually from 1 through 10 (octal). However, the exact range
of system group numbers is determined by the system manager when
the system is generated and may range as high as 37,776 (octal). These
group numbers are generally for system managers, system programmers,
and operators. In addition, the SYSTEM protection field is used for those
users with the user privilege GRPPRV, whose UIC group matches the
group of the file or volume owner UIC.

•

OWNER - the user with the same UIC as the person who created and
therefore owns the volume or file

•

GROUP - all users, including the owner, who have the same group
number in their UICs as the owner of the file

•

WORLD -

all users including those in the first three categories

Note
SYSTEM and OWNER categories always have access to magnetic
tape volumes, except as noted in Section 2.1.3.
Figure 2-1 illustrates the relationships of these categories to each other.
Each of the categories of user described above is allowed or denied several
types of access, including the following:
•

READ

•

WRITE

•

EXECUTE

2-2

Disk and Magnetic Tape Protection

Figure 2-1

Illustrating User Categories with a UIC of [100, 100]

WORLD
(All UICs)

g = Group Number
m = Member Number
NOTE: THE SYSTEM MANAGER CAN EXTEND THE SYSTEM GROUP NUMBER LIMIT TO 3776

ZK-778-82

•

DELETE

•

CONTROL

The meaning of each access type depends on the object to which it is applied
(disk or magnetic tape volume, file, or directory). Section 2.2 describes how
these types of access apply to disk and magnetic tape volumes; Section 2.3
describes how the access types apply to files and directories.
Note that CONTROL access does not appear in the protection mask. It is
never granted to the GROUP and WORLD categories of users, but is always
granted to SYSTEM and OWNER.
You can bypass all VIC-based protection checks if you have the BYPASS
user privilege. In addition, you can bypass all protection checks and gain
READ and CONTROL access to a disk file if you have the READALL user
privilege. For magnetic tapes, you can bypass VIC-based protection checks if
you have VOLPRO (volume protection override) privilege.

2-3

Disk and Magnetic Tape Protection

For information on how to set UIC-based protection, see the discussion of
protection codes in the VAX/VMS DCL Concepts Manual.

2.1.2

ACL-Based Protection
An access control list (ACL) is primarily a list of entries that grant or deny
access to a particular system resource, such as a disk file or a directory. ACLs
offer you the chance to "fine tune the action taken when access to a file is
sought. You can opt to provide an ACL on any disk file to permit as much
or as little access as is desirable in each case. In providing a more detailed
definition of who is allowed a particular kind of access, ACLs can enhance
the security of disk files. Note, however, that "fine tuning" is done at the
expense of performance; the larger the ACLs are, the more time they take to
process.
0

ACL-based protection is supported for files and directories on disk volumes
only. ACL protection is not supported for files on magnetic tape volumes.
If a file does not have an associated ACL, the system uses UIC-based
protection to determine access as described in Section 2.1.1.
If a file has an associated ACL, the system uses the ACL to determine access
as follows:
•

If the ACL includes an identifier entry for your UIC, the ACL
specification takes precedence over your UIC-based protection. However,
SYSTEM and OWNER may still have access (for detailed information on
ACL protection, see the VAX/VMS DCL Concepts Manual.

•

If the ACL does not include an identifier entry for your UIC (that is, does
not explicitly allow or refuse access), then the system uses UIC-based
protection to determine access.

If you have control access to a resource, you can define the access control list
using the following DCL commands:

•

EDIT/ACL

•

SET ACL

For more information on how to invoke, modify, and display ACLs, see
the VAX/VMS Access Control List Editor Reference Manual or the Guide to
VAX/VMS System Security.

2-4

Disk and Magnetic Tape Protection

2.1 .3

VAX/VMS ANSI-Labeled Magnetic Tape Accessibility Protection
The VAX/VMS magnetic tape file system supports accessibility protection
based on the ANSI standard. This protection scheme allows an installation
to use a routine that is designed to interpret the contents of the volume and
header label accessibility field (see Appendix B).
When the installation routine is called to interpret a VOLl label supplied as
input, the routine must return one of the following values to the magnetic
tape file system:
•

User has no access to the volume/file

•

User has complete access to the volume/file

•

Use the output of any other VAX/VMS protection mechanism specified
(for file-level access, the protection defaults to whatever was specified for
the volume)

If the installation routine determines that you have no access to a volume or
file, then you will be denied access regardless of the volume protection set
by VAX/VMS. That is, no amount of privilege granted to you by VAX/VMS
can override that decision. On the other hand, if the installation determines
that you have complete access to the file or volume, then you will be granted
complete access even if a VAX/VMS protection scheme denies you access to
that file or volume.

When the installation routine is called to return the VOLl label or HDRl
label as output, the routine must return the character to write into the
volume or file label accessibility field.
If you do not design your own installation routine, VAX/VMS will provide
a default routine for you. The routine provided by VAX/VMS will work in
the following way. The default installation routine first checks the ANSI
standard version of the label. For magnetic tapes with a version number
of 3 or less, the routine outputs either an ASCII character space (full access
without checking VAX/VMS protection) or the character specified by the
user. On input of these magnetic tapes, the routine checks for a blank (full
access without checking VAX/VMS protection) and, if the field is not blank,
returns the value that causes the file system to check for explicit override of
accessibility checking.

For magnetic tapes with a version number greater than 3, the routine outputs
either the character specified by the user or an ASCII 1 if no character was
specified. On input of these magnetic tapes, the routine checks for an ASCII
character space. If the field has an ASCII space, the user is given full access
and VAX/VMS protection is not checked. If the field contains an ASCII 1
and the VAX/VMS protection has been specified, the VAX/VMS protection is
checked.

2-5

Disk and Magnetic Tape Protection

If the field does not contain an ASCII space or an ASCII 1, the routine
returns the value to the magnetic tape file system that forces the user to
override the accessibility checking, and allows the magnetic tape file system
to check VAX/VMS protection.
For more information on how ANSI-standard accessibility protection applies
to files on magnetic tape volumes, see Section 2.3.3.

2.2

Volume-Level Protection
Disks and magnetic tapes canboth be protected at the volume level. When
you prepare a disk or magnetic tape volume for private use, you can define
the protection you want to have applied.
Volume protection for a disk or magnetic tape volume is usually set when
the volume is mounted or initialized. If you do not explicitly specify the
protection for a particular disk volume, the system will provide a default
protection for you.
To change the protection that has been set on a disk volume, use the DCL
command SET VOLUME as described in the VAX/VMS DCL Dictionary.
For more information on setting the volume protection when you mount
a volume, see the descriptions of the DCL command INITIALIZE in the
VAX/VMS DCL Dictionary, and see the VAX/VMS Mount Utility Reference
Manual.

2.2.1

Disk Volume Protection
Disk volume protection supports the following access types:
•

READ

•

WRITE

•

EXECUTE

•

DELETE

If you have READ access to a disk volume, you have the right to examine,
print, execute, or copy files on that volume.

If you have WRITE access to a disk volume, you have the right to modify
existing files on that volume. Unlike that of magnetic tape volumes, WRITE
access to a disk volume does not automatically imply READ access. That is,
it is possible to grant a user WRITE access to a disk volume, without granting
that user READ access to the volume. This is not very useful, however, since
WRITE access to a file implies READ access.

2-6

Disk and Magnetic Tape Protection

When applied a~ the volume (as opposed to the file) level, EXECUTE access
means that you have the right to create files or modify existing files. When
applied at the file level, EXECUTE access gives you the right to invoke files
that are executable (such as executable images and command procedures).
If you have DELETE access to a disk volume, you have the right to delete a
file or files on the volume.

2.2.2

Magnetic Tape Volume Protection
Only two types of access apply to magnetic tape volume protection, unlike
disk volume protection. These two access types are:
•

READ

•

WRITE

If you have READ access to a magnetic tape volume, you have the right to
examine, print, or copy a file or files from the volume. If you have WRITE
access to a magnetic tape volume, you have the right to append or write files
to the volume.

For magnetic tape volumes, WRITE access implies READ access. Thus,
granting a category of users WRITE access to a magnetic tape volume
automatically permits them to have READ access to the volume also.
There are two ways to protect a magnetic tape volume on a VAX/VMS
system. You can protect a magnetic tape volume through the UIC-based
protection scheme supported by VAX/VMS. This scheme is checked on
VAX/VMS systems only and will be ignored in any interchange with nonVAX/VMS systems. You can also protect a magnetic tape volume by using
the guidelines of the ANSI standards. This protection scheme supports the
protection of magnetic tape volumes in environments where interchange
exists between VAX/VMS and non-VAX/VMS operating systems.
2.2.2.1

Protection for VAX/VMS Magnetic Tapes
The VAX/VMS magnetic tape file system provides two levels of protection.
One level is defined by the ANSI standard and is encoded in the
ACCESSIBILITY field of the first volume label written on the magnetic tape.
The second level is UIC-based and is defined by the VAX/VMS magnetic
tape file system. This protection is encoded in the second volume label
written on the magnetic tape.

2-7

Disk and Magnetic Tape Protection

2.2.2.2

Protection for Interchange Environments

Magnetic tape volume protection is also supported for interchange between
VAX/VMS and non-VAX/VMS operating systems. Protection is supported
for interchange between VAX/VMS and DIGITAL operating systems other
than VAX/VMS (such as RSX-11M and TOPS-20) as well as between
VAX/VMS and non-DIGITAL operating systems.
For magnetic tapes processed on any operating system that supports
a version of the ANSI standard later than Version 3, the accessibility
information in the first volume label is processed exactly as described
above. Magnetic tapes processed on operating systems other than VAX/VMS
Version 4.0 or later have their protection characteristics encoded in the first
volume label of the magnetic tape volume.
In order to process a magnetic tape created on a DIGITAL operating system
other than VAX/VMS, a user must have VOLPRO privilege and must
explicitly override the check on the protection. If the magnetic tape had been
created with a specified accessibility, then a user wishing to access that tape
must have the appropriate privilege and must explicitly override the check
on accessibility. If the magnetic tape volume had not been created with such
a protection scheme, then a user wishing to access that magnetic tape would
be granted READ and WRITE access to that magnetic tape volume.
The VAX/VMS magnetic tape file system allows you to specify values
for the fields in which other DIGITAL operating systems currently write
their protection information. Except under conditions described in the two
previous sections, VAX/VMS will not process this field. This field can thus
be used to store the protection values for another operating system without
affecting VAX/VMS protection characteristics on that particular volume.

2.3

File-Level Protection
In addition to volume-level protection, the VAX/VMS operating system
supports protection at the file level for all files residing on disk volumes,
including directories. In certain cases, file-level protection is also supported
for magnetic tape files. For files residing on magnetic tape volumes, however,
only one special case (described in Section 2.3.3) exists in which distinct
file-level protection applies.
File-level protection is described as it applies to each of the following:
•

Disk file protection

•

Directory file protection

•

Magnetic tape file protection

2-8

Disk and Magnetic Tape Protection

2.3.1

Disk File Protection
Each file on a disk has its own protection code, which is distinct from the
protection that- applies to the disk volume itself.
For files residing on disk volumes, the following access types are supported:

•
•
•
•
•

READ
WRITE
EXECUTE
DELETE
CONTROL

If you have READ access to a file or group of files on a disk volume, you
have the right to examine, print, or copy that file or group of files. READ
access automatically includes EXECUTE access to a specified file or group of
files on disk.
If you have WRITE access to a file or group of files on a disk volume, you
have the right to modify the file or group of files. As with disk volume
protection, it is possible to be granted WRITE access without having READ
access. This is not very useful however, since opening a file for a write
operation implies READ access.
If you have EXECUTE access to a disk file or group of disk files, you have
the right to execute that file or group of files containing executable program
images or DCL command procedures.
If you have DELETE access to a particular disk file or group of disk files, you
have the right to delete the file or group of files.
If a user has CONTROL access to a particular disk file or group of disk files,
that user has the right to change the characteristics of the file or group of
files.
You can specify a protection code when you create or copy a file by using
the /PROTECTION qualifier, in the following example:
$CQPY/PROTECTION=(SYSTEM:RW,OWNER:RWED,GROUP:RW,WORLD)

You can also change the protection for an existing file by using the SET
PROTECTION command. For example, you can type the following:
$ SET PROTECTION=(SYSTEM:RWE,OWNER:RWED,GROUP:RE,WORLD) ABC.DAT

2-9

Disk and Magnetic Tape Protection

This command gives VAX/VMS the following instructions regarding the
file in question (ABC.DAT): SYSTEM has READ, WRITE, and EXECUTE
privileges; OWNER has READ, WRITE, EXECUTE, and DELETE privileges;
GROUP has READ and EXECUTE privileges only; and WORLD has no
access.
For SYSTEM and OWNER, CONTROL access is implied and unchangeable
and not so for GROUP and WORLD.
If you do not define a protection code for a file when you create the file, the
system applies a default protection. If a version of the file already exists,
protection is taken from the previous version of the file. For a new file,
protection is determined in one of the two following ways:
•

If the directory where the file is to be cataloged has an associated access
control entry that specifies the DEFAULT_pROTECTION entry, then the
specified protection is used.

•

If the directory does not have the DEFAULTJROTECTION entry, then
the default process protection is used. (The default process protection is
established explicitly with the SET PROTECTION/DEFAULT command,
or by default when you log in.

You can determine the current default protection by issuing the SHOW
PROTECTION command:
$ SHOW PROTECTION
SYSTEM=RWED, OWNER=RWED, GROUP=RE, WORLD=NO ACCESS

This response is the system default protection. It indicates that SYSTEM and
OWNER have all types of access, members of the owner's group have READ
and EXECUTE access, and all other users (WORLD) have no access.
To determine the current protection associated with a specific file or files, you
can use the /PROTECTION qualifier on the DCL command DIRECTORY.
For example:
$ DIRECTORY/PROTECTION MYFILE.REC
Directory DBA1:[CRAMER]
MYFILE.REC;5
(RWED,RWED,RW,R)
Total of 1 file.

You can change the default protection applied to files that you create during
an interactive session by using the SET PROTECTION/DEFAULT command.
The SET PROTECTION/DEFAULT command indicates that the protection
code you specify is to be applied to all files that you subsequently create
during the terminal session or batch job (providing that the files are not
subject to other sources of protection).

2-10

Disk and Magnetic Tape Protection

Note that to completely protect a file you must protect both the file itself
and the directory in which the file is listed. If you have files that must
be protected against unauthorized access, be sure to specify the proper
protection both for the directories in which the files are listed and for the
files themselves.

2.3.2

Directory File Protection
Each directory file has a protection associated with it. The directory
protection can override the protection of individual files in the directory.
For example, if a directory denies WORLD access, WORLD users cannot look
up even those files in the directory that permit WORLD access.
For directory file protection, the following access types are supported:

•
•
•
•
•

READ
WRITE
EXECUTE
DELETE
CONTROL

Having READ access to a file in a directory means that you have the right
to examine, print, or copy that file. If you have READ access to a directory
file, you can display the contents of the directory file with the DIRECTORY
command. For example, if you have access to the directory (JONES], you can
issue the following:
$ DIRECTORY [JONES]

This command generates a display of the files contained in the (JONES]
directory.
If you have READ access, you can access any file listed in the directory,
unless the protection on that file denies you access. If the protection applied
to the whole directory denies you READ access, then you cannot access even
those files in the directory that permit access to users in your group.
If you have WRITE access to a directory file, you have the right to modify or
write to that directory file. However, you must have both READ and WRITE
access to a directory in order to create files in that directory, to rename files
in that directory, or to perform any file operation that involves changes to
that directory file.

~-11

Disk and Magnetic Tape Protection

Note that EXECUTE access has a special meaning when applied to
directories. EXECUTE-only access to a directory file allows you to use the
DIRECTORY command to look up files that you can identify by name. It also
means that you can access files in the directory that are not protected against
users in your category, provided that you do not perform an operation that
modifies the directory file. However, you cannot list all the entries in a
directory by using wildcards.
For example, if you have EXECUTE-only access to the [JONES] directory,
you issue the command:
• DIRECTORY [JONES]

The system responds with an error message and does not list the files in
the [JONES] directory. However, if you know that the file DATAFILE.DAT
resides in the [JONES] directory, you can issue the command:
• TYPE [JONES]DATAFILE.DAT

The system displays the file. Therefore, EXECUTE-only access provides
some, but not all, of the operations that READ access provides.
If you have DELETE access to a directory file, you have the right to delete
that directory file. You must remove all entries from a directory file before
you can delete it. When you create a directory file with the CREATE
/DIRECTORY command you do not, by default, get DELETE access. If you
want to be able to delete a directory file, you must use the DCL command
SET PROTECTION to explicitly assign DELETE access to the OWNER
category.
If you have CONTROL access to a directory file, you have the right to
change the characteristics of the directory file.

Remember that to ensure that your disk files are adequately protected, you
must make certain that they are properly protected at both the directory and
file levels. ACLs allow you to further control access to disk files. For more
information on ACLs, see the VAX/VMS Access Control List Editor Reference

Manual.

2-12

Disk and Magnetic Tape Protection

2.3.3

Magnetic Tape File Protection
In general, the protection that applies to a magnetic tape volume will also
apply to all the files on that volume. For VAX/VMS ANSI-labeled magnetic
tapes, however, distinct file-level protection is also supported. For VAX/VMS
ANSI-labeled magnetic tapes, file-level protection can be determined by the
contents of the accessibility field, which is located in the first header label of
each file.
Each time that a VAX/VMS ANSI-labeled magnetic tape file is opened for
processing, the installation routine examines the contents of the accessibility
field of that file. Depending on the value returned by this routine, access
to the file in question will either be granted, denied, or defaulted to the
VAX/VMS protection scheme applied to the volume containing that file (see
Section 2.1.3).

PART II DISK AND MAGNETIC TAPE
OPERATIONS

Preparing Disk and Magnetic Tape
Volumes for Private Use
This chapter describes how to prepare private disk and magnetic tape
volumes for routine operations. The DCL commands ALLOCATE,
INITIALIZE, and MOUNT, as well as many of the qualifiers that apply to
each of these commands, are discussed. This chapter also contains examples
of command procedures that are designed to set up disk and magnetic tape
volumes for routine processing.
If you are interested in setting up public volumes, see the description in the

VAX/VMS System Manager's Reference Manual.

3.1

Setting Up a Private Volume
Under some circumstances, it may be desirable for you to perform your work
on a device that cannot be accessed by unauthorized users. By creating a
private volume and mounting it on a device allocated exclusively to your
process, you can perform your work without fear of interference from other
users.
You can set up your private volume by performing the following steps:
•

Use the ALLOCATE command to assign a disk or magnetic tape drive
exclusively to your process.

•

Use the INITIALIZE command to format the volume and write an
identifying label on it.

•

Use the MOUNT command to make a volume, and the files or data it
contains, accessible to your process.

Each of these DCL commands is discussed more thoroughly in the sections
that follow. See the VAX/VMS DCL Dictionary for complete descriptions of
the DCL commands ALLOCATE and INITIALIZE; for a description of the
Mount Utility (MOUNT), see the VAX/VMS Mount Utility Reference Manual.

3-1

Preparing Disk and Magnetic Tape Volumes for Private Use

3.2

Allocating a Drive to Your Process
Before you can begin processing files or data on a private volume, you
must first allocate a drive to your process. You can use the DCL command
ALLOCATE to logically assign a disk drive or a magnetic tape drive to your
process.
Whether you are allocating a disk drive or a magnetic tape drive, the format
for the ALLOCATE command is as follows:
ALLOCATE device-name[:] [logical-name]

Command Parameters
device-name[:]
Specifies the drive on which the volume will be loaded. The device name
can be a physical, generic, or logical name. A physical device name consists
of a device code, alphabetic controller designation, and a unit number.
A generic device name consists only of the device code. A logical name
must equate to a physical or generic name. Use of the colon is optional but
recommended by DIGITAL.
[logical-name]
Specifies an optional logical name to be associated with the specified disk or
magnetic tape drive.

The ALLOCATE command allocates only one device to a process. Except
for a list of generic device names, ALLOCATE does not accept lists of device
names in the command string. Although you can specify a list of generic
devices, the first available device will be the only one to be allocated.
The next two sections contain examples of how to use the ALLOCATE
command to allocate disk drives and magnetic tape drives.

3.2.1

Allocating a Disk Drive
This section includes examples of how to use the ALLOCATE command
to allocate disk drives. Although the examples focus on the allocation of
RK06 /RK07 drives, they are intended to apply to other disk devices as well.

3-2

Preparing Disk and Magnetic Tape Volumes for Private Use

EXAMPLES

$ ALLOCATE DM: DISK

In this example, the ALLOCATE command requests that the first available
RK06/RK07 be assigned to your process. The logical name DISK is placed
in your process logical name table and assigned the name of the allocated
device. Other users are unable to access the device.
~

$ ALLOCATE _DMB2:
DCL-I-ALLOC, _MARS$DMB2: allocated

In this example, the ALLOCATE command requests the allocation of a
specific RK06 /RK07 disk drive, that is, unit 2 on controller B. The response
from the ALLOCATE command indicates that the device was successfully
allocated.
If you wish to allocate a particular type of device, you can use the
/GENERIC qualifier with the ALLOCATE command. For example, device
DM could be an RK06 or RK07 disk. If you specifically want to allocate an
RK07, you would use the /GENERIC qualifier in the following way:
$ ALLOCATE/GENERIC RK07 MYDISK

In this case, the system would allocate the first available RK07 device to your
process. For further discussion of the /GENERIC qualifier as well as all of
the qualifiers applicable to the ALLOCATE command, see the VAX/VMS DCL

Dictionary.
3.2.2

Allocating a Magnetic Tape Drive
This section contains examples of how to use the ALLOCATE command
to allocate magnetic tape drives. It also shows how you can use the
/GENERIC qualifier with the ALLOCATE command to allocate a specific
type of magnetic tape device.

EXAMPLES

$ ALLOCATE MTA1:
IDCL-I-ALLOC, _MARS$MTA1: allocated

In this example, the ALLOCATE command specifies a physical device name
MTAl:.
VAX/VMS then informs you that MTAl has been allocated.

3-3

Preparing Disk and Magnetic Tape Volumes for Private Use

$ ALLOCATE MF, MT, MS DRIVE
%J)CL-I-ALLOC, _MARS$MTAO: allocated

In this example, the ALLOCATE command specifies a list of generic device
names. At a minimum, a generic device name consists of the device code; a
controller designation is optional. Only one of the specified generic devices
is allocated. Each element in the list must represent a unique generic device
type.
VAX/VMS then informs you that drive MTAO: has been allocated. Although
it is not indicated in the message, VAX/VMS also assigns the logical name
DRIVE to the drive MTAO:.
~

$ ALLOCATE DRIVE1: D1
%J)CL-I-ALLOC, _MARS$DBA3: allocated

In this example, the ALLOCATE command specifies a logical name DRIVEl
as the device name. (This example assumes that DRIVEl: has already been
defined.)
VAX/VMS then informs you that DRIVEl: has been allocated. Although it
is not indicated in the message, VAX/VMS also assigns the new logical name
Dl to the drive DRIVEl:.
If you wish to allocate a specific type of magnetic tape device, you can use
the /GENERIC qualifier. For· example, if you want to allocate a TU78 device
specifically, you would use the' /GENERIC qualifier with the ALLOCATE
command, as follows:
$ ALLOCATE/GENERIC TU78

TAPE_TU78

In this case, the system would allocate the first available TU78 device to your
process. For a further discussion of the /GENERIC qualifier as well as all of
the qualifiers applicable to the ALLOCATE command, see the VAX/VMS DCL

Dictionary.

3.3

Initializing a Volume
Before you can write files or data to a disk or magnetic tape volume, the
volume must be initialized. You can use the DCL command INITIALIZE to
format and write a label to the volume.
The INITIALIZE command does the following:
•

Invalidates all existing data on the volume, if any, and creates a new file
structure

•

Writes a label on the volume to identify it

•

Defines the owner UIC and the protection for the volume

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Preparing Disk and Magnetic Tape Volumes for Private Use

Whether you are initializing a disk or magnetic tape volume, the format for
the INITIALIZE command is as follows:
INITIALIZE device-name[:] volume-label

Command Parameters
device-name[:]
Specifies the name of the device on which the volume is to be physically
mounted and then initialized. To prevent initializing another person's
volume, you should allocate a device before you initialize the volume. Prior
allocation is not required, however.
volume-label
Specifies the identification to be encoded on the volume. Characters are
automatically changed to uppercase. You can specify up to 12 alphanumeric
characters for a disk volume, or up to 6 alphanumeric characters for a
magnetic tape volume. Nonalphanumeric characters other than "$" and "_"
are invalid for disk volume-label specification.

There are some cases in which you might be prevented from accessing and
initializing a particular volume. For example, if the volume that you wish
to initialize previously contained data, the protection code may prevent
you from accessing and initializing that particular volume. In the case of
a magnetic tape volume, you may not be able to initialize the volume if
the first file on the volume has not reached its expiration date, or if the
volume or file accessibility is such that the installation routine provided by
VAX/VMS does not allow you to access the volume.
If the volume is protected or if the expiration date on the first file has not
been reached, and you are not the owner or a SYSTEM user, you must have
VOLPRO user privilege to override volume protection. If you do not have ·
VOLPRO privilege, you can ask the previous owner of the volume or another
user (the system manager or operator, for example) who does have READ
/WRITE access to initialize it for you. If the installation routine provided
by VAX/VMS (or a user-designed installation routine) does not allow you
access, then consult your system manager.

When you give the volume to another user for initialization, you should
specify the following:
•

The label you want to have written on the volume

•

The protection code and owner UIC you want assigned to the volume

When you obtain a magnetic tape or disk volume, place identification on the
outside of the volume so that it can be easily identified.
The next two sections describe how to initialize disk and magnetic tape
volumes.

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Preparing Disk and Magnetic Tape Volumes for Private Use

3.3.1

Initializing a Disk Volume
This section includes two examples of how to use the INITIALIZE command
to initialize a disk volume.
By default, the INITIALIZE command builds a Files-11 structure on your
new volume. The default format for disk volumes in the VAX/VMS
operating system is called the Files-11 On-Disk Structure Level 2. The
INITIALIZE command can also initialize disk volumes in the Files-11
On-Disk Structure Level 1 format.
You do not need special privileges to override logical protection on a blank
disk volume (that is, a volume that has never been written to) or a disk
volume that is owned by your current UIC or by UIC (0,0]. In all other cases,
you must have the user privilege VOLPRO to initialize a disk volume.
The following examples include typical cases of initializing a disk.

EXAMPLES

• INITIALIZE DISK USER_DISK
In this example, the volume is given the label USER_DISK. DISK is the
logical name of the device on which it is mounted.

$ ALLOCATE DJA2: TEMP
XJ)CL-I-ALLOC, _MARS$DJA2 allocated
$ INITIALIZE TEMP: BACKUP_FILE

This example shows how to initialize an RA60 volume. First, the drive is
allocated, to ensure that no one else can access it. Then, when the volume is
physically loaded on the drive, the INITIALIZE command initializes it.

3.3.2

Initializing a Magnetic Tape Volume
This section describes how to use the INITIALIZE command to initialize a
magnetic tape volume.
The default format for magnetic tape volumes in the VAX/VMS operating
system is based on Level 3 of the ANSI standard for magnetic tape labels
and file structure for informational interchange (ANSI X3.27-1978).
You can use the DCL command INITIALIZE to encode VAX/VMS ANSIlabeled format on a magnetic tape volume. INITIALIZE writes labels to an
empty file on the magnetic tape volume in the following order:

A volume label

File header labels with the file sequence number set to 0

3-6

Preparing Disk and Magnetic Tape Volumes for Private Use

3 Two tape marks framing an empty file (BOT and EOT}
4

Corresponding end-of-file labels (EOF)

A double tape mark, specifying logical end-of-volume

The following example describes how to initialize a magnetic tape volume.
$ INITIALIZE TAPE USER

In this example, the magnetic tape volume is given the label USER. TAPE is
the logical name of the device on which it is mounted.
Note that if you use ANSI "a" characters (which are not alphanumeric) on
the volume label on magnetic tape, you must enclose the volume name in
quotation marks.
When you use the INITIALIZE command with a magnetic tape volume,
INITIALIZE always attempts to read the volume. In some cases, a blank
magnetic tape can cause unrecoverable errors, such as the following:
•

A fatal system message
Y.INIT-F-VOLINV, volume is not software enabled

•

A runaway magnetic tape
A runaway magnetic tape occasionally occurs with new magnetic tapes
that have never been written to or that have been run through verifying
machines.

Note
The only way you can stop a runaway magnetic tape is by
taking the magnetic tape drive off line and then putting it
back on line.
If either problem occurs, you can successfully initialize a magnetic tape
by repeating the INITIALIZE command from an account that has the
VOLPRO and OPER privileges and by specifying the following qualifier
in the command:
/OVERRIDE•(ACCESSIBILITY,EXPIRATION,OWNER)

This qualifier ensures that the INITIALIZE command will not attempt to
verify any labels on the magnetic tape.

~-7

Preparing Disk and Magnetic Tape Volumes for Private Use

3.4

Mounting a Volume
Before you can begin processing files or data on your private disk or magnetic
tape volume, the volume must be mounted. You can use the DCL command
MOUNT to make a disk or magnetic tape volume and the files or data it
contains accessible to your process.
When you issue the MOUNT command, the system checks:
•

That the device has not been allocated by another user

•

That the device protection allows you to allocate the device

•

That a volume is physically loaded on the device specified

•

That the label on the volume matches the label specified

You can mount a single volume or a volume set. Binding volumes into
a volume set allows you to extend the space available for your files by
adding volumes to the volume set, rather than defining new volumes. The
procedures for creating and mounting disk volume sets and magnetic tape
volume sets (as opposed to single volumes) are described in the sections that
follow.
Whether you are mounting a disk or a magnetic tape volume, the format for
entering the MOUNT command is as follows:
$MOUNT device-name[:][, ... ] [volume-label[, ... ]] [logical-name[:]]

Command Parameters
device-name[:][, ... ]
Specifies the physical device name or logical name of the device on which
the volume is to be mounted. If you specify more than one device name for
a disk or magnetic tape volume set, separate the device names with either
commas(,) or plus signs ( + ).
volume-label[, ... ]
Specifies the label on the volume. If you specify more than one volume
label, separate the labels with either commas (,) or plus signs ( + ). The
volumes must be in the same volume set. For magnetic tape volumes, the
labels must be specified in ascending order according to relative volume
number.

The volume-label parameter is not required when you mount a volume
with the /FOREIGN or /NOLABEL qualifier or when you specify
/OVERRIDE=IDENTIFICATION. To specify a logical name when you
enter either of these qualifiers, type any alphanumeric characters in the
volume-label parameter position.

3-8

Preparing Disk and Magnetic Tape Volumes for Private Use

logical-name[:]
Defines a 1 through 255 alphanumeric character string to be associated with
the device.
If you do not specify a logical name for a disk drive, the MOUNT command
assigns the default logical name DISK$volume-label to individual disk drives;
it assigns the default logical name DISK$volume-set-name to the device on
which the root volume of a disk volume set is mounted. Similarly, if you do
not specify a logical name for a magnetic tape drive, the MOUNT command
assigns only one logical name, TAPE$volume-label, to the first magnetic tape
device in the list. For a volume set, no logical name is assigned unless you
specify one.

The MOUNT command places the name in the job logical name table,
unless you specify /GROUP or /SYSTEM. In the latter cases, it places the
logical names in the group or system logical name table. You should avoid
assigning a logical name that matches the file name of an executable image
in SYS$SYSTEM. Such an assignment will prohibit you from invoking that
image.
At many installations, operators perform the physical mounting (and
dismounting) of both system and private disk and magnetic tape volumes.
Since operators at such installations assist you in your MOUNT requests, you
do not need to include the /ASSIST qualifier with the MOUNT command.
For example:
•MOUNT DMA1: DISK VOL1
%MOUNT-I-OPRQST, PLEASE MOUNT DEVICE _MARS.DMA1:

MOUNT notifies the operator of your mount request and displays a message
at your terminal.
After the device has been successfully mounted, you are notified with the
following message:
%MOUNT-I-MOUNTED, DISK mounted on _DMA1:

As an alternative to requesting a specific device, you might want to request a
device type. In the following example, MOUNT allocates an available device
of the specified type and requests operator assistance in mounting it.
• MOUNT DB: USER_DISK DISK
XMOUNT-I-OPRQST, Please mount volume USER_DISK in device _NODE.DBAO:
%MOUNT-I-MOUNTED, USER_DISK
mounted on _NODE.DBAO:
XMOUNT-I-RQSTDON, operator request canceled - mount completed successfully

DISK is the logical name created when the RP06 disk unit is allocated. Since
the device is allocated to your process, no other user can access the volume.
Your access to USER_DISK is determined by the volume protection code
and the volume UIC.

~-Q

Preparing Disk and Magnetic Tape Volumes for Private Use

Operator assist messages are sent to all operators enabled to receive TAPE
and DISK messages. Thus, if an operator assist is needed for mounting a
disk device, a message is sent to disk operators. (See Chapter 7 for more
information on operator assistance requests and replies.)
Any operator reply to a MOUNT request is written to SYS$0UTPUT to be
displayed on the user's terminal or written in a batch job log.
If no operator is available (operator is not enabled) to receive and respond
to a MOUNT request, a message is displayed to inform you of the situation.
A volume placed in the requested drive, needs no additional operator
assistance.

Note that you can specify the /NOASSIST qualifier to avoid operator
assistance.
The following sections provide examples of mounting volumes; however,
they do not all include operator assistance messages. For more examples
of operator-assisted mount requests, as well as other operator-oriented
functions, refer to Chapter 7.

3.4.1

Mounting a Disk Volume
You can use the following procedure to allocate, initialize, and mount a disk
volume:
$ ALLOCATE DMA2: TEMP
lJ)CL-I-ALLOC. _MARS$DMA2: allocated
$ INITIALIZE TEMP: BACKUP_FILE
$ MOUNT TEMP: BACKUP _FILE
XMOUNT-I-MOUNTED, BACKUP_FILE mounted on _DMA2:

If you wish to mount a foreign disk volume (that is, one in which file
structure is other than Files-11), you can use the /FOREIGN qualifier
in conjunction with the MOUNT command. The MOUNT /FOREIGN
command makes the contents of your volume available to the system, but
makes no assumptions concerning its file structure. In the following case,
assume that DISK is the logical name assigned to the device name at the time
of disk allocation.
$ MOUNT/FOREIGN DISK
XMOUNT-I-MOUNTED, BACKUP_FILE

mounted on DISK$DMA2:

Note that MOUNT reports a volume label even though the disk is mounted
as a foreign device. MOUNT reports the label because the disk has a Files-11
structure; if a disk does not have a recognized file structure, no label is
reported.
You need the user privilege VOLPRO to mount a Files-11 structured disk
with the /FOREIGN qualifier, unless its owner UIC matched your own.

3-10

Preparing Disk and Magnetic Tape Volumes for Private Use

You must use the /FOREIGN qualifier if you wish to use the VAX/VMS Bad
Block Locator Utility (BAD) to locate and record bad blocks on your disk
volume. BAD is useful for media preparation and is thus distinct from the
volume preparation tasks described in this chapter. To invoke BAD, use the
DCL command ANALYZE/MEDIA. For more information on BAD, see the
description in the VAX/VMS Bad Block Locator Utility Reference Manual
In addition to the /FOREIGN qualifier, many other qualifiers are supported
for the MOUNT command. The /MOUNT_VERIFICATION and
/COMMENT qualifiers are discussed in Chapter 7 of this guide. The
/SYSTEM qualifier is described in the VAX/VMS System Manager's Reference
Manual. The /BIND qualifier is discussed in the next section of this guide,
which describes how to mount disk volume sets. For a complete list of
the qualifiers that can be used with the DCL command MOUNT, see the
description in the VAX/VMS Mount Utility Reference Manual.

3.4.2

Mounting a Disk Volume Set
When you mount a disk volume set, the volume label specified in the list
must correspond to a device name in the same position in the device name
list.
You can bind two or more disk volumes into a volume set. The first volume
in the set is called the root volume. Each volume in the set is identified by a
relative volume number in the set, where the root volume is always relative
volume 1.
A disk volume set has a single directory structure. The master file directory
(MFD) for the entire volume set resides on the root volume, which is always
the first volume in the set.
When a disk volume set is on line and mounted, all files and directories in
the set can be accessed by specifying either of the following:
•

Device name of the device on which the root volume is mounted

•

Logical name assigned to the volume set when it was mounted

When you mount a disk volume set, each volume label specified in the list
must correspond to a device name in the same position in the device name
list.
You use the /BIND qualifier to create a disk volume set. When you use the
MOUNT command with the /BIND qualifier to create a disk volume set, the
/BIND qualifier identifies a volume set by assigning it a volume set name,
which applies to all volumes in the set. It also identifies the root volume and
creates the directory structure for the volume.

