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September 1987

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Document:	Introduction to RSX-11M-PLUS Version 4.0
Order Number:	AA-FD03B-TC
Revision:	0
Pages:	142
Original Filename:	http://bitsavers.org/pdf/dec/pdp11/rsx11m_plus/RSX11Mplus_V4.x/1/AA-FD03B-TC_RSX-11M_PLUS_V4.0_Introduction_to_RSX-11M_PLUS_Sep87.pdf

OCR Text

Introduction to
RSX-11 M-PLUS
Order No. AA-FD038-TC

Introduction to

RSX-ll M-PLUS
Order No. AA-FD03S-TC

RSX-ll M-PLUS Version 4.0

Digital Equipment Corporation

Maynard, Massachusetts

First Printing, September 1979
Revised, November 1981
Revised, July 1985
Revised, September 1987
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 ©1979, 1981, 1985, 1987 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
lAS
MASSBUS
MicroPDP-11
Micro/RSX
PDP
PDT
RSTS
RSX

UNIBUS
VAX
VAXcluster
VMS
VT

~DrnDD~D
ZK3359

HOW TO ORDER ADDITIONAL DOCUMENTATION
DIRECT MAIL ORDERS
USA & PUERTO RICO'"

CANADA

INTERNATIONAL

Digital Equipment Corporation

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

P.O. Box CS2008
Nashua, New Hampshire 03061

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 (SDC), 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 Tp(, the typesetting system developed by Donald E. Knuth at Stanford University. TP< is a trademark of the
American Mathematical Society.

Contents
Preface

Chapter 1 Gett!ng Started
1.1
1.2
1.3
1.4
1.5

1.6
1.7
1.8
1.9
1.10
1.11
1.12
1.13
1.14
1.15
1.16
1.17
1.18
1.19
1.20
1.21

Hardcopy Terminals and Video Terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Before You Start. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Before You Log In to the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1.3.1
Command Line Interpreter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Logging In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
1.4.1
Login Messages from the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Correcting Typing Mistakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
1.5.1
Correcting Mistakes on a Video Terminal . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
1.5.2
Correcting Mistakes on a Hardcopy Terminal . . . . . . . . . . . . . . . . . . . . . . . 1-8
1.5.3
Verifying Corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Deleting Entire Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Ending Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Displaying Information on Your Terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
Shortening Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Help from RSX-11M-PLUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
More Help from RSX-11M-PLUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
A Directory of Your Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
Devices on Your System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
File Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
Displaying Files on Your Terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
Defaults in File Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
Controlling Output to Your Terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
Stopping the Action Entirely . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
Setting and Showing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
Displaying System Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18
1.20.1
Tasks on the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18
Logging Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19

iii

1.22

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20

Chapter 2
2.1
2.2
2.3
2.4
2.5
2.6
2.7

2.8
2.9
2.10
2.11
2.12
2.13

2.14
2.15
2.16
2.17
2.18
2.19
2.20

2.21

Creating Files

Creating a File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
EDT, the DIGITAL Standard Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Startup Command Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Character Mode Editing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
2.4.1
The Keypad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Beginning an Editing Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
2.5.1
Entering Character Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Getting Help on EDT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Moving the Cursor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
2.7.1
Using the Arrow Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
2.7.2
Changing the Direction of Cursor Movement . . . . . . . . . . . . . . . . . . . . . . . 2-7
2.7.3
Moving the Cursor by Character, Word, and Line . . . . . . . . . . . . . . . . . . . . 2-7
Inserting Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Deleting Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
2.9.1
Undeleting Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Locating Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Moving Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Leaving the Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Line Mode Editing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
2.13.1
Range Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
2.13.2 Getting Help in Line Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
Displaying Lines of Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13
Inserting Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
2.15.1
Renumbering Text Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
Deleting Lines from Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
Searching Through Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
Moving and Copying Text Within the File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17
Replacing Words . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18
Line Mode Commands Also Used in Character Mode . . . . . . . . . . . . . . . . . . . . . . . 2-19
2.20.1
Creating a Second File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19
2.20.2 Including a Second File in Your Text . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20

Chapter 3 Using DCl Commands
3.1
3.2

3.3

3.4

Wildcards and Other Wild Things . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
DCL Commands for File Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3.2.1
COPY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3.2.2
CREATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
DELETE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3.2.3
3.2.4
DIRECTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
3.2.5
EDIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
3.2.6
PURGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
3.2.7
RENAME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
3.2.8
TYPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
DCL Commands for General System Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
3.3.1
BROADCAST. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
HELP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
3.3.2
3.3.3
RUN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
3.3.4
SET DEFAULT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
3.3.5
SET PASSWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
3.3.6
SHOW DEFAULT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
SHOW DEVICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
3.3.7
3.3.8
SHOW TIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
3.3.9
SHOW USERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
DCL Commands for the Queue Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
3.4.1
PRINT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
3.4.2
SHOW QUEUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
3.4.3
SET QUEUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
3.4.4
DELETE/ENTRY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
3.4.5
HOLD/ENTRY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
3.4.6
RELEASE/ENTRY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
3.4.7
STOP / ABORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15

Chapter 4
4.1
4.2
4.3
4.4

4.5

Automatic Command Entry

Indirect Command Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Indirect Command Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Substitution Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Writing Programs with Indirect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
4.4.1
Directives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 4-3
4.4.2
Special Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 4-3
Labels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 4-4
4.4.3
4.4.4
Comments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 4-4
Examples................................................. ... 4-4

4.6

Batch Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
4.6.1
An Example of a Batch Job . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
4.6.2
Submitting Batch Jobs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Chapter 5
5.1
5.2

5.3
5.4
5.5
5.6
5.7
5.8

Running Tasks Directly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Creating a Task Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
5.2.1
The Source Language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
5.2.2
Translating the Source File Into an Object File . . . . . . . . . . . . . . . . . . . . . . 5-4
5.2.3
Transforming the Object File Into a Task Image File . . . . . . . . . . . . . . . . . . 5-6
Running the Task . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
Using Subroutines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
High-Level Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
5.5.1
Gaining Access to High-Level Languages . . . . . . . . . . . . . . . . . . . . . . . . 5-12
Naming Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
Aborting Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14
Other References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15

Chapter 6
6.1
6.2

6.3

6.4

6.5

Working on the System

The System in Operation

Hardware and Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Applications and Operating Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
6.2.1
The Real-Time Control Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
6.2.2
The Applications Environment . . . . . . . . . . . . . . . . . . . . " . . . . . . . . . . . 6-2
6.2.3
The General-Purpose Timesharing Environment . . . . . . . . . . . . . . . . . . . . . 6-3
The Purpose of the Operating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
6.3.1
Control Through Privilege . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
6.3.2
Control Through Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
6.3.3
Control Through File Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Operating System Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
6.4.1
Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
6.4.2
The CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
6.4.3
Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
6.4.4
Stored Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
The SHOW MEMORY Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9

Glossary
Index

Figures
1-1
1-2
1-3
2-1
2-2
6-1
6-2

LA120 Printing Terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
VT100 Video Terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
VT220 Video Terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
VT100 Keypad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
VT220 Keypad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Structure of Files on a Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
SHOW MEMORY Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10

vii

Preface

Manual Objectives
This manual is intended to help new users of the RSX-IIM-PLUS operating system begin
using their system. It provides examples of commonly used commands, as well as instructions
for creating and editing files. RSX-IIM-PLUS is a complex system used for many different
purposes, but it can be quite simple for an everyday user. If you are a new user, you should
read this manual first and try the examples. By the time you finish reading and following the
instructions in this book, you will be familiar with most of the normal procedures needed for
using RSX-IIM-PLUS on the PDP-II computer.

Intended Audience
This book is designed for any new user of the RSX-IIM-PLUS system, whether familiar with
computers or not.

If you are accustomed to using a computer, you may be able to get enough information from
the examples and captions. However, most users will want to read the explanation before trying
the examples.

Structure of This Document
Chapter 1 describes the RSX-I1M-PLUS warm-up session. This session requires a terminal on
an RSX-IIM-PLUS system. You willieam how to log in and log out, how to issue commands,
and how to correct mistakes.
Chapter 2 teaches you how to create and edit files and introduces you to the EDT editor.
Chapter 3 provides a summary of the commonly used RSX-IIM-PLUS commands and gives
examples of how to use them.
Chapter 4 provides an introduction to the Indirect Command Processor and to batch processing,
which are two methods of "hands-off" use of the computer.
Chapter 5 describes how to prepare and run a program.
Chapter 6 describes system resources and controls, and how RSX-IIM-PLUS operating systems
are used.

The Glossary provides definitions of commonly used terms. All terms introduced in italics in
this book are defined in the Glossary. You will also find many other useful computer terms in
the Glossary.

Associated Documents
The more you know about RSX-IIM-PLUS, the more use you will get out of it. Good sources
of information about your system are the system manager, in-house documentation, and other,
experienced users. You should also read the system documentation.
After you finish the Introduction to RSX-llM-PLUS, you should read the RSX-llM-PLUS Command
Language Manual, which describes the DIGITAL Command Language (DCL). The RSX-llM-PLUS
Utilities Manual also includes information useful to general users of the system.
If you are a programmer, you should see the RSX-llM-PLUS Guide to Program Development for
an introduction to program development facilities on RSX-IIM-PLUS.

Conventions Used in This Document
The following conventions are used in this manual:

Convention

Meaning

A right angle bracket is the default prompt for the Monitor Console
Routine (MCR), which is one of the command interfaces used on
RSX-IIM-PLUS systems. All systems include MCR.

A dollar sign followed by a space is the default prompt of
the DIGITAL Command Language (DCL), which is one of the
command interfaces used on RSX-IIM-PLUS and Micro/RSX
systems. Many systems include DCL.

xxx>

Three characters followed by a right angle bracket indicate the
explicit prompt for a task, utility, or program on the system.

UPPERCASE

Uppercase letters in a command line indicate letters that must be
entered as they are shown. For example, utility switches must
always be entered as they are shown in format specifications.

command abbreviations

Where short forms of commands are allowed, the shortest form
acceptable is represented by uppercase letters. The following
example shows the minimum abbreviation allowed for the DCL
command DIRECTORY:
$ DIR

Convention

Meaning

lowercase

Any command in lowercase must be substituted for. Usually the
lowercase word identifies the kind of substitution expected, such as
a filespec, which indicates that you should fill in a file specification.
For example:
filename.filetype;version

This command indicates the values that comprise a file specification; values are substituted for each of these variables as
appropriate.
/keyword,
/ qualifier,
or
/switch

A command element preceded by a slash (/) is an MCR keyword;
a DCL qualifier; or a task, utility, or program switch.
Keywords, qualifiers, and switches alter the action of the command
they follow.

parameter

Required command fields are generally called parameters.
most common parameters are file specifications.

The

Commas are used as separators for command line parameters and
to indicate positional entries on a command line. Positional entries
are those elements that must be in a certain place in the command
line. Although you might omit elements that come before the
desired element, the commas that separate them must still be
included.
[g,m]
[directory]

The convention [g,m] signifies a User Identification Code (UIC).
The g is a group number and the m is a member number. The
UIC identifies a user and is used mainly for controlling access to
files and privileged system functions.
This may also signify a User File Directory (UFD), commonly called
a directory. A directory is the location of files.
Other notations for directories are: [ggg,mmm], [gggmmm], [ufd] ,
[name], and [directory].
The convention [directory] signifies a directory. Most directories
have 1- to 9-character names, but some are in the same [g,m] form
as the UIC.
Where a UIC, UFD, or directory is reqUired, only one set of brackets
is shown (for example, [g,m]). Where the UIC, UFD, or directory
is optional, two sets of brackets are shown (for example, [[g,m]]).
A vertical ellipsis shows where elements of command input or
statements in an example or figure have been omitted because
they are irrelevant to the point being discussed.

Convention

Meaning

"print" and "type"

As these words are used in the text, the system prints and the user
types.

black ink

In examples, what the system prints or displays is printed in black.
In interactive examples, what the user types is printed in red.
System responses appear in black.

xii

Chapter 1
Getting Started
RSX-IIM-PLUS is an operating system. The RSX-IIM-PLUS operating system is a collection of
software designed to make it easy to use the PDP-II hardware.
You use the terminal to communicate with the operating system. From your terminal you can
issue commands that put the system to work for you. Whenever you issue a command, the
system acknowledges and acts upon your command. Because you interact with the system,
RSX-IIM-PLUS is called an interactive system.
Generally, any mistakes you make in using an RSX-IIM-PLUS system result in an error message
that tells you what you did wrong. For the most part, there is nothing you can do to harm the
system, and there are only a few things you can do that harm your own use of the system.
This book warns you of most of the possible mistakes you might make.
You will also be learning DeL, the DIGITAL Command Language. DCL is used on many
DIGITAL operating systems, so what you learn about using DCL on an RSX-IIM-PLUS system
is also applicable on other DIGITAL computers.

1.1 Hardcopy Terminals and Video Terminals
You can use either a hardcopy terminal, also called a printing terminal, or a video terminal. A
hardcopy terminal contains a print head and paper. It looks like a typewriter. A video terminal
has a screen in place of the print head and paper.
Video terminals are faster and more versatile than hardcopy terminals, but hardcopy terminals
leave a permanent record of activity at the terminal.
Both terminals have a keyboard similar to that on a typewriter. Most terminals also have a
numerical keypad like that on a calculator.
RSX-IIM-PLUS systems support many kinds of terminals; any of these terminals may have
special features.
You may have one or more terminals manufactured by DIGITAL at your installation. For
example, your printing terminal may be the LA120 (Figure 1-1), and your video terminal may
be the VT100 or the VT220 (Figure 1-2 and Figure 1-3).

Getting Started 1-1

Figure 1-1:

LA 120 Printing Terminal

ZK-758-82

1-2 Getting Started

Figure 1-2:

VT 100 Video Terminal

Figure 1-3:

VT220 Video Terminal

ZK-1379-83

Getting Started 1-3

1.2 Before You Start
Make sure the terminal you are using is turned on. Look for an ON/OFF (or a 1/0) switch and
press it to ON (or 1). Once your terminal is working, you can begin the exercise in the first
example. The text explains what is happening.

1.3 Before You Log In to the System
Press the RETURN key a few times. (In examples, the symbol lliill indicates that you press the
RETURN key.) These prompts inform you that the system is ready to accept input. Input means
whatever you type into the computer.
For example:
$
$
$

If you are using a video terminal, a blinking indicator, called the cursor, should appear next
to the prompt. It is called a cursor because it points out the "course" you will follow, that is,

where the next character you type will appear.
If you are using a hardcopy terminal, the print head usually points to the right of where the

next character appears. On most hardcopy terminals, the print head moves to the right after
you stop typing, so that you can see what you have typed. When you press another key, the
head moves back into the print position before it prints the character.
On the left-hand side of the keyboard is a key marked CTRL, which stands for "control." Press
the CTRL key a few times. Nothing should happen. Now press the CTRL key and the C key at
the same time. (In examples, the symbollcTRL/cl indicates that you press the C while pressing
the CTRL key.) You should get a prompt composed of three letters and a right angle bracket
(> ), as follows:
$

MeR>

The CTRL key and the C key together are called "Control/C." As you will see, you can use the
CTRL key with several letters besides C. The symbol ICTRL/Z I means that you press the CTRL key
and Z keys together; the symbollcTRL/ol means that you press the CTRL and 0 keys together.
Some of these combinations appear on the screen (or paper) as a circumflex ("), also called an
up arrow, which represents the CTRL key, and the letter you typed. Thus, CTRL/Z sometimes
appears as follows:
AZ

The RETURN and CTRL/C keys are both commands to the operating system. Together, they
are the best test of whether your terminal is working. If these two commands have the effects
described here, all major components of the terminal, the operating system, and the computer
are ready for use.

1-4 Getting Started

1.3. 1 Command Line Interpreter
A command line interpreter, or CLI, is your means of communicating with the operating system.
There are two CLIs available on RSX-IIM-PLUS: the Monitor Console Routine (MCR) and the
DIGITAL Command Language (DCL). MCR is present on all RSX-IIM-PLUS systems; DCL is
optional, but it is included on most systems with many terminal users.
When you issued the CTRL/C command, the system returned a prompt composed of three
letters and a right angle bracket, as follows:
MCR>

This is called an explicit prompt, because it identifies the CLI.
Because DCL commands are English words, DCL is easier to use and learn than MCR. This
manual teaches you how to use DCL.
Note
DCL is used in this manual because it is more suited to inexperienced users. In
fact, all DCL commands are translated into MCR commands for execution by
the system. If you intend to use MCR as your CLI, you can make use of this
manual by issuing the DCL command SET DEBUG/EXECUTE. This command
causes the MCR translation to appear on your terminal before the command is
executed. This option is not recommended for inexperienced users.
Now you can log in.