3-11

Preparing Disk and Magnetic Tape Volumes for Private Use

When you create files on a volume set, the file system allocates space for the
files anywhere on the set, wherever the most space exists. When existing
files on any volume are extended, extension occurs on the same volume,
unless the volume is physically full. You can add new volumes to a volume
set whenever additional space is needed.
For example, all disk volumes that are mounted on a daily basis can be
bound into a volume set. Since this set contains all user file directories, users
do not need to specify device names in file specifications to access files on
any volume in the volume set. In fact, the physical location of a file is of no
concern to users of the system.

Note
Do not bind your system disk into a volume set. Volume sets
are not supported by VAX/VMS software updates and optional
product installation. If certain system files move or extend to
other volumes in the set, the system may fail to boot.
No special privileges are required to use volume sets. However, you must
have WRITE access to the index file on all volumes that you are attempting to
bind into a volume set; this usually means that you also must have a system
UIC, have the user privilege SYSPRV, or be the owner of the volumes.
You can create a disk volume set from newly initialized volumes or you can
create a volume set by extending an existing volume that already contains a
directory structure and files. You can also add volumes to an existing volume
set. The next three sections contain examples of how to create and/ or mount
each type of disk volume set.
3.4.2.1

Creating a Disk Volume Set from New Volumes

This section describes how to create a disk volume set from new disk
volumes. The example that follows assumes that there are no files or data on
the volumes to be bound.
1

Allocate the necessary devices and physically load the volumes.

Initialize each volume in the set. For example:
$ INITIALIZE DB1:
$ INITIALIZE DB2:
$ INITIALIZE DB3:

PAYVOL1
PAYVOL2
PAYVOL3

When you initialize volumes for a volume set, you can also use other
qualifiers with the INITIALIZE command to define the volume ownership
and protection. Protection and ownership information is obtained from
the root (first) volume. The protection and ownership of the other
volumes is ignored.

3-12

Preparing Disk and Magnetic Tape Volumes for Private Use

Use the MOUNT /BIND command to create the volume set. For example:
$ MOUNT/BIND=MASTER_SET _$DB1: , DB2: , DB3:
PAYVOL1, PAYVOL2, PAYVOL3

This MOUNT/BIND command defines the volume set name, MASTER_
SET, and defines the relative volume numbers of the volumes PAYVOLl,
PAYVOL2, and PAYVOL3.
A disk volume set name can have from 1 through 12 alphanumeric
characters. The volume set name must be different from all volume labels
within the set, and all labels in the set must be unique.
The order of the device names corresponds to the volume labels specified:
PAYVOLl must be physically loaded on DBl, PAYVOL2 on DB2, and
PAYVOL3 on DB3.
PAYVOLl, which is listed first in the list of labels, becomes the root volume
of the set. The master file directory (MFD) for PAYVOLl contains the
directory structure for the entire volume set.
Note that the MOUNT /BIND command creates the volume set and mounts
the volumes. When this command completes successfully, all volumes in the
set are ready for use: user file directories can be created.
The /BIND qualifier must be used only once to create the volume set. In
subsequent use, the volume set may be mounted with a single MOUNT
command. The following example illustrates the use of one MOUNT
command to mount a previously created volume set:
$ MOUNT DB1,DB2,DB3 PAYVOL1,PAYVOL2,PAYVOL3

3.4.2.2

Creating a Disk Volume Set from an Existing Volume

This section describes how to create a disk volume set from an existing
volume. The example that follows assumes that the volume USERFILES
already contains a directory structure and files, and that the volume is
currently located on the device DMl.
$ INITIALIZE DM2: USERFILES2
$ MOUNT/BIND=USERS _$ DM1 : , DM2:
USERFILES, USERFILES2

The initial volume USERFILES must be specified first: it becomes the root
volume of the set. When you create a volume set from an existing volume,
you must specify that volume first because the file system must build on the
existing directory structure.

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Preparing Disk and Magnetic Tape Volumes for Private Use

Note that if you attempt to create a volume set from two or more volumes
that already contain files and data, the file system does not issue an error
message when you issue the MOUNT/BIND command. However, the
volumes are unusable as a volume set because the directory structures are
not properly bound.
3.4.2.3

Adding Volumes to a Disk Volume Set

This section describes how to add volumes to an existing volume set. The
example that follows assumes that the volume set named MASTER_SET is
on line and mounted and has volumes named PAYVOLl, PAYVOL2, and
PAYVOL3:
$ INITIALIZE DB4: PAYVOL4
$ MOUNT/BIND=MASTER_SET DB4: PAYVOL4

This MOUNT command binds the volume P AYVOL4 with the existing
volume set and makes the volume ready and available for use. Note that if
the volume set MASTER_pAY was mounted with the /SYSTEM, /GROUP,
or /SHARE qualifier, the MOUNT /BIND command that adds a volume to
the set must also specify the appropriate qualifier.
When you add a volume to an existing set, the only volume in the set that
must be mounted is the root volume, relative volume 1. None of the other
volumes need be mounted.
You can also add a volume to a set at the same time you mount the set. The
following procedure assumes an existing volume set named MASTER-SET
with volumes named PAYVOLl, P AYVOL2, and PAYVOL3:
$ INITIALIZE DB4: PAYVOL4
$ MOUNT/BIND=MASTER_SET DB1:, DB2:, DB3:, DB4:
_$PAYVOL1, PAYVOL2, PAYVOL3, PAYVOL4/SYSTEM

Note that the first device/volume pair listed in the MOUNT/BIND command
is the root volume of the set. When you add a volume to a set while
mounting the set, you must list the root volume first.
Note
Once a volume is bound into a volume set, it cannot be
"unbound."
You can add volumes to an existing volume set at any time. The maximum
number of volumes in a set is 255.

3-14

Preparing Disk and Magnetic Tape Volumes for Private Use

3.4.3

Mounting a Magnetic Tape Volume
When mounting a magnetic tape volume, you specify with the MOUNT
command any qualifiers you choose, a device name, and optionally a label
and logical name.
For a discussion of how to mount magnetic tape volume sets, see Section
3.4.4.
The next two sections describe procedures and commands for mounting
single volume ANSI-labeled magnetic tapes.

3.4.3.1

Mounting an ANSI-Labeled Volume

When you use the MOUNT command to mount a magnetic tape volume,
VAX/VMS checks to see whether the volume has either a VAX/VMS or nonVAX/VMS ANSI-labeled format. If the format is ANSI labeled, the following
are checked:
•

The volume identifier field

•

The protection on the ANSI-labeled volume as described in Section 2.1.3.

You can mount an ANSI-labeled volume by including the device name and
volume identifier as follows (specifying a logical name is optional):
$ MOUNT MT: ELAINE ET
XMOUNT-I-OPRQST, please mount volume ELAINE in device $MTA1:
%MOUNT-I-MOUNTED, ELAINE mounted on MTA1:
XMOUNT-I-RQSTDON, operator request canceled -- mount completed successfully

MOUNT finds an available MT drive, MTAl :, and requests operator
assistance. The message displayed at the user terminal indicates which
drive has been selected. At this point you (or the operator) load the magnetic
tape on the drive, and the mount operation completes. No operator response
is necessary. The display informs you that the volume named ELAINE
is mounted on the drive MTAl:. Although not indicated in the message,
MOUNT also assigns the logical name ET to the volume ELAINE.
When used with the MOUNT command, the qualifiers described in the next
section affect the label format of a volume and/ or the magnetic tape file
system used to process an ANSI-labeled volume. Unless otherwise noted,
you must have VOLPRO privilege to use any of these qualifiers when the
volume is a VAX/VMS ANSI-labeled volume containing protection that
restricts your process from accessing the volume.

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Preparing Disk and Magnetic Tape Volumes for Private Use

3.4.3.2

Using MOUNT Command Qualifiers

This section describes some of the command qualifiers that you can use when
mounting a magnetic tape volume. For a complete list of all the command
qualifiers supported for the mounting of magnetic tape volumes, see the
VAX/VMS Mount Utility Reference Manual.
/BLOCKSIZE=n

You can use the /BLOCKSIZE=n qualifier to specify the block size for the
magnetic tape. The range of valid values for n varies and depends on the
density of the volume, whether the data is for input or output, and whether
the operation uses RMS.
By default, VAX/VMS writes 2048-byte blocks, which conform to the ANSI
standard. Although VAX/VMS allows you to specify a block size larger than
2048 bytes, a larger block size does not conform to ANSI standards.
You must specify /BLOCKSIZE when you are mounting volumes that do
not support the second file header label as defined in the ANSI standard or
support a block size smaller than 2048 bytes. For example, you must specify
/BLOCKSIZE=512 to mount an ·RT-11 volume.
If you wish to write files on a magnetic tape volume, you can use the
/BLOCKSIZE qualifier to set the block size to other than 2048. If you wish
only to read files from a magnetic tape volume, you do not have to use the
/BLOCKSIZE qualifier, since VAX/VMS will automatically handle the block
size given by the second file header label.

The minimum blocksize for ANSI Standard magnetic tapes is 18, while the
maximum is 2048. The minimum blocksize for VAX/VMS magnetic tapes is
14, while the maximum is 65,532.
/LABEL

You use the /LABEL qualifier to indicate that the volume contains standard
ANSI labels (this is the default). Privilege is not required to use this
qualifier.
/OVERRIDE

You can use the /OVERRIDE=(option[, ... ]) qualifier to inhibit one or more of
the access checks performed by MOUNT and the magnetic tape file system.
The options are the following:

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Preparing Disk and Magnetic Tape Volumes for Private Use

ACCESSIBILITY
If the installation allows, this option will override any character in the

accessibility field of the volume and file header labels. The necessity of
this qualifier is defined by the installation. That is, each installation has the
option of specifying a routine that the magnetic tape file system will use to
process this field. By default, VAX/VMS provides a routine that checks this
field in the following manner.
•

If the magnetic tape was created on a version of VAX/VMS that conforms

to Version 3 of ANSI, then this option must be used to override any
character other than an ASCII space.
•

If a VAX/VMS protection is specified and the magnetic tape conforms to

an ANSI standard that is later than Version 3, then this option must be
used to override any character other than an ASCII 1.
For more information on accessibility-based protection for VAX/VMS-ANSI
labeled magnetic tapes, see Chapter 2.
EXPIRATION
Overrides the expiration dates of a volume and its files. Use this qualifier
when the expiration date (in the first file header label) of any file that you
want to overwrite has not been reached.
I DENTI Fl CATION
Overrides the volume identifier in the volume label. Use this qualifier to
mount a volume for which you do not specify the volume identifier. Only
the volume identifier field will be overridden. Volume protection, if any, is
preserved.
OWNER_IDENTIFIER
Overrides the processing of the owner identifier field. You use this option
when you need to interchange protected magnetic tapes between VAX/VMS
and other DIGITAL operating systems.
SETID
Prevents MOUNT from checking the file-set identifier in the first file header
label of the first file on a continuation volume. Use this qualifier only for
ANSI-labeled volumes on which the file-set identifier of the first file on a
continuation volume differs from the file-set identifier of the first file of the
first volume that was mounted.
/OWNER_UIC=uic

You can use the /OWNER_UJC=uic to override the UIC written in the
second volume label and assigns the UIC that you specify to the volume
while it is mounted. For magnetic tape volume sets in which a continuation
volume is written, the UIC specified at mount time is written to the volume

3-17

Preparing Disk and Magnetic Tape Volumes for Private Use

only if the /PROTECTION qualifier was specified either at mount time or
when the volume had been initialized. This does not change the protection
on any volumes already created.
You can specify the UIC variable in the format:
[g,m]

is either an octal number in the range 0 through 37, 776 that denotes
the group number or an alphanumeric value (consisting of 1 through 31
characters) that describes the group.

is either an octal number in the range 0 through 177, 776 that denotes
the member number or an alphanumeric value (consisting of 1 through 3 1
characters) that describes the member.

Either square ( [ ] ) or angle ( < > ) brackets are required in the UIC
specification. For more details on UIC-based protection, see Chapter 2.
/CACHE=TAPE_DATA

The /CACHE qualifier with the TAPE_DATA option, enables the write cache
for a tape device if the tape controller supports a write cache. /NOCACHE
is the default for mounting tape devices. You must specify TAPE-DATA
to enable the write cache. If the tape controller does not support a write
cache, the option is ignored. This lets you specify /CACHE=TAPE_DATA in
command procedures that work with a variety of devices and controllers.
This option enables a form of controller-based write-back caching. The
write-back caching feature significantly improves the overall performance of
streaming tape drives. Under some rare failure conditions, however, some
written data can be lost in the cache of the controller. If a failure occurs,
the magnetic tape being written becomes seriously flawed or unreadable and
you must repeat the entire process used to write to the tape. When a failure
occurs you are always notified with an error message.
/PROTECTION=code

The /PROTECTION=code qualifier overrides the VAX/VMS protection
written in the second volume label and assigns the protection code that you
specify to the volume while it is mounted. For magnetic tape volume sets in
which a continuation volume is written, the protection code that you specify
will be written to the continuation volume. By default, your process UIC also
will be written to the continuation volume unless you explicitly specify an
alternate UIC with the /OWNER_UIC qualifier described above.

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Preparing Disk and Magnetic Tape Volumes for Private Use

Valid protection codes include READ and WRITE access for GROUP and
WORLD users; EXECUTE and DELETE access are not applicable to magnetic
tape volumes. SYSTEM users and the volume owner always have READ and
WRITE access to magnetic tape volumes regardless of the protection code
that you specify. Section 2.3 describes access and protection codes.
/NOHDR3

The /NOHDR3 qualifier controls whether special VAX/VMS header labels
are written to a volume. Privilege is not required for this qualifier. The
default is /HDR3, which allows VAX/VMS header labels to be written to a
volume. When the /NOHDR3 qualifier is used, VAX/VMS long file names
are truncated to 17 characters. Use the /NOHDR3 qualifier when writing
to volumes that will be read by a system other than VAX/VMS, such as the
RT-11 system, which does not process all file header labels correctly.
/RECORDSIZE=n

The /RECORDSIZE=n qualifier specifies the number of bytes in each record.
This qualifier does not require privilege. Use this qualifier when you mount
volumes without the second file header label (such as RT-11 volumes), or
when you mount volumes with the /FOREIGN qualifier, to provide RMS
with the size of fixed-length records or the maximum size of variable-length
records.
The record size must be less than or equal to the specified or default block
size. Refer to the /BLOCKSIZE qualifier (described previously) for details.
The VAX/VMS operating system does not write records smaller than 14
bytes on output. However, the VAX/VMS Convert Utility, described in the
VAX/VMS Convert and Convert/Reclaim Utility Reference Manual, allows you
to pad and extend the size of records up to and greater than the 14-byte
minimum record size output by VAX/VMS.
Two other qualifiers that are important for mounting magnetic tape volumes
are/ AUTOMATIC and /INITIALIZE. These qualifiers are described in the
following sections.

3.4.4

Mounting a Magnetic Tape Volume Set
When mounting a magnetic tape volume set, you can begin by following the
procedures described in Section 3.4.3 for mounting a single magnetic tape
volume. The number of volume identifiers need not equal the number of
device names specified. Thus when you mount a magnetic tape volume set,
you can specify more volume identifiers than device names or more device
names than volumes.

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Preparing Disk and Magnetic Tape Volumes for Private Use

The number of devices that you specify directly affects the action taken by
the magnetic tape file system when processing continuation volumes in a
volume set. For example, when the number of devices is greater than the
number of volumes, the magnetic tape files system requests a continuation
volume to be mounted on the first drive from the list that does not have a
volume mounted.
The next two sections describe how to create and mount a magnetic tape
volume set. The manner in which continuation volumes are handled by the
magnetic tape file system is also described.
3.4.4.1

Creating a Magnetic Tape Volume Set
If you do not create a volume set explicitly, the VAX/VMS system will
create one if necessary. If you have not mounted a volume set and a
continuation volume is required, the magnetic tape file system will request
that a continuation volume be mounted and will implicitly create a volume
set. For example, if the magnetic tape file system encounters an EQT mark
while writing a volume, it sends a message to the operator console requesting
that another volume be mounted. After you mount the next volume, the
magnetic tape file system will write the volume and header labels and then
will reissue the pending write requests to the continuation volume. The fileset identifier in the first file header label of all files written to the continuation
volume will be the file-set identifier of the first file on the first volume. The
file-set identifier for VAX/VMS volume sets is always that of the first file of
the first volume that was mounted in the set.

To explicitly create a volume set with three volumes, follow this procedure:
1

Allocate a drive on which you will load each volume.
$ ALLOCATE MTAO:
YJ>CL-I-ALLOC, _MARS$MTAO: allocated
$ALLOCATE MTA1:
incL-I-ALLOC, _MARS$MTA1: allocated

Initialize the volumes. You should specify the density and the access
protection in addition to the device name and the volume identifier in
the INITIALIZE commands, as in:
$ INITIALIZE/DENSITY=1600/PROTECTION=(G:RW) MTAO: TAPE1
$ INITIALIZE/DENSITY=1600/PROTECTION=(G:RW) MTA1: TAPE2

Mount the volumes. You should include the device name and volume
identifier. Specifying a logical name for the volume set is optional.
$MOUNT MTAO:,MTA1: TAPE1,TAPE2,TAPE3 TEST
XMOUNT-I-MOUNTED, TAPE1 mounted on _MTAO:
XMOUNT-I-MOUNTED, TAPE2 mounted on _MTA1:

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Preparing Disk and Magnetic Tape Volumes for Private Use

VAX/VMS not only confirms which volumes have been mounted but
also indicates on which drive each volume has been mounted.
VAX/VMS mounts and verifies only the volumes that are physically
loaded on the drives at mount time. However, the volume identifiers of
additional volumes that you specify will not be verified until the volumes
are accessed.
You can check the densities, volume labels, UICs, and relative volume
numbers of the volumes that are mounted on drives. To do so, specify the
SHOW DEVICES /FULL command. If you specify a generic device code
for the magnetic tape drives, such as MT, information for all the drives of
that type that are configured in the system will be displayed. To display
information for a volume mounted on a specific drive, specify the physical
device code, consisting of the generic device code, the controller designation,
and the unit number followed by a colon. For more information on the
SHOW DEVICES command, including examples of displays returned by the
SHOW DEVICE/FULL command, see Chapter 4. (See also the VAX/VMS
DCL Dictionary.)

3.4.4.2

Mounting Continuation Volumes in a Volume Set

When mounting a magnetic tape volume set, you can follow the general
procedures described in the previous section for creating a magnetic tape
volume set. Once the volume set has been created, however, there is no
need to initialize the volumes in the set when you mount the volume set.
You need not allocate a drive for each volume in the volume set. The
magnetic tape file system will request that volumes be switched to
appropriate drives when continuation volumes are required.
VAX/VMS stores, but cannot verify, the volume identifiers of volumes that
you specify but do not physically mount on drives at mount time. VAX/VMS
later verifies the volume identifiers of such volumes when the volumes are
accessed.
The VAX/VMS operating system supports the continuous processing of
mounted volumes in a magnetic tape volume set through automatic volume
switching. To do this, the magnetic tape file system uses automatic volume
recognition (AVR) and automatic volume labeling (AVL).
To take advantage of this automatic volume switching capability, you must
have more than one magnetic tape drive allocated to your volume set. If
you have two or more magnetic tape drives allocated to a volume set, the
magnetic tape file system will switch volumes for you automatically by
sequentially selecting the next magnetic tape drive allocated to the volume
set. The magnetic tape file system will expect the next volume in the volume
set to be loaded on that drive.

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Preparing Disk and Magnetic Tape Volumes for Private Use

If the file system is writing to the volume set, then it will create a label
for the magnetic tape and initialize the magnetic tape with that label and
with the protection characteristics set for the first of the volume set. If the
magnetic tape file system is reading the volume set, it will generate the label
and will try to mount the next magnetic tape with that label. If the drive has
no magnetic tape loaded on it or if the drive has the wrong magnetic tape
loaded on it, then the magnetic tape file system will send a message to the
operator console notifying the operator either to mount a magnetic tape or
mount the correct magnetic tape.

Before processing continuation volumes, the magnetic tape file system
processes the protection on that volume (as described in Section 2.1.3). If the
magnetic tape file system determines that the user does not have access to
the volume, then a message is sent to the operator to take some action.
The label generated fills the six-character volume identifier field. The first
four characters of the field contain the first four characters of the label
specified for the previous volume in the volume set. (If the label is less than
four characters, the volume identifier field will be padded with underscores.)
The fifth and sixth characters contain the relative volume number for that
reel in the volume set. Note that this allows VAX/VMS to generate only 99
unique labels for a given volume set.
With automatic volume switching enabled, the operator can load a magnetic
tape on the next drive allocated to the magnetic tape volume set anytime
before the volume being processed reaches the EQT mark. The magnetic
tape file system will mount and initialize (if INITIALIZE was specified
originally) the next magnetic tape in the volume set and then notify the
operator that the switch has occurred.
In the following example, the volume with the identifier TAPE is mounted
on MTAO:
$MOUNT MTAO: ,MTA1: ,MTA2:

TAPE

Continuation volumes for this set should be loaded on the magnetic tape
drives in the following order: MTAl:, MTA2:, MTAO:, MTAl:, MTA2:, and so
forth.
You can explicitly override automatic volume switching by specifying the
/NOAUTOMATIC qualifier when mounting a magnetic tape volume. The
default is /AUTOMATIC. If you allocate only drive to the magnetic tape
volume set, you will implicitly disable automatic volume switching.
To ensure that any volume added to the magnetic tape volume set will be
initialized prior to being written to, you can mount the volume with the
/INITIALIZE=CONTINUATION qualifier. The default is /NOINITIALIZE.

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Preparing Disk and Magnetic Tape Volumes for Private Use

The next example demonstrates the use of the
/INITIALIZE=CONTINUATION qualifier for mounting volume sets. It
also shows how volume identifiers are generated for continuation volumes.
$ INITIALIZE MTAO: MAIN
$ MOUNT/OVERRIDE=IDENTIFIER/INITIALIZE=CONTINUATION MTAO:,MTA1:

The volume labeled MAIN will be mounted on MTAO:. The second volume
in the set will receive the volume identifier MAIN02 and will be mounted
on MTAl:. The third volume in the set will receive the volume identifier
MAIN03 and will be mounted on MTAO:.
$MOUNT MTAO:,MTA1: SUN

In this example, the first volume in the set is labeled SUN and is mounted
on MTAO:. The second volume will receive the identifier SUN_02 and be
mounted on MTAl :. The third volume will receive the identifier SUN _03
and be mounted on MTAO:.
The next example illustrates a continuation volume with two volume
identifiers.
$MOUNT MTAO:,MTA1: SUN.MOON

In this case, SUN and MOON will be mounted on MTAO: and MTAl:
respectively. If a third volume is added to the set, it will be given the
identifier MOON03 and be mounted on MTAO:.
For a description of the operator functions in handling user requests to mount
magnetic tape volume sets and process continuation volumes, see Chapter 7.

3.5

Dismounting a Volume
When you have finished processing the files or data on your disk or magnetic
tape volume, you can explicitly dismount the volume. You can use the
DISMOUNT command to explicitly dismount a single volume or an entire
volume set.
If you explicitly dismount a single volume in a volume set, VAX/VMS will
dismount all the volumes in the set. For disk volume sets, however, it is
possible to explicitly dismount a single volume in the volume set without
dismounting the entire set. To do this, you must use the /UNIT qualifier.

When you issue the DCL command DISMOUNT, the volume is automatically
unloaded from the drive. You can override this automatic unloading of your
volume by specifying the /NOUNLOAD qualifier with the DISMOUNT
command.

3-23

Preparing Disk and Magnetic Tape Volumes for Private Use

Even when you specify the /NOUNLOAD qualifier with the DISMOUNT
command, your volume will still be logically dismounted from the drive.
However, the volume will remain physically loaded on the drive. If you use
the /NOUNLOAD qualifier to dismount a magnetic tape volume, the volume
will remain loaded on the magnetic tape drive and the magnetic tape reel
will be rewound to the BOT mark.
If you plan to remount or reinitialize a volume that you are dismounting, you
can save time and eliminate unnecessary handling of that volume by using
the /NOUNLOAD qualifier with the DISMOUNT command.

The following examples show how to use the DISMOUNT command. The
first example employs the /NOUNLOAD qualifier.
$ DISMOUNT/NOUNLOAD MTA1:

•In this example, the magnetic tape volume will be logically dismounted and
remain loaded on drive MTAl:. Also, the magnetic tape reel will be rewound
to the BOT mark. The VAX/VMS system returns you to DCL level.
The DISMOUNT command is also used to dismount foreign volumes. The
following command dismounts a volume that had been mounted with the
/FOREIGN qualifier on DBAO:.
$ DISMOUNT DBAO:

•In this example, the volume that had been mounted with the /FOREIGN
qualifier on DBAO: will be dismounted and automatically unloaded. The
VAX/VMS system returns you to DCL level.
As mentioned previously, you use the DISMOUNT command to dismount
an entire volume set. If you explicitly dismount any volume in a disk or
magnetic tape volume set, the entire volume set will be dismounted. For
example, if you had a volume set that consisted of DBA3: and DBA4:
and you entered the following command, the entire volume set would be
dismounted:
$ DISMOUNT DBA3:

It is possible to dismount individual disk volumes in a volume set without
dismounting the entire disk volume set. You can do this by using the /UNIT
qualifier with the DISMOUNT command. The /UNIT qualifier specifies that
only the disk volume on the specified device is dismounted. For example:
$ DISMOUNT/UNIT DBA4:

This command specifies that only DBA4: (included in the disk volume set
mentioned above) is to be dismounted.

3-24

Preparing Disk and Magnetic Tape Volumes for Private Use

You should always explicitly dismount a volume or volume set with
the DISMOUNT command, or a command procedure that contains that
command, before physically unloading that volume.
A volume will be dismounted and unloaded automatically if you log out of
the job from which you had mounted the volume. If the system crashes,
however, the drive is not automatically dismounted.
Note that data corruption can occur if a volume has not been explicitly
dismounted and the system fails. For magnetic tape volumes, data corruption
can occur if you unload a volume that contains an open file for which file
trailer labels had not been written. When you remount the volume and
attempt to access the file without file trailer labels, you will receive the
following error message:
Y.MTAACP-magnetic tape position lost

You will be able to access all the files (on that magnetic tape volume)
preceding the file whose file trailer labels had not been written. However,
you will not be able to access the file without file trailer labels.
Note that the dismount of a volume is done by the file system and is not
complete until all the open files on the volume have been closed. Thus,
a substantial amount of time can pass between the time you issue the
DISMOUNT command and the completion of the dismount. Always wait for
the drive to unload before you remove the volume. (You can verify that the
dismount is complete by using the DCL command SHOW DEVICES.)
If the device you are dismounting was allocated with an ALLOCATE
command, it remains allocated after it is dismounted with the DISMOUNT
command. If the device was implicitly allocated by the MOUNT command,
the DISMOUNT command deallocates it.

For more information on the DISMOUNT command, see the VAX/VMS DCL

Dictionary.
3.6

Deallocating Drives
The process of allocation reserves a device for exclusive use by your process.
The device will remain allocated to your process until you explicitly
deallocate it or until you log out from your process. Once you have
allocated the device, other users cannot access that device until you explicitly
deallocate it or log out.
You can use the DCL command DEALLOCATE to deallocate explicitly a
disk drive or magnetic tape drive that has been allocated to your process.
A complement to the ALLOCATE command, the DEALLOCATE command
logically disconnects a drive from your process and returns it to the pool of
devices.
~-25

Preparing Disk and Magnetic Tape Volumes for Private Use

The following examples show how to explicitly deallocate a magnetic tape
drive and a disk drive.
$DEALLOCATE MTA1:

•In this example, the DEALLOCATE command logically disconnects magnetic
tape drive MTAl: from your process. The VAX/VMS system returns you to
DCL level.
$DEALLOCATE DJAO:

•In this example, the DEALLOCATE command logically disconnects disk
drive DJAO: from your process. The VAX/VMS system returns you to the
DCL command level.
Since logging out of a process from which drives have been allocated will
automatically deallocate all explicitly and implicitly allocated drives, you
do not have to explicitly deallocate a disk or magnetic tape drive that
has been allocated to your process. However, it is a good practice to use
the DEALLOCATE command (or a command procedure containing this
command) to explicitly deallocate all the drives you allocated with the
ALLOCATE command.

3.7

Using Command Procedures to Set Up Disks and Magnetic
Tapes
Since private disk and magnetic tape volumes frequently must be set up
before you can perform operations on them, you may want to design
command procedures to facilitate the set-up procedures. This section
contains examples of command procedures that can be used to set up disk
and magnetic tape volumes for routine operations.
You can tailor command procedures to meet the needs of your own set-up
tasks. The command procedure examples in this section, although general in
nature, can serve as guiding strategies for you.
The next two sections contain examples of command procedures that are
designed to set up disk and magnetic tape volumes for routine processing.

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Preparing Disk and Magnetic Tape Volumes for Private Use

3. 7 .1

Designing Command Procedures to Set Up Disk Volumes
The following command procedure is designed to allocate, initialize, and
mount a disk volume.
You can use a text editor, such as EDT or EVE to create a file to contain
your command procedure. Assume that a file named SETUP.COM has been
created and that it contains a very basic command procedure, which, when
executed, allocates and mounts a disk.
You can construct this command procedure by entering the following text:
$ ! Place a disk in the drive
$ IF P1 .EQS. "" THEN INQUIRE P1 "enter device name"
$ IF P2 .EQS. "" THEN INQUIRE P2 "enter volume label"
$ IF P3 .EQS. "" THEN INQUIRE P3 "enter logical name"
• ALLOCATE I P1 I
$MOUNT 'P1' 'P2' 'P3'

This command procedure, although very simple, accomplishes the task of
allocating and mounting a disk, each time it is executed. It is designed to
prompt you for the device name, volume label, and logical name of the disk
device that you want to allocate and mount. By assigning logical names
to your disks, you can use this command procedure to allocate and mount
devices over and over again.
You can take further advantage of the power of a command procedure by
including a few additional tasks as well. For example, you could design the
command procedure to deallocate and dismount the disk. The command
procedure example used to set up a magnetic tape (described in the next
section) takes advantage of some of these options.
You execute the above command procedure by entering the following
command:
$

<DSETUP

You can also write command procedures to mount a volume from a batch
job. By using logical names to refer to devices and files, you can use the
same command procedures without modification each time you want to
access a volume.
For example, if you use the same RK07 disk pack to back up your files on a
weekly basis, you can submit as a batch job a command procedure such as
the following:
$ MOUNT DM: BACK_UP_GMB RK
$BACKUP/REPLACE *·* RK:•.*
$ DIRECTORY/FULL/OUTPUT=BACKUP.LOG RK:
$ DISMOUNT RK:

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Preparing Disk and Magnetic Tape Volumes for Private Use

In this command procedure, the MOUNT command will find and allocate a
device of the type DM: and create a logical name RK. The MOUNT command
substitutes the equivalence name in the message displayed at the operator
console.
When the MOUNT command notifies the operator to mount the correct
volume, the job waits until the operator responds.

3. 7 .2

Designing Command Procedures to Set up Magnetic Tape
Volumes
The command procedure below, which is more sophisticated and detailed
than the previous example, is designed to set up a magnetic tape for
processing. The ALLOCATE and MOUNT/FOREIGN commands are
included in this command procedure.
Using a text editor, you can construct a command procedure in the following
way:

$ ! First mount the tape on the drive
$ ON CONTROL_Y THEN GOTO EXIT
$ ON ERROR THEN GOTO EXIT
$WRITE SYS$0UTPUT "Welcome to FETCH."
$ WRITE SYS$0UTPUT " "
$ Li: INQUIRE/NOPUNC PHYS "Have you placed the volume in the drive? 11
$IF .NOT. PHYS THEN GOTO Li
$ INQUIRE/NOPUNC DRIVE "Which drive is the volume mounted on? "
$DRIVE= DRIVE - ":"
$ ALLOCATE 'DRIVE'
$ MOUNT/FOREIGN 'DRIVE'
$ ON ERROR THEN GOTO COMMAND_LOOP
• !

• COMMAND_LOOP: INQUIRE/NOPUNC OPTION "FETCH> II
$ IF OPTION .EQS. "DIR" THEN GOTO DIR
$ IF OPTION .EQS. "EXIT" THEN GOTO EXIT
$ IF OPTION .EQS. "FETCH" THEN GOTO FETCH
$ IF OPTION .EQS. "HELP" THEN GOTO HELP
$ IF OPTION .EQS. "LIST" THEN GOTO LIST
$ GOTO COMMAND_LOOP
• !

$ DIR: INQUIRE SPEC "Filespec"
$ DIR 'SPEC'
$ GOTO COMMAND_LOOP

3-28

Preparing Disk and Magnetic Tape Volumes for Private Use

$ HELP:
$WRITE SYS$0UTPUT "Enter any of the following commands at the prompt:"
$ WRITE SYS$0UTPUT
$ WRITE SYS$0UTPUT
$ WRITE SYS$0UTPUT "DIR
(To search for a file)"
$ WRITE SYS$0UTPUT " n
$WRITE SYS$0UTPUT "EXIT
(To exit this program)"
$ WRITE SYS$0UTPUT
$ WRITE SYS$0UTPUT "FETCH
(To perform a BACKUP RESTORE operation)"
$ WRITE SYS$0UTPUT n n
$WRITE SYS$0UTPUT "HELP
(To read this text)"
$ WRITE SYS$0UTPUT
$WRITE SYS$0UTPUT "LIST
(To perform a BACKUP LIST operation)"
$ GOTO COMMAND_LOOP
$ !
$ FETCH: INQUIRE FILE "Filespec"
$ INQUIRE SAVESET "Save set name"
$LINE:= BACKUP/LOG 'DRIVE': 1 SAVESET 1 /SELECT= 1 FILE'
$ INQUIRE EXCLUDE "Enter any filespecs you want excluded"
$ IF EXCLUDE .EQS. "" THEN GOTO L2
$LINE := 1 LINE 1 /EXCLUDE=( 1 EXCLUDE 1 )
$ !

$ L2: INQUIRE/NOPUNC TO "Where do you want the file(s)? (<RET> for current directory)"
$ IF TO .EQS. "" THEN GOTO REPLACE
$ LINE := 'LINE' 'TO'
$ GOTO L3
$ REPLACE: LINE := 'LINE' []
• !

$ L3: INQUIRE/NOPUNC NEW "Create a new version if file already exists? "
$ IF .NOT. NEW THEN GOTO NOT
$LINE := 'LINE'/NEW_VERSION
• !

$NOT: LINE := 'LINE'/OWNER_UIC=ORIGINAL
$ LINE
$ GOTO COMMAND_LOOP
• !

$ LIST: INQUIRE SPEC "Filespec"
$ INQUIRE SAVESET "Save set name"
$ INQUIRE/NOPUNC OUTPUT "What do you want to call the list file? (<RET> for SYS$0UTPUT ")
$ IF OUTPUT .EQS. "" THEN GOTO NOOUT
$LINE:= BACKUP/LIST='OUTPUT' 1 DRIVE 1 : 1 SAVESET 1 /SELECT=( 1 SPEC 1 )
$ GOTO L4
$ NOOUT: LINE:= BACKUP/LIST 1 DRIVE 1 : 1 SAVESET 1 /SELECT=( 1 SPEC 1 )
$ !

$ L4: INQUIRE EXCLUDE "Enter any filespecs you want excluded"
$ IF EXCLUDE .EQS. "" THEN GOT L5
$LINE := 'LINE 1 /EXCLUDE=( 1 EXCLUDE 1 )
$ !
$ L5: LINE
$ GOTO COMMAND_LOOP
$ !
$ EXIT:
$ DISMOUNT 'DRIVE'
$ DEALLOCATE 'DRIVE'

3-29

Preparing Disk and Magnetic Tape Volumes for Private Use

Assume that the above command procedure is contained in a file named
FETCH.COM. You would execute this command procedure by entering the
following:
<!IF ETCH

This command procedure is more complex than the two previous ones, which
were both used to set up a disk. Like the former command procedures, the
procedure contained in FETCH.COM also accomplishes the basic task of
allocating the device and mounting the volume.
In addition to its allocating and mounting functions, however, the command
procedure contained in FETCH.COM is designed to prompt you for input.
For example, it specifically asks you if the magnetic tape is on the drive.
Note that this command procedure is also designed to do a BACKUP restore
operation. It prompts you for specific options on the restore operation.
Finally, this command procedure explicitly dismounts your magnetic tape
volume and deallocates the drive, after your task has completed.

3-30

Manipulating Files on Disks and Magnetic
Tapes
This chapter describes how to manipulate disk and magnetic tape files by
using the DIGITAL Command Language (DCL). In particular, it describes
how you can use DCL commands to perform the following tasks:
•

Retrieve disk and magnetic tape file information

•

Modify disk and magnetic tape file characteristics

•

Access files residing on disk and magnetic tape volumes

It also contains examples of DCL command procedures designed to access

files for create, read, and write operations.

4. 1

Using DCL to Manipulate Files
In VAX/VMS, you can use the DCL command language to manipulate disk
and magnetic tape files. One advantage of manipulating files by way of DCL
is that you can do so without ever leaving the command level.
DCL enables you to manipulate files in the following ways. You can use
the appropriate DCL SHOW commands to retrieve disk and magnetic tape
file information such as device and protection characteristics, and display
this information on your terminal. You can use the appropriate DCL SET
commands to modify disk and magnetic tape file characteristics, such as
protection or UIC information. You can also use the DCL command language
to access disk and magnetic tape files for read and/ or write operations.
In addition to manipulating files through DCL, you can write user programs
to assist you in routine file-manipulation tasks. You can write these programs
in either VAX MACRO or in one of the higher-level languages supported by
VAX/VMS. If you wish to manipulate individual records within files that is, if you wish to access files at the record level - you should write
programs that include RMS facilities. Examples of the RMS facilities that you
can use to manipulate files at the record level are included in the VAX Record

Management Services Reference Manual.
This chapter focuses on the ways in which you can use DCL to manipulate
disk and magnetic tape files at the file level. Note the following restrictions
on the use of DCL commands for manipulating files on disk and magnetic
tape volumes:

4-1

Manipulating Files on Disks and Magnetic Tapes

•

The SUBMIT command cannot access files on allocated devices. You
can submit files on private disk volumes if you mount the volume as a
shareable volume. To submit a file on a magnetic tape volume, you must
copy the file first to a shared disk volume and then submit it from the
disk.

•

You can print a file from a privately owned volume. Note, however, that
the volume containing the file you wish to print must remain mounted
until after the file has completed printing. If you do not want to wait
until the printing completes, you can copy the file directly to the line
printer, using the DCL command COPY:
$ COPY MYPHILE.DAT LPAO:

•

Most DCL commands require file-structured devices. For a list of those
commands that do not require file-structured devices, see the VAX/VMS
DCL Dictionary.

•

You can execute a command procedure that resides on a magnetic tape
volume as long as the procedure does not invoke other procedures and
does not issue any GOTO commands referring to labels in the procedure
that precede the GOTO command. In this case, it would be better to
copy the command procedure from the magnetic tape volume to a local
disk, from which you can then invoke the command procedure.

Note that you cannot use DCL commands to read or write files that are not
in the standard formats supported by VAX/VMS (these formats are described
in greater detail in the Guide to Using DCL and Command Procedures on
VAX/VMS).

4.2

Using DCL to Retrieve File Information
The DCL command language provides commands that enable you to retrieve
information about disk and magnetic tape files, volumes, and devices. You
can use the following DCL commands to retrieve such information:

•
•
•
•
•
•

DIRECTORY
SHOW ACL
SHOW DEVICES
SHOW MAGTAPE
SHOW PROTECTION
SHOW QUOTA

See the VAX/VMS DCL Dictionary for a complete list of the command
qualifiers and parameters applicable to each of these DCL commands.

4-2

Manipulating Files on Disks and Magnetic Tapes

4.2.1

Retrieving Directory Information
You can use the DCL command DIRECTORY to retrieve information about a
file or a group of files residing on a disk or magnetic tape volume.
You can use the DIRECTORY command to list the names of all of the files in
a particular directory, or you can use it in conjunction with a file specification
to list the names of specific files in a given directory. When you include
certain command qualifiers along with the DIRECTORY command, you can
retrieve information in addition to the names of the files.
The examples that follow illustrate three cases of retrieving information from
the [MALCOLM] directory, which resides on a disk whose logical name is
DISK$DOCUMENT. Note that the asterisk wildcard character is used in the
file specifications of two of the disk directory examples.

EXAMPLES

• DIRECTORY AVERAGE.*
Directory DISK$DOCUMENT:[MALCOLM]
AVERAGE.EXE;6
AVERAGE.FOR;6
Total of 4 files.

AVERAGE.LIS;4

AVERAGE.OBJ;12

$ DIRECTORY/SIZE=USED/DATE=CREATED/VERSIONS=1/PROTECTION AVERAGE
Directory DISK$DOCUMENT:[MALCOLM]
AVERAGE.EXE;6
6
10-APR-1986 15:43 (RWED,RWED,RWED,RE)
AVERAGE.FOR;6
2
2-APR-1986 10:29 (RWED,RWED,RWED,RE)
AVERAGE.LIS;4
5
9-APR-1986 16:27 (RWED,RWED,RWED,RE)
AVERAGE.OBJ;6
2
9-APR-1986 16:27 (RWED,RWED,RWED,RE)
Total of 4 files, 15 blocks.

$ DIRECTORY/FULL/VERSIONS=1
[MALCOLM ... ]AVERAGE.EXE
Directory DISK$DOCUMENT:[MALCOLM]
AVERAGE.EXE;6
File ID: (4098,149,0)
[DOCUMENTATION.MALCOLM]
Size:
36/36
Owner:
Created: 27-JUN-1986 12:22 Revised: 27-JUN-1986 12:22 (2)
Expires:
<None specified> Backup:
3-JUL-1986 22:03
File organization: Sequential
File attributes:
Allocation: 36, Extend: 36, Global buffer count: 0
No version limit
Record format:
Variable length, maximum 255 bytes
Record attributes: Carriage return carriage control
File protection:
System:RWED, Owner:RWED, Group:RE, World:
Access Cntrl List: None
Total of 1 file, 36/36 blocks.

4-3

Manipulating Files on Disks and Magnetic Tapes

Directory DISK$DOCUMENT: [MALCOLM.TEST]
AVERAGE.EXE;!
File ID: (7714,29,0)
Size:
36/36
Owner:
[DOCUMENTATION.MALCOLM]
Created: 15-APR-1986 10:12
Revised: 15-APR-1986 10:12 (1)
Expires:
<None specified>
Backup:
15-APR-1986 22:41
File organization: Sequential
File attributes:
Allocation: 36, Extend: 36, Global buffer count: 0
No version limit
Record format:
Variable length, maximum 255 bytes
Record attributes: Carriage return carriage control
File protection:
System:RWED, Owner:RWED, Group:RE, World:
Access Cntrl List: None
Total of 1 file, 36/36 blocks.
Grand total of 2 directories, 2 files, 72/72 blocks.

Directory structures do not apply to magnetic tape volumes. However, you
can use the DIRECTORY command to search for files on magnetic tape
volumes.
This use of the DIRECTORY command is also discussed in Section 4.4.2,
which describes how to access magnetic tape files for read and write
operations.
If you want to find the names of all files on a magnetic tape volume mounted
on MTA2:, you would enter the following command:
$ DIRECTORY MTA2:

This directory command lists the file names and file types of all files on the
magnetic tape.
As in the case of the disk examples included above, you can use wildcard
characters in directory specifications for magnetic tapes. For example, if you
enter the command:
$DIRECTORY MFAO:*.*;*

VAX/VMS will search the entire volume set. Both ANSI and VAX/VMS file
names will be returned. (The difference between these two types of magnetic
tape files is described in Section 4.4.2).

4.2.2

Retrieving Device Information
You can use the DCL command SHOW DEVICES to retrieve information
about the availability of devices on your system.

4-4

Manipulating Files on Disks and Magnetic Tapes

When you issue the SHOW DEVICES command without specifying a
device or using any qualifier, information about all devices on the system
is displayed. If you specify a device name, SHOW DEVICES displays
information about that device. If you use certain qualifiers with SHOW
DEVICES, information is displayed about those devices that currently have
volumes mounted and/or that have been allocated to processes.
The device name displayed by the system uses the format ddcu, where dd is
the device code, c is the control, and u is the unit. If the system is part of a
VAXcluster, the device name will include the node name using the format
node$ddcu, where node refers to the node name of the system that the device
resides on, dd refers to the device type, c refers to the controller designation,
and u refers to the unit number. See the Guide to VAXclusters for a complete
description of the device name format on clusters.
The examples that follow include three instances of how the SHOW
DEVICES command can be used.

EXAMPLES

$ SHOW DEVICES
Device
Name
DBAO:
DBA1:
DBA2:
DBA5:
DBA6:
DBA7:
DMAO:
DLAO:
DYAO:
DYA1:
DRA3:
MFAO:
MFA1:
MTAO:
MTA1:

Device
Err.
Status
Count
Online mnt
0
Online mnt
0
Online mnt
3
Online mnt
0
Online
0
Online mnt
0
Online
0
Online
0
Online
0
Online
0
Online mnt
0
Online
8
Online
1
Online mnt
9
Online
0

Volume
Label
VMS
USERPACK1
DOCUMENT
MAS TERP

Free Trans Mount
Blocks Count Count
47088 115
1
45216
2
1
20
1
8068
28668
1
1

PROJECT

110547

RES26APR

29317

BACKUP

453

The SHOW DEVICES command displays the following information for each
device on the system:
•

Device name

•

Device status and characteristics. (Status indicates whether the device is
on line; characteristics indicate whether the device is allocated, spooled,
has a volume mounted on it, and if the volume is mounted foreign.)

•

Error count

•

Volume labels

4-5

Manipulating Files on Disks and Magnetic Tapes

•

Number of free blocks on the volume (disk only)

•

Transaction count

•

Number of mount requests issued for the volume (disk devices only

$ SHOW DEVICES/FULL DMAO
Disk $1$DMAO: (NODE1), device type RK07, is online, allocated,
served to the cluster, error logging enabled.
Error count
2
Operations completed
4527
Owner process
"SMITH"
Owner UIC
[0,0)
Owner process ID
24400133
Dev Prot
S:RWED,O:RWED,G:RWED,W:RWED
Reference count
1
Default buffer size
512
Allocation class
1

The SHOW DEVICES command requests a full listing of the status of tl
RK07 device DMAO. The device is located on NODEl in a VAXcluster.
=:J

$ SHOW DEVICES/FULL NODE2$
Disk $1$DBAO: (NODE2), device type RP05, is online, mounted, file-oriented
device, shareable, served to cluster via MSCP Server, error logging is
enabled.
Error count
0
Operations completed
120
Owner process
Owner UIC
[303,2)
Owner process ID
00000000
Dev Prot
S:RWED,O:RWED,G:RWED,W:RWED
Reference count
1
Default buffer size
512
Total blocks
171798
Sectors per track
22
Total cylinders
411
Tracks per cylinder
19
Allocation class
1
11
Volume label
HIGHNOON 11
Relative volume number
0
Cluster size
Transaction count
1
3
Free blocks
94425
Maximum files allowed
21474
Extend quantity
Mount count
8
5
11
Mount status
System
Cache name
_$255$DUA8:XQPCACHE"
Extent cache size
64
Maximum blocks in extent cache
9442
File ID cache size
Blocks currently in extent cache
0
64
Quota cache size
0
Maximum buffers in FCP cache
421
Volume status: subject to mount verification, file high-water marking, writethrough caching enabled.
Volume is also mounted on NODE1, NODE4, NODE3.
Disk NODE2$DBC1:, device type RP06, is online, error logging enabled.
Error count
0
Operations completed
0
Owner process
Owner UIC
[O, 0)
Owner process ID
00000000
Dev Prot
S:RWED,O:RWED,G:RWED,W:RWED
Reference count
0
Default buffer size
512
Host name
"NODE2"
Host type, available
V780, yes

4-6

Manipulating Files on Disks and Magnetic Tapes

Disk NODE2$DMAO:, device type RK07, is online, error logging enabled.
Error count
0
Operations completed
0
Owner process
Owner UIC
[0,0]
Owner process ID
00000000
Dev Prot
S:RWED,O:RWED,G:RWED,W:RWED
Reference count
0
Default buffer size
612
Host name
"NODE2"
Host type, available
V780, yes

In this example, you have requested a full display of information about each
device on NODE2 on the VAXcluster. Information is shown here only for
the first three devices: a mounted device and two that are not mounted.

4.2.3

Retrieving Magnetic Tape Device Information
You can use the DCL command SHOW MAGTAPE to display the current
characteristics and status of a specified magnetic tape device.
Although you can use the SHOW DEVICES command to find available
magnetic drives on your system, the SHOW MAGTAPE enables you to
retrieve additional information about the characteristics of a particular
magnetic tape device.
When you enter the SHOW MAGTAPE command at your terminal, you will
receive the following prompt:
_Device:

You must then specify the name of the magnetic tape device for which you
want to display the characteristics and status.
The following example illustrates how the SHOW MAGTAPE command is
used to retrieve information about MTAO::

EXAMPLE
$ SHOW MAGTAPE MTAO:
MTAO:,
device type TU77, is on line, error logging enabled
Error count
0
Operations completed
0
Owner process
Owner UIC
[0,0]
Owner process ID 0000000
Dev Prot S:RWED, O:RWED, G:RWED, W:RWED
Reference Count
0
Default buffer size
2048
Density
800
Format
Normal-11
Odd Parity

This SHOW MAGTAPE command displays the characteristics of the device
MTAO:. Among other characteristics, it displays the device type, density, and
format.

4-7

Manipulating Files on Disks and Magnetic Tapes

4.2.4

Retrieving Disk File Protection Information
You can use the DCL commands DIRECTORY/ ACL, SHOW ACL, or
SHOW PROTECTION to display the current process default protection.
This protection is applied to files created during your terminal session, or
batch jobs, where defaults from directories or previously existing versions are
not available.
You can change the default protection at any time with the SET
PROTECTION command. (The SET ACL and SET PROTECTION
commands are discussed in Section 4.3, which describes how to modify
file characteristics.)
This section is not applicable to magnetic tapes. Although you can use
the SHOW/SET PROTECTION commands to SHOW/SET the default
protection of magnetic tapes, the protection will not get written to the
magnetic tape volume unless you specify the /PROTECTION= qualifier
with the INITIALIZE command when you are initializing the magnetic tape
volume. See the description of initializing magnetic tape volumes in Chapter
3 of this guide.
The following example illustrates how the SHOW PROTECTION command
can be used in conjunction with the SET PROTECTION command to display
and modify the protection characteristics of a disk file.

EXAMPLE
$ SHOW PROTECTION

SYSTEM=RWED, OWNER=RWED, GROUP=RE, WORLD=NO ACCESS
$ SET PROTECTION=(GROUP:RWED,WORLD:RE)/DEFAULT
$ SHOW PROTECTION
SYSTEM=RWED, OWNER=RWED, GROUP=RWED, WORLD=RE

This SHOW PROTECTION command requests a display of the current
protection defaults. The SET PROTECTION/DEFAULT command is then
used to change the file access allowed to other users in the same group as
well as to miscellaneous system users.

4-8

Manipulating Files on Disks and Magnetic Tapes

4.2.5

Retrieving Disk Quota Information
It is frequently important to limit the amount of disk space certain users
consume. The VAX/VMS Disk Quota Utility (DISKQUOTA) provides the
system manager with this capability. Users who have READ access (R) to
the quota file can use the SHOW QUOTA command to determine how much
disk space any user on the system has been allocated. Users who do not
have READ access to the quota file can use the SHOW QUOTA command to
determine their own allotments.
You can manage the checking on a per-volume basis at mount time by using
the MOUNT qualifier /[NO]QUOTA. (You can also use DISKQUOTA to
enable and disable amounts of disk space.) You must have the VOLPRO
user privilege or your UIC must match the UIC written on the volume in
order to use the MOUNT command qualifier /QUOTA.
You can use the DCL command SHOW QUOTA to find out whether a
quota exists for any specific user on a specific disk. The display that results
from the SHOW QUOTA command gives the quotas used, authorized, and
available.
A user can have a quota for any disk volume on the system. In some
cases, the user is permitted a certain authorized limit plus an overdraft
limit. Generally, only the authorized limit applies. However, certain system
programs, such as editors, can employ the overdraft feature when the
authorized limit is exceeded.
If you should run out of disk space during the creation of a file, you receive
a system message. If you find you cannot obtain sufficient space by purging
or deleting unnecessary files, you may need to contact the system manager to
increase your disk quota. If you attempt to write a file to a spooled printer,
you must have WRITE access and have sufficient quota on the disk that is
associated with that printer.

The examples that follow contain two instances of the SHOW QUOTA
command.

EXAMPLES

• SHOW QUOTA

User [DOCUMENTATION.MALCOLM] has 2780 blocks used, 7220 available,
of 10000 authorized and permitted overdraft of 600 blocks on DISK$

The SHOW QUOTA command displays the amount of disk space authorized,
used, and still available on the current default disk for the present user. The
permitted overdraft in this example is 500 blocks.

4-9

Manipulating Files on Disks and Magnetic Tapes

$SHOW QUOTA /USER=[DOCUMENTATION,JONES]/DISK=XXX1:
Y.SYSTEM-F-NODISKQUOTA, no disk quota entry for this UIC

This SHOW QUOTA command displays the fact that the user with UIC
[DOCUMENTATION,JONESl has no disk quota allocation on device XXXl.
~

$SHOW QUOTA /USER=[DOCUMENTATION,ELAINE]
User [DOCUMENTATION,ELAINE] has 27305 blocks used, 2306 OVERDRAWN,
of 25000 authorized and permitted overdraft of 4000 blocks on DISK$

This SHOW QUOTA command illustrates a user with an overdrawn quota.

4.3

Using DCL to Modify File Characteristics
DCL provides commands that enable you to establish and modify the
characteristics of files residing on disk and magnetic tape volumes. To
establish or modify file characteristics, you can use the following commands:

•
•
•
•
•

•

SET ACL
SET DIRECTORY (disk only)
SET FILE (disk only)
SET MAGTAPE (magnetic tape only)
SET PROTECTION (disk only)
SET VOLUME (disk only)

Each of these commands is discussed in detail in the Guide to Using DCL
and Command Procedures on VAX/VMS. For a complete list of the command
qualifiers and parameters applicable to each of these DCL commands, see the
VAX/VMS DCL Dictionary.

4.3.1

Modifying ACL Characteristics
You can use the DCL command SET ACL to create or modify an access
control list (ACL) for a specified object. The format is as follows:
SET ACL/OBJECT_TYPE=object
This command enables you to manipulate an entire access control list of an
object, or to create, modify, or delete access control entries (ACEs) in the
ACL of an object. The object name can specify a file (including a directory
file) or a device.

4-10

Manipulating Files on Disks and Magnetic Tapes

The SET ACL command is used to add ACEs to an ACL by specifying the
ACEs with the/ ACL qualifier. For example, the following command adds an
ACE to the ACL of the file SALARY86.DAT so that all users associated with
the identifier PERSONNEL are allowed read access to the file:
$SET ACL/ACL=(IDENTIFIER=[PERSONNEL],ACCESS=READ) SALARY86.DAT

If the object specified with the SET ACL command does not have an ACL,
one is created.

The following example replaces the ACL of the file ACCOUNTS.LIS with the
ACL for the file USER.LIS.
$ SET ACL/LIKE=(OBJECT_TYPE=FILE,OBJECT_NAME=USER.LIS) ACCOUNTS.LIS

As an alternative to the SET ACL command, you can use the DCL commands
SET FILE/ ACL and SET DIRECTORY/ ACL to apply ACL protection to files
and directories.
For a complete description of ACLs, see the Guide to VAX/VMS System
Security. For a complete description of the Access Control List Editor,
including information about the EDIT/ ACL command and its qualifiers, see
the VAX/VMS Access Control List Editor Reference Manual.

4.3.2

Modifying Directory Characteristics
You can use the DCL command SET DIRECTORY to modify the
characteristics of one or more directories.
The examples that follow illustrate two instances of the SET DIRECTORY
command:

EXAMPLES

• SET DIRECTORY/VERSION_LIMIT=5/CONFIRM [SMITH.FORTRAN]
The SET DIRECTORY command limits the number of versions to five for
files created after the command is issued. The /CONFIRM qualifi~r requests
that you confirm whether or not the specified directory should actually be
modified.

$SET DIRECTORY/OWNER_UIC=[DOCUMENTATION,GRAY] [DAVIDSON],[USERS]

The SET DIRECTORY command modifies both the [DAVIDSON] and
[USERS] directories, changing their owner UICs. Use of the /OWNER_
UIC qualifier requires SYSPRV or GRPPRV respectively for changing the
ownership at the system or group level.

4-11

Manipulating Files on Disks and Magnetic Tapes

4.3.3

Modifying Disk File Characteristics
You can use the DCL command SET FILE to modify the characteristic
one or more files.
The examples that follow illustrate three instances of how the SET FU
command can be used to modify file characteristics.

EXAMPLES
iJ

$ SET FILE/EXPIRATION_DATE=15-APR-1986:11:00 BATCH.COM;3

The SET FILE command requests that the expiration date of the file
BATCH.COM;3 be set to 11:00 A.M., April 15, 1986.
~

$ SET FILE/BEFORE=15-APR-86/ERASE_ON_DELETE PERSONNEL*.SAL

This SET FILE command calls for all files that match the file specificat
PERSONNEL•.SAL and that are dated before April 15, 1986 to have t
disk locations erased whenever one of them is deleted with command!
as DELETE or PURGE.
~

$ SET FILE/OWNER_UIC=[DOCUMENTATION,GRAY]/VERSION_LIMIT=100 MYFILE.DAT

The SET FILE command modifies the characteristics of the file MYFILI
changing the owner UIC and assigning a file version limit of 100. Not
the /OWNER_UIC qualifier requires SYSPRV or GRPPRV respective!:
changing the ownership at the system or group level.

4.3.4

Modifying Magnetic Tape Device Characteristics
You can use the DCL command SET MAGTAPE to define the default
characteristics associated with a specific magnetic tape device for subsE
file operations. The device must not be currently allocated to any othe
The examples that follow illustrate three uses of the SET MAGTAPE
command in conjunction with the MOUNT command.

EXAMPLES
i]

$ MOUNT MTB1: /FOREIGN
$ SET MAGTAPE MTB1: /DENSITY=800

The MOUNT command mounts a foreign tape on the device MTBl:.
SET MAGTAPE command defines the density for writing to the magn
tape at. 800 bpi. (The density is reset only if the magnetic tape has ne
been written before.)

4-12

Manipulating Files on Disks and Magnetic Tapes

$ MOUNT MTAO:/FOREIGN
$ SET MAGTAPE MTAO:/SKIP=FILES:4

The MOUNT command mounts a foreign magnetic tape on the device MTAO;
the SET MAGTAPE command directs the magnetic tape position to skip four
files.
~

$MOUNT MTA1:/FOREIGN
$ SET MAGTAPE/REWIND MTA1:

The MOUNT command mounts a foreign tape on the device MTAl; the SET
MAGTAPE rewinds the volume.

4. 3. 5

Modifying File Protection Characteristics
You can use the SET PROTECTION command to change or reset
the protection characteristics for one or more files. If you include a
protection code, tJ::te file protection is changed to that code. When you
omit the protection code and do not use the /PROTECTION qualifier,
the file protection changes to the default file access established by the
SET PROTECTION/DEFAULT command. See the SET PROTECTION/
DEFAULT command for information on how to change the default file
protection.
All disk and magnetic tape volumes have protection codes that restrict access
to the volume. The protection codes for magnetic tape volumes are assigned
with the INITIALIZE and MOUNT commands. Protection characteristics
on magnetic tape volumes cannot be changed by the SET PROTECTION
command.
For disk volumes, each file on the volume can have a different protection
associated with it. The SET PROTECTION command and other filemanipulating commands allow you to define the protection for individual
files.
If you omit both the code and the /PROTECTION file qualifier, your
current default protection (established by the SET PROTECTION /DEFAULT
command) is applied to the file.

The examples that follow provide four instances of using the SET
PROTECTION command.

4-13

Manipulating Files on Disks and Magnetic Tapes

EXAMPLES
iJ

$ DELETE INCOME.DAT;3
%DELETE-W-FILNOTDEL, error deleting DISK1:[SMITH]INCOME.DAT;3
-RMS-E-PRV, insufficient privilege or file protection violation
$ SET PROTECTION=OWNER:D INCOME.DAT;3
$ DELETE INCOME.DAT;3

The file INCOME.DAT;3 has been protected against deletion. This SET
PROTECTION command changes only the owner's DELETE access for the
file INCOME.DAT;3. Now the file can be deleted.
~

$ SET PROTECTION _$ PAYROLL.LIS/PROTECTION=(SYSTEM:R,OWNER:RWED,GROUP:RW),_$ PAYROLL.OUT/PROTECTION=(SYSTEM:RWED,GROUP:RWED,W)

In this example, the SET PROTECTION command changes the protection
codes applied to two files. To the file PAYROLL.LIS, it gives the SYSTEM
READ access, the OWNER READ, WRITE, EXECUTE, and DELETE
access, and users in the owner's group READ /WRITE access. To the file
PAYROLL.OUT, it gives the SYSTEM and GROUP all types of access; the
current access for OWNER does not change, but WORLD is denied all types
of access.
~

$SET PROTECTION A.DAT, B.DAT/PROTECTION=OWNER:RWED, C.DAT

The SET PROTECTION command specifies that the file A.DAT should
receive the default protection established for your files. The existing
protection for the file B.DAT is overridden, only for the OWNER category,
to provide READ, WRITE, EXECUTE, and DELETE access. Note that no
protection is specified for the file C.DAT at either the command or file level.
Thus, like A.DAT, C.DAT receives the default protection.
Since no version numbers are specified in this example, the protection
settings affect only the highest versions of the three files.
~

$ SET PROTECTION=OWNER:D _$ [MALCOLM.SUB1]SUB2.DIR/PROTECTION=GROUP:D

The SET PROTECTION command changes the protection for the OWNER
and GROUP categories of the subdirectory [MALCOLM.SUB! .SUB2]
to permit deletion. However, the protection for WORLD and SYSTEM
categories is not changed.

4-14

Manipulating Files on Disks and Magnetic Tapes

4.3.6

Modifying Volume Characteristics
You can use the DCL command SET VOLUME to modify the characteristics
of one or more mounted Files-11 disk volumes. In order to use this
command1 you must have WRITE access to the index file on the volume.
If you are not the owner of the volume1 you must have either a system UIC
or the user privilege SYSPRV. You must then specify the name of one or
more mounted Files-11 volumes.
The examples that follow illustrate how the SET VOLUME command can be
used.

EXAMPLES

D • SET VOLUME/DATA_CHECK=(READ,WRITE) DBC5
This command requests that data checks be performed following all read and
write operations to DBCS:.
~

$ SET VOLUME/LABEL=LICENSES DBC5:

This command encodes the label LICENSES on the volume DBCS:. Note
that if characters in labels are entered in lowercase, they are changed to
uppercase by the /LABEL qualifier.

4.4

Using DCL to Access Files
In addition to executing user programs that perform 1/0 operations to files
residing on disk and magnetic tape volumes1 you can use DCL commands to
access disk and magnetic tape files for read and write operations.
Note that this section describes how to use DCL to access disk and magnetic
tape files at the file level (as opposed to the record level). Although
DCL does allow you to manipulate files at the record levet performance
considerations usually warrant the use of a conventional programming
language.
Section 4.5 contains a command procedure example that has been designed
to access a volume in order to read and write records to files on the volume.
This command procedure uses the DCL commands OPEN /READ and OPEN /
WRITE to access individual records in a file.
Although you can use such a command procedure to manipulate individual
records in a file 1 it is recommended that you write programs using the RMS
facilities that are specifically designed to access files at the record level. You
can write these programs in VAX MACRO or in any of the higher-level
languages supported by VAX/VMS.

4-15

Manipulating Files on Disks and Magnetic Tapes

If you wish to access disk and magnetic tape files at the file level, you

can take advantage of DCL. As mentioned above, you cannot use DCL
commands to read or write files that are not in the standard formats
supported by VAX/VMS. If the file formats are not standard, the volumes on
which they reside must be mounted with the /FOREIGN qualifier.
The following sections provide examples of the steps you can use to access
files on disk and magnetic tape volumes. In particular, these sections describe
how to manipulate disk and magnetic tape files (at the file level) for READ
and WRITE access.

4.4. 1

Accessing Disk Files for Read and Write Operations
You can access disk files both for read and write operations. The next three
sections show how you can use DCL to access disk files for both types of
operations.
These sections contain examples of how to:
•

Read files from a mounted disk volume

•

Write files to a disk volume that must first be allocated, initialized, and
mounted

•

Write files from a default directory to a volume that must first be
allocated, initialized, and mounted on a magnetic tape device.

Although the examples used below for accessing disk files focus on RK06 /
RK07 disk packs, they are applicable to other devices as well.
4.4. 1 .1

Reading Files from a Disk Volume
In order to read the contents of a disk file, you can use the DCL command
TYPE which displays the contents of a file on your terminal. To find the
exact location of the disk file that you want to read, you can use the DCL
command DIRECTORY, which was discussed in Section 4.2.1.
For example, if you wish to read the contents of a file named HISFILE, which
is located somewhere in the directory [CHARLES] on a disk device whose
logical name is DISK$DOCUMENT:, you can look for the exact location of
HISFILE by issuing the following command:
$DIRECTORY DISK$DOCUMENT: [CHARLES ... ]HISFILE.*

4-16

Manipulating Files on Disks and Magnetic Tapes

This command instructs VAX/VMS to search the entire [CHARLES] directory,
including all the subdirectories, for all file types and versions numbers of
HISFILE. The following information will be displayed on your terminal.
Directory DISK$DOCUMENT:[CHARLES.MEMO]
HISFILE.UPD;1
Total of 1 file.

This display informs you that there is only one version of HISFILE, that
its file type is UPD, and that this file resides in the [CHARLES.MEMO]
directory.
To read the contents of this file, you can issue the following command.
$TYPE [CHARLES.MEMO]HISFILE.UPD

The contents of HISFILE will be displayed on your terminal.
4.4.1 .2

Writing Files to a Disk Volume

Before you can write files to a disk volume, the volume must be properly
prepared (see Chapter 3).
Disks are random-access devices, and files must be listed in directories.
Therefore, after you initialize a disk, you must create a directory to contain
your files on the disk volume.
For example:
$CREATE/DIRECTORY DMA3:[PUBS]
$ DEFINE P DMA3 : [PUBS]
$COPY * ·* P
$COPY [PRIMER] *·* P
$COPY [COMMANDS] *·* P

The CREATE/DIRECTORY command creates a directory file named [PUBS]
on the device DMA3:, and the DEFINE command defines the logical name
Pas DMA3:[PUBS]. The COPY command copies the highest versions of all
files in the current default directory and in the directories [PRIMER] and
[COMMANDS] to the newly created directory.

4-17

Manipulating Files on Disks and Magnetic Tapes

4.4.1 .3

Writing Files from Disk Volumes to Magnetic Tape Volumes

The example below describes how to use DCL to write files from a default
directory on a disk volume to an ANSI-labeled magnetic tape volume. It
includes examples that show how to allocate, initialize, and use a magnetic
tape to copy a set of your disk files. The procedures are similar to those
outlined above for copying files from disk volumes to disk volumes. One
main difference, however, is that magnetic tapes are sequential-access devices
and do not have directories. (The characteristics of magnetic tape files are
described more thoroughly in the next section.)
First, allocate a drive:
$ ALLOCATE MT: TAPE_DEVICE
XDCL-I-ALLOC _MARS$MTA2: allocated

This ALLOCATE command requests the allocation of a magnetic tape drive
whose name begins with MT. TAPE_DEVICE is a logical name, which in
this case refers to MTA2:.
The system response indicates that unit 2 on controller A was available and
is now allocated to you. You can now physically load the magnetic tape on
the drive. Be sure the write ring on the magnetic tape is in place; if it is not,
you cannot write to the magnetic tape.
Next, initialize the magnetic tape:
$ INITIALIZE TAPE_DEVICE: GMB001 _$ /PROTECTION=(GROUP:R,WORLD)

The INITIALIZE command specifies the device name (MTA2) and the volume
label for the magnetic tape volume (GMBOOl). The label can be no longer
than six characters. The /PROTECTION qualifier defines a protection code
restricting group access to read and allowing no WORLD access. You can
now use the MOUNT command to mount the volume and write files to it:
$ MOUNT TAPE_DEVICE: GMB001
XMOUNT-I-MOUNTED, GMB001 mounted on _MTA2:
$ COPY *·* TAPE_DEVICE:

The MOUNT command specifies the device name and volume label of the
volume on the device. The COPY command copies the highest versions of
all files in your default directory onto the magnetic tape. The file names, file
types, and version numbers of the output files default to the same file names,
file types, and version numbers as the input files.
If you issue the COPY command with the /LOG qualifier, the system will
send a message to the current SYS$0UTPUT device after each file has been
copied. You can also use the DIRECTORY command to verify that the files
were successfully copied.
$ DIRECTORY TAPE_DEVICE:

4-18

Manipulating Files on Disks and Magnetic Tapes

The DIRECTORY command lists the file names and file types of all files on
the magnetic tape.
When you have finished using the magnetic tape, dismount and deallocate it
as shown below:
$ DISMOUNT TAPE_DEVICE:
$ DEALLOCATE TAPE_DEVICE:

If you do not dismount and deallocate the magnetic tape, the system does so
automatically when you log out.

4.4.2

Accessing Magnetic Tape Files for Read and Write Operations
When you access an ANSI-labeled volume or a file, VAX/VMS checks at the
volume and/ or file level to ensure that your process can access the volume or
file. The level at which VAX/VMS checks access depends on the operation
that you request and the type of access that the operation requires.
When you access a volume or a file, VAX/VMS reads the volume and file
header labels to determine whether access to the volume or file is restricted.
Which label will be read depends on the operation that is requested.
For example, if you want to mount a volume, your process must have
access to it. Thus, VAX/VMS will read the volume labels only. For more
detailed information on volume-level access (and protection requirements for
magnetic tapes, see Chapter 2). This section describes file-level access for
magnetic tapes.
The protection sets your access to a particular file. The expiration date
field can prevent you from overwriting or appending to a file immediately
preceding the one in question. If the date written in the expiration date field
has not been reached, the file has not expired. You cannot overwrite an
unexpired file unless you specify the /OVERRIDE=EXPIRATION qualifier
when you mount the volume.
The manner in which the file is accessed to perform the operation is called
the access type. READ and/ or WRITE privilege is required, depending on
the type of access required.
Before accessing a particular file for a read or write operation, you may
want to search the magnetic tape volume for that file. The following section
describes how you can use the DIRECTORY command to locate a file or
group of files on a magnetic tape volume.

4-19

Manipulating Files on Disks and Magnetic Tapes

4.4.2.1

Locating ANSI-Labeled Magnetic Tape Files for READ or WRITE
Access

When you specify a VAX/VMS or ANSI file name for a file residing on
magnetic tape, the magnetic tape file system compares the file name with the
file header labels of each file until it finds a match in the file identifier field
of the file header labels.
If you supply a version number in the file name, it is compared with the
generation number and generation-version number fields in the first file
header label. If you do not sp~cify a version number, the magnetic tape file
system neither defaults a version number nor checks the generation number
and generation-version number fields. The magnetic tape file system selects
the first file on the magnetic tape whose file name in the file identifier field
matches the specified file name.

Neither the directory nor the latest version number concept is supported by
VAX/VMS for magnetic tape volumes. VAX/VMS does not search for or list

the latest version of a specified file. The magnetic tape file system cannot
increment version numbers of files written to magnetic tape; therefore, two or
more files in the same volume set can have the same file name and version
number.
Because the magnetic tape file system selects the first matching file name
and version number (if specified), the position of the magnetic tape within
the volume set determines which file is returned on a search operation. A
search operation begins at the current position, so you may want to rewind
the volume set before accessing a file.
The search for a matching file and version number (if specified) continues at
the beginning of the header label set of the next file. The search ends when
the magnetic tape is positioned at the file where the search began. If the
requested file is not found on the current volume, the remaining volumes in
the volume set are searched sequentially, according to their relative volume
numbers, until either a file name match occurs or the entire volume set is
searched.
If a file name match occurs, the internal file identification number is
constructed from the file section number, file sequence number, and relative
volume number. Although you can access a disk file by its file identification
number, you cannot access a magnetic tape file this way.
VAX/VMS does support the use of wildcard characters in file specifications
for magnetic tape volumes. However, there are certain restrictions on using
wildcard characters with magnetic tape files. Unlike files on disk volumes,
which support the asterisk ( * ), percent sign ( % ), ellipses ( ... ), and minus
sign ( - ) characters, magnetic tape volumes support only the asterisk and
percent-sign wildcard characters with VAX/VMS file names. ANSI file
names support only the asterisk wildcard character.