1.4 Logging In
Logging in gains you access to the system.
LOGIN is the DCL command that logs you in. HELLO is the MCR command that logs you in.
RSX-IIM-PLUS is a multiuser system. This means there can be more than one terminal and
more than one person using the system at a time. In fact, there may be more people authorized
to use the system than there are terminals. All these things mean that the system must have
some means of keeping track of who is who. Logging in does this.
Type either the LOGIN or HELLO command. Enter the command by pressing the RETURN key.
The system responds by asking you to identify yourself. Type USER and press the RETURN
key. (Later you will use your own name or some other name assigned by the system manager,
but you must log in to the account named USER to follow the examples in this book.)
The system asks you for your password. Type the password USER, but do not press the RETURN
key yet.
Until now, everything you have typed has appeared on the terminal, but the password does
not. Passwords are supposed to be secret, so that unauthorized users cannot log in to the
system. For this reason, passwords do not appear on your screen. In the following example,
angle brackets indicate inviSibility:
$

Account or name:
Password:

Getting Started 1-5

or
$

Account or name:
Password:

The login procedure illustrates an important point about terminals. Each terminal is really two
devices in one. The keyboard is an input device for sending messages to the system. The screen
is an output device for receiving messages from the system.
Everything you have typed so far has been a message from you to the system. Everything that
has appeared on the screen has been a message from the system to you. Until you reached the
password, it looked like you were typing directly on the screen. You were not.
What you may have thought you were typing on the screen was really an echo from the system,
which confirmed that you typed what you thought you did. For the password, however, the
echo is suppressed for security purposes. Occasionally, when the system is busy, you may
notice that the echo takes a little longer than usual.
There can be many different input or output devices on your RSX-IIM-PLUS system, but the
terminal is one of the most common. Later, you will learn about others.
Now enter the password by pressing the RETURN key.
Note that the system allows 1 minute for logging in. If you do not complete the login procedure
within 1 minute, the following message appears on your terminal:
HEL - Timeout on response

Simply begin the login procedure again by typing LOGIN and pressing the RETURN key.

1.4. 1 Login Messages from the System
During the login procedure, RSX-IIM-PLUS checks your identification and password to make
sure you should be allowed on the system. If you are identified correctly, the system makes
your terminal available to you, as indicated by the return of the dollar sign ($) prompt. A
number of messages from the system may appear before you see the prompt. For example, you
may see the following messages:
$

Account or name:
Password:
-

RSX-llM-PLUS V4.0 Multiuser Operating System
14-MAR-87 08:15 Logged in on terminal TT2:
Good Morning
**Today's question: Who said "Fashions are induced epidemics"?**

1-6 Getting Started

GLB:[1.2]LOGIN.CMD
$ SET DEFAULT [USER]/NAMED

««««««««««««««««««««««««<
Hello.
You are now logged in on the
RSX-11M-PLUS Operating System.
This is the USER account. Nothing
that you do in this account can do
any harm either to the system. or to
this account.
Use this account with the terminal
warm-up session described in the book
Introduction to RSX-11M-PLUS.
Take it easy.

»»»»»»»»»»»»»»»»»»»»»»»»>
$

Whenever you log in, you may get certain messages from the system, such as "Good Morning."
In addition, you may get informal messages, such as the note about today's question. In the
USER account, the special greeting is also shown. At any rate, after everything has happened
that is going to happen, the system returns the $ prompt, which signifies that it is ready for
more input.
If the prompt does not appear, press the RETURN key.

1.5 Correcting Typing Mistakes
Typing mistakes are by far the most common error made by RSX-IIM-PLUS users. If you make
a typing mistake, press the DELETE key once for each character you want to delete. The DELETE
key always deletes the character immediately to the left of the cursor. In this book, the symbol
IDELI means that you press the DELETE key. The DELETE key on the VT200-series terminals looks
like this: <Xl.
Beware the BACK SPACE key. This key is not used in DCL. Any command line with a BACK
SPACE will either be rejected or misinterpreted by RSX-IIM-PLUS. (This key is used in editing
but never in entering commands to RSX-IIM-PLUS.)
The most common errors made by terminal users are confusing the zero (0) and the capital
letter 0 and confusing the number one (1 ) and the lowercase letter L (I) or I (i). Type these
characters to see how they differ in appearance on your terminal. After you have typed them,
delete them.
Lowercase letters are not used in the examples in this book, but RSX-IIM-PLUS generally
accepts either lowercase or uppercase commands. You may want to use the SHIFT or CAPS
LOCK key to make your examples look like ours. Note that on most DIGITAL-manufactured
keyboards the CAPS LOCK key has no effect on the number and symbol keys.

Getting Started 1-7

1.5. 1 Correcting Mistakes on a Video Terminal
The DELETE key on video terminals erases the deleted characters.
When you press the DELETE key, the character immediately to the left of the cursor disappears
and the cursor takes its place. The next character you type appears in the vacated location. You
can continue deleting until you reach the left margin, but you cannot delete prompts.
For example, type the following series of characters on your terminal:
$

You will see the following displays on the screen, in succession:
$ THIMK

After you press the DELETE key twice, the following characters remain:
$ THI

After you enter the corrections, the following word appears:
$ THINK

The danger of the BACK SPACE key is greatest on video terminals because what you see on
the screen is almost the same as what is caused by the DELETE key. The effect on the operating
system, however, is entirely different and incorrect.

1.5.2 Correcting Mistakes on a Hardcopy Terminal
The DELETE key on hardcopy terminals prints the deleted characters.
The DELETE function on hardcopy terminals takes some getting used to.
When you press the DELETE key, you eliminate the character immediately to the left of the next
print position. Since the character cannot literally disappear from the paper, the system indicates
its disappearance by printing a backslash (\) and the deleted character on your terminal. If you
press the DELETE key again, the next character to the left will also be eliminated and reprinted.
When you have eliminated what you wish, simply continue typing; the correct characters will
be echoed on your terminal.
This can create a confusing line, as you will see.
For example, type the following series of characters on your terminal:
$

You will see the following displays on the screen, in succession:
$ THIMK

After you press the DELETE key twice, the following characters appear:
$ THIMK\KM\

After you enter the corrections, the following line appears:
$ THIMK\KM\NK

The BACK SPACE key is less dangerous on printing terminals because you can see that it is not
doing what you want it to do. It simply types over what you typed before.

1-8 Getting Started

1.5.3 Verifying Corrections
CTRL/R retypes a line with corrections.
If you are confused by the reprinting of deleted characters on a line, or if you are not sure
your corrections were made, use CTRL/R. Press the keys marked CTRL and R at the same time.
This causes the system to retype your line, without the deletions and corrections. You can then
continue with whatever you were typing.

For example:
$
\KM\
$ THINK
I

Note that CTRL/R echoes as follows:
AR

CTRL/R works only on the current line before you press the RETURN key. After you use
CTRL/R you are still on the same line. You can continue typing, with additional deletions if
you wish. A command will not be entered until you press the RETURN key.
CTRL/R is most useful on hardcopy terminals, but it works on video terminals as well. You
can use it to verify that you have typed what you think you typed.

1.6 Deleting Entire Lines
CTRL/U deletes an entire line.
If you wish, you can delete an entire line by pressing CTRL/U. Press the keys marked CTRL and
U at the same time, just as you use the SHIFT key and a letter together to type an uppercase
letter. See the following example:
$
$

When you press CTRL/U on your terminal, it is echoed as a circumflex C) and a U. The line
you typed is ignored.

1.7 Ending Input
CTRL/Z indicates end-of-file or end-of-input, as shown in the following example:
More input?
$

Pressing CTRL/Z tells the system that you have finished supplying input. CTRL/Z is a command
you can try when your terminal appears to be hanging or otherwise behaving in some confusing
way. You also use CTRL/Z to terminate input to many system tasks, as you will see later.

Getting Started 1-9

1.8 Displaying Information on Your Terminal
The SHOW command displays system information.
The SHOW TIME command displays the time.
Type SHOW and press the RETURN key. DeL prompts you for the next portion of the command.
DeL always prompts you if you have not given a complete command. Some commands prompt
you more than once.
TIME is one function you can display. If you type TIME in response to the Function? prompt,
RSX-IIM-PLUS displays the current system time.
For example:
$

Function?
_
12:37:33 10-JUL-87

Now type SHOW TIME on one line and press the RETURN key, as follows:
$

12:37:33 10-JUL-87

RSX-IIM-PLUS displays the current system time. Both forms of the command-with or without
the prompt-return the same information. The Function? prompt identifies the next command
element DeL is expecting. As you will see, you can use SHOW to display a variety of system
information.
Prompts like Function? are most useful when you are learning a command or when you are
using a rarely used command. As you see in the two forms in the examples, DeL prompts you
only when you omit a necessary part of the command. Once you have learned a command
format, you probably will not need the prompts, but they will always be available.
If you decide not to enter a command, you can always press CTRL/Z at the end of the line or
in response to the prompt, and the command is not executed.

For example, type SHOW with or without pressing the RETURN key. Then press CTRL/Z as
follows:
$

or
$

Function?
$

As you can see, nothing happens. Pressing CTRL/Z cancels any command.

1-10 Getting Started

1.9 Shortening Commands
DeL does not require that you type the full command.
Try dropping letters from the SHOW TIME command. You will find that S TI is sufficient to
display the time.
For example:
$

12:37:33 10-JUL-87
$

SHOW -- Illegal function
S T
$

The full command, such as SHOW TIME, identifies the action of the command. As you will
see later, DeL commands can be quite complex, and the full form of the command is useful
to help you see what action you are performing. For everyday convenience, however, DeL
accepts abbreviations. You can abbreviate any DeL command.
In the case of SHOW, the abbreviation is S. There are several commands with I-letter
abbreviations. For most commands, three letters will be enough, and four will always be
enough. You can experiment with new commands as you learn them, shortening the command
until you get an error message like the one just shown.
In the previous example the abbreviation S T did not work because there is another DeL
command that can be abbreviated to S T, SHOW TERMINAL. Therefore, S TI is as short as
SHOW TIME can be. S TE is as short as SHOW TERMINAL can be.
For the sake of clarity this book uses only full commands in examples.

1. 1a Help from RSX-ll M-PLUS
Type the command HELP SHOW TIME and press the RETURN key. Text explaining the SHOW
TIME command appears on your screen. (You should remember that the time displayed is the
time set on the system, and it is no more accurate than any other clock.)
For example:
$

SHOW DAYTIME
SHOW TIME
The SHOW DAYTIME command displays the current time and date. The time is
in 24-hour format and the date is formatted as dd-mmm-yy.
$

As you go through this book, you should use the help available for each command that
you learn.

Getting Started 1-11

1.11 More Help from RSX-11 M-PLUS
You can also get help from RSX-IIM-PLUS while entering commands.
Type SHOW and press the RETURN key. When the Function? prompt appears, type a question
mark (?) and press the RETURN key. Help text appears, followed by another Function? prompt.
For example:
$

Function?
SHOW parameter
The SHOW command is used to display information about the following
parameters:
ACCOUNTING
ASSIGNMENTS
CACHE
CLOCK_QUEUE
COMMON

[DAY] TIME
DEFAULT
DEVICES
ERROR_LOG
GROUPFLAGS

HOST
LIBRARY
LOGICALS
MEMORY
PARTITIONS

PRIVILEGE
PROCESSOR
PROTECTION
QUEUE

SYSTEM
TASKS
TERMINAL
UIC
USERS

For further help on the qualifiers, type HELP SHOW qualifier.
Function?

As you see, you can display a great deal of information with the SHOW command. The display
you see is the same you would see if you typed HELP SHOW.
Now type? TIME in response to the Function? prompt, as follows:
Function?
SHOW DAYTIME
SHOW TIME
The SHOW TIME command displays the current time and date. The time is
in 24-hour format and the date is formatted as dd-mmm-yy.
Function?

This time, the help text you see is the same you would see if you typed HELP SHOW TIME.
Now type TIME in response to the Function? prompt. The time is displayed, as shown in the
following example:
Function?
14:53:48 10-AUG-87
$

You can get help on any DeL command in this way. If you have typed a command but are not
sure what the prompt means, type a question mark (?) to get further information. Everything
you had typed before you typed the ? is preserved for you while you get help.

1-12 Getting Started

1.12 A Directory of Your Files
The DIRECTORY command displays information about stored files.
Type DIRECTORY and press the RETURN key. What you see on your terminal should resemble
the following example, but your list of files may be somewhat different:
$

Directory DBO: [USER]
14-MAR-87 14:56
WHATSHERE.TXT;l
HELLO.TXT;l
LONG. TXT; 1
FLY.TXT;3
FLY.TXT;2
FLY.TXT;l
MYDISK.CMD;l
LOGIN.CMD;l
FLU. TXT; 1
SHOW.CMD;l

2.
25.
1.
1.
1.
4.
1.
1.
1.

27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24

Total of 40./40. blocks in 10. files

Files are one of the basic units of storage on RSX-IIM-PLUS systems. Everything on an
RSX-IIM-PLUS system either starts out or ends up as a file. Put simply, a file is the means
used to separate one significant collection of material from another. Files can contain text,
runnable programs (called tasks), or various kinds of data.
The DIRECTORY command provides you with a list of all the files stored on a particular device
in a particular directory. Later you will have a directory and an account under your own name.

1.13 Devices on Your System
All RSX-IIM-PLUS devices have names such as OBI, which is a disk drive. Notice that the
name has two letters and a number; it is followed by a colon (:) in a file specification. The
device name is important in helping you find your files.
There are many other kinds of devices besides mass-storage devices, such as disk drives. Line
printers and terminals are both devices, for instance. Your system may also have other kinds of
devices not mentioned here.

1. 14 File Specifications
Each file stored on an RSX-IIM-PLUS system has a unique identification, or specification, also
called a filespec. The device name and directory name are important parts of the file specification.
At the head of the directory listing, you will see the device name (DBO) and directory name
([USER]) where the files are stored. Within the listing, each file is identified by a file name
(WHATSHERE), a file type (TXT), and a version number (1). These five elements fully
distinguish one file from all the others on the system and also permit you to locate it.
Thus, the full file specification of the first file listed in the directory example is as follows:
DBO:[USER]WHATSHERE.TXT;l

Getting Started 1-13

A complete file specification consists of a device name, a directory name, a file name, a file
type, and a version number. There can be only one file with this full specification; there may
be others with similar, but not identical, specifications.
The following syntax rules for all fields of the file specification are really quite simple:
•

Device names have two letters and a number, which are followed by a colon (:).

•

Directory names have two possible formats. The named directory format has one to nine
of the following characters: the 26 letters A to Z and the numbers 0 to 9, or it has two
numbers separated by a comma (,) and enclosed in brackets ([ ]). The numbered directory
format has two numbers separated by a comma and enclosed in brackets.

•

File names have one to nine letters or numbers.

•

File types have one to three letters or numbers and are separated from the file name by a
period (.).

•

Version numbers start at 1 and increase; they are separated from the file type by a
semicolon (;).

As you go through the exercises in this book, you will see that each field of the file specification
has a part to play in the smooth functioning of the system.
But do not worry. Most of the time, all you will have to type is the file name and type.

1.15 Displaying Files on Your Terminal
The TYPE command displays selected files on your terminal.
Type TYPE and press the RETURN key. Give the full file specification as shown in response to
the File(s)? prompt. A short file is printed on your terminal, as shown in the following example:
$

File(s)?
Time flies like an arrow.
Space flies like a bow.
Fruit flies like a banana.

Now try the one-line form of the command; leave out the device and directory names and the
version number.
For example:
$

Time flies like an arrow.
Space flies like a bow.
Fruit flies like a banana.

You do not always have to include the full file specification to specify a given file. Some parts
are included by default if you do not specify them.
The use of the word "default" may be slightly confusing. In general, default means "for lack of
competition." If all but one runner drops out of a foot race, the last runner wins by default. On
RSX-IIM-PLUS, if you do not supply a value, the system supplies a value of its own, for lack
of competition. If you supply a value, your value always "wins."

1-14 Getting Started

1. 16 Defaults in File Specifications
The SHOW DEFAULT command displays the default device and directory for your terminal.
For example:
$

Function?

DBO: [USER]

Named

Protection UIC:

TT2:
[200,1]

The default device and directory are automatically included in every file specification, unless
you have included some other device or directory. You can find out your default device and
directory, which is "where you are" on RSX-IIM-PLUS, with the SHOW DEFAULT command.
Every file in DBO:[USER] has that disk name and directory name as part of its file specification.
(SHOW DEFAULT also tells you that your directory can use a name instead of numbers; which
terminal you are on; and your User Identification Code (UIC), but that is not part of the file
specification default.)
There may be several files on your system called FLY.TXT;3, but there is only one called
DBO:[USER]FLY.TXT;3. If you wanted to see one of the others, you would have to include its
directory name and disk name when you typed its name, such as DR2:[200,20]FLY.TXT;3.
One important default does not show. If you do not supply a version number, RSX-IIM-PLUS
defaults to the highest-numbered version.
Type and enter the following command:
$

The file FLY.TXT;3 prints on your terminal.
Now type and enter the following command:
$

As you see, two files with the same name and type but different version numbers can differ
greatly.
If you want to see a copy of a file from another device or directory, or both, include the
device name and directory name in the file specification; the defaults of DBO and [USER] are
overridden.

Type and enter the following command:
$

You should see most of the same text (if any) that is printed on your terminal when you log in.
Defaults are designed for your convenience, but you can always override them. Usually, defaults
are set to produce the most commonly used form of the command or file specification.

Getting Started 1-15

1.17 Controlling Output to Your Terminal
The NO SCROLL and HOLD SCREEN keys delay output to your terminal.
CTRLjO skips over output to your terminal.
Type and enter the following command:
$
,
File(s)?

The file begins to appear on your screen. Immediately press the NO SCROLL (VT100) or HOLD
SCREEN (VT220) key on your terminal. The file you are displaying stops right where it is.
Often on video terminals, the output from a command may scroll past on the screen too fast
for you to read. (Scroll means unroll like a scroll on your screen.)
Now press the NO SCROLL or HOLD SCREEN key again. The file starts scrolling past again.
The NO SCROLL and HOLD SCREEN keys do the same thing: they stop the scrolling, or, if you
prefer, they hold the screen. You are not missing any output when the key is in effect. These
keys allow you to read output at your own pace, rather than the terminal's.
Note
If your terminal appears to be hanging (not accepting new input), you may have
accidentally pressed the NO SCROLL or HOLD SCREEN key.