4-20

Manipulating Files on Disks and Magnetic Tapes

The asterisk wildcard character matches file specifications by field or portion
of a field. The percent sign wildcard character matches any character in a file
specification only by character positions within a field.
With VAX/VMS file names, you can specify the asterisk and the percent sign
anywhere in the file name and file type field to match file name specifications
by field or character position within a field. You cannot use the percent sign
in the version number field. Only the asterisk wildcard character can be used
in the version number field.
With ANSI file names, a single asterisk in a field is the only wildcard
character that can be used. ANSI fil~ names do support the special set of
ASCII "a" characters. Unlike VAX/VMS file names, which can consist of up
to 39 characters each for the file name and file type, ANSI file names can
have a maximum of 17 characters in length. Whether you choose VAX/VMS
file names or ANSI file names will depend on the type of applications you
wish to perform.
The examples that follow provide three instances of how you can use
wildcard characters in file specifications to search for files on magnetic tape
volumes. These examples also show the DIRECTORY command can be used
in conjunction with magnetic tapes. Note that the DIRECTORY command
does not work the same with magnetic tape files as with disk files (see
Section 4.2.1 ).

EXAMPLES

D • DIRECTORY MFA1:•.•;•
This command instructs VAX/VMS to search a volume set. Because asterisks
are used in the file specification and the asterisk is a valid wildcard character
for both ANSI and VAX/VMS file names, both VAX/VMS and ANSI file
names will be returned. Note than ANSI file names will be returned within
quotation mark characters.
~

$DIRECTORY MTA1:Y.•.*;*
$DIRECTORY MTAO:•.Y.*;*

In these two commands, the search can only match with VAX/VMS file
names because the percent sign is not valid for ANSI file names. In the
second command, the file type field must contain at least one character. Files
with no file type are not returned.
~

$ DIRECTORY MTAO:•. ;*

In this example, the DIRECTORY command instructs VAX/VMS to search
for files with ANSI file names, as well as VAX/VMS file names that have a
null file type.

4-21

Manipulating Files on Disks and Magnetic Tapes

4.4.2.2

Reading Files on Magnetic Tape Volumes

When a magnetic tape file is accessed for a read operation, the magnetic tape
is positioned at the beginning of the file section after the file header labels.
You can use the DCL command TYPE to read a file or group of files on
the magnetic tape volume, and display the contents of the file on your
terminal. For example, if you want to read the contents of a file named
TESTFILE.DOC;l (which you know from your above directory searches is a
VAX/VMS file residing on the magnetic tape device MTAl:), you can enter
the following command:
$ TYPE MTA1:TEST*.Y.*.*

You will then receive the following display on your terminal:
MTA1:TESTFILE.DOC;1
This is a test file.

When a file residing on a magnetic tape volume is accessed for reading only
the attributes in the header labels, rather than the data in the file section,
the magnetic tape file system returns the RMS attributes to your process. For
example, when you specify the DIRECTORY /FULL command for a volume,
file, or list of files, the magnetic tape file system selects the file identifiers
from the header labels, returns the file attributes to your process, and
positions the magnetic tape after the header labels of the last file accessed.
A magnetic tape file that was opened for read access is closed either
implicitly or explicitly. The file is closed implicitly when the driver
encounters a tape mark while a file is being read. The magnetic tape file
system then reads the trailer labels, closes the file, and positions the magnetic
tape at the next file.
The file is closed explicitly when you deaccess the file before all the data in
the file is read. The magnetic tape file system will then close the file without
reading the trailer labels, and the magnetic tape remains at the current
position.

4-22

Manipulating Files on Disks and Magnetic Tapes

4.4.2.3

Writing to Files on Magnetic Tape Volumes

When you use DCL to access an existing file for a write operation, one of
the following operations is actually being performed: append or update. The
difference between append and update write operations can be explained in
the following way.
•

Append Access
When a file is accessed for an append operation, the magnetic tape is
positioned at the EOF before the tape mark that precedes the trailer
labels. After the file is appended and closed, all files beyond the
appended file are lost. When the positioning is complete, the processing
is handled as if the file had been created as· described in the section on
file creation.

•

Update Access
When a file is accessed for an update operation, the magnetic tape is
positioned at the BOF section after the header labels. After the file is
written to and closed, all files beyond the updated file are lost. The
processing is handled as if the file had been created.

Note that you can only update/append magnetic tape files when the
header lable contains a value of zero for the buffer offset length. For more
information on how to update/append magnetic tape files, see Chapter 5.
In addition to updating files and appending files on a magnetic tape volume,
you can access a volume for a write operation by creating a file on the
volume. You can use the CREATE command to write a new file to the
magnetic tape volume. For example, you can enter the following command
string:
$ CREATE MTAO:MYFILE

You can then write the contents of the file, without leaving the DCL
command level, before closing the file.
If you do not specify the /OVERRIDE=EXPIRATION qualifier, the magnetic
tape file system checks the expiration date field on the file before it allows
you to write to that file. When more than one file will be overwritten,
the magnetic tape file system also checks the expiration date of the file
immediately following the file that will be overwritten. For example, before
you append to a file, the magnetic tape file system checks the expiration
dates of both the file being appended and the file immediately following. If
the expiration date of either file has not been reached, the magnetic tape file
system does not allow you to append the file.

4-23

Manipulating Files on Disks and Magnetic Tapes

When files are written to a magnetic tape volume, the magnetic tape file
system performs access checks, writes labels, and, if necessary, switches
volumes. If the new file will overwrite an existing file, the magnetic tape file
system checks the expiration date and accessibility fields of the existing file.
If overwriting is allowed, the magnetic tape file system overwrites the header
label set of the existing file, creates the file section, writes the trailer labels,
and writes two tape marks to denote the logical end-of-volume (EOV). All
files following the newly created file are lost.
To close a magnetic tape file that was opened for WRITE access, the magnetic
tape file system issues commands to the driver to write the labels, which are
followed by a double tape mark that indicates the logical EOV.

4.5

Command Procedures for Accessing Foreign Volumes
The command procedures in this section allow you to create, read, or write
magnetic tape data in a simple user-defined foreign format.

$!
$!
FOREIGN.COM
$!
$! This is the master command procedure. It sets up the user account and
$! mounts the volume with the /FOREIGN qualifier. If the user wants to
$! read a foreign volume, the FORREAD.COM command procedure is called.
$! If the user wants to write a foreign volume the FORWRITE.COM
$! command procedure is called.
$!
verify_off_on = F$VERIFY ( 0 )
ON CONTROL_Y THEN GOTO clean_up
ON WARNING THEN GOTO clean_up

••
••

$!
$! If VOLPRO privilege is not set but the user account has SETPRV, VOLPRO is
$! set to allow the user to mount a new unformatted volume. If VOLPRO
$! privilege cannot be set, the user process is notified that the process
$! has insufficient privilege to write an unformatted volume. The user is also
$! asked whether to continue or exit the procedure.
$!
volpro_off _on = F$SETPRV ( "VOLPRO" )
IF F$PRIVILEGE ( "VOLPRO" ) THEN GOTO cont
WRITE SYS$0UTPUT "Insufficient Privilege to write an unformatted volume!"
INQUIRE/NOPUNC continue "Do you wish to continue (YIN) ? "
IF .NOT. continue THEN GOTO clean_up
$ cont:

•••
••

4-24

Manipulating Files on Disks and Magnetic Tapes

•
••
••
•••
•
•••
•••
•

$!
$! Find out where the volume is mounted
$!
get_drive:
INQUIRE tape_drive "Tape drive"
IF tape_drive .EQS. "" THEN GOTO get_drive
tape_drive = tape_drive-": 11 + 11 : 11
IF .NOT. F$GETDVI (TAPE_DRIVE, 11 EXISTS 11 )
THEN GOTO NOSUCHDEV
ASSIGN 'tape_drive' tape
$!
$! Try allocating and mounting the volume
$!
ALLOCATE tape:
MOUNT/NOASSIST/FOREIGN/OVERRIDE=(ACCESSIBILITY,EXPIRATION) tape:
The user is asked whether a file will be read or written

$ read_write:
$
INQUIRE/NOPUNC operation "Read or Write a file ? 11
$
IF F$LOCATE ( operation, "READ" ) .EQ. 0 THEN GOTO read_op
$
IF F$LOCATE ( operation, "WRITE" ) .EQ. 0 THEN GOTO write_op
$
GOTO read_write

•

$ read_op:
$
GFORREAD
$
GOTO clean_up

•

$ write_op:
$
GFORWRITE

•
•
••
•••
••
•

$ clean_up:
$!
$!
$!

Reset the user account the way it was before the command procedure began
SET NOON
DISMOUNT/NOUNLOAD tape:
DEALLOCATE tape:
DEASSIGN tape
volpro_off _on = F$SETPRV
verify_off_on = F$VERIFY

volpro_off_on
verify_off_on

$ EXIT
$ NOSUCHDEV:
$
WRITE SYS$0UTPUT "No Such Device"
$
GOTO get_drive

4-25

Manipulating Files on Disks and Magnetic Tapes

$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!
$!

••
••
••
•

FORWRITE.COM

Writes Data to a Foreign Volume

This command procedure writes data to a foreign volume.
The data format is as follows:
Each record is a block.
Records are variable length.
The first four characters of a record are digits that are
padded on the left with spaces. This sequence field starts at
1 and increases by 1 with each record.
The fifth character of a record is a comma.
The sixth through ninth characters are digits that are padded on the
left with spaces. This is a size field, which is the size of the data
field.
The tenth character of a record is a vertical bar.
The rest of the record is data.
Records are padded to be at least 20 characters long.

seq_num = 0
spaces = ff

initialize the sequence number
used to pad records less then 20 chars

$
OPEN/WRITE tape_file tape: ! open the output file
$ next_line:

$!
$!
$!

•
•

seq_num = seq_num + 1

increment the sequence number

Prompt the user for the data
close the file and exit if -z is entered
READ/PROMPT="Record # 'seq_num' : 11 /END_OF_FILE=end_of_input SYS$COMMAND user_data

$!
$!
$!
$
$
$

Find the size of the record and the number of pad characters needed
Note That a negative number of pad characters does not return any characters

$!
$!
$

Construct the output record using FAQ

•

••
••

data_size = F$LENGTH ( user_data )
pad_chars = 10 - data_size
IF pad_chars .LT. 0 THEN pad_chars

out_rec = F$FAO ( "!4UL, !4ULI !AS", seq_num, data_size, user_data) + -F$EXTRACT ( 1, pad_chars, spaces
WRITE tape_file out_rec ! write the formatted output record
GOTO next_line

$ end_of_input:
$
CLOSE tape_file

4-26

Manipulating Files on Disks and Magnetic Tapes

$!
$!
$!
$!
$!
$!

••
•
•••
••
••
•
•
••
••
•••

FORREAD.COM

Reads Data from a Foreign Volume

This command procedure is called when data will be read. The procedure
reads data on a foreign volume. The data format is defined in
FORWRITE.COM command procedure.
seq_num = 0

! initialize the sequence number

$
OPEN/READ tape_file tape: ! open the output file
$ next_line:

$!
$!
$!

seq_num = seq_num + 1

! increment the sequence number

READ/END_OF_FILE=end_of_input tape_file in_rec
- - II II - - II II - - II II
record_num = F$EXTRACT ( 0, 4, in_rec
record_num = F$INTEGER ( record_num )
IF seq_num .NE. record_num THEN WRITE SYS$0UTPUT "Error possible data lost, record sequence broken!"

Find the size of the data and extract the data
data_size
data_size
data_rec

- - II II
F$EXTRACT ( 6, 4, in_rec
F$INTEGER ( data_size )
F$EXTRACT ( 10, data_size, in_rec

WRITE SYS$0UTPUT data_rec ! write the data output record
GOTO next_line

$ end_of_input:
$
CLOSE tape_f ile

4-27

Transferring Disk and Magnetic Tape
Information
This chapter describes the facilities that VAX/VMS provides for transferring
information contained on disk and magnetic tape media. In particular, it
describes how to use the DCL command COPY and the VAX/VMS Convert
and Exchange Utilities to transfer disk and magnetic tape information. This
chapter also contains examples of command procedures that are designed to
transfer information on disks and magnetic tapes.

5. 1

Transferring Information Within and Across Operating Systems
In many cases, you will be able to transfer information without physically
transporting media. You may, however, find it necessary to transfer files
between systems that are not connected by a communications link. In
these circumstances, you must be able to physically move your files from
one location to another. This is conveniently done by copying your files to a
portable volume, such as a magnetic tape reel or disk pack, and then carrying
that volume to the location of the other system.
The VAX/VMS operating system supports the transfer of information,
contained on disks and magnetic tapes, both within the VAX/VMS system
and across other operating systems. It provides a number of facilities to
assist you in both types of information transfer. The two most frequently
used facilities for transferring information are the DCL command COPY and
the VAX/VMS Exchange Utility (EXCHANGE).
In many cases, you will find the COPY command and the Exchange
Utility sufficient for accomplishing information transfers. You may also
find the VAX/VMS Convert and Analyze/RMSJile Utilities useful for
transferring information, especially in foreign volume or non-file-structured
environments.
Under some circumstances, you will need to use the Backup Utility
(BACKUP) to transfer files. For example, BACKUP is the only means of
transferring entire directory trees or files that are not sequentially structured
using magnetic tape.
Each of the information transfer facilities provided by the VAX/VMS system,
except BACKUP, is described in the sections that follow. This chapter also
includes examples of command procedures that contain the commands and
utilities provided by VAX/VMS for transferring information.

"-1

Transferring Disk and Magnetic Tape Information

Chapter 6 provides information on the use of BACKUP, including examples
of command procedures for performing backup tasks.

5.2

Using the COPY Command to Transfer Information
One way of transferring information on disk and/ or magnetic tape media is
to use the DCL command COPY. You can use the COPY command to copy
files from:
•

Disk to disk

•

Disk to magnetic tape

•

Magnetic tape to disk

•

Magnetic tape to magnetic tape

The sections that follow describe how the COPY command is used with both
disk and magnetic tape files.

5.2.1

Copying Files from Disk Volumes
This section describes how to use the COPY command to copy files from
disk volumes to other disk volumes and from disk volumes to magnetic tape
volumes.
The default format for files on disk is called Files-11 Structure Level 2.
You can also initialize disks in the Files-11 Structure Level 1 format.
Structure Level 1 is the format used by other DIGITAL operating systems,
including RSX-llM, RSX-llM+, RSX-llD, and IAS. The Files-11 structure
for magnetic tapes is discussed in Section 5.2.2.
In the example that follows, the COPY commands copy the highest versions
of all files in the current default directory and in the directories [PRIMER]
and [COMMANDS] to the directory [PUBS].
$DEFINE P DMA3:[PUBS]
$ COPY *· * P:
$COPY [PRIMER]*.* P:
$COPY [COMMANDS]*.* P:

If you wish to copy files from a disk directory such as your default directory
on a public disk volume to a private Files-11 disk volume, you can also use
the COPY command. Before copying these files, however, you must set up
(allocate, initialize, and mount) a disk device as described in Chapter 3.

5-2

Transferring Disk and Magnetic Tape Information

In the following example, assume that the disk device DMAS: has been
allocated to your process and that a disk volume has been initialized and
mounted on that device. Assume also that you have a directory called
PRIVATE already created on that volume. You can copy all of the files
in your default directory to the directory on that volume by entering the
following command:
$COPY*·* DMA6:[PRIVATE]

You can also use the COPY command to copy files from a disk volume to a
magnetic tape volume. The procedure for copying files from disk volumes
to magnetic tape volumes is similar to those outlined above for copying files
across disk volumes. Note that magnetic tapes are sequential-access devices
and do not have directories.
Again, you must set up a magnetic tape device (ALLOCATE, INITIALIZE,
and MOUNT) before copying disk files to the magnetic tape volume. In the
following example, assume that MTA2: has been allocated to your process
and that a magnetic tape volume has been initialized and mounted on that
device.
You can now use the COPY command to write files to the magnetic tape
volume.
$ COPY *·* MTA2:

In this case, the highest versions of all files in your default disk directory are
copied to the magnetic tape volume on MTAO:. The file names, file types,
and version numbers of the output files default to the same file names, file
types, and version numbers as the input files. Restrictions that apply to the
use of version numbers for magnetic tapes are discussed in Section 5.2.2.
If you issue the COPY command with the /LOG qualifier, the system will
send a message to the current SYS$0UTPUT device after each file has been
copied. To verify that the files were successfully copied, use the DIRECTORY
command. For example, the following command will list the file names and
file types of all files on the magnetic tape volume:
$ DIRECTORY MTA2:

5.2.2

Copying Files from Magnetic Tape Volumes
The default format for files on magnetic tapes is the ANSI-labeled volume.
The VAX/VMS system supports sequential, relative, and indexed files on
disks, but only sequential files can be copied to ANSI-labeled volumes. The
only valid record formats are variable-length (ANSI D) and fixed-length
(ANSI F).

5-3

Transferring Disk and Magnetic Tape Information

Although VAX/VMS supports stream and VFC records, it encodes these
records in a variable-length format on ANSI-labeled volumes. NonVAX/VMS systems do not distinguish stream records from VFC records;
instead, they interpret both as variable-length records. Therefore, neither
stream nor VFC records should be created on volumes that will be used for
information interchange to a non-VAX/VMS system.
When you copy files from disk to ANSI-labeled volumes, the following items
are not preserved:
•

Directory specifications

•

Individual file protection

•

User identification code (UIC)

•

Creation time (but the date is preserved)

•

Revision and backup dates and times

The full set of ASCII "a" characters are supported only for ANSI-labeled
volumes, not for disk volumes. Therefore, when you copy files with ANSI
file names from magnetic tape to disk, specify a standard VAX/VMS file
name for the output file name specification.
If you do not specify a VAX/VMS file name on output, your process receives
the following error message:
RMS-F-FNM, error in file name

This message indicates that the ANSI file name is not a valid file name
specification.
The entire set of Files-11 file names is supported for magnetic tapes. You
can copy a disk file with the following file name to a magnetic tape volume,
without having to modify the file name:
THIS-1S$A_VAXVMSLONGJILE.LONG_EXT
The following examples illustrate ways of copying files to and from magnetic
tape volumes.

5-4

Transferring Disk and Magnetic Tape Information

EXAMPLES

• COPY/LOG MTA1: Y.ll*?!SKI!

11
111111
SEASON.DAT
Y.COPY-S-COPIED, MTA1: [] 11 1.ll*?!SKI! """· ;1
copied to WRKD:[MANUAL]SEASON.DAT;1 (120 records)

Since the /LOG qualifier was specified, VAX/VMS returns a message that
confirms the file was copied as specified and informs you how many records
were copied. The ANSI file %•?!SKI!#"(# means space) is copied to the file
SEASON.DAT on the default disk and directory WRKD:[MANUAL]. The file
could not have been copied to disk unless the new file name was specified.
VAX/VMS provided defaults for segments of the file specification that were
not specified.
~

$ COPY/LOG FORTAP .DAT MTA1: "Y.ll*? !SKI! 1111 "
Y.COPY-S-COPIED, WRKD:[MANUAL]FORTAP.DAT;1
copied to MTA1: Cl"Y.ll*?!SKI! 111111 • ;O (120 records)

In this command an ANSI file name was specified as the output file
specification. Note that VAX/VMS truncates the trailing space in the file
name %&•?!SKI!##"# (where# means space).

$ COPY/LOG VAXVMS_LONG$FILE_NAME.LONG_EXT MTA1:
Y.COPY-S-COPIED, WRKD:[MANUAL]VAXVMS_LONG$FILE_NAME_EXT;1
copied to MTA1:VAXVMS_LONG$FILE_NAME.LONG_EXT;1 (80 records)

In this example, a VAX/VMS long file name with a long extension will be
copied to the volume MTA 1: with the same file name and type that had
been on the disk volume.
~

$ COPY Y.Y..JOU;* MTA1:*.*
Y.COPY-S-COPIED, WRKD:[MANUAL]C6.JOU;1 copied to MTA1:[]C6.JOU;1 (4 records)

In this example, all files with a 2-character file name and a file type of JOU
will be copied to the volume MTAl: with the same file name and type as
they had on the disk volume. Version numbers are preserved.
~

$ COPY MTAO: * . * *
Y.COPY-S-COPIED, MTAO:[]TASTETEST.DAT;1
copied to WRKD:[FOOD]TASTETEST.DAT;1 (249 records)
Y.COPY-S-COPIED, MTAO:[]CUKES.DAT;1 copied to WRKD: [FOOD]CUKES.DAT;1 (148 records)
Y.COPY-S-NEWFILES, 2 files created

In this example, neither file on the volume had an ANSI file name.
Therefore, both files were copied to the disk volume.

5-5

Transferring Disk and Magnetic Tape Information

$COPY MTA1:*.* [SOURCE]
Y.COPY-S-COPIED, MTA1: []TAPETEST.DAT;1 copied to WRKD:[SOURCE]TAPETEST.DAT;1 (101 records)
Y.COPY-E-OPENOUT, error opening WRKD: [SOURCE] 11 1..t• () ! SKI! 111111 • ; 1 as output
-RMS-F-FNM, error in file name
XCOPY-W-NOTCOPIED, MTA1:[]"%.t•0!SKI! 111111 .;1 not copied
XCOPY-E-OPENOUT, error opening WRKD:[SOURCE]"SANFRANXXY." 1111 .;1 as output
-RMS-F-FNM, error in file name
XCOPY-W-NOTCOPIED, MTA1:[] 11 SANFRANY.XX" 1111 • ;1 not copied
XCOPY-S-COPIED, MTA1:[]VAXVMS_LONG$FILE_NAME.LONG_EXT;1
copied to WRKD$: [SOURCE]VAXVMS_LONG$FILE_NAME.LONG_EXT;1 (80 records)
XCOPY-S-COPIED, MTA1: []C6.JOU;1 copied to WRKD:[SOURCE]C6.JOU;1 (4 records)
Y.COPY-S-NEWFILES. 2 files created

The COPY command string specifies that all files on the volume mounted
on drive MTAl: should be copied to the current default disk and directory
WRKD:[SOURCE]. However, files with ANSI file names are not copied;
VAX/VMS returns an error message to the process.
The following sections provide guidelines for interchanging volumes.

5.2.3

Copying Files to and from Non-File-Structured Volumes
The VAX/VMS operating system supports the transfer of files between
file-structured and non-file-structured volumes. You can use the COPY
command to transfer files in the following ways:
•

from file-structured volumes to non-file-structured volumes

•

from non-file-structured volumes to file-structured volumes

The next two sections contain examples of each type of transfer.
5.2.3.1

Copying Files to a Non-File-Structured Volume

This section contains a procedure for copying files from a file-structured
volume to a non-file-structured or foreign volume.
The procedure copies three files from an ANSI-labeled volume to a foreign
volume.

Mount the volumes involved in the copy operation.
$MOUNT MTA1: FRESKI
Y. MOUNT-I-MOUNTED, FRESKI mounted on _MTA1:
$ MOUNT/FOREIGN MTAO:
%MOUNT-I-MOUNTED, mounted on _MTAO:

5-6

Transferring Disk and Magnetic Tape Information

Specify the COPY command string, including the full device and file
name specifications in the input specification, but specify the device
name only in the output specification. File names are specified on input
because the volume from which files will be copied is ANSI-labeled and
file structured. However, only the device name is specified on output
because the volume to which the files will be copied is foreign and is not
file structured.
$COPY/LOG MTA1:PROG1.EXE, PROG2.EXE, PROG3.EXE MTAO:
Y.COPY-S-COPIED, MTA1:[]PROG1.EXE;1 copied to MTAO: (92 records)
1.COPY-S-COPIED, MTA1:[]PROG2.EXE;6 copied to MTAO: (70 records)
Y.COPY-S-COPIED, MTA1:[]PROG3.EXE;2 copied to MTAO: (77 records)
Y.COPY-S-NEWFILES, 3 files created

Because no version numbers were specified for the files copied from the
ANSI-labeled magnetic tape volume, the first version of each specified file
that the MTAACP finds on the ANSI-labeled volume will be the version of
the file that is copied to the foreign volume.
When you use the /LOG qualifier with the COPY command, the system
informs you which files are copied and tallies the number of records copied
and the number of files created.
When you copy files as shown in this example, the structure of the resulting
magnetic tape is referred to as unblocked, non-file-structured. Each file
record becomes a physical record on the magnetic tape. Each file boundary is
indicated on the magnetic tape by a single tape mark. Two consecutive tape
marks indicate end of volume. No label, file name, or attribute information
is present.
5.2.3.2

Copying Files from a Non-File-Structured Volume

This section contains a procedure for copying data segments from a non-filestructured or foreign volume to a file-structured ANSI-labeled volume.
Note that you must specify a COPY command for each segment of data that
you copy from a foreign or non-file-structured volume to a file-structured
volume.

Mount the volumes as follows:
• MOUNT/NOLABEL MTA1: II II COLD:
1.MOUNT-I-MOUNTED, mounted on _MTA1:
$ MOUNT MTAO: FEVER SEASON:
Y.MOUNT-I-MOUNTED, FEVER mounted on _MTAO:

5-7

Transferring Disk and Magnetic Tape Information

Specify a COPY command for each segment on the foreign volume that
will be copied to files on the file structured volume. Because the volume
to which data segments are copied is file structured, you must specify a
file name in the output file specification.
$ COPY/LOG COLD: SEASON:FILE1.DAT
Y.COPY-S-COPIED. MTA1: copied to SEASON:FILE1.DAT;1 (92 records)
$ COPY/LOG COLD SEASON:FILE2.DAT
Y.COPY-S-COPIED. MTA1: copied to SEASON:FILE2.DAT;1 (62 records)
$ COPY/LOG COLD: SEASON:FILE3.DAT
Y.COPY-S-COPIED. MTA1: copied to SEASON:FILE3.DAT;1 (23 records)
$ COPY/LOG COLD: SEASON:FILE4.DAT
Y.COPY-S-COPIED. MTA1: copied to SEASON:FILE4.DAT;1 (48 records)
$ COPY/LOG COLD: SEASON:FILE6.DAT
Y.COPY-S-COPIED. MTA1: copied to SEASON:FILE6.DAT;1 (37 records)
$ COPY/LOG COLD: SEASON:FILE6.DAT
Y.COPY-S-COPIED. MTA1: copied to SEASON:FILE6.DAT;1 (10 records)

Since the /LOG qualifier was used with the COPY command, VAX/VMS
informs you that the files you specified were copied to the appropriate
device, and tallies the number of records transferred.

5.3

Using the Convert Utility to Transfer Information
This section describes how to use the VAX/VMS Convert Utility (CONVERT)
to transfer information to non-file-structured or foreign volumes. It also
describes how the VAX/VMS Analyze/RMS_File Utility (ANALYZE/RMS_
FILE), which is useful in determining record size, is used in conjunction with
CONVERT.
There may be cases in which you will be unable to transfer information to
a non-file-structured or foreign volume by using the COPY command. For
example, files containing records smaller than 14 bytes cannot be copied
successfully to a foreign volume with the COPY command. However, they
can be transferred by using CONVERT.
CONVERT allows you to pad and extend the record size to make it suitable
for a foreign volume. The following procedure illustrates how to use the
Convert Utility.
Procedure

Mount both volumes. Specify the /RECORDSIZE and /BLOCKSIZE
qualifiers in addition to either the /NOLABEL or /FOREIGN qualifier
when you mount the foreign volume.
$ MOUNT/FOREIGN/RECORDSIZE=80/BLOCKSIZE=2400 MTA1:
Y.MOUNT-I-MOUNTED, mounted on _MTA1:
$ MOUNT MTAO: LATER TODAY
Y.MOUNT-I-MOUNTED, LATER mounted on _MTAO:

5-8

Transferring Disk and Magnetic Tape Information

VAX/VMS informs you that the foreign volume is mounted on drive
MTAl:, and that the target volume is mounted on MTAO:. The
/RECORDSIZE and /BLOCKSIZE specify that tape will be written
as 80-byte records that are blocked in 2400-byte blocks.

Check the size of the largest record within a file. To do so, use the
Analyze/RMSJile Utility as shown in the following example:
$ ANALYZE/RMS_FILE/STATISTICS TODAY:TICKET.DAT

RMS File Statistics
TODAY:[]TICKET.DAT;3

14-JUN-1986 21:33:20.07

FILE HEADER
File Spec: TODAY:[]TICKET.DAT;3
File ID: ( 1 , 1, 1)
Owner UIC: [012,141]
Protection: System: RWED, Owner: RWED, Group: RWED, World: RWED
Creation Date:
6-APR-1986 00:00:00.00
Revision Date:
17-NOV-1868 00:00:00.00, Number: 0
Expiration Date: none specified
Backup Date:
none posted
Contiguity Options: none
Performance Options: none
Reliability Options: none
RMS FILE ATTRIBUTES
File Organization: sequential
Record Format: variable
Record Attributes:
carriage-return
Maximum Record Size: 0
Longest Record: 77
Blocks Allocated: 0, Default Extend Size: 0
End-of-File VBN: 1, Offset: Y.X 1 0000 1
The analysis uncovered NO errors.
ANALYZE/RMS_FILE/STATISTICS TODAY:TICKET.DAT

Extend the size of records smaller than 14 bytes to that specified in
the MOUNT command and ensure the record size that you specify is
sufficient. To do so, specify the following commands:
• CONVERT/PAD/FDL=SYS.INPUT
._Input: TODAY:TICKET.DAT
._Output: MTA1 :
RECORD
SIZE 80
FORMAT FIX 15 EXIT

•Specifying the above CONVERT command string and input and output
parameters pads and extends the size of records when copying them
from the ANSI-labeled volume mounted on MTAO: to the foreign
volume mounted on MTAl :. CONVERT command and qualifiers can
pad short records to correspond to the record size specified by the

5-9

Transferring Disk and Magnetic Tape Information

MOUNT command in the first step. After you specify the command
line, CONVERT prompts you for input and output parameters. At the
$-1nput: prompt, supply the specification of the file containing the
records that were too short. At the $_Output: prompt, specify only
the physical or logical device name of the foreign volume. Specifying
CTRL/Z terminates the file description and causes CONVERT to run. To
verify that the file was copied to the foreign volume, you can rewind the
foreign volume and type the volume as shown in the steps below.

To rewind a foreign volume, specify the SET MAGTAPE/REWIND
command string shown below.
$SET MAGTAPE/REWIND MTA1:

•
5 To verify the contents of a file, specify the TYPE command as shown
below.
$TYPE MTA1:
This is a test file.
Some records contain less than 14 bytes.
This file was copied to a foreign volume with the
RMS Convert Utility.
Any record less than 80 bytes was extended and padded to
80 bytes.

The TYPE command types the first data segment on the volume. If you
copy multiple files to a foreign volume with the RMS Convert Utility,
each file is copied to the volume in a separate data segment. Therefore,
you must specify a TYPE command for each data segment copied to the
volume until you reach the segment that you want to verify.
This example produces what is referred to as a blocked non-file-structured
volume. Each record of the input file is placed into an 80-byte area of a
2400-byte tape block. Tape marks are used to delimit files, as in the previous
example.

5.4

Using the Exchange Utility to Transfer Information
The VAX/VMS system provides a utility called Exchange, which enables you
to read to or write from disk and magnetic tape media being interchanged
with DIGITAL-supported, non-VAX/VMS operating systems. With the
VAX/VMS Exchange Utility (EXCHANGE), you can manipulate mass-storage
volumes that are written in formats other than those normally recognized by
VAX/VMS. You can also use EXCHANGE to manipulate Files-11 files that
are images of foreign volumes.

5-10

Transferring Disk and Magnetic Tape Information

You can use EXCHANGE to transfer files between foreign volumes and
VAX/VMS file-structured volumes. You can also use EXCHANGE to perform
volume-specific initialization and manipulation functions on the foreign
volumes. The Exchange Utility enables you to convert the format of the
files, as appropriate, when transferring files between volumes with different
structures.
You can use the Exchange Utility to perform file transfers and format
conversions for:
•

DOS-11 magnetic tape volumes

•

Files-11 volumes

•

RT-11 block-addressable volumes

In addition to transferring files, the Exchange Utility allows you to mount
and dismount foreign volumes, initialize foreign volumes, list directories
of volumes, delete files from block-addressable volumes, and locate bad
blocks on the volume. For further information on how to use EXCHANGE to
accomplish these tasks, see the VAX/VMS Exchange Utility Reference Manual.

5.4.1

Invoking and Terminating the Exchange Utility
To invoke EXCHANGE, enter the following command in response to the
DCL prompt:
$ EXCHANGE

EXCHANGE>

When. you receive the EXCHANGE prompt (EXCHANGE> ), you are in
the Exchange Utility. Once you are in this utility, you can enter any of the
command strings supported for EXCHANGE. For example:
EXCHANGE> DIRECTORY MFAO:/VOLUME=DOS11/FULL

This command lists all the files on the DOS-11 magnetic tape mounted on
MFAO:. In this case, the magnetic tape will be rewound before the files are
listed.
The following example illustrates the use of the MOUNT command within
the EXCHANGE utility:
EXCHANGE> MOUNT DMA1:
%EXCHANGE-I-WRITELOCK, volume is write-locked
%EXCHANGE-I-MOUNTED, volume DMA1: mounted

This command mounts the foreign volume that is loaded in the RK07 device
DMAl:, making the volume available for subsequent commands. In this
case, EXCHANGE recognizes that the volume itself is write-locked, and
displays the message.

5-11

Transferring Disk and Magnetic Tape Information

For a complete list of all the commands, qualifiers, and parameters that are
supported for EXCHANGE, see the VAX/VMS Exchange Utility Reference
Manual.
To exit from EXCHANGE and return to DCL level, you can use the
EXCHANGE command EXIT or CTRL/Z.

5.4.2

Using EXCHANGE at DCL Command Level
In addition to using EXCHANGE interactively as a utility, you can use
EXCHANGE as a DCL command. To do this, you append a command string
to the DCL command EXCHANGE as follows:
$EXCHANGE DIRECTORY DMA1:/VOLUME_FORMAT=RT11

This DCL command lists the directory of the RT-11 volume mounted
(/FOREIGN) on DMAl:. At DCL level, EXCHANGE executes the single
command and returns to the DCL prompt.
At DCL level, you can process only one command at a time. Some tasks
for which EXCHANGE was designed, however, require more than one
EXCHANGE command. For example, the use of virtual devices requires
multiple EXCHANGE commands.
Tasks requiring more than one EXCHANGE command cannot be performed
at DCL level. You can, however, design a command procedure to execute
more than one EXCHANGE command for a particular task. In that case, you
could execute the command procedure without leaving the DCL command
level. For further details on how to construct command procedures using
EXCHANGE, see Section 5.5.2.

5.5

Using Command Procedures to Transfer Information
You can design command procedures to facilitate routine transferring of
information on disk and magnetic tape media.
Two examples of command procedures are included in this section. The first
example is designed to transfer information by way of the COPY facility. The
second example employs the Exchange Utility to transfer the information.

5-12

Transferring Disk and Magnetic Tape Information

5.5.1

Using a Command Procedure to Copy Files
The sample command procedure in this section can be used for a variety of
purposes. This procedure can copy from disk to similar disk, from disk to
dissimilar disk, and from magnetic tape to magnetic tape.
Note that the command procedure mounts the volume as non-file-structured.
If you are using magnetic tape media, this command procedure will not work
for multi-reel magnetic tape volume sets. Magnetic tape to magnetic tape
transfer is supported for single volumes only.