Again, type and enter the following command:
$

This time, immediately press CTRL/O. The output display from the TYPE command stops
immediately. Press CTRL/O again. The output display from the TYPE command starts again,
but it is not at the same place.
CTRLjO works like the fast-forward switch on a tape recorder. Use CTRLjO to skip over
output you do not want to see.
You can either skip the rest of the file entirely or skip down rapidly. You are only skipping
what you would see on the screen. You are doing nothing to the file. Use the TYPE command
to display the file again to be sure.

1. 18 Stopping the Action Entirely
The ABORT command halts execution of a command or a task resulting from a command.
Type the DIRECTORY command and press the RETURN key. Press CTRLjC before the directory
listing is complete.
Now, in response to the explicit prompt, type ABORT DIRECTORY and press the RETURN key.
The directory will run a few lines more and then a message verifying the abort will appear.
The message mentions MCR because MCR actually executes the command, but your terminal
remains set to DCL.
Later you will learn to abort tasks by name as well.
\

1-16 Getting Started

1. 19 Setting and Showing
The SET and SHOW commands can be used to change and display system attributes.
The SET TERMINAL command sets, and resets, the attributes of your terminal.
For example, SET TERMINAL/LOWERCASE causes your terminal to leave lowercase input
unchanged. SET TERMINAL/UPPERCASE causes your terminal to convert lowercase input to
uppercase.
The SHOW TERMINAL command displays attributes of your terminal and other terminals on
the system.
Type and enter the following command:
$

Remember, you can use either the prompting form or the one-line form for DCL commands.
Now type and enter the following command:
$

TT2:

[USER] [200.1] 14-MAR-87 14:47 1 A. USER
CLI = DCL
BUF = 80.
HFILL = 0
LINES = 24.
TERM = VT100 OWNER = none
BRO
LOWER NOPRIV NOHOLD NOSLAVE NOESC CRT
NOFORM
ECHO
NOVFILL HHT
NOFDX WRAP
NORPA NOEBC
CTRLC NOAVO ANSI
DEC
EDIT
NOREGIS NOSOFT
SERIAL NOHSYNC NOPASTHRU
TTSYNC NOPRINTER_PORT

NOABAUD
NOREMOTE
TYPEAHEAD
NOBLKMOD

RSX -11 M-PLUS displays all the attributes set for your terminal. Most of these attributes look
very technical, and they are. Most terminal attributes are more of interest to programmers than
users. If a particular terminal attribute is important, your terminal will probably already have it
set. We are using SET TERMINAL and SHOW TERMINAL for this example because the effects
are simple, obvious, and harmless.
In the list of attributes for your terminal, you will see LOWER. LOWER means that whatever
you type in lowercase is sent to the system in lowercase. If your terminal is not set LOWER,
any lowercase character you type is echoed in uppercase. The echo lets you see exactly what
the system received. (Actually, in most cases it makes no difference to the system whether the
characters are uppercase or lowercase.)
Not all the terminal attributes listed by SHOW TERMINAL have obvious meanings, but they
include your terminal number, the width of your screen (under BUF), and the length of
your screen (under LINES). The other terminal attributes are explained in the RSX-11M-PLUS
Command Language Manual and the help files.
Now, type and enter the following command:
$

Your terminal is now set to translate any lowercase characters you type into uppercase before
transmitting them. Any lowercase character you type will be echoed in uppercase. Why would
you want to do this? Well, some computer programs do not understand lowercase. But the
only reason for doing it in this example is for practice in setting something.
Now type and enter the SHOW TERMINAL command again. Where the display listed LOWER,
you now see NOLOWER (which is a computer way of saying UPPER).

Getting Started 1-17

For example:
$

TT2:

[USER] [200.1] 14-MAR-87 14:47 1 A. USER
CLI
BUF = 80.
HFILL = 0
= DCL
BRO
LINES = 24.
TERM = VT100 OWNER = none
NOFORM
NOLOWER NOPRIV NOHOLD NOSLAVE NOESC CRT
NORPA NOEBC
ECHO
NOVFILL HHT
NOFDX WRAP
DEC
EDIT
NOREGIS NOSOFT
CTRLC NOAVO ANSI
TTSYNC NOPRINTER_PORT
SERIAL NOHSYNC NOPASTHRU

NOABAUD
NOREMOTE
TYPEAHEAD
NOBLKMOD

Try typing something in lowercase. It comes out in uppercase. You will probably want to set
your terminal back to LOWER before continuing with this warm-up session.

1.20 Displaying System Information
The SHOW USERS command displays a list of logged-in users.
Type SHOW USERS and press the RETURN key. RSX-IIM-PLUS displays a list of everyone
currently logged in on the system. For each user, the list includes the terminal number, the
default directory, the protection UIC (User Identification Code), the login time, the number of
active tasks, and the user's name.
For example:
$

Function?
TTl:
[FREUD]
TT2 :
[USER]
TT4:
[7.11]
TT5:
[TREVISANI]

[303.4]
[200 . 1]
[7.11]
[7.57]

19-FEB-87 11:27
19-FEB-87 13:05
19-FEB-87 09:19
19-FEB-87 08:15

0
1
1
1

S. FREUD
A. USER
A. HUN

F. TREVISANI

Note that the terminal number has the same form as other device names: two letters, a number,
and a colon. The two letters identify the device type, in this case, a terminal.

1.20. 1 Tasks on the System
The command SHOW TASKS/ACTIVE displays a list of tasks that are active at your terminal.
The system displays the tasks currently active at your terminal. User tasks are identified by the
terminal from which they are being run. The display from SHOW TASKS/ACTIVE includes, at
least, DCL, which you are running, and something called SHOT with a number. This second
task is the SHOW command itself; the T and the number identify the terminal that issued the
SHOW command.
Type SHOW TASKS/ACTIVE and press the RETURN key, as follows:
$

Function?

The command SHOW TASKS/ACTIVE/ALL displays a list of all tasks active on the system.

(

1-18 Getting Started

1.21 Logging Out
LOGOUT is the DCL command that logs you out of the system. BYE is the MCR command
that logs you out of the system.
When you are through using RSX-IIM-PLUS, you must log yourself out by using either the
LOGOUT or the BYE command. For example, if your system's CLI is DCL, log out using the
DCL command, as follows:
$

Connect time:
o hrs 30 minutes
CPU time used: o hrs
0 minutes
Task total:
84
Have a Good Afternoon
14-MAR-87 14:48 TT2: logged off

8 sees
23 sees

You can also log out using the MCR command, as follows:
>
Connect time:
0 hrs 30 minutes
CPU time used: 0 hrs
0 minutes
Task total:
84
Have a Good Afternoon
14-MAR-87 14:48 TT2: logged off

8 sees
23 sees

RSX-IIM-PLUS gives you some statistics on your system use when you log out. Notice the
disparity between CONNECT TIME, which shows you how long you were logged in, and CPU
TIME USED, which shows you how much of that time you were actually using the central
processing unit or CPU. The CPU is the part of the computer that actually computes.
For most of the time that you were logged in, the system was waiting for input from you. This
is one of the main reasons why it is possible for several users to do work simultaneously on
the system. While the system is waiting for input from you-even between the time you type
one character and the next, which is a long time to a computer-some other user's needs can
be served.
As part of logging you out, the LOGOUT command cleans up behind you, aborting any active
tasks and returning resources to the system.
There is just one more point you should know about the RSX-IIM-PLUS system: sometimes
systems crash, or fail.
Sometimes, nothing seems to work, not even pressing CTRL/C or entering the LOGOUT
command. In fact, you can type without getting any response from the system. On these
occasions, the system may have crashed. Crashing is not as serious as it sounds either. If the
system crashes, it is probably not your fault. A crash is the system's response to an unstable
condition, and it is usually caused by a privileged user, a privileged task, or a hardware problem.
If the system should crash, it will probably be brought back up (restored) in a few minutes.
No one is logged in if the system has crashed and then has been restarted.

Getting Started 1-19

1.22 Summary
In this chapter, you have learned the following most common ways of eliminating confusion
from your terminal and restoring tranquility:
•

Pressing CTRL/Z to end input

•

Pressing CTRL/C to get the explicit prompt

•

Entering the ABORT command to stop a program

•

Typing HELP or question mark (?) to get help

•

Typing LOGOUT to end your use of the system

You now know enough about using your terminal and the system to move on to some of the
more complex, and useful, facilities of the RSX-IIM-PLUS system.
You have had to learn some computer jargon and some RSX-IIM-PLUS jargon, and you will
be learning some more as you continue working with this book. RSX-IIM-PLUS is part of the
RSX family of computer operating systems. These systems can be quite complex. If you learn
the correct terms from the beginning, your chances of understanding what is happening on the
system are improved.
You should understand that all the commands discussed so far have been commands to the
operating system itself. The system also includes many utilities to help you.
The next chapter of this book demonstrates the use of one of these utilities, an editor, which is
used to create files.

1-20 Getting Started

Chapter 2
Creating Files
A file is a collection of data significant to a user.
This definition covers a lot of territory. Files in RSX-IIM-PLUS systems can be of many types.
Text files, like FLY.TXT, are in a form you can read. Other files, such as task image files (files
that contain a runnable program), are in a form that only the computer and operating system
can read.
The file type-the 3-letter identification after the file name, such as TXT-usually gives a clue to
the contents of a file. See the RSX-11M-PLUS Command Language Manual for a list of common
file types.
This chapter tells you how to create and edit files on an RSX-IIM-PLUS system.
You will create and edit a text file called DOCTOR.FEL. The instructions in this chapter have
been designed to introduce you to many of the commands you need to know to create and edit
text files. Follow the examples closely, so you can see how everything works.

2. 1 Creating a File
The CREATE command creates files.
Type CREATE and press the RETURN key. In response to the File? prompt, supply the file
name DOCTOR and the file type FEL and press the RETURN key.
The prompt does not appear. Type the line of text shown in the following example and press
the RETURN key. Note that the RETURN key works like a typewriter carriage return. Then press
CTRL/Z. The dollar sign ($) prompt returns.
For example:
$

File?
$

Creating Files 2-1

While you were typing, you were "in" the CREATE task. CREATE is not only a DIGITAL
Command Language (DCL) command; it is also a system task used to create files. While you
were in this task, you were not in DCL. DCL commands have no effect inside the CREATE
task.
Pressing CTRL/Z indicated the end of your input to the CREATE task. It took you "out" of the
CREATE task and returned you to DCL level.
You have now created a file called DOCTOR.FEL. It is automatically numbered version 1 and
placed in the default directory, which is [USER]. Thus, the file has the file specification of
DUO:[USER]DOCTOR.FEL;1. You can use the DIRECTORY command to see that the file is
there.
Note that although you have created a text file, the file type is not TXT. RSX-IIM-PLUS
permits you to give whatever name and file type you like to your files. On the other hand,
RSX-I1M-PLUS systems also provide default file types for various purposes; these are discussed
in the RSX-IIM-PLUS Command Language Manual. (There is no default file type for the CREATE
command.)
The CREATE command is handy for making notes, but you cannot really do much in CREATE.
You cannot go back up a line to change something, for instance. For fuller functionality,
RSX-IIM-PLUS provides an editor, a system task designed to make creating and changing files
easier.

2.2 EDT, the DIGITAL Standard Editor
The EDIT command invokes EDT, the DIGITAL standard editor.
EDT, the editor included on RSX-IIM-PLUS systems, is also found on a number of other
DIGITAL operating systems. It is a general-purpose interactive text editor with two modes
of operation. Line mode has English-like commands and works on either video or hardcopy
terminals. As the name implies, line mode editing is done on one line of text at a time.
Character mode works on video terminals only. When you use character mode editing, you can
work on an entire file.
In this book there are brief introductions to both modes of EDT. However, the emphasis is
on character mode editing, because it is the more common mode of editing used on video
terminals. More information on both types of editing can be found in the EDT Editor Manual.

2.3 Startup Command Files
EDT allows you to set the characteristics of your editing session by using a file called a startup
command file. For example, you can create a startup command file that specifies how many
characters per line appear on the screen and whether you want character mode editing. The
default name for this file is EDTINI.EDT, for EDT initialization.
EDT looks for a file named EDTINI.EDT each time you begin an editing session. If it finds
one, EDT executes the commands in it. If there is no such file, EDT simply uses its default
characteristics, including line mode editing.
\

2-2

Creating Files

The following sample EDTINI.EDT file does only two things. It sets the editing mode to
character mode and sets the wrap (that is, when the line breaks) to 75 characters, as follows:
SET MODE CHANGE
SET WRAP 75

You will probably want to create an EDTINI.EDT file in your own account. However, the
[USER] account simply uses the default characteristics of EDT.

2.4 Character Mode Editing
EDT character mode allows you to edit at any position in your text. Your screen always contains
an accurate picture of the part of the file you are working on. The cursor shows exactly where
you are at all times.
Character editing uses the keypad on your terminal. If your terminal has no keypad, see the
EDT Editor Manual for information on using character mode.

2.4. 1 The Keypad
Character (or keypad) editing works on the VT100- and VT200-series video terminals and other
terminals with a numerical keypad. In character editing, you request editor functions by pressing
keys on the keypad. No RETURN is required to enter the command. Anything you type on
the regular keyboard, including RETURN, is inserted into the file as text.
It is a good idea to keep a copy of the keypad diagram handy while you are learning character

editing. The keys on your terminal are not labeled with EDT commands but with numbers
and some other characters. Figures 2-1 and 2-2 show the meaning of each key on the keypad
for the VT100 and VT220. The numbers or characters shown in the upper right of each key
correspond to what you see on the key.
In this chapter, the keypad key number is noted in parentheses the first time the key is
mentioned, but not afterward. For instance, GOLD (PF 1) indicates that the GOLD function uses
the key labeled PF 1.
As shown in the diagrams, most keys perform two functions. When you want to use the upper
of the two functions listed, simply press the key. To use the lower (shaded) function, first press
and release the GOLD function (PF1) and then press the key you want to use.

Creating Files 2-3

Figure 2-1:

VT 100 Keypad

J 1J(-J ~J

ZK-1377-83

2-4 Creating Files

Figure 2-2:

VT220 Keypad

B
INSERT
HERE

FIND

REMOVE

SELECT

PREV
SCREEN

NEXT
SCREEN

~
15

i
J

----j
13

ZK-1380-83

2.5 Beginning an Editing Session
Type and enter the EDIT command.
DOCTOR.FEL, as follows:

At the File? prompt, type and enter the file name

File?
1 I do not like you. Doctor Fell.

*[EOB]
*
The line appears on the screen, followed by an asterisk ( • ), which is the EDT line mode prompt.
The asterisk signifies that you are "in" EDT and that EDT is ready to accept your line mode
commands.
Note that the line has the line number 1. EDT automatically numbers lines. Line numbers are
one way of locating text in your file.

Creating Files 2-5

Now press the RETURN key. You see the symbol [EOB], which means end-of-buffer, and another
asterisk prompt. In EDT, a buffer is a workspace used in editing files. In this case, the buffer
contains one line of text. The [EOB] tells you that you have reached the end, or bottom, of the
buffer.
As you will see, the end of the buffer keeps moving down as you add lines to your file. For this
practice session, you will be working mostly in a buffer called MAIN. The EDT editor permits
you to create more buffers if you need them. See the EDT Editor Manual for more information.

2.5. 1 Entering Character Mode
At the asterisk prompt, type and enter the CHANGE command (abbreviation C) to enter
character mode.
When you issue the CHANGE command, the one-line file and the [EOB] symbol appear at the
top of the screen. You are ready to begin editing.
Type the following lines and press the RETURN key where indicated:

2.6 Getting Help on EDT
You can get help on the keypad functions any time during an editing session. Simply press the
HELP function (PF2) key. This prints a copy of the keypad diagram on your screen. While the
diagram is displayed, you can press any keypad key to get help on using that key. When you
are through with the HELP function press the space bar to return to editing. Try it out now.

2.7 Moving the Cursor
The cursor always appears where the next character will appear or the next action will take
place. You can move the cursor in many different ways. Experience will teach you which is
best in a given situation.

2.7. 1 Using the Arrow Keys
The easiest way to move the cursor is by using the arrow keys. On a VT100 terminal the four
arrow keys are located at the top of the keyboard. On the VT200-series terminals, they are
located between the keyboard and the keypad.
The LEFT and RIGHT arrows move the cursor one character to the left or right. If the cursor is
at the end of a line, the RIGHT arrow moves it to the beginning of the next line. Conversely,
if the cursor is at the beginning of a line, the LEFT arrow moves it to the end of the previous
line ..
The UP and DOWN arrows move the cursor one line up or down. The column position of the
cursor does not change, unless there is no text in the corresponding column above or below.
In that case, the cursor moves to the end of the preceding or following line.
Try using the arrow keys. Note that the cursor will not move beyond the limits of the buffer.
If you try to go beyond the limits, the message "Advance past bottom of buffer" or "Backup
past top of buffer" appears on the screen.

2-6 Creating Files

2.7.2 Changing the Direction of Cursor Movement
The keypad functions ADVANCE (4) and BACKUP (5) change the direction in which the
cursor moves. The ADVANCE function causes the cursor to move forward, toward the end of
the buffer. The BACKUP function causes the cursor to move back through the text, toward the
top of the buffer.
When you start editing, the cursor moves forward by default. You may want it to move
backward if you are searching for a word or making a series of changes. However, it can be
confusing to edit a file with the BACKUP function in effect. In general you should follow any
use of the BACKUP function immediately with the ADVANCE function.
The TOP (GOLD +5) and BOTTOM (GOLD +4) functions move the cursor to the top and to
the bottom of the file, respectively. Note that these two functions use the GOLD function plus
ADVANCE or BACKUP.
Use the TOP function to move the cursor to the top of your file, as follows:
I do not like yoo, Doctor Fell,
The reason why I cannot tell.
But this I know and know full well,
I do not like you, Doctor Fell.

2.7.3 Moving the Cursor by Character, Word, and Line
You can move the cursor one character at a time with the CHAR ( 3) function and one word at
a time with the WORD ( 1 ) function.
The LINE (0) function moves the cursor to the beginning of the next line; the EOL (2) function
moves the cursor to the end of the line.
Remember that if the BACKUP function is in effect, these functions will move the cursor
backward instead of forward.
Use the LINE and WORD functions to move the cursor to the word "why," as follows:
I do not like you, Doctor Fell,
The reason-Why I cannot tell.
But this I know and know full well,
I do not like you, Doctor Fell.

You can also move the cursor through larger entities of text with the PAGE (7) and SECT (8)
functions. However, this file is not long enough to try them out. For more information, see the
EDT Editor Manual.

Creating Files

2-7

2.8 Inserting Text
There are two ways to insert text.
One way to insert text is simply to move the cursor to where you want the new text to appear
and begin typing.
To try this out, move the cursor to "tell" and type the words "and will not." The screen appears
as follows:
I do not like you, Doctor Fell,
..
The reason why I cannot and will not ;!!~:ell.
But this I know and know full well,
I do not like you, Doctor Fell.

The other way to insert text is to open a line first. The OPEN LINE (GOLD +0) function opens
a line immediately above the cursor.
Move the cursor to the beginning of the second line and try it out. The screen appears as
follows:
I do not like you, Doctor Fell,
The reason why I cannot and will not tell.
But this I know and know full well,
I do not like you, Doctor Fell.

2.9 Deleting Text
The DELETE key functions in EDT the same way it does at the system level. It deletes a character
at a time to the left of the cursor.
In EDT, however, you can also delete text by the character, by the word, and by the line, as
follows:
DEL C (,)

Deletes the character the cursor is on.

DEL W (-)

Deletes a word, starting with the letter the cursor is on and going to the next
space.

DEL L (PF4)

Deletes a line, starting with the letter or space the cursor is on and going to
the next RETURN.

Use DEL L to delete the blank line.
Move the cursor and use DEL W three times to delete the words "and will not."
I do not like you, Doct9F Fell,
The reason why I cannot ii?~ell.
But this I know and know full well,
"I do not like you, Doctor Fell.

2-8 Creating Files

2.9. 1 Undeleting Text
You can restore text you have deleted by using the UNDELETE functions. These functions use
the GOLD function plus the DEL L, DEL W, and DEL C functions.
To try this out press DEL W; "tell" is deleted. Now press UND W; "tell" is restored.
Try each of these functions by deleting and undeleting a line, a word, and a character. Note
that you can restore only the last piece of text you have deleted. For example, if you use
DEL C twice, you can only restore the second character that you deleted.

2.10 Locating Text
The FIND (GOLD +PF3) function lets you search through a file for a specific string.
To follow this example, first move the cursor to the top of the file.
Press the two keys of the FIND function. The words "Search for:" appear highlighted at
the bottom of the screen. Type the word "not." To search forward through the file, press
ADVANCE (4).
The screen looks like this:
I do'}~ot like you, Doctor Fell,
The reason why I cannot tell.
But this I know and know full well,
I do not like you, Doctor Fell.

The FIND NEXT function lets you search for repeated occurrences of a string. To find the
next occurrence of "not," simply press FNDNXT (PF3). Continue to press FNDNXT until the
message "String was not found" appears at the bottom of the screen.
Note that to search back through the text you use the BACKUP function in place of ADVANCE.
Try searching back through the text for the word "like."

2.11 Moving Text
You can move sections of contiguous text from one location in the file to another with the CUT
and PASTE functions.
The SELECT (.) function marks a range of text, in this case the text you are going to move.
The text you put in the select range is highlighted on the screen.
The following example moves the third line to the first line.
First, move the cursor to the first letter of "But." Press SELECT. Then press LINE. The third line
appears highlighted, indicating that it has been marked by SELECT. (If you select the wrong
text, use RESET (GOLD +.) to undo it.)
CUT (6) moves the text in the select range from the buffer you are working in to a buffer
named PASTE. The PASTE buffer does not appear on the screen.
Press CUT. The selected text disappears from the screen, as follows:
I do not like you, Doctor Fell,
!he reason why I cannot tell.
;'-:~:' do not like you, Doctor Fell.

Creating Files 2-9

PASTE (GOLD +6) moves the text from the PASTE buffer back to the main buffer, locating it
at the cursor.
For this example, move the cursor to the top of the file. Press PASTE.
~ut this I know and know full well,
{i':do not like you, Doctor Fell,
The reason why I cannot tell.
I do not like you, Doctor Fell.

The text in the PASTE buffer is not deleted until you replace it with new text or end your
editing session. Move the cursor to the beginning of the last line and press PASTE again. The
same line appears. Use TOP and DEL L to delete the first line and go back to the original
format.

2.12 Leaving the Editor
The EXIT command takes you out of EDT and makes a new file.
The QUIT command takes you out of EDT but does not make a new file.
EXIT and QUIT must be issued from line mode. To get back to line mode, press CTRL/Z.
At the asterisk prompt, type EXIT and press the RETURN key. You are out of EDT. The file
name appears on the screen along with the number of lines in the file. The dollar sign ($)
prompt returns, which signifies that EDT is no longer active at your terminal.

Note
You can use the COMMAND (GOLD +7) function to issue line mode commands
while still in character mode. Line mode commands issued from character mode
are entered with the ENTER key.
Now type and enter the command TYPE DOCTOR.FEL. The file is printed on your terminal.
Look at your directory. You now have two versions of DOCTOR.FEL. You created version 1
with the CREATE command. When you edited version I, you automatically created version 2.
Return to EDT by using the EDIT command and naming DOCTOR.FEL as the file to be edited.
Use the CHANGE command to enter character mode. Delete the first two lines of the file.
Again type CTRL/Z and, at the asterisk, type QUIT and press the RETURN key. The dollar
sign ($) prompt returns immediately. EDT prints no messages on your terminal. The QUIT
command directs EDT not to create a new version of the file.
Type and enter TYPE DOCTOR.FEL. The full paragraph is printed on your terminal. Deleting
the two lines had no permanent effect because you left EDT by using the QUIT command
instead of the EXIT command. If you had used the EXIT command, the new version of the file
would have been only two lines long and numbered version 3. (Version 1, the one-line version,
and version 2, the four-line version, would still be in existence.)
Why would you use the QUIT command? If you wish to use EDT just to read a file, to search
for some lines, for instance, you can QUIT when you are through because you have not really
done any permanent editing. If you start to edit and then change your mind, QUIT is also
useful. Or, if you make a major error, such as deleting a large number of lines that you wish
to keep, it may be simpler to QUIT and start over.

2-10

Creating Files

Remember though, if you type QUIT accidentally, you will lose all the editing work that you
have performed. The EDT command QUIT is one EDT command that can cause you to lose
work if you use it when you do not mean to.

2.13 Line Mode Editing
Line mode has all the editing functions that character mode does. Instead of using keypad
functions, line mode uses English-like commands. For example, INSERT, DELETE, FIND, and
MOVE are all line mode commands. Line mode commands are typed at the asterisk prompt.
They are entered by pressing the RETURN key or the keypad key labeled ENTER. You can find
more information about all line mode editing commands in the EDT Editor Manual.
To begin, type and enter EDIT DOCTOR.FEL. The first line of text appears on the screen; notice
that it is numbered.
For example:
$

I do not like you. Doctor Fell.

*
When you created DOCTOR.FEL, you supplied no line numbers, but when you brought the file
into EDT, line numbers were assigned. These line numbers are used only by EDT. They are
not a part of your file. When you return to DCL, you leave the line numbers behind. Because
keypad editing operates on the whole file, it does not use the line numbers EDT assigns.
However, because line mode editing operates on the file a line at a time, it depends on them.
Type TYPE 1 and press the RETURN key. EDT prints line 1 and returns the prompt.
Now type T 1 and press the RETURN key. Line 1 is printed again.
Note
EDT has stricter rules for shortening commands than DCL. Type commands
exactly as shown in the examples.

2. 13. 1 Range Specifications
Line mode can display all or part of a buffer. The lines displayed are selected by range
specifications; range specifications can be line numbers or descriptive words.
Type T WHOLE and press the RETURN key. The entire buffer (four lines) is printed on your
terminal, with line numbers.
Now type T BEGIN and press the RETURN key. EDT returns to the beginning of the buffer
and prints line 1. EDT uses an invisible line pointer to keep track of where you are in a buffer.
When you move from one place to another in a buffer, you are moving the line pointer.
Now type TYPE END and press the RETURN key. The line pointer moves to the end of the
buffer and EDT displays [EOB].
Now type TEND -1 and press the RETURN key. The line pointer moves "up" one line and
EDT displays the last line.
The expressions BEGIN, END, and END -1 are all ways of specifying a range for the
TYPE command.

Creating Files 2-11

2. 13.2 Getting Help in Line Mode
The EDT HELP command provides help on EDT. Typing HELP on a line by itself gives
information on the HELP command and lists other EDT help that is available. Since you have
just used some simple forms of EDT ranges, you can now try some other ways to specify ranges
in EDT.
Type HELP RANGE and press the RETURN key. After a pause, EDT displays quite a bit of text
explaining the different ways of expressing a range. What you have been doing is combining
range specifications with the TYPE command to specify the lines you wish listed. Notice that
there are many more forms of range expression besides those you have already used.
For example:

*
RANGE
Range specifications select the exact lines of text on which the line
editing command will operate.
There are several general classes of range specifications:
1.
2.
3.

Single line ranges specify a single line of text.
Multiple line ranges specify blocks of text. such as an entire buffer
or all lines from the current line to the end of the buffer.
Compound ranges combine single line ranges with operators to specify
multiple lines of text.
Noncontiguous ranges specify multiple lines that are not necessarily
adjacent to one another.

Additional information available:
ALL
FOR
SELECT

AND
LAST
STRING

BEGIN
MINUS

BEFORE

THRU

WHOLE

NUMBER

BUFFER
ORIGINAL

DOT
PLUS

END
REST

*
Now type HELP RANGE MINUS and press the RETURN key. EDT displays text explaining how
the minus sign (-) is used in range specifications. Similar help is available for all EDT line
mode commands, as well as for concepts such as RANGE.
For example:

*
RANGE
MINUS
The minus sign (-) in ranges selects a single line that is a specified
number of lines before a specified line.
Format: [range] - [n]
Range is a single line range. and n is an integer. The line selected is
the line that is n lines before the line specified by range. If you
omit range. the current line is used; if you omit n. 1 is used.
Ex:

TYPE 15 - 3

Display the third line before the line numbered 15.

TYPE END -1

Display the last line in the buffer.

TYPE -

Display the previous line.

*
2-12

Creating Files

As you go through this editing exercise, use the HELP command whenever you want further
information. Type HELP on a line by itself for information on what help is available from EDT.

2. 14 Displaying Lines of Text
As you have seen, the TYPE command moves the line pointer to the beginning of a range.
There are many ways of expressing ranges.
Type T 1 and press the RETURN key. Line 1 is printed on your terminal. The TYPE command
moved the line pointer to line 1 and printed it.
Now type 1 by itself and press the RETURN key. Once again, line 1 is printed on your terminal.
This has the same effect as the previous command. If the range expression for a type command
begins with a number, you need not type TYPE or T.
For example:

I do not like you. Doctor Fell.

Press the RETURN key on a line by itself. Line 2 is printed. Line 2 is the next line past the line
pointer.
Type T . and press the RETURN key. Line 2 is printed. The dot, or period (.), is a range
expression meaning "where the line pointer is./I
Now type a period (.) and press the RETURN key. Line 2 is printed. The line pointer has not
moved. The period is considered a line number. Thus, you did not have to type the T.
For example:

*
*

The reason why I cannot tell.

This time type TYPE 1 THRU 2 and press the RETURN key. Both lines are printed.
Type 1 THRU 2 and press the RETURN key. The range begins with a line number. No TYPE
command is needed.
Again, type and enter the period. Although EDT printed both lines in the range, the line pointer
is still pointing at the first line in the range. The period will always tell you where the line
pointer is.

Creating Files 2-13

For example:

*
*
*

1
2

I do not like you, Doctor Fell,
The reason why I cannot tell,

1
2

I do not like you, Doctor Fell,
The reason why I cannot tell,

I do not like you, Doc~or Fell,

Now type TYPE WH and press the RETURN key. The entire buffer is printed.
Finally, type WH and press the RETURN key. You get an error message, "Unrecognized
command." WHOLE is a range expression that does not begin with a number, so it does not
work without the TYPE (or T) command. Since you entered an illegal command, nothing
happened. You received the message and the asterisk (*) prompt returned. Your text is
unaffected, and the line pointer stays in place.
For example:

1
2
3
4
[EOB]

I do not like you, Doctor Fell,
The reason why I cannot tell,
But this I know and know full well,
I do not like you, Doctor Fell.

*
Unrecognized command

2.15 Inserting Text
The INSERT command (abbreviation I) inserts text ahead of the line pointer.
The RESEQUENCE command (abbreviation RES) renumbers lines.
Type 1 and press the RETURN key. Line 1 is printed on your terminal.
Now type I (for INSERT) and press the RETURN key. Type the new line of text shown in the
following example, and then end the insertion by pressing CTRL/Z on a line by itself:

I do not like you, Doctor Fell,

Now type T WH and press the RETURN key. The new line you entered appears ahead of line 1.
The line pointer was pointing to line 1 when you issued the INSERT command. The INSERT
command inserts text ahead of the line pointer. (If the line pointer had been pointing at the
end of the buffer, the new text would have been inserted at the end of the file.)
/

2-14 Creating Files

For example:

0.1
1
2

3
4

All around the mulberry bush.
I do not like you. Doctor Fell.
The reason why I cannot tell.
But this I know and know full well.
I do not like you. Doctor Fell.

[EOB]

Notice that the new line number is line 0.1. EDT keeps your lines in numerical order by using
numbers with decimal points when you insert new material between existing lines. Since these
numbers can become confusing after a complicated series of inserts, EDT provides a means of
resequencing line numbers.

2. 15. 1 Renumbering Text Lines
Type RESEQUENCE and press the RETURN key. Now type T WH and press the RETURN key.
The lines have been renumbered, as follows:

*
*

5 lines resequenced
1
2
3
4
5
[EOB]

All around the mulberry bush.
I do not like you. Doctor Fell.
The reason why I cannot tell.
But this I know and know full well.
I do not like you. Doctor Fell.

2.16 Deleting Lines from Text
The DELETE command eliminates text.
Display line 1 by typing the following line:

All around the mulberry bush.

Now type DELETE 1 and press the RETURN key. EDT informs you of the deletion and prints
the next line on your terminal, as shown in the following example:

*1 line deleted
2

I do not like you, Doctor Fell.

Type T WH again and press the RETURN key; you will see that the excess line is gone. The
screen will appear as follows:
2
3
4
5
[EOB]

I do not like you, Doctor Fell.
The reason why I cannot tell,
But this I know and know full well,
I do not like you, Doctor Fell.

Creating Files 2-15

Type and enter RESEQUENCE to renumber the lines correctly.

2.17 Searching Through Text
The FIND command moves the line pointer past the string you are searching for.
You can search for a string by quoting it. You can search again for the same string by typing
just the quotation marks ('"').
You can search for a group of lines by quoting from the beginning of the first line and the end
of the last line.
You can move the line pointer with plus (+) and minus (-) commands.
Type FIND BEGIN and press the RETURN key as follows:

*
*

The EDT prompt returns, but nothing else is printed on your terminal. The line pointer is now
at the beginning of the buffer. Remember that the TYPE command moves the line pointer and
also prints the line. The FIND command also moves the line pointer but does not print the
line.
Type "Fell," including the quotes and press the RETURN key. The line containing the quoted
string is printed on your terminal. Now do the same thing again. Your screen should appear
as follows:

I do not like you, Doctor Fell,

String was not found
1
I do not like you, Doctor Fell,

*
EDT reports that the string was not found and reprints the line. When EDT finds a string, the
line pointer moves past that string. When EDT cannot find a quoted string, it reprints the last
line pointed to. This tells you that the line pointer has not moved. This may seem confusing,
but as you use EDT, particularly with larger files, you will find it less so.
Now type F BE and press the RETURN key. F is the abbreviation for the FIND command and
BE is the abbreviation for the BEGIN range expression. The EDT prompt returns, but you see
nothing else. The line pointer is at the beginning of the buffer again. Your screen should
appear as follows:

*
*
Type two quotation marks ("") with nothing between them and press RETURN. The first line is
printed. EDT remembers the last string that you searched for and searches for it again when you
type the quotation marks with nothing between them. Your screen should appear as follows:

I do not like you, Doctor Fell,

*
Return to the beginning of the buffer with F BE.