The magnetic tape to magnetic tape copy is done using the asterisk ( • )
wildcard character.
$ vol_priv = f$setprv("volpro")
$ Type sys$input
$ on control_y then goto cleanup
$ on warning then goto cleanup

•

$ get_source:
$
write sys$output "Enter drive holding the write-locked master."
$
inquire source "[CS1$DRBO:, DBxx:, DDxx:, DJxx:, DLxx:, DMxx:, DQxx:, DRxx:, DUxx:, DYxx:,
MFxx:, MTxx:, MUxx: ,] "

$
$

•

if source .eqs. "" then goto get_source
source= source-":"+":"

$ get_target:
$
inquire target "Enter drive holding the write-enabled target."
$
if target .eqs. "" then goto get_target
$
target= target -":"+":"
$
kit_type := 'f$extract(0,1,source)
$
if f$locate("CS",source) .eq. f$length(source) .and. f$locate("CS",target) .eq. f$length(target) then goto prepare

•
•
$
$

•Note• -- This section checks to see if the console is configured into the system.
If it does not exist, SYSGEN will be run to configure it in

$ connect_console:
$
! (NOTE• For 750,730 media copying CONSOLE must be configured)
$
if f$getdvi("CS:1","exists") then goto prepare
$
set noon
$
proc_priv = f$setprv("cmkrnl,cmexec")
$
run sys$system:sysgen
connect console
$
proc_priv = f$setprv(proc_priv)
$
set on

5-13

Transferring Disk and Magnetic Tape Information

•
••
••
••
•••
••
••

$ prepare:
$
allocate 'source'
$
inquire start "Ready source volume ''source' for mounting and press return"
begin:
allocate 'target'
mount/foreign 'source'
inquire start "Ready target volume ''target' for initialization and press return"
volume_lbl = f$getdvi(source,"VOLNAM")
if (volume_lbl .eqs. "") then volume_lbl := "console"
init 'target' 'volume_lbl'
If (kit_type .eqs. "M") then goto tape_copy
mount/foreign 'target'
backup/physical/verify 'source' 'target'
goto copy_done

$ tape_copy:
$
mount/over:id 'target'
$
copy 'source'*·* 'target'•/log

••
••
••
••
••
••
•••
••
••
••
•••
••

copy_done:
dismount 'target'
deallocate 'target'
write sys$output "Copy is complete"
dismount/nounload 'source'
inquire answer "Do you want to make another copy of the Source volume?"
if .not. answer then goto new_source
write sys$output "Please place volume in the target device ''target'." n
goto begin

new_source:
deallocate 'source'
inquire answer "Do you want to make a copy using a new Source device?
if answer then goto get_source
goto finish
cleanup:
if f$getdvi(target,"mnt") then dismount 'target'
if f$getdvi(source,"mnt") then dismount 'source'

finish:
vol_priv = f$setprv(vol_priv)
if f$getdvi(target,"all") then deallocate 'target'
if f$getdvi(source,"all") then deallocate 'source'
exit

5-14

Transferring Disk and Magnetic Tape Information

5.5.2

Using a Command Procedure to Exchange Information
This command procedure is designed to exchange files between the console
device and the current directory on disk.
The files that are to be copied are assumed to be in standard format as
determined by file type.
$ WRITE SYS$0UTPUT " Command file to copy files to/from the system"
$WRITE SYS$0UTPUT" console storage medium and the current directory."
• WRITE SYS$0UTPUT II II
$ INQUIRE MOUNT "Is system console storage medium mounted (Y/N)?"
$ IF MOUNT THEN GOTO MOUNTED
$ WRITE SYS$0UTPUT "Please place the system console medium in the console drive"
$ INQUIRE MOUNT "and type <RET> when ready"
$ RUN SYS$SYSTEM:SYSGEN
CONNECT CONSOLE
$ MOUNT/SYSTEM/FOREIGN CSA1: "VAX console"

•

$ MOUNTED:
$ INQUIRE DIR "Copy from console medium (Y/N)?"
$ IF DIR THEN GOTO FROMCON
$ INQUIRE SOURCE "Enter file name(s)"
$ IF SOURCE .EQS. "" THEN GOTO EXIT
$ EXCHANGE COPY /LOG 'SOURCE' CSA1:
$ GOTO EXIT

•

$ FROMCON:
$ INQUIRE SOURCE "Enter console file name"
$ IF SOURCE .EQS. "" THEN GOTO EXIT
$ EXCHANGE COPY /LOG CSA1: 'SOURCE' *
$ EXIT:
$ DISMOUNT CSA1:
$ MOUNT/SYSTEM/FOREIGN/NOWRITE CSA1: "VAX console"

Maintaining Data Integrity on Disk and
Magnetic Tape Volumes
This chapter discusses methods of maintaining data integrity on disk
and magnetic tape media. In particular, it focuses on how to use the
VAX/VMS Backup Utility (BACKUP) to perform routine types of data
integrity operations.
The term integrijy, as it applies to disk and magnetic tape media, means
unimpaired condition of the data on the volumes. Maintaining that integrity
means ensuring that the data contained in those volumes is protected against
both accidental and deliberate corruption.
You will find that it is good practice to employ a number of methods to
ensure the safety of your files and volumes. For example, you can set the
type of protection you need on individual files and volumes, and you can
establish user identification codes (UICs). By setting protection or employing
UICs, you control the extent of privileges given to others who use your files
or volumes. Protection codes and security-related topics are discussed in the
Guide to VAX/VMS System Security as well as in Chapter 2 of this guide.
One of the most effective ways you can prevent loss is by creating
functionally equivalent copies of the originals - that is, by "backing up"
your files and volumes. You can do this by using the VAX/VMS Backup
Utility. If you use BACKUP on a regular basis, you reduce the chances of
losing data that might otherwise be destroyed by volume or file corruption.
You should store the backup copies in a secure place so that if all else fails,
you still have an uncorrupted version of the original.
Protection is not the only reason for backing up files, however. If you have
limited disk space, it is often practical to store seldom used disk files on
magnetic tape until you need to retrieve them.
The following section provides an introduction to the VAX/VMS Backup
Utility and the various types of backup media. Subsequent sections
describe how to perform backup tasks that are frequently used. For detailed
information on BACKUP, including descriptions of command qualifiers,
parameters, and restrictions, refer to the VAX/VMS Backup Utility Reference

Manual.
This chapter does not include standalone BACKUP, which is used primarily
as a system management tool. For information on using standalone
BACKUP, refer to the VAX/VMS System Manager's Reference Manual.

6-1

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.1

Using BACKUP to Maintain Data Integrity
In order to keep your backup copies up to date, you should perform backups
on a regular basis. The VAX/VMS Backup Utility is designed to help you
with the process of creating and retrieving backup copies. Depending on
both the nature of the data on your volumes and the frequency of change to
the data, you can choose to back up your files as frequently or infrequently
as you like. You can accomplish this through the use of various BACKUP
command qualifiers.
The operation you choose depends on the nature of your work or the
sensitivity of the data in your files. You also have the option of performing
selective backup operations through the use of a single DCL command. With
selective backup operations, you tell BACKUP to select only the files that
meet specific criteria, such as version number, file type, VIC, date and time
of creation, expiration date, or modification date. You can save a great deal
of time and storage space by performing selective backups on a regular basis,
rather than backing up entire volumes on which only a small percentage of
files have been modified.
Backup operations that select only those files that have been modified since
the last backup operation are called incremental backups. In a typical
operating environment, a system manager or operator might perform
incremental backups either daily or two or three times a week, then perform
full backups (the entire volume) at the end of each week. For detailed
information on performing incremental backups, see the VAX/VMS System
Manager's Reference Manual.
You can use BACKUP to perform five basic types of operations: COPY,
SAVE, RESTORE, COMPARE, and LIST. You will find it helpful to gain an
understanding of how these operations differ from each other in order to
determine your particular backup needs (Section 6.2.2 provides a description
of each). You have the option of using some of these operations together
in one command line. For example, you can use the list operation in
conjunction with the copy operation to provide a list of the files as they
are being copied.
You will also find it helpful to understand the use of BACKUP media (Section
6.3 provides a description of BACKUP media and save sets). For example,
you can choose to back up your data as a functionally equivalent copy on
either a Files-11 structured disk in standard format; or as a save set on
magnetic tape, a standard Files-11 structured disk, or a sequential disk. It
is especially important to recognize the difference between a functionally
equivalent copy and a backup save set.

6-2

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

The remainder of this chapter describes the kinds of media that you can use
with BACKUP, the various types of backup operations that are frequently
used in a VAX/VMS environment, and the steps you need to take to perform
these operations.

6.2

Choosing Backup Operations
When you perform backups, you have two basic decisions to make regarding
the operation you wish to perform:
1

What you want to back up

How you want BACKUP to perform the operation

The following sections discuss the choices.

6.2.1

Deciding What to Back Up
You have the option of performing backups in the following modes of
operation:
•

File by file
You can back up individual files or directories.

•

Image
An image operation allows you to create a functionally equivalent copy
of the entire volume or volume set.
The image backup requires more time to perform than a physical backup
(see the description of physical backups below), but an image backup
offers two significant features that are not available with a physical
backup:

•

When an image copy operation is performed (or an image save set is
restored), the files and free space are reorganized and compacted.

You can selectively restore individual files.

Physical
Like the image operation, the physical backup operation copies, saves,
restores, or compares the entire volume. However, instead of creating a
functionally equivalent duplicate, it creates an exact duplicate by ignoring
the file structure on the disk and copying logical blocks.
A physical backup is considerably faster than an image backup in most
cases, but an image backup offers significant features that are unavailable
with a physical backup (see the description of image operations above).

6-3

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

•

Selective
BACKUP can process files or volumes selectively, according to criteria
such as version number, file type, UIC, date and time of creation,
expiration date, or modification date.

•

Incremental
The incremental backup saves only those files that were created or
modified since the last backup. Incremental backups are typically
performed by system managers or operators on a regular basis. For
detailed information on performing incremental backups, see the

VAX/VMS System Manager's Reference Manual.
6.2.2

Deciding How to Back Up Files or Volumes
Once you know what you want to back up, you need to determine how you
want BACKUP to operate - that is, what type of BACKUP operation is best
suited to your needs. The five choices of operation are as follows:
•

Copy

•

Save

•

Restore

•

List

•

Compare

You define the type of operation you want to perform when you enter the
DCL command string. The input and output specifiers and the qualifiers you
use indicate to BACKUP what type of operation to perform.
The remainder of this section describes the various operations performed by
the Backup Utility.
6.2.2.1

Copying Files

The copy operation allows you to create an equivalent copy of files,
directories, directory structures, and disks.
You should be aware that the BACKUP copy operation produces results that
are different from those of the DCL command COPY. The DCL command
COPY makes new copies of files, updating the revision dates and assigning
protection from the applicable defaults. The backup copy is, however,
identical in all respects to the original, including date and protection.

6-4

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.2.2.2

Saving Files

A BACKUP save operation places a selected disk file or directory into a save
set on disk or magnetic tape. A save set is a file created by the VAX/VMS
Backup Utility and written in a format that only BACKUP can interpret.
You will find more information on save sets in Section 6.3, which discusses
backup media.
6.2.2.3

Restoring Files

The BACKUP restore operation enables you to recover the data that resides
in a BACKUP save set. The restore operation converts the data back to its
original format and sends the file to the output devi'ce that you specify.
6.2.2.4

Comparing Files

After you have performed a BACKUP copy, save, or restore operation, you
may want to check the integrity of the file or volume you have processed.
One way to do this is by using the BACKUP compare operation, which can
compare a save set with files on disk, or files on disk with other files on disk.
For example, after a save operation you can compare the save set you have
created against the original files.
You should be aware that the compare operation is intended for use only
with files or volumes that were copied using BACKUP. Comparing sets of
files that were not produced by BACKUP can cause errors, even though the
files may otherwise appear to be identical.
6.2.2.5

Listing Files
If you need information concerning the contents of a save set, you can use
the BACKUP list operation. Because save sets are written in a format that
can be interpreted only by BACKUP, the list operation is the only way you
can determine the contents of a save set without actually restoring it first.
The information, which can be sent to either your terminal or a specified
output file, includes the date and time the save set was created, the name of
the person who created it, and the names of the files it contains.

In addition, you can perform the list operation in conjunction with any other
BACKUP operation.

6-5

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.2.3

Invoking the VAX/VMS Backup Utility
All of the BACKUP commands are issued at the DCL command level (except
for standalone BACKUP). For most operations, the DCL command BACKUP
requires an input specifier and an output specifier.
Generally, BACKUP assumes that an input or output specifier that refers to
a Files-11 disk is a standard VAX/VMS file specification; the /SAVE_SET
qualifier is used to specify a save set on a Files-11 volume. An input or
output specifier that refers to magnetic tape is always a save set. You cannot
use save-set specifiers for both the input specifier and output specifier.
Save-set specifiers can include node names; file specifications cannot.
The input and output specifiers given in the command line indicate the type
of backup operation to be performed. In addition, various qualifiers are
available: BACKUP command qualifiers, input specifier qualifiers, and output
specifier qualifiers (see the VAX/VMS Backup Utility Reference Manual).

6.3

Using BACKUP Media
The number of parameters you include with the BACKUP command depends
on the type of operation you are performing. For a copy, save, restore, or
compare operation, you need an input specifier and an output specifier; a list
operation requires only an input specifier. These specifiers refer to the media
(disk or magnetic tape) on which you are performing the backup operation.
If your input or output specifier refers to a disk, the data may be in either
standard Files-11 disk structure format or in the format of a backup save set;
if the specifier refers to a magnetic tape or a sequential disk, the data must
be in the format of a save set.
A save set specifier is a file specification that identifies a file containing data
in BACKUP format; there is no default file type for save-set specifiers.
You can write save sets to the following types of media:

•

Magnetic tape

•
•
•

Files-11 disk
Sequential disk
Remote Files-11 disk

The following sections discuss how you can use BACKUP with magnetic
tape, Files-11 disks, and sequential disks.

6-6

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.3.1

Using BACKUP with Magnetic Tape
Magnetic tape is the most commonly used medium for storing backup data.
It is less expensive than disk media, and its compact size makes it practical
for storage purposes.
You can use more than one tape device at a time to save or restore data; this
allows processing to continue on another tape while the one most recently
used is rewinding. If no save-set name is given for an input magnetic tape,
the first save set encountered on the tape will be read.
Before you write save sets on magnetic tape, you must remember to mount
the magnetic tape volume as a foreign device. You do this by using the
DCL command MOUNT /FOREIGN (more information on the VAX/VMS
Mount Utility is available in the VAX/VMS Mount Utility Reference Manual).
Magnetic tape volumes generally do not need to be initialized; however,
if you plan to use BACKUP with a fresh magnetic tape, you will need to
first initialize the magnetic tape by including the /REWIND qualifier with
the BACKUP command. As an alternative, you can use the DCL command
INITIALIZE before mounting the magnetic tape. For more information
concerning magnetic tape volumes, see Section 6.4.2.
Save-set names on magnetic tape are limited to 17 characters, including the
delimiter (.)and file type. For example:
27SEP1985SAV.WORK
The save-set file name consists of 12 characters; therefore, the file type is
limited to 4 characters.

6.3.2

Using BACKUP with Files-11 Disk Volumes
You can write save sets on a Files-11 disk, using standard Files-11 format. If
you are writing to a disk volume set, all volumes in the set must be mounted,
as described in Chapter 3.
You indicate to BACKUP that you want to create a save set by using a
qualifier, /SAVE-5ET, in the DCL command string. If you do not use the
/SAVE_SET qualifier, BACKUP assumes that you want to create a copy on
the output volume, rather than a save set of the selected files.

6-7

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.3.3

Using BACKUP with Sequential Disk Volumes
Sequential disk save sets allow you to treat a Files-11 disk volume as you
would treat a magnetic tape save set. The primary advantage of using
sequential disk save sets is that you can mou~t multivolume save sets one
volume at a time; this is particularly useful on systems without tape that have
a large fixed-media disk and a small removable disk. When one sequential
disk is full, BACKUP prompts you for another disk, as it would for save sets
on magnetic tape.
To write sequential disk save sets, you must mount the output disk using the
DCL command MOUNT /FOREIGN. Although the disk is mounted with the
/FOREIGN qualifier, BACKUP manages the disk using Files-11 structure.
When you perform a save operation to a disk, you must use the /SAVE_SET
output qualifier. You must not specify a directory name for the save set; save
sets are entered in the master file directory, (MFD) on the disk. You need
the user privilege LOG-10 to read or write a multivolume sequential disk
save set. You can use more than one disk device at a time to save or restore
data; this allows processing to continue on another disk while the one most
recently used is spinning down.
BACKUP does not initialize the first sequential disk volume, since the default
is /NOINITIALIZE; however; continuation volumes are always initialized.
Unless you use the /INITIALIZE qualifier, the following restrictions apply to
the output volume:
•

The disk must be Files-11 Structure Level 2.

•

The disk must not be part of a normal Files-11 volume set.

•

The cluster factor of the disk must be 1.

•

The free space on the disk cannot be fragmented into more than 100
contiguous extents.

•

The index file cannot be extended.

•

The master file directory (MFD) cannot be extended.

Volumes that are to be used for sequential disk save sets should be either
freshly initialized or should contain only save sets. Volumes that have been
used for general file processing are usually unsuitable for use with sequential
disks. Sequential disk format is designed for handling relatively large save
sets on relatively small disks. In a situation in which a large number of small
save sets are to be placed on a disk, you should use Files-11 disk save sets
(see Section 6.4.3.1).
You can read a sequential disk save set in either of two ways: as a sequential
disk save set (mounted with the /FOREIGN qualifier) or as a normal Files-11
save set.

6-8

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

If a save set is read as a sequential disk save set, one volume can be mounted

at a time (as in creating a sequential disk save set). The default directory for
the save-set file specification is the directory [000000] (the MFD on the disk).
If a save set is read as a normal Files-11 save set, all volumes of the save

set must be mounted (as is true for any Files-11 volume set). The default
directory is your process default directory, so to read the save set you must
specify the directory [000000].
Save-set files that used the file system for write operations to a disk, can
also be read in sequential mode. You must specify the directory from which
the save set is to be read. This mode of operation is useful when you are
using standalone BACKUP. If the save set was written to a volume set using
Files-11 disk structure, you must observe the following rules:

6.3.4

•

All volumes of the volume set must be mounted. You must mount the
volumes with the /FOREIGN qualifier. (If you are using standalone
BACKUP, the volumes are implicitly mounted.)

•

When you specify the volumes in the input specifier, you must specify
the names of the devices in the same order as the relative volume
number of the volumes mounted on those devices. For example, the
volumes named USEROl and USER02 in a volume set are mounted on
two drives, DRA3 and DRAS. The save-set specifier for the volume set
must be DRA3:[directory]save-set-name.ext;v, DRAS:.

Remote Files-11 Save Sets
You can create or access a save set on a remote node by specifying the
node name in the save-set specifier. The save set must be located on a
publicly accessible disk on the remote node. Depending on the volume
and file protection at the remote node, you may need to specify an access
control string, which includes the login information of USERNAME and
PASSWORD (for more information on access control strings, see the
VAX/VMS DCL Concepts Manual).

6.3.5

Rotating Backup Sets
If you use disks for backups, you can make use of a rotating backup set," in
0

which several disks or sets of disks are used in rotation on the system. At
the end of each period of use (for example, once a month), the volume or
volume set currently in use is copied to the oldest set of disks, the current
volume is retired, and the new copy is put on line for use during the next
period.
You will find that there are advantages and disadvantages to rotating backup
sets.

6-9

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

A rotating backup set offers two major advantages:

Your backup copy (the volume or volume set just retired) is known to
be good, since it has been in use. The integrity of the new copy will be
confirmed by its subsequent use; any defects discovered can be repaired
using the backup copy.

The free space on the new volume is compressed, and all the files on it
are made contiguous or almost contiguous, resulting in better file system
performance.

There are four disadvantages to a rotating backup set:

6.4

Rotating backup sets are more vulnerable to disk errors than sets created
by retiring the copy and continuing to use the original. A disk error
during the copy operation results in corrupted data on your new volume;
disk errors in directories or file headers will result in the loss of one or
more files. Thus, you must monitor the copy operation very carefully for
errors and manually repair any problems that arise.

You cannot perform the copy operation while users are updating files.
The volume or volume set must be write-locked so that the copy will
be consistent. This restriction only applies to rotating backup sets; it
does not apply when you make a backup copy that will be retired for
backup use. (Even though individual files may be incomplete, they will
be covered by the next incremental backup.) For examples of how to
perform and restore from incremental backups, refer to the VAX/VMS
System Manager's Reference Manual.

Files created with explicit placement lose their placement when the
volume is copied. This means you should not use a rotating backup set
if the volume's primary contents are a set of database files that were
carefully placed for optimized performance.

Rotating backup sets are expensive to apply to fixed-media disks (as
opposed to removable media).

Performing BACKUP Tasks
This section describes how to perform the various backup tasks that are
commonly used in daily system operations: copying, saving, restoring,
listing, and comparing files or volumes. Examples are included for each kind
of task. For an overview of these types of operations, see Section 6.2.2.

6-10

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.4.1

Copying Disk Files, Directories, and Volumes
When you use BACKUP to copy disk files, directories, or volumes, BACKUP
creates a functional equivalent of the original. The backup copies are
identical to the originals, including revision dates and protection.
Note that the BACKUP copy is not supported for DECnet operations.

6.4.1.1

Copying Single Files with BACKUP

You can create a backup copy of a single file by entering a command in the
format:
BACKUP filespec filespec
For example, to make a backup copy of your EDTINl.EDT file and place it in
a directory named [HARRIS.MISC], you would enter the following command:
$BACKUP EDTINI.EDT [HARRIS.MISC]

This command places a duplicate of EDTINI.EDT in the directory
[HARRIS.MISC]. When you specify only the directory name, BACKUP
assumes a wildcard value for the file name and retains the original.
You can rename the file during the copy by specifying the new file name as
you would with the DCL command COPY. For example:
$BACKUP/LOG EDTINI.EDT [HARRIS.MISC]OLDEDTINI.EDT
XBACKUP-S-CREATED, created DISK$DEFAULT:[HARRIS.MISC]OLDEDTINI.EDT;4

This command effectively renames EDTINI.EDT by copying it to a file named
OLDEDTINI.EDT in the directory [HARRIS.MISC]. The /LOG qualifier
directs BACKUP to display information about the processed file. Note that
the copied file retains the version number of the original, even though it is
the only file processed. If you do not include a version number with the
input file, BACKUP processes all existing versions of the file and applies
their version numbers to the respective output files. In this case, only one
EDTINl.EDT file exists, with a version number of 4.
6.4.1.2

Copying Multiple Files with BACKUP

You can make backup copies of multiple files in a single command line. The
output specification must be a directory or wildcard character; it cannot be a
list or a single file name. For example:
$BACKUP/LOG ELEMENT.DAT,MATERIAL.DAT,SUBSTANCE.DAT [.STUFF]
XBACKUP-S-CREATED, created DISK$DEFAULT:[HARRIS.STUFF]ELEMENT.DAT;1
YJ3ACKUP-S-CREATED, created DISKS$DEFAULT:[HARRIS.STUFF]MATERIAL.DAT;1
XBACKUP-S-CREATED, created DISK$DEFAULT: [HARRIS.STUFF]SUBSTANCE.DAT;l
R-11

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

All files in the input specifier are copied to the named output directory. If
the output specification had attempted to rename the files by giving three
new file names, the operation would have failed and BACKUP would have
issued an error message. The operation would also have failed if the output
specifier had attempted to concatenate the input list into one file.
6.4.1.3

Copying an Entire Directory Tree with BACKUP

You can copy an entire directory tree by using the following format:
BACKUP [directory ... ] [directory ... ]
If the specified output directory does not exist, BACKUP creates it. All files
and subdirectories represented by the ellipses ( ... ) are copied from the input
directory specification to the output directory specification. For example:
$BACKUP/LOG [HOT.STUFF ... ] [OLD.STUFF ... ]
lSACKUP-S-CREDIR, created directory DISK$DEFAULT:[OLD.STUFF]
lSACKUP-S-CREATED, created DISK$DEFAULT:[OLD.STUFF]ELEMENT.LIS;1
Y.BACKUP-S-CREATED, created DISK$DEFAULT:[OLD.STUFF]ESSENCE.LIS;1
lSACKUP-S-CREATED, created DISK$DEFAULT:[OLD.STUFF]MATERIAL.LIS;1
lSACKUP-S-CREDIR, created directory DISK$DEFAULT:[OLD.STUFF.MORESTUFF]
lSACKUP-S-CREATED, created DISK$DEFAULT:[OLD.STUFF.MORESTUFF]MATTER.DAT;1
Y.BACKUP-S-CREATED, created DISK$DEFAULT:[OLD.STUFF.MORESTUFF]NOMATTER.DAT;1
Y.BACKUP-S-CREDIR, created directory DISK$DEFAULT:[OLD.STUFF.MORESTUFF.WHAT]
lSACKUP-S-CREATED, created DISK$DEFAULT:[OLD.STUFF.MORESTUFF.WHAT]GOO.YUK;2
Y.BACKUP-S-CREDIR, created directory DISK$DEFAULT:[OLD.STUFF.NOMORESTUFF]
Y.BACKUP-S-CREATED, created DISK$DEFAULT:[OLD.STUFF.NOMORESTUFF]NUTHIN.LIS;1
Y.BACKUP-S-CREATED, created DISK$DEFAULT:[OLD.STUFF.NOMORESTUFF]ZILCH.DAT;1
Y.BACKUP-S-CREDIR, created directory DISK$DEFAULT:[OLD.STUFF.NOMORESTUFF.REALLY]
lSACKUP-S-CREATED, created DISK$DEFAULT:[OLD.STUFF.NOMORESTUFF.REALLY]ZIP.ZAP;1
Y.BACKUP-S-CREATED, created DISK$DEFAULT:[OLD.STUFF]SUBSTANCE.LIS;1

BACKUP creates the directory [OLD.STUFF] and copies all files and
subdirectories in [HOT.STUFF] to the new directory. It also creates the
subdirectories and copies the corresponding files into them.
6.4.1 .4

Copying a Disk Volume to a Disk with BACKUP
If you want to copy an entire disk volume to another disk volume, you
should use the /IMAGE qualifier and specify only device names, as follows:
$ MOUNT/FOREIGN DBA2:
$ BACKUP/IMAGE DBA1: DBA2:

The /FOREIGN qualifier is necessary when you mount the output volume
for an image copy operation; BACKUP initializes the volume using the
initialization data from the input volume. All the files on DBAl: are copied
to DBA2:, creating a functionally equivalent copy of the entire volume.

6-12

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

To use the /IMAGE qualifier, you need write access to both the volume index
file (INDEXF.SYS) and the bit map file (BITMAP.SYS); as an alternative, the
input medium may be write-locked.
6.4.1 .5

Copying a Disk Volume Set to a Disk with BACKUP

To copy a disk volume set, you use the name of the volume set as the
input specifier. The output specifier must include a device specification for
each volume in the set. The following example creates an image copy of a
two-disk volume set:
$MOUNT/FOREIGN DBA1:,DBA2:
$BACKUP/IMAGE WORK$: DBA1:,DBA2:

6.4.2

Saving Disk Files, Directories, and Volumes to Magnetic Tape
You must mount magnetic tapes with the /FOREIGN qualifier in order to
use them in any BACKUP operation. (For detailed information, see the
VAX/VMS Mount Utility Reference Manual.) You do not need to initialize
magnetic tape volumes; note, however, that if you plan to use BACKUP
with a fresh magnetic tape, you will need to initialize the magnetic tape first
by including the /REWIND qualifier with the BACKUP command. As an
alternative, you can use the DCL command INITIALIZE before mounting the
magnetic tape.
If you have more than one magnetic tape drive available, you can use
multiple magnetic tape volumes to save or restore data. If you have a large
number of disk volumes to process, you may find that the multivolume
magnetic tape feature is very useful for minimizing the time it takes to
perform a save or restore operation. Once a magnetic tape volume is full,
BACKUP rewinds it while writing to the continuation volume on the second
drive. You can then mount a fresh magnetic tape on the first drive; when the
second volume is full, BACKUP immediately resumes processing on the first
drive.
If you want to mount multiple tape volumes, you can accomplish the task
with a single command by separating the device names with a comma. For
example:
$MOUNT/FOREIGN MTAO:,MTA1:,MTA2:

6-13

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.4.2.1

Saving Disk Files to Magnetic Tape

You can create a save set on magnetic tape of a single disk file by entering a
command in the following format at the DCL prompt:
$ BACKUP filename save-set-specifier

The save-set specifier can include any file type that you like; typically, the
BCK extension is used to identify the file as a save set. Note, however, that
save-set names on magnetic tape are limited to 17 characters (see Section
6.3.1). For example, you might save the disk file CONTRACTS.DAT as
follows:
$BACKUP CONTRACTS.DAT MTAO:CONTRACTS.BCK

To save a list of files, separate the file names with commas as in the
following example:
$BACKUP PAPERFILE,DBAO: [METALFILE]NAILFILE.DAT MTA1:MYFILES.BCK

Note that by default BACKUP saves all versions of each file. If you want to
save only the most recent versions of files in a directory, use the following
format:
BACKUP [directory]*.*; save-set specifier
For example:
$BACKUP [AUDIOFILE ... ]*.*; MTAO:MYPHILE.BCK

BACKUP saves the most recent version of each file in the directory
[AUDIOFILE], as well as the most recent version of each file in its
subdirectories.
6.4.2.2

Saving Directories to Magnetic Tape

You can create a save set of the current default directory and all its contents
as follows:
$ BACKUP *

MTAO:OCT12SAVE.BCK

All the files in the current default directory will be saved in a save set named
OCT12SAVE.BCK (a reminder that the save operation was done on October
12). This example assumes that your target tape is mounted on device
MTAO:.

6-14

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.4.2.3

Saving a Directory Tree to Magnetic Tape

To create a save set that contains all files and subdirectories of a directory
named (ACCOUNTS], enter the following:
$BACKUP [ACCOUNTS ... ]

MTAO:OCT12ACC.BCK

All files in the directory [ACCOUNTS], all subdirectories of [ACCOUNTS],
and all the files in those subdirectories will be included in the save set
OCT12ACC.BCK. For more information on the use of BACKUP wildcard
characters, see the VAX/VMS Backup Utility Reference Manual.
6.4.2.4

Saving Disk Volumes to Magnetic Tape
If you wish to save an entire disk volume, you should use the /IMAGE
qualifier in the following format:

BACKUP /IMAGE ddcu: save-set-specifier
The image save operation saves all files on the input volume; therefore, the
/IMAGE qualifier is incompatible with other file selection qualifiers. Note
that if a file is entered in more than one directory on the input volume, the
file is saved only once.
You can use the /IMAGE qualifier to save a disk volume to a multivolume
save set on more than one tape drive. For example:
$BACKUP/IMAGE DBAO: MTA1:20JUL.BCK,MTA2:/REWIND

You specify the save-set name only in the first element of the output-specifier
list. Assuming that you have mounted the two magnetic tape volumes (as
discussed in Section 6.4.2), BACKUP automatically continues the save
operation on MTA2: after MTAl: is full.
6.4.2.5

Saving Unstructured Disk Volumes to Magnetic Tape
If the disk volume you want to save is unstructured, use the /PHYSICAL
qualifier.
$BACKUP/PHYSICAL DMAO: MTA2:PHYSBACK.BCK

The input volume DMAO: is saved in terms of logical blocks. Note that
the resulting save set PHYSBACK.BCK can only be restored with a physical
restore operation (using the /PHYSICAL qualifier).

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.4.3

Saving Disk Files, Directories, and Volumes to Disks
You can write save sets to a disk in either of two modes: standard Files-11
disk structure, or sequential. In either case, you must use the output save-set
qualifier /SAVE_SET. The /SAVE_SET qualifier indicates to BACKUP that
you want the output disk to contain a save set rather than a copy of the
selected files.
The format for saving a disk file to a disk is as follows:
$BACKUP filespec ddcu:save-set-name/SAVE_SET

However, the procedure that is appropriate for mounting the output disk
depends upon whether the save set is to be written in standard Files-11
format (file structured) or sequential format.

6.4.3.1

Writing Save Sets on File-Structured Disk Volumes

To write save sets on a file-structured disk, mount the disk as follows:
$ MOUNT ddcu volume-label

For more information on the VAX/VMS Mount Utility, refer see VAX/VMS
Mount Utility Reference Manual.
You can use the following commands to mount a standard Files-11 disk
on drive DBA2: and save the file CONTRACTS.DAT to a save set named
CONTRACTS.BCK in the directory [SAVE]:
$ MOUNT DBA2 volume-label
$BACKUP CONTRACTS.DAT DBA2: [SAVE]CONTRACTS.BCK/SAVE_SET

The qualifier /SAVE_SET is necessary for writing the output file in BACKUP
format. Without the /SAVE_SET qualifier, the output file would be a copy
of the original.

6.4.3.2

Writing Save Sets on Sequential Disk Volumes

As an alternative to standard Files-11 structure, you can write save sets to a
disk sequentially, as they would be written on magnetic tape. The primary
advantage in using sequential disk save sets is that you can treat the disk
volume as you would a magnetic tape save set; this flexibility allows you to
mount multivolume save sets one volume at a time. See Section 6.4.3.3 for
more information on multivolume save sets.
To save data to a sequential disk save set, make certain that the output
specifier includes a device name for a disk device, a save-set name, and the
qualifier /SAVE_SET; do not include a directory name.

6-16

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

To write sequential disk save sets, you must mount the output disk with the
/FOREIGN qualifier. Although the volume is mounted foreign, BACKUP
manages the disk using Files-11 structure.
Volumes that are to be used for sequential disk save sets should be either
freshly initialized or should contain only save sets. Volumes that have been
used for general file processing are usually unsuitable for sequential disk use.
You can initialize the volume by using the BACKUP qualifier /INITIALIZE.
For example, you can use the following commands to mount and initialize
a sequential disk on drive DMAO: and save the file CONTRACTS.DAT to a
save set named CONTRACTS.BCK:
$ MOUNT/FOREIGN DMAO:
$ BACKUP/LOG CONTRACTS.DAT DMAO:CONTRACTS.BCK/SAVE_SET/INITIALIZE_$ /LABEL=SAVEWORK
XBACKUP-S-COPIED, copied DBA2:[USER]CONTRACTS.DAT;1

The MOUNT/FOREIGN command tells BACKUP to write to the output
volume sequentially. The /SAVE_SET qualifier on the BACKUP command
output specifier is necessary for writing the output file in BACKUP format.
The /INITIALIZE qualifier destroys any previous structure information on
the disk, enables the volume to be overwritten, and assigns the volume label
SAVEWORK.
When you initialize the volume, the volume label you specify is permanent;
that is, the label remains in effect until either of the following takes place:
•

You change it with the DCL command SET VOLUME/LABEL.

•

The volume is reinitialized.

See the VAX/VMS Backup Utility Reference Manual for more information
on BACKUP /INITIALIZE. See the VAX/VMS DCL Dictionary for more
information on SET VOLUME.
6.4.3.3

Writing Multivolume Sequential Disk Save Sets

You may find the multivolume option particularly useful if your system has
no tape drive but does have a large fixed-media disk and a small removable
disk. When one sequential disk is full, BACKUP prompts you for another
disk, as it would for save sets on magnetic tape. You can use more than
one disk device at a time to save or restore data; this allows processing
to continue on another disk while the one most recently used is spinning
down. Note that you need the user privilege LOG-10 to read or write a
multivolume sequential disk save set.

6-17

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

BACKUP normally does not initialize the first sequential disk volume, as
the default is /NOINITIALIZE; however, continuation volumes are always
initialized. You can initialize the first volume of a sequential disk save set by
specifying the /INITIALIZE qualifier.

6.4.4

Backing Up Full Volumes and Volume Sets
If you wish to back up an entire disk volume or volume set, you should use
the /IMAGE qualifier. You can perform an image backup in a copy operation
(disk to disk, as described in Section 6.4.1) or in a save operation. When you
use the /IMAGE qualifier in a save operation, BACKUP creates a save set
that contains data necessary for reinitializing the disk volume. (The attribute
record that contains this information is called the save-volume summary
record.)

When you use the /IMAGE qualifier in a copy or restore operation, the
output volume is reinitialized and the restored volume is a functionally
equivalent copy of the original volume. If the output volume has already
been initialized as a Files-11 volume, you can use the /NOINITIALIZE
qualifier to reinitialize the volume using the volume initialization parameters
found on the volume.
You cannot use other file selection qualifiers with the /IMAGE command
qualifier. All files on the disk are saved; this includes reserved files and lost
files (files that have no directory entry).
The following example shows a save operation from a Files-11 disk to
magnetic tape:
$ BACKUP /IMAGE DRU :

MTAO: 1JUN. BCK

If you use magnetic tape as the backup medium, you may need to mount
additional magnetic tapes. The number of magnetic tapes depends on the
size of the disk being saved and the amount of space in use on the disk.
If you use disk as the backup medium, you can use BACKUP to either copy
files to the new disk or to create a save set on the new disk. If you create a
save set on the new disk, you must create a directory to which the save set
will be written and you must use the /SAVE_SET output save-set qualifier.
The directory must be included in the save-set name or it must be your
default directory.

For example:
$ SHOW DEFAULT
DMA1 : [SYSTEM]
$ BACKUP/IMAGE DMA1: DB4: [BACKUPS]21JANDMA1.BCK/SAVE_SET

6-18

Maintaining Data Integrity on Disk and M_a_gnetic Tape Volumes

You should specify the /RECORD command qualifier if you are performing
the full volume backup in conjunction with incremental backups that use the
/RECORD qualifier. (For more information on incremental backups, refer to
the VAX/VMS System Manager's Reference Manual.)
You can back up an entire volume set by following the same procedures
outlined for backing up a disk volume. Simply name the device on which
the root volume (volume number 1) is mounted.
6.4.4.1

Backing Up a Disk Volume Set When Drives are Limited

When you use BACKUP with a volume set, you must mount all volumes
of the set. Therefore, it may not be possible to copy a large volume set
directly to a disk if you have a limited number of disk drives. The following
example shows how you can copy the volume set one volume at a time with
the BACKUP /IMAGE/VOLUME command, using one more drive than the
number of volumes in the volume set. You must write-lock the volume set
during the entire procedure to ensure consistency.
(suitable warning broadcasts)

$ DISMOUNT/NOUNLOAD DRAO:
$ MOUNT/SYSTEM/NOWRITE DRAO:,DRA1:,DRA2: PUBLIC01,PUBLIC02,PUBLIC03
Y.MOUNT-I-MOUNTED, PUBLIC01 mounted on _DRAO:
Y.MOUNT-I-MOUNTED, PUBLIC02 mounted on _DRA1:
Y.MOUNT-I-MOUNTED, PUBLIC03 mounted on _DRA2:
$ MOUNT/FOREIGN DRA3:
Y.MOUNT-I-MOUNTED, SCRATCH01 mounted on _DRA3:
$ BACKUP/IMAGE/VOLUME=! DRAO: DRA3:
$ DISMOUNT DRA3:
$ MOUNT/FOREIGN DRA3:
Y.MOUNT-I-MOUNTED, SCRATCH02 mounted on _DRA3:
$ BACKUP/IMAGE/VOLUME=2 DRAO: DRA3:
$ DISMOUNT DRA3:
$ MOUNT/FOREIGN DRA3:
%MOUNT-I-MOUNTED, SCRATCH03 mounted on _DRA3:
$ BACKUP/IMAGE/VOLUME=3 DRAO: DRA3:
$ DISMOUNT DRA3:
$ DISMOUNT/NOUNLOAD DRAO:
$MOUNT/SYSTEM DRAO:,DRA1:,DRA2: PUBLIC01,PUBLIC02,PUBLIC03
%MOUNT-I-MOUNTED, PUBLIC01 mounted on _DRAO:
Y.MOUNT-I-MOUNTED, PUBLIC02 mounted on _DRA1:
Y.MOUNT-I-MOUNTED, PUBLIC03 mounted on _DRA2:

(announce public disk is available again)

6-19

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

The operator needs to back up a three-volume set. Thus, at least four drives
are required. The operator warns the users that drives DRAO:, DRAl:, and
DRA2: are about to be WRITE-LOCKED for backups. Next the operator
issues MOUNT commands for the volumes PUBLICOl, PUBLIC02, and
PUBLIC03 on drives DRAO:, DRAl:, and DRA2:, respectively, to specify
write-locking with the /NOWRITE qualifier. Note that PUBLICOl is the
root volume. A scratch volume is mounted on drive DRA3: to be used for
the target volumes. As the volume on DRA3: is filled, it is dismounted and
a new scratch volume is mounted. This procedure repeats until the third
volume has been copied. Then the last volume on DRA3: is dismounted. To
enable writing on the volume set again, the operator dismounts (but does not
unload) DRAO:, then mounts the volumes again, omitting the /NOWRITE
qualifier. As a final step, the operator announces to the users that the volume
set is available again for writing.

Note
Do not simply WRITE-LOCK a mounted volume; doing so is
likely to cause errors and/or suspension of system activity. You
must dismount the public volume set, remount it write-locked,
and continue as described previously. This is critical to the
success of the operation.

6.4.5

Performing Selective Backups
You may find selective backups necessary for certain groups of files that
require special treatment. Generally, if files must be backed up regularly,
you should create a command procedure that contains the required backup
commands.
For more information on creating command procedures, see Section 6.6
of this guide or see the Guide to Using DCL and Command Procedures on
VAX/VMS.

One way to perform selective backups is through the use of wildcard
characters. For example, you can use the asterisk wildcard character ( * )
to select files by criteria such as file name, file type, or version number. This
command selects files by version number and copies them to the directory
[SAVE] on a specified RK07 drive:
$BACKUP/LOG *.*;3 DMA1:[SAVE]
Y.BACKUP-S-CREATED, created DMA1:[SAVE]CHARTS.DAT;3
Y.BACKUP-S-CREATED, created DMA1: [SAVE]FIGURES.DAT;3
Y.BACKUP-S-CREATED, created DMA1: [SAVE]LISTS.DAT;3
Y.BACKUP-S-CREATED, created DMA1: [SAVE]TABLES.DAT;3

6-20

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

The commands in the following example copy files from a directory and a
directory tree on DMAO: to newly created directories on DMAl:. All files in
the [GEORGE] directory and its subdirectories on the source disk are copied
to directories with the same name on the target volume; the /OWNER_
UIC=ORIGINAL qualifier ensures that the output files retain the owner UICs
of the input files. All files with the file name DUNGEON in the [SYSEXE]
directory on the source disk are copied to the [SYSEXE] directory on the
target volume.
$BACKUP DMAO: [GEORGE ... ] DMA1: [• ... ]/OWNER_UIC=ORIGINAL
$BACKUP DMAO: [SYSEXE]DUNGEON.•;• DMA1:[SYSEXE]

BACKUP has qualifiers that allow you to select files according to criteria such
as UIC, creation date, expiration date, and modification date. For example,
you can select files according to UIC by using the /OWNER_UIC qualifier
as follows:
$BACKUP/LOG [.MEM]/OWNER_UIC=[300,16] $1$DLA2:[USER]
Y.BACKUP-S-CREATED, created $1$DLA2: [USER]ASSIGN.LIS;1
Y.BACKUP-S-CREATED, created $1$DLA2:[USER]BBALL.DIS;19
Y.BACKUP-S-CREATED, created $1$DLA2:[USER]BBLEAGUE.FISTATEMENT;1
Y.BACKUP-S-CREATED, created $1$DLA2:[USER]BRULES.LIS;1
Y.BACKUP-S-CREATED, created $1$DLA2:[USER]GYM.MAI;1
7J3ACKUP-S-CREATED, created $1$DLA2: [USER]INFO.DAT;2
Y.BACKUP-S-CREATED, created $1$DLA2: [USER]MEMO.MAI;1
Y.BACKUP-S-CREATED, created $1$DLA2:[USER]NEWS.MAI;1
Y.BACKUP-S-CREATED, created $1$DLA2:[USER]TEAM.LIS;19

In this example, all files residing in the subdirectory [.MEM] with an owner
UIC of [300,16] are processed. Note that the brackets are required when you
specify the UIC code. You can specify the UIC of the current default process
by simply entering the /OWNER_UIC qualifier without a code.
If you want to select your input files according to their date of creation, you
can use the /CREATED qualifier with /BEFORE or /SINCE. The following
command copies all files in the directory [TRUBBLE] that were created on or
since April 3, 1985:
$BACKUP DMA1: [TRUBBLE]•/SINCE=03-APR-1985/CREATED DBA2:[SPRS]

You can use the /EXPIRED qualifier with /SINCE or /BEFORE to select files
according to the expiration date recorded in the file header.
$BACKUP •.COB;•/BEFORE=20-JUL-1985:/EXPIRED MFAO:JUL20SAVE.BCK

In this example, all versions of all files in the current default directory, with
a file type of .COB and an expiration date earlier than July 20, 1985, will be
saved to JUL20SAVE.BCK on MFAO:.

6-21

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

In some cases, you may find it more practical to exclude certain files from a
backup operation. You can do this as in the following example:
$BACKUP DBA2:[0SCAR ... ]/EXCLUDE=(•.LOG;•,NOTES.•;•) MTA1:SAVE.BCK

This command directs BACKUP to save all the files in the directory [OSCAR]
and its subdirectories, except for those with a file type of LOG and those
with the file name NOTES, regardless of file type or version number.
The parentheses are required when a list is specified with the /EXCLUDE
qualifier.

6.4.6

Protecting a BACKUP Save Set
You can use the output save-set qualifiers /OWNER_UIC and
/PROTECTION to protect save sets on magnetic tape, sequential disk, or
Files-11 disk. Specifying the protection and owner UIC for a save set can
prevent nonprivileged users from mounting a save-set volume or accessing
a Files-11 save set (anyone who has access to a save set can read any data
contained in the save set).
For example:
$BACKUP [HOOVER ... ] MFA2:PINKERTON.BCK/OWNER_UIC=[300,99]/REWIND

The directory tree [HOOVER. .. ] is saved to PINKERTON.BCK on the
magnetic tape drive MFA2: The output qualifier /OWNER_UIC assigns
an owner UIC of [300,99) to the save-set volume.
Because the protection on magnetic tape is encoded in the volume label,
the /OWNER_UIC and /PROTECTION qualifiers are effective on magnetic
tape save sets only if you specify the /REWIND qualifier (to initialize the
magnetic tape).
$ BACKUP [PAYROLL] MFA2:KNOX.BCK/OWNER_UIC=[3,3] _$

/PROTECTION=(S:RWE,O:RWED,G:RE,W)

In this example, the directory [PAYROLL) is saved to KNOX.BCK on the
magnetic tape drive MFA2:. The /OWNER_UIC qualifier assigns an owner
UIC of [3,3) to the save set. The /PROTECTION qualifier assigns the owner
of 'the save-set volume READ, WRITE, EXECUTE, and DELETE access.
SYSTEM users are assigned READ, WRITE, and EXECUTE access; GROUP
users are assigned READ and EXECUTE access; and WORLD users are
assigned no access.

6-22

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.4. 7

Restoring Disk Files, Directories, and Volumes from Save Sets
The format for restoring from a save set is as follows:
BACKUP save-set-specifier[/SAVE_SET] output-specifier
You use the /SAVE_SET qualifier when the save-set specifier refers to a
disk volume. The output specifier can be a device, directory, file name, or
wildcard character.
The following sections describe how to perform various restore operations.

6.4. 7 .1

Restoring Disk Files from Save Sets on Magnetic Tape

You can restore all files in the save set to the current default directory as
shown in the following example:
$ BACKUP TAPE:NOV12SAVE.BCK []

The following command restores files to a subdirectory tree:
$BACKUP TAPE:NOV12SAVE.BCK [LYKINS ... ]

If you want to restore a specific file from a save set, you can use the
/SELECT qualifier. For example:
$ MOUNT/FOREIGN MTAO:
XMOUNT-I-MOUNTED, NOV25A mounted on _MTAO:
$ BACKUP
_From: MTAO:NOV2SAVE.BCK/SELECT=[LYKINS.GLENDO]STRAT1.DAT;5
_To:
STRAT1.DAT;5
$ DIRECTORY STRAT1.DAT
Directory [LY-KINS.GLENDO]
STRAT1.DAT;5
Total of 1 file .

•The file STRATI.DAT in the directory [LYKINS.GLENDO] has been
accidentally deleted. The user had previously saved the file in the save
set NOV2SAVE.BCK and now restores it to its original directory by using the
/SELECT qualifier.
If you omit a save-set name for an input magnetic tape, BACKUP reads the
first save set it encounters on the magnetic tape and stops processing when
it reaches the end of that save set. Since BACKUP does not automatically
rewind until it reaches the EOT, you can proceed to the next save set (if any
exists) by repeating the command. As an alternative, you can include an
asterisk ( * ) with the device specification, which directs BACKUP to read all
of the save sets on the magnetic tape volume.

6-23

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.4. 7 .2

Restoring Disk Files from Save Sets on Sequential Disk

You can read a sequential disk save set in either of two ways: as a sequential
disk save set (mounted with the /FOREIGN qualifier) or as a normal Files-11
save set.
If you choose to read the save set as sequential, you can mount one volume

at a time (as you can do when you create a sequential disk save set). The
default directory for the save set file specification is the directory [000000],
which is the master file directory (MFD) on the disk; therefore, you do not
need to include the directory in the input specification. For example:
$ MOUNT/FOREIGN DMAO:
$ BACKUP/LOG DMAO:CONTRACTS.BCK/SAVE_SET CONTRACTS.DAT
Y.BACKUP-S-CREATED, created DBA2: [USER]CONTRACTS.DAT;1

Since the volume is mounted foreign, the DCL command DIRECTORY would
fail and generate an error message; however, BACKUP recognizes the format
and expects to find the save set CONTRACTS.BCK in the MFD directory.
The /SAVE_SET qualifier is required on any operation that restores from a
disk.
As an alternative, you can read the save set as a normal Files-11 volume. If
the save set is multivolume, you must mount all volumes of the set (as you
must for any Files-11 volume set).
$ MOUNT DMAO: SAVEWORK

$ BACKUP/LOG DMAO: [OOOOOO]CONTRACTS.BCK/SAVE_SET

CONTRACTS.DAT
Y.BACKUP-S-CREATED, created DBA2: [USER]CONTRACTS.DAT;1

The default directory is your process default directory, so you must specify
the directory [000000]. The SAVE_SET qualifier is necessary for restoring
the file to its original structure; without the /SAVE_SET qualifier, the save
set would simply be copied.
Save-set files written to a disk using the file system can also be read in
sequential mode; you may find this mode of operation useful if you use
standalone BACKUP. You must specify the directory from which the save set
is to be read. If the save set was written to a volume set using Files-11 disk
structure, you must observe the following rules:
•

All volumes of the volume set must be mounted. You must mount the
volumes with the /FOREIGN qualifier. (If you are using standalone
BACKUP, the volumes are implicitly mounted.)

6-24

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

•

6.4. 7 .3

When you specify the volumes in the input specifier, you must specify
the names of the devices in the same order as the relative volume
numbers of tht: volllmes mounted on those devices. For example, the
volumes named USEROl and USER02 in a volume set are mounted on
two drives, ORA3: and ORAS:. The save-set specifier for the volume set
must be as follows:
ORA3:[directory]save-set-name.ext;v, ORAS:

Restoring Disk Files from Save Sets on Multiple Volumes
If your save set encompasses more than one tape or sequential disk volume,
it is possible to begin restore operations without mounting the first volume
of the save set. However, if you use the /IMAGE qualifier, processing must
begin with the first volume. If the tape that you mount is not the first
volume in the save set, you will receive the warning message:
Y.BACKUP-W-NOT1STVOL, tape 'name' is not the start of a save set

If you restore a small number of files from a large save set, it is a good idea
to use the /LOG qualifier. This enables you to monitor the files as they are
restored. The BACKUP command will continue processing until it reaches
the end of the save set. Once the files you need have been restored, you can
press CTRL/Y to terminate processing.

6.4.8

Restoring Entire Disk Volumes
To restore an entire disk volume from a save set that was created using the
/IMAGE command qualifier, you must mount the new volume using the
OCL command MOUNT/FOREIGN. You must then restore the volume with
the BACKUP /IMAGE command.
When a save set is created using the /IMAGE command qualifier, the data
necessary for reinitializing the volume is placed in the save set. When the
/IMAGE command qualifier is used to restore the volume, the new volume
is initialized using that data in the save set.
For example:
$ MOUNT/FOREIGN DRA1
Y.MOUNT-I-MOUNTED, 24JUND mounted on _DRA1:
$ BACKUP/IMAGE MTA0:24JUNDMA1.BCK DRA1:

The volume is initialized using the initialization parameters saved in the save
set. All files and directories in the save set are restored to the new volume.
To restore a volume set in image mode, you must mount all the volumes of
the set as foreign volumes. You must also specify the list of devices on which
the volumes are mounted in the output-specifier of the BACKUP command.

6-25

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

$ MOUNT/FOREIGN DRAO:
iMOUNT-I-MOUNTED, PUBLIC01 mounted on _DRAO:
$ MOUNT/FOREIGN DRA1:
iMOUNT-I-MOUNTED, PUBLIC02 mounted on _DRA1:
$ MOUNT/FOREIGN DRA2:
iMOUNT-I-MOUNTED, PUBLIC03 mounted on _DRA2:
$ BACKUP /IMAGE MTAO: 31JUNPUB DRAO: , DRA1 : , DRA2 :

The volumes receive volume set numbers in the order in which they are
listed in the BACKUP command. In this example, DRAO:, DRAl:, and DRA2:
become volumes 1, 2, and 3, respectively.
6.4.8.1

Changing Volume Initialization Parameters Before Restoring

If you wish to change the volume initialization parameters for a volume, you
need to perform the following steps:
1

Initialize the new volume using the new initialization parameters.

Mount the new volume using the /FOREIGN qualifier.

3 Restore the volume with BACKUP, using the /NOINITIALIZE command
qualifier.
In the following example the cluster size of the volume is being changed to
3. The other volume initialization parameters take the default values from
the INITIALIZE command.
$ ALLOCATE DRA2
iDCL-I-ALLOC, _DRA2: allocated
$ INITIALIZE/CLUSTER_SIZE=3 DRA2: TEST_PROGS
$ MOUNT/FOREIGN DRA2
iMOUNT-I-MOUNTED, TEST_PROGS mounted on _DRA2:
$ BACKUP/IMAGE/NOINITIALIZE/TRUNCATE MTA0:1JUN.BCK DRA2:

The only initialization parameter that you cannot change is the structure level
of the volume. If you change the cluster factor, as in the above example, it is
good practice to include the /TRUNCATE qualifier.

6.4.9

Listing the Contents of a BACKUP Save Set
You can use the /LIST command qualifier to list information about files in
a save set, either at the terminal or to a specified output file. BACKUP can
perform this operation in conjunction with any other BACKUP operation, or
by itself.
The following command will list save-set information at the terminal:
$ BACKUP/LIST 2MAR1665.BCK/SAVE_SET

6-26

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

To list the same information in a file named INFO.LIS, enter the following
command:
$ BACKUP/LIST=INFO.LIS 2MAR1555.BCK/SAVE_SET

If you do not know the save set names on a magnetic tape volume, you can

specify the device alone. Note, however, that BACKUP then performs the
list operation as it would a restore operation with only a device specification:
It reads the first save set it encounters on the magnetic tape and stops
processing when it reaches the end of that save set. BACKUP does not
automatically rewind until it reaches the EOT (unless you have specified the
/REWIND qualifier); therefore, you can proceed to the next save set (if any
exists) by repeating the command.
By including an asterisk ( *) with the device specification, you can direct
BACKUP to list all of the save sets on the volume:
$ BACKUP/LIST MTAO:*

If you want to list only the names of the save sets on a volume, without the

names of the files in the save sets, you need to mount the magnetic tape
volume as Files-11; then use the DCL command DIRECTORY. For example:
$ MOUNT MTAO: SAVEWORK TAPE
%MOUNT-I-MOUNTED, SAVEWORK mounted on _MTAO:
$ DIRECTORY/SIZE/DATE/PROTECTION TAPE:
Directory MTAO: []
CONTRACTS.BCK;1
5 13-JUN-1985 12:11
JUL20SAVE.BCK;1
3 20-JUL-1985 23:59
MYPHILE.BCK;1
2 28-SEP-1985 12:00
Total of 3 files, 10 blocks.

6.4.10

(RWED,RWED,RE,)
(RWED,RWED,RE,)
(RWED,RWED,RE,)

Comparing Files with BACKUP
You can use the BACKUP compare operation either to compare a save set
with files on a disk, or to compare files on a disk with other files on a
disk. Note that the /COMPARE qualifier should be used only to compare
a save set against original files or to compare files or volumes copied using
BACKUP. BACKUP processes files by blocks. Comparing files that were not
produced by BACKUP may cause errors.
You can compare a save set with files on a disk as in the following example
(this command directs BACKUP to compare the contents of the save set
2MAR1555.BCK with the directory [LYKINS]):
$ BACKUP/COMPARE TAPE:2MAR1555.BCK [LYKINS]

6-27

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

The following example compares files on a disk; note that in this
example, there is an inconsistency in block 16 between UPLIFT .EXE;4
and UPLIFT.EXE;3:
$BACKUP/COMPARE UPLIFT.EXE;3 UPLIFT.EXE;4
verification error for block 16 of WRKD$: [LYKINS]UPLIFT.EXE;4

~ACKUP-E-VERIFYERR,

6.5

Using BACKUP Journal Files
A BACKUP journal file contains records of BACKUP save operations and the
file specifications of the files that were saved with each operation. To find a
particular file in a multivolume save set, you can review the BACKUP journal
file to find the magnetic tape volume that contains the file.
Use the /JOURNAL qualifier to create, or append information to, a
BACKUP journal file. If no file specifier appears with the /JOURNAL
command qualifier, the name of the BACKUP journal file defaults to
SYS$DISK:BACKUP .BJL. The default file type for BACKUP journal files
is BJL.
If the specified BACKUP journal file does not exist, it is created; if it already
exists, the new journal information is appended to the existing journal file.
You can start a new version of a BACKUP journal file by creating an empty
file with an editor such as EDT or the DCL command CREATE.

To list a BACKUP journal file, enter the command:
BACKUP /LIST[=file-spec]/JO URNAL[=file-spec]
You must not specify an input or output specifier with a BACKUP /JOURNAL
/LIST command. If the file specification is omitted from the /LIST qualifier,
output is directed to SYS$0UTPUT; if the file specification is omitted from
the /JOURNAL qualifier, the default BACKUP journal file is used.
You can use file selection qualifiers with the BACKUP /JOURNAL/LIST
command. This allows you to locate a set of files in a save set just as the
DIRECTORY command allows you to locate a set of files on a disk. The
following example shows all files in the directory [SMITH.PROGS] backed
up after October 5, 1985, listed in the BACKUP journal file ARCH.BJL:
$ BACKUP/LIST/JOURNAL=ARCH.BJL/SELECT=[SMITH.PROGS]/SINCE=6-0CT-1985

6-28

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

The following example shows the use of BACKUP journal files:
$BACKUP/JOURNAL/LOG/IMAGE DRA2: MTA0:30CT.FUL
(first set is printed here)
Y.BACKUP-I-RESUME, resuming operation on volume 2
Y.BACKUP-I-READYWRITE, mount volume 2 on _MTAO: for writing
Press return when ready: IRETI
(second set is printed here)
$ BACKUP/JOURNAL/LIST
Listing of BACKUP journal
Journal file _DB2:[SYSMGR]BACKUP.BJL;1 on 3-0CT-1985 00:40:56.36
Save set 30CT.FUL created on 3-0CT-1985 00:40:56.36
Volume number 1, volume label 30CT01
[COLLINS]ALPHA.DAT;4
[COLLINS]EDTINI.EDT;5
[COLLINS]LOGIN.COM;46
[COLLINS]LOGIN.COM;45
[COLLINS]MAIL.MAI;1
[COLLINS]MAR.DIR;1
[COLLINS.MAR]GETJPI.EXE;9
[COLLINS.MAR]GETJPI.LIS;14

[LANE]LES.MAI;1

Save set 30CT.FUL created on 3-0CT-1985 00:40:56.36
Volume number 2, volume label 30CT02
[LANE]MAIL.MAI;1
[LANE]MEMO.RN0;5
[LANE]MEMO.RN0;4

[WALTERS.VI]KD.RN0;52
End of BACKUP journal

6-29

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

6.6

Using Command Procedures to Perform Backup Operations
If you have specific backup operations that you perform on a regular basis,
you may find that command procedures are useful. For example, if you
have files that should be saved on a daily basis, you probably use the same
command strings repeatedly. You can use a command procedure to issue the
necessary commands for you, as in the following sample:
$ ON CONTROL_Y THEN GOTO EXIT

$ ON ERROR THEN GOTO EXIT
$ GET_DRIVE: INQUIRE DRIVE "Drive"
$ IF DRIVE .EQS. "" THEN GOTO GET_DRIVE
$ ALLOCATE 'DRIVE'
$ MOUNT/FOREIGN 'DRIVE'
$ GET_SAVESET_SPEC: INQUIRE SPEC "Save set name"
$ IF SPEC .EQS. "" THEN GOTO GET_SAVESET_SPEC
$ BACKUP/RECORD/IGNORE=INTERLOCK/SINCE=BACKUP [ ... ]
$ EXIT:
$ DISMOUNT 'DRIVE'
$ DEALLOCATE 'DRIVE'

DRIVE 1 : 1 SPEC 1 /SAVE_SET

This command procedure allocates, initializes, and mounts a specified
device. It allows you the flexibility of employing either a magnetic tape
or a sequential disk output volume.
The procedure also performs an incremental backup on the current directory
tree, saving only the files that have been modified since the last backup
operation. (For more information on incremental backups, refer to the

VAX/VMS System Manager's Reference Manual.)
Note that if you do not have an ON ERROR statement in your command
procedure and BACKUP returns a FATAL or ERROR status code, the
command procedure exits immediately after the BACKUP command is
executed. If you want your command procedure to complete, you should
include an ON ERROR statement such as the one in this procedure.
Note also that this procedure assumes a colon is not included with the
device name. If you were to include the colon, the operation would fail
because the colon is given in the BACKUP command string. (The extra
colon would cause BACKUP to attempt a network function, interpreting the
device specification as a node name.) You can create a more sophisticated
procedure that checks for the extra colon and removes it if necessary, as in
the following example:

6-30

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

$ ON CONTROL_Y THEN GOTO EXIT
$ ON ERROR THEN GOTO EXIT
$WRITE SYS$0UTPUT "Welcome to FETCH."
$ WRITE SYS$0UTPUT 11 11
$ L1: INQUIRE/NOPUNC PHYS "Have you placed the volume in the drive? "
$ IF .NOT. PHYS THEN GOTO L1
$ INQUIRE/NOPUNC DRIVE "Which drive is the volume mounted on? "
$DRIVE= DRIVE - ":"
$ ALLOCATE 'DRIVE'
$ MOUNT/FOREIGN 'DRIVE'
$ ON ERROR GOTO COMMAND_LOOP
• !

$ COMMAND_LOOP: INQUIRE/NOPUNC OPTION "Fetch> "
$ IF OPTION .EQS. "DIR" THEN GOTO DIR
$ IF OPTION .EQS. "EXIT" THEN GOTO EXIT
$ IF OPTION .EQS. "FETCH" THEN GOTO FETCH
$ IF OPTION .EQS. "HELP" THEN GOTO HELP
$ IF OPTION .EQS. "LIST" THEN GOTO LIST
$ GOTO COMMAND_LOOP
• !

$ DIR: INQUIRE SPEC "File spec"
$ DIR 'SPEC'
$ GOTO COMMAND_LOOP
• !

$ HELP:
$WRITE SYS$0UTPUT "Enter any of the following commands at the prompt:"
$ WRITE SYS$0UTPUT 11 11
$ WRITE SYS$0UTPUT
$WRITE SYS$0UTPUT "DIR
(To search for a file)"
$ WRITE SYS$0UTPUT " "
$ WRITE SYS$0UTPUT "EXIT
(To exit this program)"
$ WRITE SYS$0UTPUT 11 11
$ WRITE SYS$0UTPUT "FETCH
(To perform a BACKUP RESTORE operation)"
$ WRITE SYS$0UTPUT 11 11
$WRITE SYS$0UTPUT "HELP
(To read this text)"
• WRITE SYS$0UTPUT " II
$ WRITE SYS$0UTPUT "LIST
(To perform a BACKUP LIST operation)"
$ GOTO COMMAND_LOOP
• !

$ FETCH: INQUIRE FILE "Filespec"
$ INQUIRE SAVESET "Save set name"
$LINE:= BACKUP/LOG 1 DRIVE 1 : 1 SAVESET 1 /SELECT= 1 FILE'
$ INQUIRE EXCLUDE "Enter any filespecs you want excluded"
$ IF EXCLUDE .EQS. "" THEN GOTO L2
$LINE := 1 LINE 1 /EXCLUDE=( 1 EXCLUDE 1 )

6-31

Maintaining Data Integrity on Disk and Magnetic Tape Volumes

• !

$ L2: INQUIRE/NOPUNC TO "Where do you want the file(s)? (<RET> for current directory)"
$ IF TO .EQS. "" THEN GOTO REPLACE
$ LINE := 'LINE' 'TO'
$ GOTO L3
$ REPLACE: LINE := 'LINE' []
• !

$ L3: INQUIRE/NOPUNC NEW "Create a new version if file already exists? "
$ IF .NOT. NEW THEN GOTO NOT
$LINE := 1 LINE 1 /NEW_VERSION
• !

$ NOT: LINE := 1 LINE 1 /0WNER_UIC=ORIGINAL
$ LINE
$ GOTO COMMAND_LOOP
• !

$ LIST: INQUIRE SPEC 11 Filespec"
$ INQUIRE SAVESET "Save set name"
$ INQUIRE/NOPUNC OUTPUT "What do you want to call the list file? (<RET> for SYS$0UTPUT 11 )
$ IF OUTPUT .EQS. "" THEN GOTO NOOUT
$LINE:= BACKUP/LIST='OUTPUT' 1 DRIVE 1 : 1 SAVESET 1 /SELECT=( 1 SPEC 1 )
$ GOTO L4
$ NOOUT: LINE:= BACKUP/LIST 1 DRIVE 1 : 1 SAVESET 1 /SELECT=( 1 SPEC 1 )
• !

$ L4: INQUIRE EXCLUDE "Enter any filespecs you want excluded"
$ IF EXCLUDE .EQS. "" THEN GOT L5
$LINE := 1 LINE 1 /EXCLUDE=( 1 EXCLUDE 1 )
•

$ L5: LINE
$ GOTO COMMAND_LOOP
• !

$ EXIT:
$ DISMOUNT 'DRIVE'
$ DEALLOCATE 'DRIVE'

Like the previous procedure, this sample allows you the flexibility of
choosing either a magnetic tape or a disk device. However, the functions
provided are quite different and more complex. After you invoke the
procedure, you are in a program that displays its own prompt (Fetch> )
and has its own set of command options.
In addition to allocating and mounting the specified device, the program can
perform a BACKUP restore or list operation. Whatever function you choose
causes the program to prompt you with additional options.
You can tailor these procedures to suit your own needs. If you need further
information on DCL command procedures, see the Guide to Using DCL and

Command Procedures on VAX/VMS.

6-32

Handling Operator-Oriented Disk and
Magnetic Tape Functions
This chapter describes some of the disk and magnetic tape functions typically
handled by VAX operators. Operator functions discussed include:

7 .1

•

Using the operator terminal to communicate with users

•

Handling mount requests

•

Handling requests from the Backup Utility

•

Handling mount verification tasks

Using the Operator Terminal to Handle User Requests
One of the chief operator functions, communicating with users in handling
requests, must be performed at terminals that have been defined as operator
terminals. Operators themselves can set up an operator terminal by using the
DCL command REPLY /ENABLE at the desired terminal. When you enter
this command, the following Operator Communication Facility (OPCOM)
message will be displayed at the terminal.
OPCOM, dd-mmm-yyyy hh:mm:ss,cc, Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Operator _nodename$terminal-name: has been enabled, username USERNAME

Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.

This message tells you which terminal has been established as an operator
terminal and when it was established.
To communicate with you (the operator), users can issue the REQUEST
command, specifying the /REPLY command with the /TO qualifier.
If the user issues a REQUEST/REPLY command, the request is displayed at
the operator terminal in the following format:
OPCOM,dd-mmm-yyyy hh:mm:ss.cc Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
request request-id from user USERNAME __ terminal-name:,
"message-text"
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.

This message tells you which user sent the message, the time the message
was sent, the request identification number assigned to the message, the
originating terminal, and the message itself.

7-1

Handling Operator-Oriented Disk and Magnetic Tape Functions

If the user issues a REQUEST command, the request is displayed at the
operator terminal in a format similar to the one above, but without a request
identification number. The message will have the following format:

XXXXXXXXXXX

OPCOM,dd-mmm-yyyy hh:mm:ss.cc XXXXXXXXXXX
request from user USERNAME __terminal-name:, "message-text"

When a user issues a REQUEST/REPLY command and you have disabled
all operator terminals with the appropriate REPLY /DISABLE commands,
OPCOM returns a message to the user indicating that no operator coverage
is available, but records all subsequent user's requests in the operator log file.
A sample copy of an operator log file that contains typical disk and magnetic
tape related requests is included in Section 7.4. For more information on the
operator log file, see the VAX/VMS System Manager's Reference Manual.
You respond to user requests with one of the following REPLY commands:
•

REPLY/ ABORT=identification-number "message-text"

•

REPLY /PENDING=identification-number "message-text"

•

REPLY /TO=identification-number "message-text"

•

REPLY /TO=identification-number "SUBSTITUTE device-name"

The /ABORT qualifier indicates that the user request has been canceled. The
/PENDING qualifier places the user in a waiting state until the request can
be fulfilled or aborted. The /TO qualifier indicates that the user request has
been fulfilled. The /TO qualifier, with the word SUBSTITUTE and a device
name in place of message-text, redirects the mount operation to the specified
device. For this qualifier you must load the user's volume on the alternate
device and ready the device before you issue the REPLY command. You
can abbreviate the word SUBSTITUTE to S and can use upper or lowercase
characters. Here is an example:
$ REPLY/T0=24 "SUBSTITUTE

DMA1"

This chapter describes the OPCOM facility and the REPLY command only
as they relate to disk and magnetic tape functions handled by operators. For
more detailed information on the REPLY command, including a list of all the
command qualifiers, see the VAX/VMS DCL Dictionary. For more information
on OPCOM, see the VAX/VMS System Manager's Reference Manual.

7-2

Handling Operator-Oriented Disk and Magnetic Tape Functions

7 .2

Handling User Requests for Mounting Volumes
At many installations, operators perform the physical mounting and
dismounting of both system and private disk and magnetic tape volumes. At
these installations, users do the following:
•

Allocate a device of the required type.

•

Enter the MOUNT or MOUNT /COMMENT command to issue the
mount request and send a message to you specifying the following: the
name of the device allocated, the volume requested to be mounted, the
physical identification on the outside of the volume, and its location.

•

Wait until the system responds with a message indicating that the
volume is mounted.

As an operator handling user requests for mounting volumes, you do the
following:
•

Place the volume on the specified device.

•

Perform the necessary start-up procedure. On disk drives, the start-up
procedure requires pressing the START or RUN button; on magnetic tape
drives, it requires pressing the LOAD button.

If the user intends to write on a magnetic tape volume to be mounted, make

sure the magnetic tape contains a write ring before you load the volume on
the drive. A volume that does not contain a write ring is write-locked and
thus cannot be accessed for write operations.
If the user wants a particular disk to be checked for bad blocks, make sure

that the volume has been mounted with the /FOREIGN qualifier. For more
information on how to invoke and use the Bad Block Locator Utility (BAD),
see the VAX/VMS Bad Block Locator Utility Reference Manual.
The following sections describe the operator's function in mounting disk and
magnetic tape volumes. For more information on the user's role in mounting
volumes, see Chapter 3. For a complete list of all of the MOUNT command
qualifiers and parameters, see the VAX/VMS Mount Utility Reference Manual.

7-3

Handling Operator-Oriented Disk and Magnetic Tape Functions

7 .2.1

Requests for Mounting Disks and Single Magnetic Tape Volumes
When a user requests a specific disk or magnetic tape to be mounted on a
device, the following type of message is displayed on the operator terminal:
OPCOM dd:mmm:yyyy:hh:mm:ss:cc
request NUMBER, from user USERNAME
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.

Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.

For example, a user requesting to mount the volume TESTJILES on the
device DMA2:, could issue the following command:
$ MOUNT DMA2: TEST_FILES/COMMENT="Shelf slot 68"

This command notifies you by displaying the following message at the
operator terminal:
OPCOM, 11-JUN-1985 15:47:50.26 Y.1.Y.1.Y.Y.Y.Y.1.1.1.
request 5, from user MALCOLM
Please mount volume TEST_FILES in device _DMA2:
Shelf slot 68
Y.Y.Y.1.1.Y.1.Y.1.Y.1.

The user receives a message indicating that you have received the request:
1.MOUNT-I-OPRQST, Please mount volume TEST_FILES in device _DMA2:
Shelf slot 68

After you locate the physical volume and place it on the device, the user
receives the messages:
%MOUNT-I-MOUNTED, TEST_FILES mounted on _DMA2:
Y.MOUNT-I-RQSTDON, operator request canceled -- mount completed successfully.