2-16

Creating Files

Now type HI doH THRU HFell. Hand press the RETURN key. Notice that this time the period is
included in the second string. The entire poem is printed on your terminal. The line pointer
has not moved, however, as you can confirm by typing a period ( .) and entering it. The period
means "the current line. H
For example:
*F BE

lliill

1
2
3
4

I do not like you, Doctor Fell,
The reason why I cannot tell,
But this I know and know full well,
I do not like you, Doctor Fell.

I do not like you, Doctor Fell,

You can also move the line pointer down using the plus (+) command or up using the
minus ( - ) command as shown in the example. You can also combine the plus or minus with
other range expressions in commands, such as TYPE BEGIN + 1, or TYPE "reason" + 1, or TYPE
END -1. END -1, by the way, is the last line in the buffer, since END is the actual end of
the buffer, meaning there is no line there.
For example:

*
*
*
*
*

But this I know and know full well,

The reason why I cannot tell,

But this I know, and know full well.

I do not like you, Doctor Fell.

2.18 Moving and Copying Text Within the File
The MOVE command moves text.
The COpy command copies text.
Type 1 and press the RETURN key. Line 1 is printed, as shown in the following example:

I do not like you, Doctor Fell,

Now type MOVE 1 TO END and press the RETURN key. EDT informs you that one line has
been moved, as follows:

1 line moved

Type RES (RESEQUENCE) and press the RETURN key. Your screen should appear as follows:

4 lines resequenced

Creating Files 2-17

Print the whole buffer by typing T WH and entering it, as follows:

1
2
3
4

The reason why I cannot tell,
But this I know and know full well,
I do not like you, Doctor Fell.
I do not like you, Doctor Fell,

[EOB]

*
Now type COpy 4 TO 1 and press the RETURN key. The command means "Make a copy of
line 4 and place it just ahead of line 1." Resequence again and print the whole buffer by using
the T WH command.
For example:

*1 line copied
*
5 lines resequenced
*

1
2
3
4
5

I do not like you, Doctor Fell,
The reason why I cannot tell,
But this I know and know full well,
I do not like you, Doctor Fell.
I do not like you, Doctor Fell,

[EOB]

*
Notice that the COpy command leaves the copied line in place, while the MOVE command
deletes the line from one location and places it in another location.
Type and enter DELETE 5 to restore the poem to its original form.

2.19 Replacing Words
The SUBSTITUTE command replaces text. The SUBSTITUTE command makes its substitution
on the first matching string it encounters on the current line. You can also make substitutions
throughout a range or throughout an entire file.
The SUBSTITUTE command searches for a string of text and replaces that string with a new
string. The old and new strings are marked by slashes (j), or delimiters.
Begin this example by moving the line pointer to line 1. Type 1 and press the RETURN key.
Type Sjelljumblej and press the RETURN key. EDT searches the line for the string "ell," makes
the substitution, and prints the new line, as follows:
1

I do not like you, Doctor Fumble,

1
I do not like you, Doctor Fumble,
1 substitution

Now type SjelljumblejWHOLE and press the RETURN key. WHOLE means the entire buffer,
as usual. EDT searches for the string "ell" throughout the buffer, making the substitution and
printing each new line. When EDT has completed its operations, it informs you of the number
of substitutions made.

2-18 Creating Files

For example:

2
The reason why I cannot tumble,
3
But this I know and know full wumble,
4
I do not like you, Doctor Fumble.
3 substitutions

*
Return to line 1 and substitute "ell" for "umble," to restore the original poem.

2.20 Line Mode Commands Also Used in Character Mode
WRITE and INCLUDE are two line mode commands that have no direct character mode
equivalents. They are used in both line and character editing.
Remember that you can use the COMMAND (PFl +7) function in character mode to enter line
mode commands.

2.20. 1 Creating a Second File
The WRITE command takes a specified range of text and creates a new file containing that text.
This command can be useful if you are going to use a section of a file in more than one piece
of writing, for example, in several different reports.
The following example creates a file named LIKE.DOC that contains the first two lines of
DOCTOR.FEL:

DBO:[USER]LIKE.DDC;l

2 lines

The two lines are not deleted from DOCTOR.FEL.

2.20.2 Including a Second File in Your Text
The INCLUDE command inserts a file into your existing file at the point you specify. The
default position is at the line pointer (or at the cursor in character mode).
The following example moves the line pointer to the end of your file and inserts the file
LIKE.DOC:

*[EDB]

*
*

1
2
3
4
5
6
[EDB]

I do not like you, Doctor Fell,
The reason why I cannot tell,
But this I know and know full well,
I do not like you, Doctor Fell.
I do not like you, Doctor Fell,
The reason why I cannot tell,

*
The file LIKE.DOC still exists; you could include it in other files.

Creating Files

2-19

2.21 Summary
This concludes your introduction to EDT. You have learned to use the following most common
editing functions in both character and line mode:
•

Creating new files and new versions of files

•

Moving around in a text file

•

Inserting and deleting text

•

Moving and copying text

•

Making local and global substitutions

•

Using range specifications

•

Getting help

EDT has additional capabilities that have not been explained here. See the EDT Editor Manual
for more information on EDT, including the following advanced features:
•

Multiple buffers that permit you to work on smaller blocks of text while you build a large
file in the main buffer. If, for instance, you have text that must be repeatedly inserted in a
file-"boilerplate" of some kind-you can store that text in an alternate buffer and use the
COpy command to insert it wherever you need it.

•

A journaling facility that protects you against losing your files should the system crash while
you are editing.

•

A means of defining new commands in line mode and new keys in character mode. Any
time you need to do one series of editing commands over and over again, you should
consider defining keys or commands.

•

Detailed information on EDTINI.EDT files for saving your defined commands and using
them over and over without having to redefine them every time.

EDT is quite versatile, and this introduction is only a beginning. Once you get used to using
EDT as taught here, you should explore the EDT help files and the EDT Editor Manual for ideas
and suggestions on how you can use the advanced features of EDT.

2-20 Creating Files

Chapter 3
Using DCl Commands
RSX-IIM-PLUS has hundreds of available commands and qualifiers. These commands enable
you to specify in precise detail exactly what you want the system to do. In most cases,
however, complex (and confusing) commands are not necessary. This chapter describes the
DIGITAL Command Language (DCL) commands most likely to be of everyday use to an average
RSX-IIM-PLUS system user. The RSX-IIM-PLUS help files and the RSX-11M-PLUS Command
Language Manual have detailed descriptions of all the DCL commands, qualifiers, and concepts.
So far you have not used any qualifiers with DCL commands. Qualifiers are attached to a
command by a slash (j) and are used to change the effect of the command. For instance, if
you type DIRECTORY, you will see a 3-column listing of all the files in the USER account, but
if you type DIRECTORY jBRIEF, you will see a I-column listing of all the files.
Most DCL commands require you to name a file. Just as a book can contain anything that can
be printed, a file can contain anything that can be put on a computer disk or put into computer
memory. A file can contain a memo, or it can contain a computer program.
All files, regardless of their contents, have a lot in common. In particular, all files have names
in the same form. The file name can be no more than nine characters and is usually followed
by a 3-letter file type. The name of a file generally tells you quite a bit about what is in the
file. For instance, there is a file in the USER account called WHATSHERE.TXT. This text file is
an annotated list of all the files included in the USER account.
This chapter explains more about how to use DCL and summarizes the most often-used DCL
commands. Section 3.1 discusses wildcards, which are tools for specifying files in groups.
Section 3.2 discusses file management. DCL provides many commands for managing your files
and Sections 3.2.1 to 3.2.8 provide a detailed discussion of some of the commands you can use
to manage your files.
You have done some file management already in the previous chapters when you used the
DIRECTORY and TYPE commands. You have also created files in previous chapters by using
the EDIT and CREATE commands.
Section 3.3 provides a discussion of the DCL commands for general system use, and
Sections 3.3.1 to 3.3.9 provide a detailed description of these commands.

Using DCL Commands 3-1

Section 3.4 provides a discussion of the DCL commands for the Queue Manager, and
Sections 3.4.1 to 3.4.7 provide a detailed discussion of these commands.

3.1 Wildcards and Other Wild Things
Directories can be quite large. Most of the time when you look in a directory, you do not want
to see the whole list, but only to see if certain files are available. If you want to check on a
single file, for example, a file named FLY.TXT, you can type the following command:
$

The command lists only the most recent version of FLY.TXT.
The following command line lists all versions of FLY. TXT:
$

The asterisk (.) is called a wildcard and functions exactly as a wildcard does in card games.
It can stand for anything. In this case, the asterisk means "all version numbers./I Without the

asterisk, you would have had to type the following to list all three versions:
$

And even then you could not be sure that you had listed all versions.
For many commands, you can use wildcards in place of most fields in the file specification. The
examples in this section use the DIRECTORY command, but you can use wildcards on all the
commands discussed in Section 3.2, as well as some other commands.
Some of this is going to look complicated, but once you get used to it, you will find it very
useful. For instance, the following command asks for the latest versions of all files with the file
type TXT:
$

The next command asks for all files in all directories on the disk. Try it. You will probably
want to press CTRL/C to stop it.
$

You cannot use wildcards for device names, but you can use them for directory names, file
names, file types, and version numbers.
Wildcards can get wilder. If you type the following command line, you are asking for the latest
version of all TXT files whose names start with F:
$

You are asking for the latest version of all TXT files whose names end with F if you type the
following command line:
$

And, if you type the following command line, you are asking for the latest version of all TXT
files whose names include an F:
$

Combining letters and the asterisk wildcard only works on file names and file types.

3-2 Using DCL Commands

Another wildcard for file names and file types is the percent sign (%). The percent sign is a
wildcard that stands for a single character. Therefore, to ask for the latest version of all TXT files
whose names start with FL and end with one other character, you use the following command:
$

As you can see, wildcards are a way of specifying lots of files, or narrowing down the number
of files you have to look at, without doing lots of typing or thinking. You will find more
information on wildcards in the RSX-IIM-PLUS Command Language Manual.
There are also some DCL command qualifiers that help you specify groups of files without
knowing anything about their exact names. These qualifiers can be combined with wildcards in
commands.
Many of these qualifiers relate to when the files in your directory were created. You can show
all the files created on or since a specified date, or during a specified time period.
To ask for all the files you created today, type the following:
$

To ask for all the files you created on April 12, 1987, type the following command line:
$

The /SINCE:28-FEB-87 qualifier means you are asking for all the files you created on or after
February 28, 1987.
The /THROUGH qualifier allows you to use /THROUGH:03-SEP-87 to mean all files created
on or before September 3, 1987.
You can use /SINCE and /THROUGH together to ask for files created between two dates, as
follows:
$

And, finally, there is the /EXCLUDE qualifier. Use this if you want to see all your files except
the file you specify. For example, to ask for all files in the directory except those named
FLU.TXT, type the following command line:
$

These qualifiers can be combined with wildcards. You can ask for all the TXT files you created
today by typing the following command line:
$

The more systematic you are about naming your files, the more useful you will find wildcards
and these special DCL qualifiers.
Note
The next section discusses other file management commands that accept
wildcards and special qualifiers. Wildcards and special qualifiers are easiest
to use with the DIRECTORY and TYPE commands. You should wait until
you are confident of your ability to use them before trying them out on more
complex commands, such as RENAME or COPY. This is especially true for the
DELETE and PURGE commands.

Using DCL Commands 3-3

3.2 DCL Commands for File Management
This section describes RSX-llM-PLUS file management commands in alphabetical order: COPY,
CREATE, DELETE, DIRECTORY, EDIT, PURGE, RENAME, and TYPE.

3.2.1 COpy
The COpy command makes a duplicate of one or more files. The file that you create with the
COPY command does not have to have the same name as the original file.
The following example duplicates the file HELLO.TXT; the new copy of the file has the name
MESSAGE.TXT:
$

From?
To?
$

If you have just looked at a file from the fixed disk and wish to make a copy on your diskette,
use a command similar to the following:
$

From?
To?
$

You will then have two copies of the file, one on the fixed disk and one on DUl in the directory
named [JOHNSON]. Naturally, there must be a directory named [JOHNSON] on the diskette
volume in DUl for this command to work.
(Later in this chapter you will find a description of the CREATE/DIRECTORY command that
shows you how to create a directory to do this.)
The following two qualifiers to the COPY command are quite useful:
/OWN
/REPLACE
The /OWN qualifier specifies that the new copy of the file belongs to the directory you sent
it to, and not to the directory you copied it from. This helps keep the protection of the file
consistent. If you encounter confusion about the protection of copied files, copy the file again
using this qualifier, and you will probably be all right.
There is a full discussion of file protection in the RSX-llM-PLUS Command Language Manual.
For the time being, all you need to know is that if you are making a copy of the file for yourself,
you will not need to use the /OWN qualifier, but if you are making a copy for someone else,
you will need to use it. Otherwise, the person you are making the file for may have trouble
editing or deleting the file.
The /REPLACE qualifier specifies that if the directory you are sending the copy to already has
a file of that name, the old file will disappear and be replaced by the new copy you have
just sent.

3-4

Using DCL Commands

3.2.2 CREATE
The CREATE command lets you create a text file without using the editor. After you issue the
command, type the text of the file on your terminal. You can delete a line by pressing CTRL/U.
You can close the file by pressing CTRL/Z.
For example:
$

File?
$

3.2.3 DELETE
The DELETE command erases one or more files from a directory. Once you delete a file, it is
gone forever. That makes DELETE the most dangerous command you have learned so far. If
you are deleting a whole list of files, aborting the DELETE command may stop the last ones on
the list from being deleted, but it will not save the first ones.
DELETE works fine with wildcards and the special qualifiers, but you should be sure you know
what you are deleting. You may want to look at a directory before deleting from it. For
instance, type the following command line first:
$

Then type the following:
$

You may have forgotten about something that you want to keep.
You have to specify a version number with the name of the file you are deleting. You can use
a wildcard if you are deleting all versions of a file. If you do not specify a version number,
RSX-IIM-PLUS prompts you with each version of the file and asks whether you want to delete
it.
The following two qualifiers to the DELETE command are useful:
fLOG
fQUERY
The fLOG qualifier lists the names of files as they are deleted. This gives you a list of what
you deleted, but it gives you no chance to change your mind.
The fQUERY qualifier gives you a second chance. It allows you to delete selectively after
specifying a group of files. You are prompted with a list of file names, based on your original
command. As each file in the list is named, you are asked whether you want to delete it.

Using DCL Commands 3-5

The possible responses are as follows:
Y

Delete the file.

Save the file.

Save the file and quit.

Go ahead and delete all remaining candidates.

@ill

Save the file.

Y, N, and RETURN will continue with the next possible file, unless you press CTRL/Z, which
stops all further deleting.
The following example was issued with the defaults of DB3:[SCHUBERT]:
$

Delete file
Delete file
Delete file
Delete file

DB3:[SCHUBERT]LIEDER.TMP;1
DB3: [SCHUBERT]TROUT.TMP;l
DB3: [SCHUBERT]FRANZ.TMP;l
DB3:[SCHUBERT]ROSAMUNDE.TMP;1

[Y/N/G/Q]?
[Y/N/G/Q]?
[Y/N/G/Q]?
[Y/N/G/Q]?

The following files have been deleted:
DB3:[SCHUBERT]VIENNA.TMP;1
DB3:[SCHUBERT]LANDLER.TMP;1
DB3: [SCHUBERT]UNFINISHED.TMP;l
DB3: [SCHUBERT] SYMPHONY.TMP;1
$

The user was able to delete the first two files one at a time with the Y response, save the third
file with the N response, and delete all remaining files with the G response.
CAUTION

Do not use the DELETE command unless you mean it. In particular, do not use
DELETE with wildcards or special qualifiers until you are sure of what you are
doing.

3.2.4 DIRECTORY
The DIRECTORY command lists files in your directory. Remember that if you do not name a
particular file or group of files with the DIRECTORY command, you will see a listing of all the
files in the directory. If you name one file, then the directory listing is limited to that file.
The following qualifiers are available for the DIRECTORY command:
jBRIEF

jFREE
jFULL
jOUTPUT:filespec
jPRINTER
jSUMMARY
The DIRECTORY command lists the files in your directory. Normally, this is a 3-column listing.
The three columns show you the complete file names, the number of blocks used by the file,
and the creation date of the file. At the end of the directory listing is a summary listing of the
total number and space requirements of all files listed. If you use the jBRIEF qualifier, you get

3-6 Using DCL Commands

a 1-column listing that shows only the file names. If you use the jFULL qualifier, you get a
great deal of information about each file.
The jFREE qualifier shows you the amount of free space on the mass-storage device you specify.
For example:
$

DB3: has 169709. blocks free. 170961. blocks used out of 340670.
Largest contiguous space = 152069. blocks
15243. file headers are free. 8757. headers used out of 24000.
$

Task image files, which are runnable programs, need contiguous space, as do certain other kinds
of files. Since each file has a header, the number of free headers is the number of additional
files you can make.
The jOUTPUT qualifier allows you to store the directory listing in a file instead of printing it
on your terminal. Include the name you want the file to have with the jOUTPUT qualifier,
such as jOUTPUT:FOLEY.LIS.
The jPRINTER qualifier allows you to print the directory on your printer, if you have one.
The jSUMMARY qualifier tells you how many files you have in your directory and how much
space they take up.

3.2.5 EDIT
The EDIT command starts up EDT, the DIGITAL standard editor, which is used to create and
edit text files. Editing files is discussed in Chapter 2 of this book.
Several qualifiers to EDIT are described in the RSX-IIM-PLUS Command Language Manual; they
can increase the fleXibility and convenience of EDT.