The first message notifies the user that the volume has been mounted. The
second informs the user that the operator has been notified that the original
user request is no longer outstanding.
Instead of requesting a specific device for mounting a volume, the user can
also make a generic MOUNT request by specifying a device type. To mount
the volume CITIES on a magnetic tape drive whose name begins with MT,
for example, the user would issue the following command:
$ MOUNT MT:

CITIES/COMMENT="Slot 12c"

If the user has already allocated a drive whose name begins with MT, the
VAX/VMS Mount Utility (MOUNT) will request that you mount CITIES on
that particular drive. If the user has not allocated a drive whose name begins
with MT, the MOUNT utility will allocate the first available TE16, TU45, or
TU77 tape drive it finds and issue a request to you to mount CITIES on that
drive.

7-4

Handling Operator-Oriented Disk and Magnetic Tape Functions

7 .2.2

Requests for Mounting Magnetic Tape Volume Sets
The procedure for mounting a magnetic tape volume set is similar to the
procedure for mounting a single magnetic tape volume described in the
previous section. When mounting a volume set, however, you should make
sure that all the volumes in the set contain write rings if the user intends to
write to any one of the volumes in the set. If even one of the volumes in the
set does not contain a write ring at mount time, all volumes will be writelocked and thus not be able to be written. You can then load the volumes on
the drives that have been allocated and place the drives on line.
The next two sections describe how to handle user requests to mount a
magnetic tape volume set when:

7 .2.2.1

•

Automatic volume switching is enabled

•

Automatic volume switching is disabled

Mounting Volume Sets with Automatic Switching

The VAX/VMS operating system supports automatic volume recognition
(AVR) and automatic volume labeling (AVL) for magnetic tapes. If the
magnetic tape volume is mounted with AVR and AVL enabled, then the
only task required of the operator is to physically place the next volume
in the drive. The system will automatically read the label and then mount
the volume. The system will then send a message to the operator terminal
informing you that a volume switch has occurred.
The magnetic tape file system switches volumes by issuing pending read
or write requests to the next volume in the set. For more information on
how automatic volume switching occurs, including examples of processing
continuation volumes in a volume set with automatic switching, see
Chapter 3.
With automatic volume switching, you can load each successive magnetic
tape in the volume set on one of the allocated drives any time before
the magnetic tape being processed reaches an end-of-tape position. The
magnetic tape file system will mount and/ or initialize the next magnetic
tape, and then notify you that a switch has occurred.
Note that to take advantage of the automatic volume-switching capability,
more than one magnetic tape drive must be allocated to the magnetic tape
volume set. Automatic volume switching will be implicitly disabled if the
user allocates only one magnetic tape drive for the volume set. Note also
that a user can explicitly override automatic volume switching by mounting
the volume set with the /NOAUTOMATIC qualifier.

7-5

Handling Operator-Oriented Disk and Magnetic Tape Functions

7 .2.2.2

Mounting Volume Sets without Automatic Switching

This section describes how to handle requests for mounting continuation
volumes in a volume set when automatic volume switching is disabled or
when the magnetic tape file system cannot mount a given volume.
When a user is in the process of reading or writing to a magnetic tape and
that tape reaches an end-of-tape condition, the system suspends processing
and sends a request to the operator to mount the next magnetic tape in the
volume set. The user does not see this message and may not realize that
another tape is needed to complete the read or write operation.
After you load the continuation volume on the drive specified in the mount
request, you mount the volume by issuing the REPLY /TO command,
specifying the identification number in the mount request. If the volume
does not restrict access and it is the correct volume, the magnetic tape file
system (MTFS) mounts the volume and reissues pending read or write
requests to the continuation volume.
If a read operation was being performed when the volume switching
occurred, specifying the volume identifier is optional. The MTFS performs
checks on the continuation volume to ensure that it is the correct volume.

Before it mounts a volume for which a volume identifier was not specified,
the magnetic tape file system performs the access checks described in Chapter
2. If the volume fails any of these access checks, the magnetic tape file
system will not mount the volume.
If a write operation is in progress when a continuation volume is needed,
the volume identifier of the continuation volume must be specified in either
the mount request or the REPLY command. Specifying a volume identifier
ensures that the correct volume is mounted on the drive and links the
continuation volume to the volume set.

To satisfy a mount request from a magnetic tape file system when a write
operation is in progress, one of three qualifiers must be specified with the
REPLY command:
•

/BLANK_TAPE

•

/INITIALIZE_TAPE

•

/TO

The volume identifier and the format written on the continuation volume
determine which qualifier should be used.

7-6

Handling Operator-Oriented Disk and Magnetic Tape Functions

For example, assume that the magnetic tape file system issued the following
mount request:
OPCOM, 14-JUN-1986 16:23:31.78 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
request 3, from user PLAW
MOUNT new relative volume 2 (DWOQT2) on MTA1:
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.

When the volume identifier written on the continuation volume is the same
as that specified in the mount request, the /TO qualifier should be used with
the REPLY commands to satisfy the request, as shown in the two examples
below.
$ REPLY /T0=3
$ REPLY/T0=3 "DWOQT2"

The first REPLY command does not specify the volume identifier; the second
does.
If you initialize and mount a volume set in which each volume has a unique

accessibility character and you wish to retain that accessibility character,
you must not specify the volume identifier. If you do specify the volume
identifier, as in the second REPLY command, the accessibility character of the
first volume in the set that was mounted will be written to the continuation
volume, rather than the character specified at initialization.
When the volume identifier on the continuation volume does not match the
one specified in the mount request, the /INITIALIZE_TAPE qualifier should
be specified with the REPLY command to reinitialize and mount the volume
with the volume identifier.
The magnetic tape file system will then perform access checks and initialize
the volume as if the INITIALIZE command had been specified (see Chapter
3). However, if the volume fails any of the access checks of the magnetic
tape file system, the magnetic tape file system cannot override them, and the
volume cannot be initialized.
The two examples that follow illustrate uses of the /INITIALIZE_TAPE
qualifier.
$ REPLY/INITIALIZE_TAPE=3
$ REPLY/INITIALIZE_TAPE=3 "DWOQT2"

The first example does not specify the volume identifier; the second does.

7-7

Handling Operator-Oriented Disk and Magnetic Tape Functions

When a volume is unformatted, the /BLANK_TAPE qualifier must be
specified to initialize the volume. The user privileges VOLPRO and OPER
are required to avoid a runaway tape or timeout condition (see Chapter 3).
Either of these next REPLY commands is valid.
$ REPLY/BLANK_TAPE=3
$ REPLY/BLANK_TAPE=3 11 DWOQT2 11

The first command specifies a volume identifier; the second does not.

7 .3

Handling Requests from the Backup Utility
When a backup operation is submitted as a batch job, you receive requests
to load the next volume of a save set and to reload a volume in the event of
an error. (These requests go to the user when the Backup Utility is invoked
interactively.)

7 .3.1

Writing to a Save Set
If a save operation (writing from files to a save set) requires the loading of an
additional volume, you receive messages stating the date and time, a request
number, the user name, and the device name, as shown in the following
example:
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1985 17:02:32.31 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Request 24, from user TOM.
lBACKUP-1-READYWRITE, mount volume 2 on _MTAO: for writing

To continue the backup operation, load a scratch volume, ready the device,
and type a REPLY /TO command, as shown in the following example:
$ REPLY/T0=24
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM,

6-JUN-1985 17:02:34.14 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Request 24 completed by operator OPAO.

You can also abort the backup operation by typing a REPLY/ABORT
command, as shown in the following example:
$ REPLY/ABORT=24
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1986 17:02:34.14 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Request 24 aborted by operator OPAO.

7-8

Handling Operator-Oriented Disk and Magnetic Tape Functions

7 .3.2

Reading from a Save Set
If a restore operation (reading from a save set to files) requires the loading
of an additional volume, you receive messages stating the date and time,
a request number, the user name, and the device name, as shown in the
following example:
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1986 17:02:32.31 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Request 24, from user TOM.
lBACKUP-1-READYREAD, mount volume 2 on ~MTAO: for reading

To continue the restore operation, place the next volume of the save set on
the drive, ready the device, and type a REPLY /TO command, as shown in
the following example:
$ REPLY/T0=24
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1986 17:02:34.14 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Request 24 completed by operator OPAO.

You can also abort the restore operation by typing a REPLY/ ABORT
command, as shown in the following example:
$ REPLY/ABORT=24
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM,

6-JUN-1986 17:02:34.14 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Request 24 aborted by operator OPAO.

7 .3.3

Recovering from an Error
On certain errors, you receive messages stating the date and time, a request
number, the user name, the device name, and reply options. On read errors
from the save set, the options are usually CONTINUE and QUIT. On write
errors to the save set, the options are usually RESTART and QUIT. You
should take one of the following actions:
•

REPLY /TO °CONTINUEn - If you can fix the problem and are given
the CONTINUE option, ready the device, and issue a REPLY /TO
command specifying the word CONTINUE as text.

•

REPLY /TO RESTART" - If you can fix the problem and are given the
RESTART option, load (if necessary) the volume, ready the device, and
issue a REPLY /TO command specifying the word RESTART as text.

•

REPLY /TO QUIT" - If you cannot fix the problem, issue a REPLY /TO
command specifying the word QUIT as text.

The text in the REPLY /TO command can be uppercase or lowercase, and
can be abbreviated down to the first character. See the VAX/VMS Error Log
Utility Reference Manual for additional information on errors and recovery
procedures.
7-9

Handling Operator-Oriented Disk and Magnetic Tape Functions

Assume, for example, that you receive the following messages during a
restore operation (the save set is being read):
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1986 17:02:30.68 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Message from user RESJOB.
Y.BACKUP-E-FATALERR, fatal error on MT:[]SAVE.;
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1986 17:02:30.89 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Message from user RESJOB.
-SYSTEM-F-MEDOFL, medium is offline
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. Y.OPCOM, 6-JUN-1986 17:02:31.06 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Request 24, from user RESJOB.
%BACKUP-I-SPECIFY, specify option (QUIT or CONTINUE)

You check the drive and find that it simply lost its vacuum. Remedy the
situation by readying the tape drive and issuing the following command:
$ REPLY/T0=24 "CONTINUE"
CONTINUE
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1986 17:02:33.41 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Request 24 completed by operator OPAO.

If you find the drive inoperable, you issue the QUIT reply:
$ REPLY/T0=24 "QUIT"
QUIT
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1986 17:02:33.41 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Request 24 completed by operator OPAO.

If the error occurs during a save operation (the save tape is being written),

you have a choice of QUIT or RESTART:
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1986 17:02:30.68 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Message from user RESJOB.
Y.BACKUP-E-FATALERR, fatal error on MT:[]SAVE.;
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1986 17:02:30.89 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Message from user RESJOB.
-SYSTEM-F-MEDOFL, medium is offline
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1986 17:02:31.06 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Request 24, from user RESJOB.
%BACKUP-I-SPECIFY, specify option (QUIT or RESTART)
(You ready the magnetic tape drive.)

$ REPLY/T0=24 "RESTART"
RESTART
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 6-JUN-1986 17:02:33.36 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Request 24 completed by operator OPAO.

The RESTART option permits you to restart a multivolume backup operation
at the beginning of the current volume. If you specify the QUIT option, you
must restart the backup operation completely.

7-10

Handling Operator-Oriented Disk and Magnetic Tape Functions

7 .4

Handling Mount Verification Tasks
The mount verification feature of Files-11 disk handling generally protects
users in situations where a mounted disk has gone off line and returned
on line or in some other way has become unreachable and then restored.
Mount verification is enabled by default with the /MOUNT_VERIFICATION
qualifier when the disk is mounted. To disable mount verification, the user
must have specified /NOMOUNT_VERIFICATION when mounting the disk.
Note that this feature does not apply to foreign disks or to magnetic tapes.
Mount verification sends messages to OPCOM. Because there are cases
where mount verification messages are needed at the operator console and
OPCOM might not be able to provide them, mount verification also sends
special messages with the prefix %SYSTEM-I-MOUNTVER to the system
console only, that is, to OP AO:. For example, if the system disk undergoes
a mount verification or if the OPCOM process is not present on a system,
you would at least receive the messages with the %SYSTEM-I-MOUNTVER
prefix. Under normal circumstances, both messages are received at OP AO:,
with the %SYSTEM-I-MOUNTVER message arriving first.

7 .4.1

Mount Verification for Offline Devices
If a mounted disk volume goes off line while mount verification is enabled,
you can follow the steps in the procedure below to resume operations.
Procedure

When a device is taken off line, the steps in mount verification are as follows:
1

Because of a hardware or user error, a disk volume is taken off line
(for example, it might be spun down). Most disk drives generate a
special interrupt when the volume comes back on line, which causes
the software to mark the volume as invalid. However, some disk drives
(such as the RXOl, RX02, RL02, and TU58) do not generate online
attention interrupts. For these devices, an offline condition is only
detected when an 1/0 operation is initiated for the drive.

An 1/0 operation fails with a "medium offline" or "volume invalid"
status. The software marks the volume to indicate that it is undergoing
mount verification, and all 1/0 operations to the disk are stalled.

OPCOM issues a message to the operators enabled for DISKS and
DEVICES to announce the disk's unavailability, as follows:
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, dd-mmm-yyyy hh:mm:ss.cc
Device device-name is offline.
Mount verification in progress.

Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.

7-11

Handling Operator-Oriented Disk and Magnetic Tape Functions

You may simply choose to take the disk out of the offline and
verification-pending state by shutting down mount verification with
one of the techniques described in Sections 7.3.3 and 7.3.4. These
techniques cause the pending and future I/Os to the volume to fail.

Otherwise, you take corrective action. Perhaps the drive can be brought
back on line. If the disk drive is faulty, but another functioning drive
is available on the same controller, you can move the disk to the
functioning drive and swap the unit select plugs.

The disk comes back on line, which is detected by the mount verification
software that polls the disk drive.

The system verifies that the disk's home block matches the one in the
database of mounted volumes, thus confirming that this is the same disk
as the one previously mounted.

If the drive does not contain the correct volume, OPCOM issues the
following message:
Y.Y.Y.XY.Y.Y.Y.Y.XY.Y. OPCOM, dd-mmm-yyyy hh:mm:ss.cc Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Device device-name contains the wrong volume.
Mount verification in progress.

After the mount verification succeeds, the disk is marked as valid.
OPCOM issues the following message:
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, dd-mmm-yyyy hh:mm:ss.cc Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Mount verification completed for device device-name

At this point IfO operations to. the disk are allowed to proceed.
Example
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 15-JUN-1985 11:54:54.12 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Device DMAO: is offline.
Mount verification in progress.
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 15-JUN-1985 11:57:34.22 Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.
Mount verification completed for device DMAO:

The message from OPCOM informs you that device DMAO: has gone off
line and mount verification has been initiated. You find that the drive was
accidentally spun down and successfully spin it back up. The next message
indicates that mount verification is satisfied that the same volume is on
the drive (which it has found is on line again), and all I/Os to the volume
resume.
Note that if a device continues to go off line because of hardware problems,
you should consult your DIGITAL Field Service Representative.

7-12

Handling Operator-Oriented Disk and Magnetic Tape Functions

7.4.2

Mount Verification for Write-Locked Devices
If for some reason a mounted disk volume becomes write-locked while
mount verification is enabled, you can follow the steps in the procedure
below to resume operations.
Procedure

A Files-11 disk volume is mounted for writing (the /WRITE qualifier is
the default). Through some hardware or user error, the disk becomes
write-locked.

The software discovers that the disk is write-locked (typically an 1/0
fails with a write-lock error). The disk is marked that verification is in
progress. OPCOM issues a message to the operators enabled for DISKS
and DEVICES to announce the disk's unavailability, as follows:
OPCOM, dd-mmm-yyyy hh:mm:ss.cc
Device device-name has been write-locked.
Mount verification in progress.

Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.

Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.

You may simply choose to take the disk out of the verification pending
state by shutting down mount verification with one of the techniques
described in Sections 7.3.3 and 7.3.4. These techniques cause the
pending and future I/Os to the volume to fail.

Otherwise, you take corrective action. Perhaps the drive can simply
be write enabled by toggling the drive's hardware write-lock switch. If
the disk drive is faulty, but another functioning drive is available on
the same controller, you can move the disk to the functioning drive
and swap the unit select plugs. (Note that switching to another drive
will cause the volume to undergo offline mount verification. Once that
completes, the write-lock mount verification continues.)

The mount verification software that polls the disk drive determines
that the volume is in a writable state. At this point, 1/0 operations to
the disk are allowed to proceed. However, OPCOM does not issue a
message indicating that the write-lock mount verification has completed.

Example
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, 29-JUN-1986 16:28:64.07
Device DMA1: has been write-locked.
Mount verification in progress.

Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.

The OPCOM message informs you that device DMAl: is write-locked. You
toggle the write-lock switch on the drive to eliminate the write lock. 1/0
operations to the disk resume, with no further messages.

7-13

Handling Operator-Oriented Disk and Magnetic Tape Functions

7 .4.3

Canceling Mount Verification
If you fail to either bring a system disk back on line or to write-enable it as
appropriate while mount verification is enabled, the whole system can hang,
because normal system operation depends on performing 1/0 to the system
disk. This problem extends to other public disks that contain secondary
paging and swap files, the authorization database, and so forth. Failure to
bring such a disk back on line is generally fatal to the system.

In addition, obscure interdependencies within VAX/VMS may cause the
system to suspend activity in rare circumstances - even when a nonsystem
disk goes off line. If this type of problem occurs, you can clear it by using
either the first or second technique described below for canceling mount
verification requests.
Normally, you can cancel a mount verification request in one of three ways:

Allow the mount verification in progress to continue for the number of
seconds defined by the system parameter MVTIMEOUT. When the time
expires, the system automatically cancels th~ pending mount verification.
Note that a mount verification initiated by a write-lock will not time out.

Invoke a special canceling routine from the console terminal.

3 Dismount the volume with the DCL command DISMOUNT from a
process that is not hung.

7 .4.4

Dismounting a Volume to Abort Mount Verification
In some cases, a user can abort mount verification by dismounting the
volume in question. This only works if it is possible for the user to issue the
DCL command DISMOUNT for the volume (for example, if the system file
ACP is not hung).
Procedure

2 Enter the DCL command DISMOUNT/ABORT for the volume
3 When you cancel a pending mount verification by dismounting the
volume, OPCOM issues the following message:
Y.Y.Y.Y.Y.Y.Y.Y.Y.Y.Y. OPCOM, dd-mmm-yyyy hh:mm:ss.cc Y.Y.Y.Y.Y.Y.Y.7.Y.Y.7.
Mount verification aborted for device device-name

7-14

Handling Operator-Oriented Disk and Magnetic Tape Functions

If you do not have access to the volume, you will receive an error
message. You can try again if you can find an appropriate process to
use. If your process hangs, it is the system file ACP that is hung (first
condition above was not met), and you cannot use this technique to
cancel mount verification.

Once the cancellation succeeds, remove the volume from the drive.

For more information on Mount Verification, see the description in VAX/VMS
System Manager's Reference Manual.

7-15

A
A. 1

VAX/VMS Disk Files and Volumes

Files-11 Disk Structure
The VAX/VMS system recognizes two disk file structures: Files-11 On-Disk
Structure Level 1 and Files-11 On-Disk Structure Level 2. Files-11 On-Disk
Structure Level 2 is the default disk structure of the VAX/VMS system,
and Files-11 On-Disk Structure Level 1 is a structure used by DIGITAL's
RSX-llM, RSX-llD, RSX-llM-PLUS, and IAS operating systems.
Nine files control the structure of a Files-11 On-Disk Structure Level 2
volume. Only five of these files are used for a Files-11 On-Disk Structure
Level 1 volume. Table A-1 identifies all nine files, which are referred to as
reserved files, and indicates to which Files-11 On-Disk Structure Level they
pertain.

Table A-1

VAX/VMS Reserved Files

Reserved File

File Name

Index file

INDEXF.SYS;1

Storage bit map file

BITMAP .SYS; 1

Bad block file

BADBLK.SYS; 1

Master file directory

000000.DIR; 1

Core image file

CORIMG.SYS; 1

Volume set list file

VOLSET.SYS;1

Continuation file

CONTIN.SYS; 1

Backup log file

BACKUP.SYS; 1

Pending bad block

BADLOG.SYS; 1

Structure
Level 1

Structure
Level 2

x
x
x
x
x

x
x
x
x
x
x
x
x
x

All the files listed in Table A-1 are listed in the master file directory (MFD),
[000000].

A-1

VAX/VMS Disk Files and Volumes

A.1.1

Index File
Every Files-11 volume has an index file, which is created when the volume
is initialized. This index file identifies the volume to the operating system as
a Files-11 structure and contains the access data for all files on the volume.
The index file, which is listed in the master file directory as INDEXF.SYS;l,
contains the following information:

A.1 .2

•

Bootstrap block - The volume's bootstrap block is virtual block number
1 of the index file. If the volume is a system volume, this block contains
a bootstrap program that loads the operating system into memory. If
the volume is not a system volume, this block contains a program that
displays a message that the volume is not the system device but a device
that contains users' files only.

•

Home block - The home block establishes the specific identity of the
volume, providing such information as the volume name and protection,
the maximum number of files allowed on the volume, and the volume
ownership information. The home block is virtual block number 2 of the
index file.

•

Backup home block - The backup home block is a copy of the home
block. It permits the volume to be used even if the primary home block
is destroyed.

•

Backup index file header - The backup index file header permits
recovery of data on the volume if the index file header becomes
damaged.

•

Index file bit map - The index file bit map controls the allocation of
file headers and thus the number of files on the volume. The bit map
contains a bit for each file header that is allowed on the volume. If the
value ofa bit for a given file header is 0, a file can be created with this
file header. If the value is 1, the file header is already in use.

•

File headers - The largest part of the index file is made up of file
headers. Each file on the volume has a file header, which describes
such properties of the file as file ownership, creation date and time, file
protection, and location of the data in the file. The file header points to
all the information needed for gaining access to the file.

Storage Bit Map File
The storage bit map file controls the available space on a volume; this
file is listed in the master file directory as BITMAP.SYS;l. It contains a
storage control block, which consists of summary information intended to
optimize the Files-11 space allocation, and the bit map itself, which lists the
availability of individual blocks.

A-2

VAX/VMS Disk Files and Volumes

A. 1 .3

Bad Block File
The bad block file, which is listed in the master file directory as
BADBLK.SYS;l, contains all the bad blocks on the volume. The system
detects bad disk blocks dynamically and prevents their reuse once the files to
which they are allocated have been deleted.

A. 1 .4

Master File Directory
The master file directory (MFD) itself is listed in the MFD as 000000.DIR;l.
The MFD, which is the root of the volume's directory structure, lists the
reserved files that control the volume structure and may list both users' files
and users' file directories. Usually, however, the MFD is used to list the
reserved files and users' file directories; users seldom enter files in the MFD,
even on private volumes. In fact, on a private volume, it is most convenient
for a user to create a directory that has the same name as the user's default
directory on a system disk. For an explanation of users' file directories and
file specifications, see the VAX/VMS DCL Concepts Manual.
When the VAX/VMS Backup Utility (BACKUP) creates sequential-disk
save sets, it stores the save-set file in the MFD. (See Section 6.4.3.2 for a
discussion of sequential-disk save sets.)

A.1 .5

Core Image File
The core image file is listed in the MFD as CORIMG.SYS;l. It is not
supported by VAX/VMS.

A.1.6

Volume Set List File
The volume set list file is listed in the MFD as VOLSET.SYS;l. This file is
used only on relative volume 1 of a volume set. The file contains a list of the
labels of all the volumes in the set and the name of the volume set.

A.1 .7

Continuation File
The continuation file is listed in the MFD as CONTIN.SYS;l. This file is
used as the extension file identifier when a file crosses from one volume to
another volume of a loosely coupled volume set. This file is used for all
but the first volume of a sequential-disk save set (see Section 6.4.3.2 for a
discussion of sequential-disk save sets).

A-3

VAX/VMS Disk Files and Volumes

A.1 .8

Backup Log File
The backup log file is listed in the MFD as BACKUP.SYS;!. This file is
reserved for future use.

A.1.9

Pending Bad Block Log File
The pending bad block log file is listed in the MFD as BADLOG.SYS;l. This
file contains a list of suspected bad blocks on the volume that are not listed
in the bad block file.

A.1 .10

Files-11 On-Disk Structure Level 1 Versus Structure Level 2
Files-11 On-Disk Structure Level 2, a compatible superset of Structure Level
l, is the preferred disk structure on VAX/VMS for reasons of performance
and reliability. At volume initialization time (see the INITIALIZE command
in the VAX/VMS DCL Dictionary), Structure Level 2 is the default. Structure
Level 1 should be specified only for volumes that must be transportable to
RSX-llM, RSX-110, RSX-llM-PLUS, and IAS systems, as these systems
support only that structure level. Additionally, you may be required to
handle Structure Level 1 volumes transported to VAX/VMS from one of the
above systems.
Where Structure Level 1 volumes are in use on the system, you should bear
in mind the following limitations on them:
•

Directories - No hierarchies of directories and subdirectories, and no
ordering of directory entries (that is, the file names) in any way (RSXllM, RSX-11D, RSX-11M-PLUS, and IAS systems do not support
subdirectories and alphabetical directory entries)

•

Disk quotas -

•

Multivolume files and volume sets -

•

Placement control -

•

Caches - No caching of file header blocks, file identification slots, or
extent entries

•

System disk -

•

VAXcluster access -

•

Clustered allocation -

Not supported

•

Backup home block -

Not supported

A-4

Not supported
Not supported

Not supported

Cannot be a Structure Level 1 volume
Local access only; cannot be shared across a cluster

VAX/VMS Disk Files and Volumes

•

Protection code E VAX/VMS

Means extend for RSX- llM but is ignored by

•

File versions -

•

Enhanced protection features (for example, access control lists) are not
supported

Limited to 32,767; version limits are not supported

Future enhancements to VAX/VMS will be based primarily on Structure
Level 2, so that further restrictions on Structure Level 1 volumes may be
incurred.

A-5

VAX/VMS ANSI-Labeled Magnetic Tape

This appendix briefly describes ANSI labels, data, and record formats
supported by VAX/VMS. It also describes support for the various ANSI
labels on VAX/VMS. For a complete description of these labels, please refer
to the ANSI standard (American National Standard X3.27-1978). Use this
standard to write VAX/VMS standard tapes.

8.1

Logical Format of ANSI-Labeled Volumes
The format of VAX/VMS ANSI-labeled magnetic tape volumes is based on
Level 3 of the ANSI standard for magnetic tape labels and file structure for
information interchange. This standard specifies the format, content, and
sequence of volume labels, file labels, and file structures. According to this
standard, volumes are written and read on 9-track magnetic tape drives only.
The contents of labels must conform to prescribed data and record formats.
All labels must consist of ASCII "a" characters.
The VAX/VMS ANSI-labeled format allows you to write binary data in the
file sections (see Figure B-1) of files. However, if you plan to use such files
for information interchange across systems, make sure that the recipient
system can read the binary data.

8.2

VAX/VMS Magnetic Tape Ancillary Control Process (MTAACP)
The VAX/VMS magnetic tape ancillary control process (MTAACP) is the
internal software process of the operating system that interprets the logical
format of VAX/VMS ANSI-labeled volumes. Transparent to your process,
the MTAACP process reads, writes, and interprets VAX/VMS ANSI labels
before passing this information to VAX Record Management Services (RMS)
and Queue 1/0 ($QIO) system services. These services in tum read, write,
and interpret the record format of the data written in the file section.

B-1

VAX/VMS ANSI-Labeled Magnetic Tape

8.3

Basic Components of the VAX/VMS ANSI-Labeled Format
The format of VAX/VMS ANSI-labeled magnetic tape consists of four basic
components:
•

Beginning-of-tape (BOT) and end-of-tape (EOT) markers

•

tape marks

•

file sections

•

volume, header, and trailer labels.

Figure B-1 displays the arrangement and function of these components.

B.3.1

Beginning-of-Tape and End-of-Tape Markers
Every volume has beginning-of-tape (BOT) and end-of-tape (EOT) markers.
These markers are pieces of photoreflective tape that delimit the writable
area on a volume. ANSI standards require that a minimum of 14 feet to a
maximum of 18 feet of magnetic tape precede the BOT marker; a minimum
of 25 feet to a maximum of 30 feet of magnetic tape, of which 10 feet must
be writable, must follow the EOT marker. The EOT marker indicates the
start of the end of the writable area of the tape, rather than the physical end
of the tape. Therefore, data and labels can be written after the EOT marker.

B.3.2

Tape Marks
Tape marks separate the file labels from the file sections, separate one
file from another, and denote the logical end-of-volume. On the basis of
the number and relative placement of tape marks written on a volume,
VAX/VMS determines whether a tape mark delimits a label, a file, or a
volume.
Tape marks are written both singly and in pairs. Single tape marks separate
either a file section from the header and trailer labels or one file from
another. When written after a set of header labels, a single tape mark signals
the beginning of a file section. When written before a set of trailer labels,
a single tape mark indicates the end of a file section. When written after a
trailer label set, a single tape mark separates one file from another.
Double tape marks indicate that either an empty file section exists or that
the logical end-of-volume has been reached. A VAX/VMS system creates an
empty file when a volume is initialized.

B-2

VAX/VMS ANSI-Labeled Magnetic Tape

Figure B-1

Basic Layout of a VAX/VMS ANSI-Labeled Volume
~

Beginning-of-Tape
Marker (BOT)
Volume Label
(VOL1)
File Header Labels
(HDR1, HDR2, HDR3)
Tape Mark (TM)

File Section

Tape Mark (TM)
File Trailer Labels
(EOF1, EOF2, EOF3,
EOV1, EOV2, EOV3)
Tape Mark

Tape Mark

Marks beginning of writeable area on a volume

Identifies the volume

Describes and delimits each file

Separates header labels from file section

Contains user data. Data in volumes interchanged to
non-VAX/VMS systems must be ASCII "a" characters.
Data in volumes interchanged to VAX/VMS systems can
be in binary form.

Separates file section from trailer labels
Describes and delimits files. When a volume is continued, EOV labels are written instead of EOF labels. EOF3
or EOV3 labels are written only when a HDR3 label is
written.
Indicates the logical end-of-volume. Two consecutive
tape marks are always written after the trailer labels of
the last file on a volume.

Scratch Tape

Indicates tape that is blank or that has not yet been
overwritten. Scratch tape can exist between the logical
end of volume and the EOT marker.

End of Tape
Marker (EOT)

Marks beginning of the end of the writeable area.

ZK-981-82

B-3

VAX/VMS ANSI-Labeled Magnetic Tape

B.3.3

Labels
Labels identify, describe, and control access to volumes and their files.
VAX/VMS ANSI-labeled format supports volume, header, and trailer labels.
The volume labels are the first labels written on a volume. They identify
the volume and the volume owner and specify access protection. Header
and trailer labels are sets of labels that identify, describe, and delimit files.
Header labels precede files; trailer labels follow files.
Table B-1 lists the labels supported by VAX/VMS. All other ANSI labels are
ignored by VAX/VMS on input.
Although each type of label uses a different format to organize its contents,
all labels conforming to Version 3 of the ANSI standard must consist of
ASCII "a" characters. Some labels contain reserved fields designed for future
system use or future ANSI standardization. Reserved fields also must consist
of ASCII "a" characters; however, VAX/VMS ignores these characters on
input.

B.4

Volume and File Configurations
VAX/VMS ANSI-labeled volumes support four file/volume configurations:
•

single file/single volume

•

single file/multivolume

•

multifile /single volume

•

multifile/multivolume.

All these configurations conform to the following guidelines:
•

The file sequence number field allows as many as 9999 file sections for
one file. In effect, the file length is unlimited.

•

Only one file section of a given file is written on a volume.

•

When multiple sections exist for one file, each file section is written
to a separate volume in the volume set. The file section numbers of
each section are written consecutively in ascending order (section n+l is
written immediately following section n); file sections of other files are
not interspersed.

Each of the file/volume configurations is illustrated in the subsections that
follow.

B-4

VAX/VMS ANSI-Labeled Magnetic Tape

Table B-1

Labels and Components Supported by VAX/VMS
Symbol

Meaning

BOT

Beginning-of-tape marker

EOF1

First end-of-file label

EOF2

Second end-of-file label

EOF3

Third end-of-file label

EOF4

Fourth end-of-file label

EQT

End-of-tape marker label

EOV1

First end-of-volume label

EOV2

Second end-of-volume label

EOV3

Third end-of-volume label

EOV4

Fourth end-of-volume label

HDR1

First header label

HDR2

Second header label

HDR3

Third header label

HDR4

Fourth header label

VOL1

First volume label

VOL2

Second volume label

Tape mark

TMTM

Double tape mark indicates an empty file section or the logical
end-of-volume

B-5

VAX/VMS ANSI-Labeled Magnetic Tape

B.4.1

Single File/Single Volume Configuration
A single file/single volume configuration consists of one file on one volume.
The components of the ANSI-labeled format for this configuration are
illustrated in Figure B-2.

Figure B-2

• • •

Single File/Single Volume Configuration

BOT

VOL1

HDR1

HDR2

HDR3

First File

EOF1

EOF2

EOF3

TM TM

Scratch
Tape

•••
ZK-346-81

B-6

VAX/VMS ANSI-Labeled Magnetic Tape

B.4.2

Single File/Multivolume Configuration
A single file/multivolume configuration consists of one file that spans two or
more volumes in a volume set. Figure B-3 illustrates the components of the
ANSI-labeled format for this configuration.

Figure 8-3

Single File/Multivolume Configuration

• • •

BOT

VOL 1

HDR1

HDR2

HDR3

First Section of First File

EOV2

EOV3

TM TM

• • •

HDR2

HDR3

EOT

• • •

Continuation Volume

• • •

BOT

VOL 1

HDR1

Second Section of File

EOF3

TM TM

• • •

*When the driver encounters an EQT marker during a write operation, the MTAACP writes
the approP.riate trailer labels and performs a volume switch, if necessary.
ZK-347-81

B-7

VAX/VMS ANSI-Labeled Magnetic Tape

B.4.3

Multifile/Single Volume Configuration
A multifile/single volume configuration consists of two or more files on
a single volume. It is the most common file and volume configuration.
Figure B-4 illustrates the components of the ANSI-labeled format for this
configuration.

Figure 8-4 Multifile/Single Volume Configuration

• • •

BOT

HDR1

VOL 1

HDR2

HDR3

First File

TM EOF1

EOF2

EOF3

HDR1

HDR2

Second File

EOF1

EOF2

EOF3

TM TM

Scratch
Tape

EQT

Scratch
Tape
ZK-345-81

B-8

VAX/VMS ANSI-Labeled Magnetic Tape

8.4.4

Multifile/Multivolume Configuration
A multifile/multivolume configuration consists of two or more files that span
two or more volumes in the same volume set. Figure B-5 illustrates the
components of the ANSI-labeled format for this configuration.

Figure B-5

• • •

Multifile/Multivolume Configuration

BOT

VOL 1

HDR1

HDR2

HDR3

First File

EOF3

HDR1

HDR2

First Section of Second File

EOV2

EOV3

TM TM

• • •
ZK-348-81

B.5

VOLUME LABELS
The sections that follow describe the first volume (VOLl) and second volume
(VOL2) labels.

8.5.1

VOL 1 Label
The SO-character volume label (VOLl) is the first label written on a
VAX/VMS ANSI-labeled volume. It defines the label type, name, and
owner of the volume. Although there are many fields in a VOLl label, this
section describes only those fields that you can access or that can inhibit
access to a volume and its files on VAX/VMS.

B-9

VAX/VMS ANSI-Labeled Magnetic Tape

B.5.1.1

Volume Identifier Field

The volume identifier field is a 6-character field that contains the name of the
volume. You specify the volume identifier in the command string when you
initialize or mount a volume (see Chapter 4). The volume identifier consists
of six ASCII "a" characters. Lowercase characters are not in the "a" set, but if
you specify them, VAX/VMS will change them to uppercase. If you specify
fewer than six characters, VAX/VMS pads the field by right-justifying the
field with the ASCII space character.
B.5.1.2

Accessibility Field

The accessibility field is a 1-character field that allows an installation to
control access to a volume. See Section 2.1.3 for a description of accessibility
support.
B.5.1 .3

Implementation Identifier Field

The implementation identifier field contains the identifier of the
implementation that creates the magnetic tape. This field controls how
certain implementation-specific fields and volume labels are interpreted. The
magnetic tape file system's implementation identifier is DECFILEII A.
B.5.1.4

Owner Identifier Field

The owner identifier field is available to the user. This field does not affect
the checking of a user's access to a volume, except as noted in Chapter 2 of
this guide.

B.5.2

VOL2 Label
In addition to the first volume (VOLl) label described above, VAX/VMS also
provides a second volume (VOL2) label.
The next section describes the volume-owner field of the VOL2 label.