3.2.6 PURGE
The PURGE command is very similar to the DELETE command, except that PURGE always
leaves one or more copies of the file around. Normally, PURGE will delete all but the
highest-numbered copy of a file. This command is very useful for cleaning up your disks.
For instance, if you edit a file, look at it, edit it again, look at it, change your mind, edit it
again, and so forth, pretty soon you will have a large number of files with the same name
and different version numbers. Usually, you will only want to keep the latest version. The
following command allows you to delete all but the last version:
$

You may want to use the following PURGE qualifiers:
jKEEP:n
JLOG
The jKEEP qualifier allows you to specify that the last n versions (by number) be saved. In
other words, instead of keeping just the latest copy and deleting all the others, you can keep
two or more of the latest versions by using jKEEP.
The JLOG qualifier lists the names of the files deleted on your terminal.

Using DCL Commands 3-7

The following command purges all the files in your directory:
$

This is a good command to issue at the end of the day if you have done a lot of editing or
other file creating.
CAUTION
Do not use PURGE unless you mean it. In particular, do not use PURGE with
wildcards or special qualifiers until you are sure of what you are doing.

3.2.7 RENAME
The RENAME command changes a file's name.
For example:
$

Old file name?
New file name?
$

This example changes BROWNS.STL (old file name) to ORIOLES.BLT (new file name).
The following command line allows you to rename all the versions of a file:
$

All files named WRONG.TXT are changed to the name SONG.TXT. All the version numbers
stay in order. Other wildcards and special qualifiers will work with RENAME, but you should
generally only rename one file at a time until you are confident of your ability to handle
wildcards and special qualifiers.

3.2.8 TYPE
The TYPE command prints files on your terminal. You can use any combination of file
specifications, wildcards, and special qualifiers with the TYPE command.
For example:
$

The TYPE command prints on your terminal all TXT files in your directory, excluding all
versions of FLU. TXT.

3.3 DCl Commands for General System Use
This section describes, in alphabetical order, a number of commands for general system use.
These include BROADCAST, HELP, RUN, SET DEFAULT, SET PASSWORD, SHOW DEFAULT,
SHOW DEVICES, SHOW TIME, and SHOW USERS.

3-8 Using DCL Commands

3.3.1 BROADCAST
The BROADCAST command sends a one-line message to one or more terminals.
For instance, the following command sends a message to terminal TT2:
$
To?

Message?

You can also broadcast to another user by user name, as follows:
$
To?

Message?

In this case, the broadcast goes to all the terminals that user Brando happens to be logged in
on.
If you leave the quotation marks ("") off the message, it appears on the receiving terminal in
UPPERCASE. With the quotation marks included, the message appears exactly as you sent it.

Privileged users can send messages to all terminals, or to all logged-in terminals, by using the
following qualifiers:
JALL
jLOGGED-IN
The following command sends the broadcast to every terminal that has power on, whether
logged in or not:
$

Message?

But the following command sends the broadcast only to terminals with a user logged in:
$

Message?

3.3.2 HELP
The HELP command gives you information about using the system. Most RSX-IIM-PLUS
systems have help files available for users.
H and a question mark (?) are both abbreviations for the HELP command. You can also get
help by typing a question mark in response to a prompt from a DCL command. In that case,
after the help file appears on the screen, the prompt returns. You can either answer, or you
can ask for more help by typing another question mark.
If you simply issue the HELP command at the dollar sign ($) prompt, you will see a list of the
available help files for your system. You can also ask for information on a specific command
or qualifier by typing the following commands:
$
$

Usually, each screen of help text will point you to further help text when it is available.
The EDT command HELP works similarly. (See Chapter 2.)

Using DCL Commands 3-9

3.3.3 RUN
The RUN command starts a task (or working program) executing.
For example, the following command runs a program called HIYA:
$

The RSX-11M-PLUS Command Language Manual provides more information about running tasks.

3.3.4 SET DEFAULT
The SET DEFAULT command sets either your default directory or device, or both. When you
log in, you log in on a particular device, for example, DBO, and in a particular directory, for
example [KILROY]. Therefore, DBO:[KILROY] is your default. You can use the SHOW DEFAULT
command to find out what your defaults are.
For example, you can name a file in the following way:
$

File(s)?

However, the system will interpret the command as if you had specified the default device and
directory, as in the following command line:
$

File(s)?

If you want to print a file from another disk or directory, you have to include the disk or

directory name in your command. For example:
$

File(s)?

If you want to do a number of things with files from DB3:[JANE], use the SET DEFAULT

command, as shown in the following example:
$
$

When you are through with DB3:[JANE], you can go back to your original disk and directory
with another SET DEFAULT command.

3.3.5 SET PASSWORD
The SET PASSWORD command changes your password. You must enter your old password
before you are allowed to change it. You must enter your new password twice, the second
time for verification. Type carefully when entering the password information, because it is not
echoed. You would not want to have an unknown password because your finger slipped. (If
this does happen, the system manager can straighten it out.)
In the following example, the passwords are shown in brackets, but remember that they do not
appear on your terminal:
$

Old password:
New password:
Verification:

3-10 Using DCL Commands

The next time you log in, you will have a new password.

3.3.6 SHOW DEFAULT
The SHOW DEFAULT command tells you your current default device and directory. It also
tells you the type of directory you have and which terminal you are logged in on.
For example:
$

DBO:[USER] Named TT2:
Protection Ule: [200.1]
$

Only the device and directory are important to know in order to use defaults in file specifications.
The directory type, NAMED, is the default directory type. It indicates that your directory can
use either the name or number format. The protection User Identification Code (UIC) identifies
you to the system and controls what system privileges you have.

3.3.7 SHOW DEVICES
The SHOW DEVICES command tells you which devices are on your system and which are
available. If you name a device type, only information about devices of that type is shown. For
example, the following command gives information about some of the DB devices on a system:
$

DBO:
DB1:
DB2:
DB3:

Loaded Type=RP06
Loaded Type=RP06
Offline Loaded Type=unknown
Public Mounted Loaded Type=RP06

DBO and DBl are both loaded, which means the driver for each is present in memory. They
have not been mounted, which indicates they are not presently being used. The device is an
RP06, which is a type of disk.
DB2 is reported to be off line and loaded, but type unknown. Loaded means that the software
is present to handle such a device if it exists. However, since the device is off line, the system
knows nothing about it.
DB3 is mounted public, which makes it accessible to all users. The device is an RP06; its driver
is loaded.
If you issue the SHOW DEVICES command without naming any device, you will see a list of all
devices on the system, including terminals and pseudo devices. Pseudo devices are not physical
devices. They are names used by the system as stand-ins for real device names. This makes it
possible to refer to a device on any RSX system without knowing its name and number. On
any RSX system, the operating system itself is always on pseudo device LB, regardless of which
physical device it might be. Similarly, your terminal is always pseudo device TI, regardless of
its number or model.

Using DCL Commands 3-11

3.3.8 SHOW TIME
The SHOW TIME command displays the current time and date. The time is in 24-hour format,
and the date is formatted as dd-mmm-yy.
For example:
$

15:27 03-SEP-87
$

3.3.9 SHOW USERS
The SHOW USERS command tells you which terminals are logged in, as well as providing
some information about the user logged in to the terminal. The following display shows the
terminal number, the directory, and the protection UIC (User Identification Code) for each user,
followed by the login time, the number of active tasks, and the user's name:
$

TT2:
TT6:

[FREDDY]
[7.40]
[WAREHOUSE] [303.5]

18-MAY-87 10:57 0
18-MAY-87 15:04 3

F. SANFORD
R. ROGERS

3.4 DCl Commands for the Queue Manager
The Queue Manager, or QMG, is the system task that keeps track of jobs that have been directed
to batch processors, printers, or other output devices, making sure that they are separate and in
order.
Commands that involve the Queue Manager include the following: PRINT, SHOW QUEUE,
SET QUEUE, DELETE/ENTRY, HOLD/ENTRY, RELEASE/ENTRY, and STOP/ABORT.
The commands discussed in Sections 3.4.2 to 3.4.7 can be used for both print and batch jobs.
The SUBMIT command, described in the next chapter, places jobs in batch queues just as the
PRINT command places jobs in print queues.

3.4.1 PRINT
The PRINT command prints files on a printer, if your system has one, as shown in the following
example:
$

File(s)?
PRI - Job 141. name "WHATSHERE". submitted to queue "PRINT II
$

Once you receive the message that the print job has been submitted to a queue, you can go on
with your other work. The job name comes from the name of the first, or only, file. The job
number is unique and can be used in other commands to the Queue Manager, such as SHOW
QUEUE, SET QUEUE, DELETE/ENTRY, and STOP/PRINTER.
The following qualifiers to the PRINT command are particularly useful:
/ AFTER: (dd-mmm-yy hh:mm)
/COPIES:n

3-12 Using DCL Commands

The / AFTER qualifier allows you to print your job after a time you specify, perhaps at a time
when no one is around. Without this qualifier, the job would go directly to the printer.
You may specify either the date, or the time, or both. If you do not specify a date, the current
date is assumed. To specify the date without the time, omit the hh and mm values.
The date must be in the following format:
i8-MAY-87

The month is indicated by the first three letters of its name.
The time must be in the 24-hour format.
Examples
S
File(s)?

Prints the file after 6 P .M ..
S
File(s)?

Prints the file on April I, 1987.
The /COPIES qualifier lets you print more than one copy of the file, as shown in the next
example.
S
File(s)?

Prints two copies of the file.
If you are printing more than one file at the same time, but only want extra copies of one, put
the /COPIES qualifier after that file name, as shown in the next example.
S
File(s)?

Prints two copies of the file RUTH. TXT and one copy of the other two files.
$

File(s)?

Prints one copy of the first file, two of the second, and three of the third.

Using DCL Commands

3-13

3.4.2 SHOW QUEUE
SHOW QUEUE displays information about print or batch jobs in queues, such as where they
are and what their entry numbers are.
The SHOW QUEUE command by itself lists full information on all jobs in all queues.
If you want brief information on all jobs in all queues, use the following command:
$

If you want information on a particular job, type a command similar to the following:
$

3.4.3 SET QUEUE
SET QUEUE allows you to change attributes of print or batch jobs after they have been placed
in a queue.
The following example shows you how you can print two copies of the file HOLIDAY. LIS, even
though you did not specify two copies in the initial PRINT command:
$

File(s)?
PRI - Job 141, name "WHATSHERE", submitted to queue "PRINT"
$

The /FILEJOSITION qualifier refers to the position of the file within this job, as follows:
$
$

The SET QUEUE command works for most of the qualifiers to the PRINT and SUBMIT
commands.

3.4.4 DELETE/ENTRY
DELETE/ENTRY removes an entry from a queue. If you change your mind after issuing a
PRINT or SUBMIT command, use DELETE/ENTRY. The following example shows how you
can delete a print job, even though you have already submitted it to the print queue:
$

File(s)?
PRI - Job 141, name "WHATSHERE", submitted to queue "PRINT"
$
$
$

3-14

Using DCL Commands

3.4.5 HOLD/ENTRY
If you submit a print or batch job to a queue and then wish to delay processing for some
reason, use the HOLD/ENTRY command. The following example shows how you can delay
processing of a job after you have submitted it to the print queue:
$

File(s)?
PRI - Job 141, name "WHATSHERE", submitted to queue "PRINT"
$
$
$

3.4.6 RELEASE/ENTRY
Use the RELEASE/ENTRY command when you are ready to begin processing a job that you
have delayed with HOLD/ENTRY. The following example releases the job that was held up in
the previous example:
$
$

3.4.7 STOP/ABORT
Finally, if you want to cancel the currently active print job, you can issue the following
command:
$

or
$

You have to know the name of the physical device serving as your system's printer (for example,
LPO: or TTl:) to use the STOP/ABORT command.
There are many more qualifiers to all the Queue Manager commands. See the RSX-I1M-PLUS
Batch and Queue Operations Manual for more information.

Using DCL Commands 3-15

Chapter 4
Automatic Command Entry
Often while working on the system, you need to use the same command or sequence of
commands repeatedly. It is tiresome to retype the same commands each time you need
them. With complicated commands, typing mistakes are particularly annoying. You can use
a command processor (called Indirect) and batch processing to pass commands automatically to
the system.
With both the Indirect Command Processor (ICP) and the batch processor, you place the
commands or series of commands you want executed in a file and pass the file to the system
for processing. Otherwise, the two processors are very different.
In particular, the Indirect Command Processor works from a logged-in terminal, while a batch
job logs itself in, which allows you to use your computer when you are not even there. The
batch job can be scheduled to run at a particular time, while Indirect runs immediately. Batch
jobs can be scheduled by priority, while Indirect always runs at the same priority. Batch
jobs provide you with a batch log indicating how the job ran. Indirect includes a complete
programming language, while batch jobs provide only slight programming capability.
These two methods of automatic command entry can easily work together. A batch job can
include a command to run Indirect, and Indirect can issue the SUBMIT command to run a batch
job.
The following sections describe more about each processor. The material in this chapter is more
difficult. Study it carefully and then create your own examples.

Automatic Command Entry 4-1

4. 1 Indirect Command Processing
Indirect (the Indirect Command Processor) lets you execute several DIGITAL Command
Language (DCL) commands by typing one Indirect command line.
You create a file and put the DCL commands you want to execute into it in the order you want
them processed. To execute this command file, type an at sign (@) and then the name of the
file. Indirect and DCL then do all the work.
For example, the file SHOW.CMD in the [USER] directory contains the following DCL command
lines:
SHOW TIME
SHOW USERS
SHOW DEVICES

To execute this command file, type the following command line:
$

Indirect, which is invoked by the at sign (@), reads the commands in the file one at a time,
waiting until each command has been executed before going on to the next one.
There are only two command files in the [USER] directory. For the other examples in this
chapter, use EDT to create new command files. The examples in this chapter use all uppercase
letters, but Indirect accepts both uppercase and lowercase. Since Indirect looks for CMD file
types by default, you should create your files with this type. If you use another file type, you
must specify that file type whenever you want to execute the file.

4.2 Indirect Command Files
Indirect command files are used for many different things. One example is a login command
file. When you log in, the system automatically runs the command file LOGIN.CMD, which
can set various characteristics for your terminal or automatically run other programs or files.
Take a look at the LOGIN.CMD file in the [USER] directory.
To illustrate, you can use LOGIN.CMD to change the characteristics of your terminal if the
ones you want are different from the terminal's default characteristics. Put the necessary DCL
command lines in LOGIN.CMD. The characteristics will be changed automatically when you
log in. Here is an example of a login command file:
SET TERMINAL/SPEED: (9600.9600)/WIDTH:80
ClCOOKIE
SHOW USERS
SHOW TIME

This command file sets two different characteristics for the terminal: speed and width. (See the
RSX-IIM-PLUS Command Language Manual for more information about these commands.) The
command file also runs another command file, COOKIE.CMD. When COOKIE.CMD finishes
executing, Indirect returns to the first file (the login command file) to continue executing it. The
SHOW commands display the users currently logged in on the system, and they then display
the current time and date.

4-2

Automatic Command Entry

When you put commands into a login command file, you do not have to type those commands
every time you log in; Indirect does all the work for you. Putting repetitive sequences of
commands that you are going to use often into a file is what Indirect is especially good for.
Using indirect command files saves you time and prevents mistakes. "Repetitive sequences of
commands" can be just about anything. A few examples are listing files in your directory,
mounting volumes, backing up files, or doing quick tests at your terminal.

4.3 Substitution Mode
You may need to change indirect command files often to make them do exactly what you want
to do each time. For example, you might use a command file to do a backup procedure but
find that you have to edit the file to change the name of the device drive or its unit number.
For such cases, Indirect has substitution mode.
Substitution mode allows you to place a special word-called a symbol-in the command line.
When you run the command file, it asks you (through a special Indirect command line) for
the information that is to be substituted for the symbol. An Indirect directive (or command),
.ENABLE SUBSTITUTION, allows you to use substitution mode. Symbols are put in single
quotes ("). The single quotes tell Indirect to substitute a value for the symbol name before
executing the command.

4.4 Writing Programs with Indirect
As you can see, Indirect can be used to write programs. Many common programming techniques
are available in Indirect. These techniques include looping, counters, variables, arithmetic and
logical operations, and testing system conditions. The techniques are performed through the
use of Indirect directives, symbols, and labels.

4.4. 1 Directives
The .ENABLE SUBSTITUTION directive is one of the many Indirect directives. This chapter
does not describe all the directives, but it acquaints you with a few that you are most likely
to use frequently. You can use .ENABLE and its companion directive, .DISABLE, to set and
change several other modes in Indirect.
All Indirect directives begin with a period (.), except for the logical end-of-file directive, which
is a slash (/).
For a complete list of the Indirect directives, see the RSX-IIM-PLUS Indirect Command Processor

Manual.

4.4.2 Special Symbols
Indirect has special symbols that it defines automatically. The definitions of the symbols depend
on specific system characteristics and the replies to queries given during command file execution.
Special symbols can be compared, tested, or substituted and are of three types: logical, numeric,
or string. All special symbols have a common format: angle brackets ( < > ) enclose the
special symbol name.
For a list of the special symbols for Indirect, see the RSX-IIM-PLUS Indirect Command

Processor Manual.

Automatic Command Entry 4-3

4.4.3 Labels
You can also use labels in command files. Labels allow you to organize your file more coherently
and to jump to other lines in the file, depending on the results of conditional statements.
Labels are one to six characters in length, begin with a period (.), and end with a colon (:).
(The period and colon are not included in the six characters.) When you use labels in command
lines within the command file, however, you only need to use the name; you do not need to
include the period and colon. The .GOTO directive allows you to go to the different sections
of the file marked by different labels.