B-10

VAX/VMS ANSI-Labeled Magnetic Tape

B.5.2.1

Volume-Owner Field

The volume-owner field contains the VAX/VMS protection information that
has been written on the magnetic tape. A second volume label is written
only if a VAX/VMS protection scheme had been specified on either the
MOUNT or INITIALIZE command.
The volume-owner field also contains a value that incorporates the user
identification code (UIC) with the VAX/VMS protection code specified for
a volume. By default, VAX/VMS does not write a UIC to this field, thus
allowing all users READ and WRITE access. Note, however, that EXECUTE
and DELETE access are not applicable to magnetic tape volumes. Also
note that regardless of the protection code that you specify, both SYSTEM
users and the volume owner always have READ and WRITE access to a
volume. The contents of the volume-owner field depends on the VAX/VMS
protection code that you specify.

B.6

Header Labels
VAX/VMS supports four file header labels: HDRl, HDR2, HDR3, and
HDR4. The HDR3 and HDR4 labels are optional. The following sections
describe and illustrate each file header label.

B.6.1

HDR1
Every file on a volume has a HDRl label, which identifies and describes the
file by supplying the VAX/VMS MTAACP with the following information:
•

File identifier

•

File-set identifier

•

File section number

•

File sequence number

•

Generation and generation version numbers

•

File creation and expiration dates

•

Accessibility code

•

Implementation identifier

B-11

VAX/VMS ANSI-Labeled Magnetic Tape

B.6.1.1

File Identifier Field
The file identifier field contains the first 17 characters of the file name that
you specify. The remainder of the file name is written into the HDR4 label,
provided that this label is allowed. If no HDR4 label is supported, a file
name longer than 17 characters will be truncated. You may use either an
ANSI file name or a VAX/VMS file specification of the following format:
filename.type;version

VAX/VMS file specifications are a subset of ANSI file names. However,
ANSI file names are valid only for magnetic tape volumes; VAX/VMS file
specifications are valid for disk and tape volumes. Both types of file specifiers
are compatible with compatibility mode.
A VAX/VMS file specification consists of a file name, a file type, and an
optional version number. Valid file names contain a maximum of 39
characters. Valid file types consist of a period followed by a maximum
of 39 characters. The semicolon separates the version number from the file
type.
Except for wildcard characters, only the characters: A through Z, 0 through
9, and the special characters ampersand ( & ), hyphen ( - ), and dollar sign ( $)
are valid for VAX/VMS file names and types. The period and semicolon are
the only valid special characters, and they are always separators.
ANSI file names do not have a file type field. An ANSI file name consists of
a 17-character name string, a period, a semicolon, and an optional version
number. You can specify a name string consisting of a maximum of 17 ASCII
"an characters, but you must enclose the string in a pair of quotation marks
(as in, for example, "file name"). When you specify fewer than 17 characters,
the string is padded on the right with spaces to the 17-character maximum
size. If you specify a file name that has trailing spaces, VAX/VMS truncates
them when the file name is returned. In addition, the space-padded field
prevents you from specifying a unique file name that consists of spaces.
-Although you can specify longer file names - up to 79 characters the first 17 characters of the file name will be used in interchange.

only

The quotation mark character requires special treatment because it is both
the file name delimiter and a valid ASCII "an character that can itself be
embedded in the name string. You must specify two quotation marks for
each one that you want VAX/VMS to interpret. The additional quotation
mark informs VAX/VMS that one of the quotation marks is part of the name
string, rather than a delimiter.
Embedded spaces also are valid characters, but embedded tabs are not.
Lowercase characters are not in the ASCII "an character set but if you specify
them, VAX/VMS converts them to uppercase characters.
B-12

VAX/VMS ANSI-Labeled Magnetic Tape

If you do not specify a file type or version number on input, VAX/VMS will
supply a period (the default file type) and a semicolon (the default version
number). However, the period and semicolon will not be written to this field
on the tape.

Although VAX/VMS considers version numbers for ANSI and VAX/VMS
file names to be part of the file name specification, the version number of a
file is not written to the file identifier field, but is mapped to the generation
number and generation version number fields as described in Section B.6.1.4.
Examples below display ANSI file names. The input is the format that you
specify. The output shown displays the VAX/VMS format returned to your
process and the format written to the label. The number sign ( #) in the
examples indicates a space character. In the last example, a VAX/VMS file
name is enclosed in quotation marks, like an ANSI file name, on input.
However, the VAX/VMS operating system returns the file name to the
process as a VAX/VMS file name, rather than an ANSI file name. Therefore,
when you enclose a valid VAX/VMS file name in quotation marks on input,
VAX/VMS parses the file name as a VAX/VMS file name.
Input

"AB2ctD""FgHI•k4""#-M";2

Output to User Process

Output to HDR1 Label

"AB2&D 1111 FGHI•K4 1111 #-M 11 ;2

AB2&D"FGHI•K4 11 #-M

"1###1###1#"

"" ·;

nn11nnnnnnn11n11nnn1111nnnnnn11n11;

11n1111111111111111n111111111111111111111111111111n11.,

#################
llllllllllHllllllllllllll####

"DWDEVOP.DAT 11

DWDEVOP.DAT;

DWDEVOP.DAT######

"VMS_LONG_FILENAME.LONG_FILETYPE"

VMS_LONG_FILENAME.LONG_FILETYPE

VMS_LONG_FILENAME

B.6.1.2

File-Set Identifier Field
The 6-character file-set identifier field denotes all files that belong to the
same volume set. The file-set identifier for any file within a given volume set
should always be the same as the file-set identifier of the first file on the first
volume that you tnount. For VAX/VMS, the file-set identifier is the same as
the volume identifier of the first volume that you mount.

B.6.1.3

File Section Number and File Sequence Number Fields
The file section number is a 4-character field that specifies the number of the
file section.
The file sequence number is a 4-character field that specifies the number of
the file in a file set.

VAX/VMS ANSI-Labeled Magnetic Tape

B.6.1.4

Generation Number and Generation-Version Number Fields

The generation number (a decimal number from 0001 to 9999) and
generation-version number (a 2-digit decimal number) fields store the file
version number that is specified on input and written by VAX/VMS on
output. The VAX/VMS operating system does not increment the version
number of a file, even when the version of the specified file already exists
on the volume. Therefore, if the file that you specify has the same file name
and version number as an existing file, you will have at least two files with
the same version number on the same volume set.
On input, VAX/VMS computes the version number by using this calculation:
version number =
[(generation number - 1)100] + generation-version number + 1

Version numbers larger than 32767 are divided by 32768; the integer
remainder becomes the version number.
On output, the generation number is derived from the version number with
this calculation:
generation number = [(version number - 1)/100] + 1

If there is a remainder after the version number is divided by 100, the
remainder becomes the generation-version number. It is not added to 1 to
form the generation number.

B.6.1.5

Creation Date and Expiration Date Fields

The creation date field contains the date the file is created. The expiration
date field contains the date the file expires. VAX/VMS interprets the
expiration date of the first file on a volume as the date that both the file
and the volume expire. VAX/VMS stores the creation and expiration dates in
the Julian format. This 6-character format {#YYDDD) consists of a space ( # ),
the year, and the day. Only dates are relevant for these fields; time is always
returned as 00:00:00:00.
By default, VAX/VMS writes the current date to both the creation and
expiration date fields when you create a file. Because the expiration date
is the same as the creation date, the file expires on creation and you can
overwrite it immediately. If the expiration date is a date that is later than the
creation date and if the files that you want to overwrite have not expired, you
must specify the /OVERRIDE=EXPIRATION qualifier with the INITIALIZE
or MOUNT command.
To write dates other than the VAX/VMS defaults in the date fields in this
label, specify the creation date field (CDT) and the expiration date field (EDT)
of the RMS date and time extended attribute block (XABDAT).
B-14

VAX/VMS ANSI-Labeled Magnetic Tape

When you do not specify a creation date, RMS defaults the current date to
the creation date field.
To specify a zero creation date, you must specify a year before 1900. If you
specify a binary zero in the date field, the system will write the current date
to the field.
For details on the XABDAT, see the VAX Record Management Services

Reference Manual.
B.6.1.6

Accessibility Field

The contents of this field are described previously, in the volume label use of
accessibility.
B.6.1. 7

Implementation Identifier Field

The implementation identifier field specifies, using ASCII "a" characters, an
identification of the implementation that recorded the Volume Header Label
Set.

B.6.2

HDR2 LABEL
The HDR2 label describes the record format, maximum record size, and
maximum block size of a file.

B.6.2.1

Record Format Field

The record format field specifies the type of record format the file contains.
The VAX/VMS operating system supports two record formats: fixed length
(F) and variable length (D). When files contain record formats that VAX/VMS
does not support, VAX/VMS cannot interpret the formats and classifies them
as undefined.
Fixed-length records are all the same length. No indication of the record
length is required within the records because either the HDR2 label defines
the record length, or you specify the record length with the /RECORDSIZE
qualifier.
A fixed-length record can be a complete block, or several records can be
grouped together in a block.
When records are blocked, it is not necessary that the block be filled with
data. If a block is not filled, it will be padded with circumflex characters
(" ). This means that you cannot have a fixed-length record containing only
circumflexes; the system will interpret this as padding, not data.
B-15

VAX/VMS ANSI-Labeled Magnetic Tape

Figure B-6 shows a block of fixed-length records. Each record has a fixed
length of 50 bytes. All six records are contained in a 300-byte block. The
records are blocked-that is, grouped together as one entity-to increase
processing efficiency; when records are blocked, you can access many of
them with one I/O request. The block size should be a multiple of the
record size.
Figure B-6

REC
50 Bytes

Blocked Fixed-Length Records

REC
50 Bytes

BLOCK
300 Bytes

ZK-353-81

The size of a variable-length record is indicated by a record control word
(RCW). The RCW consists of four bytes at the beginning of each record. A
variable-length record can be a complete block, or several records can be
grouped together in a block.
Two variable-length records are shown in Figure B-7. The first consists of 54
bytes, including the RCW. The second consists of 112 bytes, including the
RCW. The records are contained in a 166-byte block.
Do not use system-dependent record formats on volumes used for
information interchange. VAX/VMS system-dependent formats are stream
and variable with fixed-length control (VFC).

B-16

VAX/VMS ANSI-Labeled Magnetic Tape

Figure B-7

Variable-Length Records

Record Size = 54 Bytes

Record Size = 112 Bytes

r-------------\ - - - - - - - - - -------RCW
54

DATA
50 Bytes

RCW
112

DATA
108 Bytes

Pad
Characters
14 Bytes

BLOCK
180 Bytes

ZK-354-81

B.6.2.2

Block Length Field

The block length field denotes the maximum size of the blocks. According to
the ANSI standard, valid block sizes range from 18 to 2048 bytes. However,
VAX /VMS allows you to specify a smaller or larger block size using the
/BLOCKSIZE qualifier with the MOUNT command. To specify the block
size using RMS, see the BLS field in the file access block (FAB) in the VAX
Record Management Services Reference Manual. When you specify a block size
that is outside the ANSI standard range, the volume may not be processed
correctly by other systems that support the ANSI standards.
B.6.2.3

Record Length Field

The record length field denotes either the size of fixed-length records or the
maximum size of variable-length records in a file. Valid VAX/VMS record
sizes vary, depending on the record format. The range for fixed-length
records is 1 to 65 ,534 bytes; the range for variable-length records is 4 to
9,999 bytes, including the 4-byte RCW. Therefore, the maximum length of
the data area of a variable-length record is 9,995 bytes. To comply with
ANSI standards, the record size should not be larger than the maximum
block size of 2,048 bytes, even though VAX/VMS allows larger record sizes
(when the block size is larger).

B-17

VAX/VMS ANSI-Labeled Magnetic Tape

For volumes containing files that do not have HDR2 labels, you must specify
MOUNT /RECORDSIZE=n at mount time. The variable n denotes the record
length in bytes. Files without HDR2 labels were created by a system that
supports only level 1 or 2 of the ANSI standard for magnetic tape labels and
file structure. Records should be fixed length because this is the only record
format that either level supports. If you do not specify a record size, each
block will be considered a single rec()rd.
B.6.2.4

Implementation-Dependent Field

The implementation-dependent field contains two 1-character subfields that
describe how VAX/VMS interprets record format and form control.
The first subfield, character position 16, denotes whether the RMS attributes
are in this label or the HDR3 label. If character position 16 contains a space,
the RMS attributes are in the HDR3 label; if it contains any character other
than a space, character position 16 is the first byte of the RMS attributes in
the HDR2 label. The attributes appear in character positions 16 through 36
and 38 through 50.
For volumes created by any version of VAX/VMS up to and including
Version 2.0, the system-dependent fields of the HDR2 label contain the
RMS file attributes in binary format. For volumes created on versions of
VAX/VMS later than Version 2.0 (Version 2.1 to the present), the magnetic
tape file system stores the RMS attributes.
The second subfield, the form control field at character position 37, specifies
the form control that defines the carriage control applied to records within
a file. Possible values supported for VAX/VMS magnetic tape volumes are
listed below.

B.6.2.5

First byte of record contains FORTRAN control characters.

The record contains all form control information.

space

Line-feed/carriage-return combination is to be inserted between records
when the records are written to a carriage-control device, such as a
line printer or terminal. If form control is not specified when a file is
created, this is the default.

Buffer-Offset Length Field

For implementations that support buffer offsets, the buffer-offset length
field indicates the length of information that prefixes each data block. The
magnetic tape file system supports the input of buffer offset, which means
that the buffer offset length obtained from the HDR2 label (when reading
the file) is used to determine the actual start of the data block. The magnetic
tape file system does not support the writing of a buffer offset.

B-18

VAX/VMS ANSI-Labeled Magnetic Tape

Note that if you open a file for append or update access, and the buffer-offset
length is nonzero, the open operation will not succeed.

B.6.3

HDR3 LABEL
The HDR3 label describes the RMS file attributes. For RMS operations,
data in the HDR3 label supersedes data in the HDR2 label. To write a VAX
standard tape use the current ANSI standard.
Although the HDR3 label usually exists for every file on a VAX/VMS ANSIlabeled volume, there are two situations in which this label will not be
written. The first is when an empty dummy file is created during volume
initialization; no HDR3 label is written because the empty file does not
require RMS attributes. The second is when you specify MOUNT /NOHDR3
at mount time. You should use the /NOHDR3 qualifier when you create
files on volumes that will be interchanged to systems that do not process
HDR3 labels correctly.
The RMS attributes describe the record format of a file. These attributes are
converted from 32 bytes of binary values to 64 bytes of ASCII representations
of their hexadecimal equivalents for storage in the HDR3 label.

B.6.4

HDR4 Label
The HDR4 label contains the remainder of a VAX/VMS file name that would
not fit in the HDRl file identifier field. To write a VAX standard tape use the
current ANSI standard.

B.7

Trailer Labels
VAX/VMS supports two sets of trailer labels: end-of-file (EOF) and end-ofvolume (EOV). A trailer label is written for each header label.
EOF and EOV labels are identical to their file header label counterparts
except that:
•

The label identifier field (characters 1-3) contains EOF or EOV.

•

The block count field (characters 55-60) in the EOFl and EOVl labels
contains the number of data blocks in the file section.

The particular label that VAX/VMS writes depends on whether a file extends
beyond a volume. If a file terminates within the limits of a volume, EOF
labels are written to delimit the file (see Figure B-2). If a file extends across
volume boundaries before terminating, EOV labels are written, indicating
that the file continues on another volume (see Figure B-3).
R-1Q

Index
A
Access
append• 4-23
CONTROL• 2-2, 2-9, 2-11, 2-12
DELETE•2-2, 2-9, 2-11, 2-12
EXECUTE• 2-2, 2-9, 2-11, 2-12
file attributes• 4-22
READ• 2-2, 2-9, 2-11
to file• B-15
magnetic tape• 4-19
to volume
magnetic tape• 4-19
types of•4-24
update• 4-23
WRITE• 2-2, 2-9, 2-11
Access category
GROUP•2-2
OWNER•2-2
summary of• 2-2
SYSTEM•2-2
WORLD•2-2
Access control list
See ACL
Accessibility field• 2-13, B-10, B-15
ACL (access control list)
defining with DCL • 2-4
description• 2-4
modifying characteristics• 4-10
ACL-based protection• 2-4
See also ACL
ALLOCATE command• 3-25
See also Allocation
magnetic tape• 4-18, 5-3
Allocation
of disk volume• 4-9, 4-10
of drive• 3-2
disk•3-2
generic• 3-3, 3-4
magnetic tape• 3-3

Allocation (cont'd.)
of magnetic tape volume• 4-18
Analyze/RMS_File Utility
(ANALYZE/RMS_ FILE)• 5-8
ANSI data • B-1
ANSI file name• 4-21, B-12
ANSI-labeled volume• B-1, B-4
accessibility protection• 2-5
copying files from• 5-3 ,
Append access• 4-23
ASCII "a" characters• 5-4, B-1
ASCII "a" character set• B-1, B-4
percent sign• 4-22
Asterisk (*) • 4-21, 4-22
Automatic volume labeling (A VL)
See AVL
Automatic volume recognition (A VR)
See AVA
A VL operator function • 7-5
A VR operator function • 7-5

B
BACKUP
See Backup Utility
BACKUP.SYS• A-4
Backup home block• A-2
Backup index file header• A-2
Backup log file• A-4
Backup Utility (BACKUP)• 6-2
backup media • 6-6
Files-11 disk•6-7, 6-16
magnetic tape• 6-7, 6-13
remote save set• 6-9
rotating backup set• 6-9
sequential disk • 6-8
batch mode • 7-8
command procedure • 6-30
comparing files• 6-27
See also Compare operation

Index

Backup Utility (BACKUP) (cont'd.)
copy
See Copy operation
full-volume save• 6-18
initializing a magnetic tape• 6-13
invoking • 6-6
journal file• 6-28
journal files• 6-28
listing files• 6-26
See also List operation
magnetic tape • 6-7
operations
compare • 6-2 7
See also Compare operation
copy• 6-11 to 6-13
See also Copy operation
image•6-12, 6-15, 6-18
list• 6-26
See also List operation
overview of• 6-3 to 6-5
physical • 6-15
restore• 6-23 to 6-26
See also Restore operation
save • 6-13 to 6-19
See also Save operation
volume-by-volume • 6-19
operator assistance requests• 7-8
restore
See Restore operation
restoring from image• 6-25
save
See Save operation
save set
See also Save set
protection• 6-22
restoring from• 6-23
selective backups• 6-20 to 6-22
creation date• 6-21
expiration date• 6-21
/EXCLUDE qualifier• 6-22
UIC• 6-21
wildcard character• 6-20
sequential disk save set• 6-16
multivolume • 6-17
/COMPARE qualifier• 6-27

lndex-2

Backup Utility (BACKUP)
/COMPARE qualifier (cont'd.)
See also Compare operation
/EXCLUDE qualifier• 6-22
/IMAGE qualifier• 6-12, 6-15, 6-18, 6-25
See also Image operation
/INITIALIZE qualifier• 6-17
/JOURNAL qualifier• 6-28
/LIST qualifier• 6-26, 6-28
See also List operation
/LOG qualifier
directing output with • 6-11
/OWNER_UIC qualifier• 6-21, 6-22
/PHYSICAL qualifier• 6-15
/PROTECTION qualifier• 6-22
/REWIND qualifier• 6-7, 6-13
wildcard character
selective backups• 6-20
BADBLK.SYS • A-3
Bad block file• A-3
BADLOG.SYS • A-4
Batch job
accessing devices• 3-27
Beginning-of-tape marker
See BOT
Binary data • B-1
Bit map
index file• A-2
storage• A-2
BITMAP.SYS• A-2
Blocked record • B-15
Block length field • B-1 7
Bootstrap block• 1-6, A-2
BOT (beginning-of-tape)• B-2
BOT marker• B-4
Buffer-offset length field • B-18

c
Close operation• 4-22, 4-24
Command procedure
accessing foreign volumes• 4-24
backup operations• 6-30
magnetic tape restriction• 4-2

Index

Command procedure (cont'd.)
setting up disk volume• 3-27
setting up magnetic tape volume• 3-28
setting up volume• 3-26
using to copy files • 5-13
Compare operation (BACKUP)• 6-5, 6-27
CONTIN.SYS • A-3
Continuation file• A-3
Continuation volume mounting• 3-21
CONTROL access
See Access
Convert Utility (CONVERT)
and non-file-structured volumes• 5-8
COPY command• 5-1, 5-2
ANSI-labeled volumes
copying from• 5-4
copying from magnetic tape• 5-3
DCL
copying files with• 4-2
disk files• 5-2
magnetic tape• 4-18
copying to • 5-3
non-file-structured volumes• 5-6
/LOG qualifier• 5-7
Copy operation (BACKUP)• 6-11 to 6-13
copying files• 6-4, 6-11
copying multiple files • 6-11
disk volume
image• 6-12
disk volume set• 6-13
entire directory tree • 6-12
full volumes and volume sets• 6-1 8
Core image file• A-3
CORIMG.SYS• A-3
Corruption of data• 3-25
CREA TE/DIRECTORY command• 4-17
CREA TE command
magnetic tape• 4-23
Creation date field • 8-14
zero creation date• 8-15

D
DCL commands
restrictions on• 4-1

DEALLOCATE command• 3-25
magnetic tape • 4-1 9
DELETE access
See Access
Device
See also Mount verification
accessing in batch job• 3-27
magnetic tape
retrieving information• 4-7
mounting volumes • 7-3
offline • 7-11
write lock• 7-13
Directory
creating • 4-1 7
DIRECTORY command• 4-2, 4-21
magnetic tape• 4-4, 5-3
/ ACL qualifier• 4-8
/FULL qualifier• 4-22
Disk
allocation of• 4-9, 4-10
allocation of space on• 1-4
block
cluster• 1-2
description • 1-2
record• 1-5
concepts
basic• 1-2
copying files• 5-2
deallocating drives• 3-25
default format• 5-2
file
copying
See also COPY command
See also Copy operation
copying to magnetic tape• 4-18
file characteristics
modifying • 4-12
mounting• 3-10
structure
Files-11•1-6
volume protection
See Protection
volume set
See Volume set
Disk quota • 4-9

lndex-3

Index

Disk structure
Files-11 • A-1
DISMOUNT command• 3-23, 3-25
magnetic tape• 4-19
/NOUNLOAD qualifier• 3-23
/UNIT qualifier• 3-23
DOS-11
volume• 5-11
Double tape mark• 8-2

E
End-of-tape marker
See EQT
EOF label• B-4, 8-19
EQT (end-of-tape)• 8-2
EQT marker• 8-4
EOV label• B-4, 8-19
Exchange Utility (EXCHANGE)• 5-1, 5-10
DCL level• 5-12
DIRECTORY command• 5-11
exiting from• 5-12
invoking • 5-11
MOUNT command• 5-11
EXECUTE access
See Access
Expiration date field• 4-19, 8-14

F
FAB BLS field•B-17
File
BACKUP
using to compare• 6-27
See also Compare operation
copying from magnetic tape• 5-3
copying to magnetic tape• 4-18
format
nonstandard• 4-2
identifier field • B-12
reserved
Files-11 disk• A-1
volume configurations• 8-4, B-6, 8-7, 8-8,
9,.9

lndex-4

File access
See Access
File header• 1-6
description • 1-7
files-11 structure• A-2
File header label
See Header label
File name
ANS1•4-21
File protection
See Protection
Files-11 disk
BACKUP•6-7
Exchange Utility (EXCHANGE) • 5-11
-save set• 6-16
structure• A-1
Level 1 •5-2
Level 2•5-2
reserved files• A-1
structure levels compared• A-4
File section number field• 8-13
File sequence number field• 8-13
File-set identifier field • 8-13
File specification • 8-12
ANSl•4-21
File type field• B-12
Fixed-length record • 8-15
Foreign volumes
mounting • 3-10
Format
ANSI-labeled volume • 8-1

G
Generation number• 4-20, 8-13, 8-14
Generation-version number• 4-20, 8-14

H
HDR1 label
See Header label

Index

HDR2 label
See Header label
HDR3 label
See Header label
HOR label
See Header label
Header label • B-4
HDR1 label•4-20, B-11
accessibility field• B-15
creation date field• B-14
expiration date field • B-14
file identifier field • B-12
file section number field• B-13
file sequence number field • B-13
file-set identifier field • B-13
generation number field• B-14
generation-version number field• B-14
HDR2 label•B-11, B-15
block length field • B-17
buffer-offset length field• B-18
record format field • B-15
record length field• B-17
system-dependent field • B-18
HDR3 label•B-11, B-19
RMS attributes field • B-19
HDR4 label•B-11, B-19
Home block• 1-6, A-2

I
Image operation• 6-18
copy•6-12, 6-18
overview of• 6-3
restore• 6-18, 6-25
save • 6-1 5, 6-18
INDEXF.SYS• A-2
Index file• A-2
bit map•A-2
description • 1-6
INITIALIZE command• 3-4
See also Volume
continuation volumes• 3-22
Files-11 On-Disk Structure • 3-6
magnetic tape• 5-3
protection codes• 4-13

INITIALIZE command (cont'd.)
sequential disk • 6-18
Interchange environment
protection • 2-8

J
Journal file• 6-28
See also Backup Utility

L
Label
ANSl•B-1, B-4
EOF•B-19
EOV•B-19
HDR1 •8-11
HDR1 •4-20
HDR2 •8-15
HDR3•B-19
header• B-11
trailer• 8-19
VOL 1 •8-9
List operation (BACKUP)
listing files• 6-5
wildcard characters• 6-27
Logical name
MOUNT command• 3-8

M
Magnetic tape
allocation of• 4-18
ANSI-labeled
mounting • 3-15
BACKUP
using with • 6-7
basic concepts of• 1-7
block• 1-7
copying files from • 5-3
deallocating drives• 3-25
density• 1-7
DOS-11 •5-11
file• 1-9

lndex-5

Index

Magnetic tape
file (cont'd.)
reading• 4-22
file protection
See Protection
initializing• 3-6
initializing with BACKUP• 6-13
interrecord gap (IRG) • 1-7
modifying device characteristics• 4-12
mounting• 3-1 5
multiple volumes• 6-13
reading from• 4-22
record blocking • 1-8
record format• 5-3
retrieving device information• 4-7
runaway• 3-7
save set
multivolume • 6-13
restoring from• 6-23
writing to•6-7, 6-14
specifying block size • 3-1 6
specifying record size • 3-19
9-track drive• B-1
volume•5-3
See Volume
volume protection
See Protection
volume set
See Volume set
write ring• 7-3
writing files to• 4-18, 4-23
Magnetic tape ancillary control process
See MTAACP
Master file directory
See MFD
Media
See Backup Utility
See Disk
See Magnetic tape
MFD (master file directory)• A-3
sequential disk save sets• 6-8
MOUNT command• 3-8, 3-25
See also ALLOCATE command

lndex-6

MOUNT command (cont'd.)
See also DISMOUNT command
See also INITIALIZE command
See also Mounting
logical names• 3-8
magnetic tape • 5-3
protection codes • 4-13
qualifiers• 3-16
I ASSIST qualifier• 3-9
/AUTOMATIC qualifier• 3-22
/BIND qualifier• 3-11
/BLOCKSIZE qualifier• 3-16, 5-8, B-17
/CACHE=T APE_DA TA qualifier• 3-18
/COMMENT qualifier
example • 7-3
/FOREIGN qualifier• 4-16, 5-6, 6-7, 6-8,
6-12, 6-13, 6-17, 6-24
/GROUP qualifier• 3-9
/HDR3 qualifier• 3-19
/INITIALIZE qualifier• 3-22
/LABEL qualifier• 3-16
/NOLABEL qualifier• 5-8
I OVERRIDE qualifier• 3-1 6, 4-1 9
/OWNER_UIC qualifier• 3-17
/PROTECTION qualifier• 3-18
/RECORDSIZE qualifier• 3-19, 5-8, B-18
/SYSTEM qualifier• 3-9
specifying record size • 3-1 9
specifying UIC • 3-17
Mount request• 3-9
MT AACP process• 7-5
Mount verification
abort by dismount• 7-14
cancellation of• 7-14
operator functions• 7-11
procedure for device offline • 7-11
MTAACP process• B-1
mount request• 7-5
Multifile/multivolume configuration• B-9
Multifile /single volume configuration • B-8
Multivolume save set
magnetic tape • 6-13
Multivolume sequential disk save set• 6-8

Index

0
OPCOM
mount verification• 7-11
for offline devices• 7-11
OPCOM message
continuation volume request• 7 -7
device write-locked • 7-13
enabling an operator terminal• 7-1
mount request• 7-4
mount verification aborted • 7-14
mount verification completed• 7-12
request display• 7-1
unavailable device• 7-11
wrong device • 7 -1 2
Operator Communication Facility
See OPCOM
Operator function • 7-1 to 7-1 5
mounting volume sets
with automatic switching• 7-5
without automatic switching • 7-6
mount verification
canceling• 7-14
for write-locked devices • 7-1 3
handling tasks• 7-11
user requests
for generic mount • 7 -4
for mounting volumes• 7-3, 7-4
for mounting volume sets• 7-5
handling• 7-1
responding to• 7-2
Operator terminal
setting up• 7-1
user requests• 7-1

p
Pending bad block log file• A-4
Percent sign (%) • 4-22
Private volume
See Volume
Protection
access category• 2-2

Protection (cont'd.)
ACL-based • 2-4
BACKUP save set• 6-22
categories • 2-1
code• 3-19
changing• 2-9
specifying• 2-9
default
changing• 2-10
file• 2-1
default• 2-10
directory• 2-8, 2-11
disk• 2-8, 2-9
magnetic tape• 2-3, 2-8, 2-13
for interchange environments• 2-8
UIC-based • 2-2
volume• 2-1
ANSI-labeled• 2-5
disk• 2-6
magnetic tape• 2-6, 2-7

Q
$010 call• B-1

R
RCW (record control word)• B-16
READ access
See Access
Read operation• 4-16
continuation volumes• 7-6
disk• 4-16
magnetic tape• 4-19, 4-22
ANSI-labeled• 4-20
Record control word
See RCW
Record format• B-1 5
Record format field • B-1 5
Record length field• B-17
REPLY command
/BLANK_TAPE qualifier•7-6
/DISABLE qualifier• 7-2
/ENABLE qualifier• 7-1
/INITIALIZE_TAPE qualifier• 7-6
/TO qualifier• 7-6

lndex-7

Index

Request
See Operator function
REQUEST command
/REPLY qualifier• 7-1
/TO qualifier• 7-1
Restore operation (BACKUP)• 6-5, 6-23 to
6-26
restoring files
from magnetic tape save sets• 6-23
from multivolume save sets• 6-25
from sequential disk save sets• 6-24
restoring volumes
entire disk volumes• 6-25
RMS (Record Management System)
See VAX RMS
Rotating backup set• 6-9
RT-11
volume• 3-16
block-addressable• 5-11

s
Save operation (BACKUP) • 6-13 to 6-19
directories
saving to disks• 6-16
saving to magnetic tape• 6-13, 6-14
directory tree
saving to magnetic tape• 6-15
disk volume
saving an unstructured• 6-15
files
saving to disks • 6-16
saving to magnetic tape•6-13, 6-14
file-structured disks
saving to• 6-16
full volumes and volume sets
saving• 6-18
image• 6-15
multiple volumes
to magnetic tape volumes • 6-15
saving files• 6-5
saving volumes
to magnetic tape• 6-13
sequential disk
multivolume, saving to• 6-17

lndex-8

Save operation (BACKUP)
sequential disk (cont'd.)
saving to• 6-16
volume
saving to magnetic tape• 6-1 5
volumes
saving to disks • 6-16
Save set • 6-6
comparing with disk files• 6-27
See also Compare operation
Files-11 disk• 6-7, 6-16
Files-11 disks• 6-16
listing contents of• 6-5, 6-26
See also list operation
magnetic tape•6-7, 6-13, 6-14
multivolume • 6-13
name restriction • 6-7
protection• 6-22
remote•6-9
restoring from• 6-23
sequential disk• 6-8, 6-16
multivolume • 6-8, 6-17
Selective backup• 6-20 to 6-22
creation date• 6-21
expiration date• 6-21
/EXCLUDE qualifier• 6-22
UIC
using• 6-21
wildcard character• 6-20
Sequential disk
save set on • 6-8
multivolume • 6-8
writing• 6-16, 6-17
SET ACL command•4-10
I ACL qualifier• 4-11
/LIKE qualifier• 4-11
/OBJECT_TYPE qualifier•4-10
SET DIRECTORY command•4-10, 4-11
I ACL qualifier• 4-11
/CONFIRM qualifier• 4-11
/OWNER_UIC qualifier• 4-11
/VERSION_LIMIT qualifier• 4-11
SET FILE command•4-10, 4-12
I ACL qualifier• 4-11
/BEFORE qualifier• 4-12

Index

SET FILE command (cont'd.)
/EXPIRATION qualifier• 4-12
/OWNER_UIC qualifier• 4-12
SET MAGT APE command• 4-10, 4-12
SET PROTECTION command• 2-9, 4-8,
4-10, 4-14
/DEFAULT qualifier• 2-10, 4-13
SET VOLUME command• 4-10
/DAT A_CHECK qualifier• 4-15
/LABEL qualifier• 4-15, 6-17
SHOW ACL command• 4-2, 4-8
SHOW command• 4-1
SHOW DEVICE command• 3-21, 4-2, 4-4
SHOW MAGT APE command• 4-2, 4-7
SHOW PROTECTION command• 4-2, 4-8
SHOW QUOT A command• 4-2, 4-9
Single file/multivolume configuration• B-7
Single file/single volume configuration• B-6
Storage bit map file• A-2
Stream record type• B-16
SUBMIT command• 4-2
System-dependent field • B-18

T
Tape
See Magnetic tape
Tape mark• B-2, 8-4
Trailer label• B-4, B-19
TYPE command
foreign volumes• 5-10
magnetic tape• 4-22

u
UIC (user identification code)
backups
in selective• 6-21
UIC-based protection• 2-2
to bypass• 2-3
Unstructured disk volume
saving to magnetic tape with BACKUP•
6-15
Update access• 4-23

User identification code
See UIC
User requests
See Operator functions

v
Variable-length record• 8-16
VAX RMS (Record Management Services) •
B-1 B-14 B- 17
attributes• 8-18, B-19
Version number•4-20, 8-13
VFC (variable with fixed-length control)
record format • B-16
VOL 1 label
See Volume label
VOL label
See Volume label
VOLSET.SYS• A-3
Volume
ANSI-labeled • B-4
copying files from • 5-3
ANSI-labeled magnetic tape
mounting• 3-15
backing up full volumes and volume sets•
6-18
continuation• 3-22
file configurations • B-4, B-6, B-7, B-8, B-9
foreign • 3-10
initializing• 3-4, 3-6
label•B-4
magnetic tape• 5-3
copying files from • 5-3
deallocating• 4-19
dismounting• 4-19
initializing• 4-18
mounting• 3-15
record format• 5-3
writing files to • 4-18
modifying characteristics of disk• 4-15
mounting•3-8, 3-10, 7-3
operator assistance• 7-3
operator functions• 7-3
I

lndex-9

Index

Volume (cont'd.)
mounting with EXCHANGE• 5-11
mounting without HDR2 labels• 8-18
operator assistance• 3-9
owner field • 8-11
private• 3-1
Volume identifier• 8-10
Volume label
EOF label• 8-4
EOV label • 8-4
VOL 1 label• 8-9
accessibility field• 8-10
volume identifier field • 8-10
VOL label • 8-4
Volume protection
See Protection
Volume RT-11 •3-16
Volume set
creation of• 3-12, 3-13
disk• 3-12
add volume• 3-14
mounting• 3-11
initializing• 3-12
list file• A-3
loosely coupled• A-3
magnetic tape
automatic volume switching• 3-2 1
continuation volumes• 3-21
creating• 3-20
mounting • 3-19
mounting• 3-8, 3-11

w
Wildcard character (*) • 4-3
DIRECTORY command• 4-4
file specification
magnetic tape• 4-20
selective backup operations• 6-20
WRITE access
See Access
Write lock
mount verification • 7-13
Write operation• 4-16

lndex-10

Write operation (cont'd.)
continuation volumes • 7-6
disk •4-17
magnetic tape• 4-18, 4-19, 4-23
ANSI-labeled• 4-20

x
XA8DA T block• 8-14
CDT field • 8-14
EDT field • 8-14

z
Zero creation date • 8-1 5

Guide to VAX/VMS Disk and
Magnetic Tape Operations
Al-Y506B-TE

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Guide to VAX/VMS Disk and
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