4.4.4 Comments
Comments can be used to describe what the file is supposed to do and to explain what the
command lines do or to give additional information about them. Comments that begin with a
period and semicolon (;) are not displayed on the terminal when the file is executed. Comments
that begin with only a semicolon or an exclamation point (!) are displayed.
The following examples will give you an idea of the usefulness and versatility of Indirect. A
brief description follows each example. For more information on Indirect (directives, symbols,
error messages, and so on), please see the RSX-IIM-PLUS Indirect Command Processor Manual.

4.5 Examples
This section contains two examples of an Indirect file. Each example is followed by an
explanation. See the RSX-IIM-PLUS Indirect Command Processor Manual for more examples.

Example
The following command file creates a file named after the current date:
.ENABLE SUBSTITUTION
.SETS DATE <DATE>
.SETS DAY DATE[1:2]
.SETS MONTH DATE[4:6]
.SETS YEAR DATE[8. :9.]
.ASKS TYPE What file type?
.SETS NAME DAY+MONTH+YEAR+"."+TYPE
EDIT 'NAME'

In this file, substitution mode is enabled, and then the symbol DATE is set to the contents of
the Indirect special symbol <DATE> (for example, 15-JUL-87). The symbol DAY is then set
to the two characters for the date (15), which are the first and second characters contained in
<DATE> . The symbol MONTH is then set to the three characters for the month aUL), which
are the fourth through sixth characters contained in <DATE>. The symbol YEAR is set to
the two characters for the year (87), which are the eighth and ninth characters contained in
<DATE> . (By default, Indirect considers numbers to be octal. Unless .ENABLE DECIMAL is
in effect, you must use a decimal point (.) after a number for Indirect to accept it as decimal.
Notice the decimal points after 8 and 9 in the example. See the RSX-IIM-PLUS Indirect
Command Processor Manual for more information on .ENABLE DECIMAL.)

4-4 Automatic Command Entry

The .ASKS command line asks you for the file type of the file being created, and the symbol
NAME becomes the concatenation of the previous three symbols and TYPE. NAME, therefore,
becomes the name of the file being created; for example, lSJUL87.TXT. The last command line
in the file invokes EDT to edit the new file.
Example

You can also use Indirect directly from the terminal without running a command file. The
following command line lets you work with Indirect interactively:
$

AT.>

When Indirect responds with AT.> (the task-name prompt), you can enter Indirect command
lines, invoke command files, or display the values of special symbols. To display a symbol, use
the .ENABLE SUBSTITUTION directive, and then request the symbol in the following format:
AT.>

For example:
AT.>
AT.>

Indirect responds with the following:
$ ;15:51:56

AT.>

The semicolon before the symbol indicates that Indirect should display the time on the terminal,
but DCL should not try to execute it as one of its commands.
To exit from Indirect, press CTRL/Z, as follows:
AT.>
$ CI <EOF>
$

4.6 Batch Processing
Batch processing is an alternative method of passing commands to the operating system automatically. The following paragraphs illustrate how batch processing works on
RSX-I1M-PLUS.
Batch jobs differ from indirect command files in that a batch job is a complete terminal session,
whereas an indirect command file is only part of a terminal session. You must be logged in on
a terminal to run an indirect command file, but you can run a batch job long after you have
logged out and gone home. A batch job runs on a special kind of terminal called a virtual
terminal, which is really software.
Another difference between batch processing and Indirect processing is that batch jobs can
produce a log of the job as it runs.
A final difference is that batch processing does not have the complete programming capability
of the Indirect directives. You can, however, invoke indirect command files from within a
batch job.

Automatic Command Entry 4-5

4.6. 1 An Example of a Batch Job
The following file, called BATCH.BAT, is an example of a batch file:
$!Sample Batch Job
$JOB HIYA [200/1]
$COPY OLDFILE.TXT HIYA.TXT
$APPEND JOHN.TXT.COVERT.DAT HIYA.TXT
$PRINT HIYA.TXT
$GINFORM
$PRINT SYSTEM.DAT
$EOJ

This is a complete user batch job. In batch jobs, a dollar sign ($) precedes batch-specific and
DCL commands. The dollar sign notifies the batch processor that a command follows.
A line without a dollar sign in the first position notifies the batch processor that the line contains
data. The DATA and EOD commands can be used to include data in batch jobs but are not
necessary.
The JOB command logs the batch job onto the virtual terminal. This command also gives the
name HIYA to the user batch job and, by including the slash in the User Identification Code
(UIC), keeps all but important login messages out of the batch log.
The COPY, APPEND, and PRINT commands work as usual, as does the indirect command file
INFORM.CMD
Comments can be included in the batch job, and thus in the batch log, by using an exclamation
point (!) after the dollar sign and before the comment.

4.6.2 Submitting Batch Jobs
You pass the batch job to the batch processor with the DCL command SUBMIT. For example:
$

The SUBMIT command places the batch job in the batch queue, from which it will run after
17:30 (5:30 P.M.) on the day it was submitted. When the job runs, it produces a log similar to
the following one, which is printed on the line printer when the job completes:
QMG Batch Job - BATCH
Processor BAPO
10:37:05

BPR V04.00

31-Aug-87 10:37

$JOB HIYA [200/1]
Terminal VT2:
User Job - HIYA
UIC = [200.1]
====================================

TERM
RSX-11M-PLUS V4.0 BL24

4-6 Automatic Command Entry

[4.54] System

AMITY

Page 1

$~LB:[1.2]SYSLOGIN.CMD

10:37:06
10:37:08
10:37:13
TERM

$COPY OLDFILE.TXT HIYA.TXT
$APPEND JOHN.TXT.COVERT.DAT HIYA.TXT
$PRINT HIYA.TXT
PRI - Job 43. name "BATCH
". submitted to queue "PRINT II
$~INFORM

10:37:14
TERM
10:37:16
TERM
10:37:17
TERM

$~ <EOF>
$PRINT SYSTEM.DAT
PRI - Job 43. name "BATCH
". submitted to queue "PRINT"
$EOJ
Connect time: 0 hrs 0 mins 25 secs
CPU time used: 0 hrs 0 mins
5 secs
Task total:
20

The batch log includes a record of all commands and data that the batch job passed to the
virtual terminal as well as any output sent to the virtual terminal. You should try to relate the
lines in the batch job to the lines in the log. The file HIYA. TXT is printed on the second page
of the batch log, and the file SYSTEM.DAT is printed on the third page.
For more information on batch processing, see the RSX-IIM-PLUS Batch and Queue

Operations Manual.

Automatic Command Entry 4-7

Chapter 5
Working on the System
Everything that is done on or by an RSX-IIM-PLUS system is done by a task or group of tasks.
The system itself is a group of tasks and an Executive.
When you issue a command like SHOW TIME, you set the following series of tasks in motion:
1. The terminal driver, a part of the Executive named TTDRV, reads what you have typed on
your terminal and looks for a task that can do what you have asked. In this case, a task
named MCR ... , the command dispatcher, answers the call. In these examples the dots are
part of the task names.
2.

MCR ... checks the command over and passes it to the DIGITAL Command Language (DCL)
parser, a task named ... DCL.

3. A copy of DCL is started and given a name that includes your terminal. For example, if
you entered the command from terminal TTIO, the copy of DCL is named DCLTIO.
4.

DCLIO translates your SHOW TIME command into the equivalent Monitor Console Routine
(MCR) command, which is TIM, and passes that command to a task named ... MCR. Your
copy of ... MCR is named SHOTIO, for the command and the terminal from which it was
entered.

5. SHOTIO goes to the Executive to find out what time it is, translates the time into readable
form, and sends it to SHOTIO to be written to your terminal.
This is a simplified description, of course. Each of these tasks may also employ other tasks. All
this activity must be coordinated.
The operating system is a collection of tasks cooperating under the direction of the Executive
to make your use of the PDP-II computer easier. DCL is a task that provides you with the
means of putting the rest of the system tasks to work.
DCL commands are not executed directly by DCL. Most DCL commands are translated and
passed to MCR. Others are passed to system utilities, such as EDT, the standard DIGITAL text
editor, or the Peripheral Interchange Program (PIP). These utilities are themselves tasks.
The file management commands you learned in the last chapter rely for the most part on PIP.
This utility is used to move files around the system, from one peripheral device to another.

Working on the System 5-1

DeL makes PIP transparent to the user. This means you can use it without seeing it. DeL
commands give you access to a number of utilities. Each of these utilities has commands of its
own, just like EDT. DeL saves you the trouble of learning the commands for commonly used
system utilities. (If you want to see the commands in the format the utility uses, use the SET
DEBUG command. See the HELP file for more information.)
See the RSX-IIM-PLUS Utilities Manual for more information on what the system utilities will
do. If there is some utility function that you want to use that does not seem to be available
under DeL, you can run the utility at your terminal.

5.1 Running Tasks Directly
You can run utilities directly from your terminal.
Type RUN $PIP and press the RETURN key. The dollar sign ($) tells the system where to look
for PIP.
PIP will come back with its own prompt (PIP> ). You can then issue commands directly to PIP,
instead of through DCL. These commands must be PIP commands and not DCL commands.
Type ILl and press the RETURN key. You get the same list of files produced by the DCL
command DIRECTORY. This occurs because the DIRECTORY command causes the DCL task
to issue a PIP ILl command to the system.
When you are through using PIP, type CTRL/Z, to signify end-of-input and a return to DeL.
For example:
$

PIP>
Directory DBO: [USER]
10-JUN-87

10:00

WHATSHERE.TXT;l
HELLO. TXT; 1
LONG. TXT; 1
FLY.TXT;3
FLY.TXT;2
FLY.TXT;l
MYDISK.CMD;l
LOGIN.CMD;l

3.
2.
25.
1.
1.
1.
4.
1.

27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24
27-JAN-87 16:24

PIP>
$

By contrast, the EDIT IEDT command starts EDT running, but you can also start EDT with the
command RUN $EDT.
The RUN command is itself a task. Loosely speaking, a task is a "computer program." Strictly
speaking, a task is the fundamental executable unit in RSX-IIM-PLUS systems.
As you know, a program is nothing more than a set of procedures. As such, it can be written
on paper. In France, two centuries ago, tables of complex mathematical functions were prepared
by hundreds of clerks; each of whom followed simple written-out procedures.

5-2

Working on the System

Thus, there were programs before there were computers. There was software before there was
hardware.

5.2 Creating a Task Image
This section demonstrates how a written procedure becomes an executable task image that will
run on the PDP-II hardware.
You do not need to be a programmer to do this demonstration. It is not a programming
demonstration. It is a demonstration of how the system does things.
A written procedure becomes an executable task image when you perform the following four
steps:
1. You must design the procedure, using a source language to define it.
2.

You must type the source program as a text file, using an editor or the CREATE command.

You must translate the source file into a machine-readable object module, using an assembler
or compiler.

You must transform the object module into an executable task image, using the LINK
command.

For this demonstration, the first two steps have already been done for you. A source program
called HIYA.MAC has been designed and entered as a text file. In the demonstration, you will
translate this source file into an object module and then transform the object module into a task
image.

5.2. 1 The Source Language
In the directory for the USER account, you will find a file named HIYA.MAC. The MAC file type
identifies the file as a source program written in the MACRO-II assembly language. Display
the file on your terminal by using the TYPE command, as follows:
$

.TITLE
.LIST
.NLIST
.ENABL

HIYA
TTM
BEX
LC

MACRO LIBRARY CALLS
.MCALL EXIT$S,QIOW$,DIR$,GTSK$
INDPB: QIOW$
OUTDPB: QIOW$
SYSDPB: GTSK$

IO.RLB,5,l"IOST
IO.WLB,5,l, ,IOST,<, ,40>
SYSBUF

; LOCAL EQUATES
BSIZE=80.

ACCEPTS NAMES UP TO 80 CHARACTERS

; LOCAL DATA BUFFERS
MSG1:
.ASCII
MSG1L=.-MSGl

/Could I have your name please?/
; THE LENGTH OF MSGl

MSGMP: .ASCII
MSGMPL=.-MSGMP

/RSX-llM-PLUS calling /
; THE LENGTH OF MSGMP

Working on the System 5-3

MSGM:
.ASCII
MSGML=.-MSGM

/RSX11M calling /
THE LENGTH OF MSGM

BUFF:

BSIZE

.BLKB

;

SET UP BUFFER LENGTH = BSIZE

As you see, the first two steps of the process have been accomplished. The program has been
designed and entered. Do not worry if you cannot understand it. You will see what it does in
a few minutes. Take particular note of the lines labeled MSGI: and MSGMP: and MSGM:.
A source language is your means of defining the procedure you want followed. MACRO-II is
one of several source languages that can be used on RSX-IIM-PLUS systems. It was chosen
for this demonstration because all RSX-IIM-PLUS systems include MACRO-It. In fact, most
of the system tasks were originally written in MACRO-II.
All source files, regardless of language, are encoded in the American Standard Code for
Information Interchange (ASCII). ASCII is a universal code used to convert characters we can
read into binary machine code that the computer can work with.
Before HIYA.MAC can run on the system, it must first be translated from text into binary
machine code, and then it must be transformed into a task image.

5.2.2 Translating the Source File Into an Object File
The MACRO command invokes the MACRO-II assembler. The MACRO command uses the
default file type MAC. The MACRO-II assembler assembles, or translates, a MACRO-I1 source
file into an object file.
Using the DIRECTORY command and wildcards, check the directory of the USER account for
files named HIYA. You should find only a single file with the file type MAC. For example:
$

Directory DBO: [USER]
10-JUN-87 10:07

HIYA.MAC;1

27-JAN-87 08:58

Total of 6./6. blocks in 1. file
$

Type the command MACRO and press the RETURN key. Respond to the File(s)? prompt with
the file name HIYA. Notice that you have given only the file name in response to the MACRO
command prompt. You do not have to give a file type or version number.
$

File(s)?
$

The MACRO command invokes the MACRO-II assembler. The version number defaults to the
most recent version, as usual. The file type defaults to MAC because the MACRO-I1 assembler
can only assemble MACRO-11 input files. Therefore, it is simplest to give your MACRO-I1
source files the MAC file type.
\

5-4 Working on the System

After a short delay, the prompt returns, which signifies completion of the assembly. If you
like, while you are waiting, you can issue the SHOW TASKS/ACTIVE command to see that the
assembly is taking place.
Now check the directory again. You should find two files named HIYA. The new file has the
file type OBJ, which identifies it as an object file. This file type is the default for output files
produced by the MACRO-II assembler.
For example:
$

Directory DBO: [USER]
10-JUN-S7 10:0S
HIYA.MAC;1
HIYA.OBJ;1

6.
2.

27-JAN-S7 OS:5S
10-JUN-S7 10:0S

Total of S./S. blocks in 2. files

Notice that the files are not the same size. The object file is smaller, because it has been
translated from the less efficient, readable text, including comments, into the efficient binary
machine code, without the comments.
This completes the third step of the process, creating an object module.
machine-readable only. People cannot read object files.

Object files are

Now print the object file on your terminal by using the TYPE command. This will work on
either a video or hardcopy terminal, but it will use a lot of paper on the hardcopy terminal.
You may prefer to wait until you have a video terminal to try it out.
The terminal will buzz, beep, or ring the bell and issue dozens of line feeds while printing the
file. The file itself will seem to consist mostly of confused jabber. This is because the assembler
has translated the instructions that were in text form in the source file into binary machine code.
For example:
$

3G/L4:brG4:"G)s)GG(4H}hO«Could I have your name please?RSX-11M-PLUS
callingGAw
G3APw
GA'w
h}3Iq(h}*f3

DSW = IOS*T =
$

The jabber is the terminal's attempt to interpret binary machine code as if it were ASCII.
Caution
Displaying binary files on your terminal may cause your terminal to hang. If
this happens, try pressing CTRL/Z or CTRL/C, or try turning your terminal off
and on.

Now display the file again, but this time be ready to press the NO SCROLL or the HOLD
SCREEN key, so you can look at the first part of the file. In the midst of the jabber, you will
see the two messages that the HIYA task will eventually issue. These are not translated from
ASCII because the machine does not need to read them. Since they are only read by people,
they are left as they were typed.

Working on the System 5-5

Although the object file is machine-readable, it still is not a task.
Here is what happened so far. The assembler has checked the source code in the source file for
errors. It has translated the source code from text to binary machine code, and it has assigned
relocatable (provisional) addresses to all parts of the program. These addresses are assigned as
if HIYA were going to have the computer all to itself.
Finally, the assembler has constructed a symbol table that contains all symbols referenced by
the program. Some of these symbols, called local symbols, are defined in the program. Other
symbols are global, which means that they are not defined in the program. The OBJ file contains
references to all local and global symbols, but the resolution of the global symbols still remains
to be done.
In HIYA.MAC, examples of local symbols include BSIZE, which is the number of characters a
program will accept, and MSG 1L, which is the length of the first message. An example of a
global symbol is $CBDSG, a routine from the system library, which converts a binary number
to a signed decimal ASCII representation. The global symbol $CBDSG is not defined in the
program; it is defined in the system library (LB:[l,l]SYSLIB.OLB).
Again, the description is greatly simplified.

5.2.3 Transforming the Object File Into a Task Image File
The LINK command invokes the Task Builder. The LINK command uses the default file type
OBJ. The Task Builder transforms an object file into a task image file.
Type the command LINK HIYA after the prompt appears, as follows:
$

File(s)?

Even though there are now files in the directory named HIYA, you still do not have to give a
file type with the LINK command. The LINK command invokes the Task Builder, and the Task
Builder can only process object files. Therefore, the file type defaults to OBJ.
Thus, you can see that if you give your source file a file type that properly identifies the
language used in the file, you do not have to include the file type with subsequent commands
used to turn the source file into a runnable task image.
Again, there will be a short delay while the Task Builder transforms the object file into a task
image file.
Look at your directory for files named HIYA, as follows:
$

Directory DBO: [USER]
10-JUN-87 14:06
HIYA.TSK;l
HIYA.OBJ;l
HIYA.MAC;l

2.
6.

C 10-JUN-87 14:04
10-JUN-87 10:08
27-JAN-87 08:58

Total of 13./13. blocks in 3. files

5-6 Working on the System

The directory should now include the following files:
1. Your original source file with the MAC file type

2. The object file made by the assembler with the DB} file type
3. The task built by the LINK command with the TSK file type
Notice that the TSK file is larger than the DB} file, perhaps as large as the MAC file. It is larger
than the DB} file because it includes the symbol definitions that were left unresolved by the
assembler. (The relative sizes of source, object, and task image files vary considerably from task
to task. Only in a simple case, such as this, can you expect the relative sizes to be clear.)
The C in the directory listing identifies the TSK file as a contiguous file. None of the other files
you have created has been contiguous. A noncontiguous file may be scattered all over the disk;
its file header contains a map of the blocks used in the file. Task image files must be contiguous,
meaning they are not scattered, but are together in one location. Not all contiguous files are
task images, but all task image files are cont~guous.
Since the task image file is contiguous, it can be located quickly on the disk and brought into
the system. (Many data files that must be used by tasks are contiguous for the same reason, to
save time on I/O.)
Task image files are not readable, but they are different from object modules. Display the task
image file on your terminal by using the TYPE command. If you have a hardcopy terminal,
you may prefer to wait for a chance to try this on a video terminal.
Once again, the terminal tries to interpret the file as if it were ASCII. The jabber produced is
different from the jabber produced by the attempt to print the object file. It takes much longer
to finish.
The two ASCII messages are still there and are still readable, if you can catch them.
For example:
$

~O-SYSYSYSYTICLzI~Tx-zVxTI~Could

I have your name please?RSX-11M-PLUS call-

ing ~zAw ~APw

%ff

Nc
v

W%
$

Here is what happened to the object module as a result of the LINK command. The Task
Builder resolved the reference to the undefined global symbol $CBDSG by finding its definition
in the system library. This made it possible for the Task Builder to complete the symbol table
constructed by the assembler.

Working on the System 5-7

The Task Builder also changed the relocatable addresses into addresses that the system can
use. As you recall, the assembler assigned addresses as if the resulting task would have the
computer to itself. However, no task that is run under a multiuser system like RSX-11M-PLUS
has the computer to itself. Therefore, the Task Builder applied a special addressing scheme that
makes it possible for the task to run in competition with other tasks.
Resolving symbol references and assigning addresses are major functions of the Task Builder.
The Task Builder may also build tasks out of more than one object module, as will be
demonstrated later in this chapter.

5.3 Running the Task
The RUN command installs, runs, and removes tasks. It uses the default file type TSK.
Now type and enter a RUN command. When you receive the Task? prompt, type the name
HIYA. You do not need to specify the file type, because the RUN command defaults to TSK.
For example:
$

Task?
Could I have your name please?
RSX-11M-PLUS calling Pancho Villa
$

When the HIYA task requests your name, type it. In this case, your name is data to be processed
by the task. The processing consists of returning your name in a different form.
The DCL commands themselves are tasks that process data. Proper data for a RUN command
is the name of a task image file. The RUN command processes this data by performing the
following tasks:
1. Finding the file
2.

Naming the task

3. Installing the task
4.

Running the task

5. Removing the task when its run is completed
As it is generally used, the RUN command is actually a combination INSTALL-RUN-REMOVE
command.
The INSTALL command is the task that makes HIYA known to the system by placing a Task
Control Block (TCB) in the System Task Directory (STD). The INSTALL command also requests
that the task be run. As soon as the Executive grants this request (when space is available in
memory), the task is run. Once the task has finished running, the REMOVE command takes
over. The REMOVE command is a task that makes HIYA unknown to the system by taking the
TCB out of the STD.
Privileged users can install tasks with a separate INSTALL command. That is how system tasks
are made available to everyone. Nonprivileged users can only install tasks by using the RUN
command. These tasks only stay installed while they are in use.

5-8 Working on the System

Since the RUN command includes the INSTALL command, you will sometimes get error
messages referring to the INSTALL command instead of the RUN command.

5.4 Using Subroutines
Now run EDT by using the command line shown in the example. This command line directs
EDT to use HIYA.MAC as an input file and, after editing it, to create the output file NEWHI.MAC,
as follows:
$

*
Previously, when you invoked EDT, you did not specify an output file. You did, however,
specify by default an output file of the same name and type as the input file but with a version
number one higher than that of the input file.
This time, you are giving the output file a new name, one that does not appear in the directory,
and thus will be version 1. The file NEWHI.MAC;I will be created when you exit from EDT.
As before, both the new and old form of the file being edited will still exist, but where before
the new form had only a new version number (by default), now the new form will have an
entirely new file specification (by explicit action).
When EDT returns with its prompt, search for the second instance of the string EXIT$S. This is
the line in the MACRO-II program that causes the task to exit when it has finished running.
Use the following command sequence:

.MCALL EXIT$S.QIOW$S.DIR$.GTSK$

EXIT$S

; LEAVE

*
You are now going to insert a new line ahead of the line so that the program will call a
subroutine named STARS. This reference to STARS puts another undefined global symbol in the
program. Finally, you will exit from EDT.
Use the following command sequence:

*
*

DBO:[USER]NEWHI.MAC;1 150 LINES
$

The symbollTABI means that you press the TAB key. Tab positions are set every eight spaces.
The TAB key moves you to the next tab position, which mayor may not be eight spaces from
where you are.
The semicolon (;) marks the beginning of a comment. The text preceding the semicolon is
code.
Now exit from EDT.

Working on the System 5-9

Show a directory of only MAC files. There may be others, but you will at least have files
named HIYA.MAC, NEWHI.MAC, and STARS.MAC. The STARS.MAC file is the source file for
the subroutine for which you just inserted a call.
An object module can contain a subroutine, which can greatly alter the performance of a task.
You can link more than one object module to form a task image.
Now use the MACRO command to tum the source program NEWHI.MAC and the source
subroutine STARS.MAC into object modules. STARS.OBI includes the global definition of the
global symbol STARS.
After issuing the first MACRO command, wait for the return of the prompt before issuing the
second MACRO command, as follows:
$
$

Type and enter the LINK command, naming both object modules: NEWHI, STARS. Separate
the module names with a comma. When the Task Builder is through, run NEWHI, as follows:
$
$
$

Could I have your name please?
RSI-llM-PLUS calling Ruddigore

*********************************
$

As you see, the STARS subroutine has altered the performance of the task. When you built
HIYA.TSK the first time, you used only one object module. References to local symbols were
resolved by the assembler. The Task Builder had to resolve the reference to the global symbol
$CBDSG, which is defined in the system library. NEWHI.MAC, however, contains a reference
to an additional global symbol, STARS, which is defined in STARS.OBI. The Task Builder
will always look to the other object modules specified in a LINK command for global symbol
definitions before it goes on to the system libraries to try to resolve them.
Try linking NEWHI.OBI without the STARS. OBI; you will get an error message stating that the
symbol STARS is undefined.
In addition to linking subroutines, the Task Builder can also go to the system library of
object modules supplied with your system or to libraries created at your installation for
special purposes.

5-10 Working on the System

5.5 High-Level Languages
So far, this demonstration has concentrated on the MACRO-II assembly language because the
MACRO-II assembler is bundled with every RSX-IIM-PLUS system. Most systems will include
one or more high-level languages in addition to MACRO-Il.
Each computer must have an assembly language. This language is designed at the same time
as the hardware. In general, one line of assembly language translates into one line of machine
language. The ASCII text of one line of MACRO-II code becomes one line of binary machine
code.
This is a major distinction between an assembly language and the high-level languages. The
high-level languages-such as COBOL or FORTRAN-are compiled. Each statement in a
high-level language typically translates into more than one line of machine language.
Machine language is different on every machine, but FORTRAN is much the same from
machine to machine and company to company. Naturally, there are differences related to how
the hardware works, but, generally speaking, a FORTRAN program is transportable from one
computer to another and from one operating system to another. All it takes is a FORTRAN
compiler.
The compiler is designed to translate source files into binary machine code. Thus, whereas
input files-source text files-are transportable, output files from the computer-object files-are
different on different computers.
Each high-level language is designed for a particular kind of use. Programmers say that any
program can be written in any language, but, in fact, different languages were designed with
different applications in mind. FORTRAN was designed for scientific applications. FORTRAN
stands for FORmula TRANslator. COBOL stands for COmmon Business-Oriented Language and
was designed for commercial applications. BASIC stands for Beginners All-purpose Symbolic
Instruction Code and is widely used as a first programming language.
All these languages are supported on RSX-I1M-PLUS. This means that language compilers,
libraries, and other necessary software have been prepared to run on a PDP-II computer with
the RSX-IIM-PLUS operating system.
Although the MACRO-II assembler and the various high-level language compilers translate
source files written in different languages, the assembler and compilers both produce object files.
The Task Builder processes object files without regard to the source language. Thus, the object
file is a common goal for any assembler or compiler operating on RSX-IIM-PLUS systems, a
target at which they all aim.
The high-level languages are supported, but they are not bundled. This means that they must
be purchased separately. Some of them may not be available at your installation, and there
may be other languages at your installation that are not mentioned here.

Working on the System 5-11

5.5. 1 Gaining Access to High-Level Languages
DCL includes commands analogous to the MACRO command for the most popular languag~s.
There is a FORTRAN command, and two different FORTRAN compilers are supported. There
is also a COBOL command. If your installation includes compilers for which specific DCL
commands are not supplied, you can use the RUN command to run the compiler at your
terminal.
BASIC-PLUS-2 programs can be compiled, but a special procedure is used. BASIC-PLUS-2,
the form of BASIC supported on RSX-IIM-PLUS, is an enhanced version of BASIC used in
commercial applications.
In most cases, high-level languages include more conveniences for the programmer than
assembly languages. Programs in assembly language must be explicit in everything they
do. You may have noticed that HIYA.MAC goes into great detail at the labels MSGM: and
MSGMP: to determine the length of each message. That kind of detailed programming is rarely
needed in a high-level language. By the same token, programs written in a high-level language
should be more readable. They include a higher level of information than assembly language
programs.
On the other hand, MACRO-II was named after its capacity for using macros. Macros allow
programmers to gather a number of lines of assembly language code under one name. Thus,
a macro (like the EXIT$S macro referred to when you edited HIYA.MAC into NEWHI.MAC)
actually assembles into more than one line of binary machine code. With this capacity for
including macros, MACRO-II can, in effect, sidestep some of the detail of assembly language
programming while remaining close to the actual workings of the computer.
Regardless of your programming language, familiarity with MACRO-II can benefit you as a
programmer. All higher-level languages supported on RSX-IIM-PLUS systems include the
capability of calling assembly language subroutines. These subroutines can often increase the
speed and efficiency of your program.
A further demonstration of running tasks follows.

5.6 Naming Tasks
Tasks initiated by the RUN command are named after the terminal from which the RUN
command was issued. Tasks initiated by other commands are named after the command itself
and the terminal from which it was issued.
Run PIP, but do not issue any commands. Instead, press CTRL/C. The explicit DCL prompt
shows that you have interrupted the execution of the PIP task and can issue a DCL command.
For example:
$

PIP>
DeL>

Type SHOW TASKS/ACTIVE and press the RETURN key. (If you get an error message, issue
the command again. If you still get an error message, press CTRL/Z to terminate PIP and
try again.)
\

5-12 Working on the System

For example:
DCL>
SHOT10
TT10

(TT10:)
(TT10:)

DCL returns a list of the tasks active at your terminal. The SHOW task is identified by a name
in the form SHOTnn. The task name gives you the following information about the task itself:
•

The SHO indicates that the task was initiated with a SHOW command.

•

The T indicates that the command was issued from a terminal.

•

The nn is the number of the terminal.

The RUN command differs from other commands in how tasks resulting from it are named.
Tasks initiated by a RUN command are named directly after the terminal from which the
command was issued. Thus, in the example, PIP is named TTIO after the terminal from which
the RUN command was issued.
More than one task at a time can be run from your terminal. The /TASK-NAME qualifier to
the RUN command overrides standard task naming.
Type RUN $PIP and press the RETURN key. You should get the PIP> prompt.
Now press CTRL/C. Type and enter RUN HIYA in response to the DCL prompt. You should
get a RUN error message saying that the task name is already in use.
For example:
$

PIP>
DCL>
RUN -- Task name already in use
$

This may seem confusing, because you know you are not running HIYA.
HIYA is the name of the file that contains the task image, but it is not the task name referred
to by the error message. The message refers to the name in the form TTnn, where nn is the
number of the terminal from which the RUN command was issued. Since PIP is already using
that name, you cannot simply issue another RUN command to run a task. Instead, you must
give the task some other name for your second RUN command.
Type RUN/TASK-NAME:LURG HIYA and press the RETURN key. As you see, both PIP and
HIYA are now active. In the example, PIP has the name TTIO and HIYA has the name LURG.
After HIYA has finished, press CTRL/Z to leave PIP.

Working on the System 5-13

For example:
PIP>
DCL>
PIP>
Could I have your name please?
PIP>
RSX-11M-PLUS calling Gus Mahler
$

PIP>

Run PIP again, but use the ITASK-NAME qualifier to keep PIP from being named after your
terminal. Name it LOLA instead. Since PIP is now installed under a different name, the PIP
prompt is changed to LOL. Make sure it is really PIP by issuing a ILl command to the LOL
prompt. You should get a directory listing.
For example:
$

LOL>
Directory DBO: [USER]
10-JUN-87 14:33
A.A;1
AZ.CMD;1
COPY.CMD;2
EDT.CMD;5
LOL>

1.
t.
t.
t.

12-FEB-87 13:16
13-MAR-87 15:38
16-FEB-87 12:27
28-MAR-87 13:30

An explanation of how to abort a renamed task, such as LOLA, follows.

5.7 Aborting Tasks
You can abort tasks by name as well as by command.
In an earlier section, you learned to abort tasks by aborting the command that initiated them.
You can abort tasks by name as well, by using the ITASK qualifier to the ABORT command.
This qualifier works very much like the ITASK-NAME qualifier to the RUN command.
If you tried to abort PIP through the ABORT RUN command, you would receive the following
error message:
ABO -- Task not in system

You cannot use the ABORT RUN command here, because that command looks for a task whose
name includes your terminal number. Since you overrode that task name, as confirmed by
SHOW TASKS I ACTIVE in the following example, you must abort the task by specifying the
name you gave it.

5-14 Working on the System

Type ABORT/TASK LOLA and press the RETURN key as follows:
LOL>
DeL>:
DeL ...
SHOT10
LOLA

(TT10: )
(TT10: )
(TT10: )

LOL>
DeL>
$

16:66:18

Task II LOLA II terminated
Aborted via directive or eLI
and with pending 10 requests

5.8 Other References
This completes the terminal warm-up session.
Now you should look up the commands you have learned in the RSX-11M-PLUS Command
Language Manual. You will find there are many additional ways of using the commands you
have already learned.
After you have looked at the RSX-11M-PLUS Command Language Manual, you may want to
look in the RSX-11M-PLUS Utilities Manual for information on the full functions of the system
utilities.
If you are a programmer, you should also read the documentation for your programming
language. There are many features of the high-level languages that are found only on DIGITAL
versions of these languages, and DIGITAL versions may differ from one operating system to
another.

Chapter 6 of this manual will teach you a little about how what you do at your terminal fits with
the operations of the rest of the system. It includes a demonstration of the SHOW MEMORY
command, which produces a live-action picture of what is happening on the system.

Working on the System

5-15

(

Chapter 6
The System in Operation
Thus far, this manual has taken the point of view of the terminal user. For most of the time
that you are using the operating system, you will feel as if you are the only user.
In fact, some systems may have dozens of terminals as well as other peripheral devices for
passing input to the system and receiving output from it, but the operating system makes it
possible for each user to act independently.
This chapter presents some generalizations about RSX-IIM-PLUS. You can follow up on these
generalizations to learn the particulars of the system you are using. As an individual user, you
will generally not need to concern yourself about most of the topics presented here, but some
points may become important to you as you gain more experience.

6. 1 Hardware and Software
RSX-IIM-PLUS offers a wide range of services and utilities; the system supports many kinds of
input and output devices. RSX-IIM-PLUS is designed as a general-purpose system that can be
customized for each installation. License holders can choose from unbundled software options,
or users can write their own system software.
Once the hardware and software elements have been chosen, the process of system generation
ties these choices together into a customized system. The system you are using has been
generated to include your installation's mix of hardware and software.
Because each installation is different, not all installations have all the capabilities discussed in
this and other system manuals. For example, some systems include support for the DECnet
package, which means they can be tied into networks of computers, and some do not.
In general, systems with heavy terminal use-general-purpose, timesharing systems-will include
most of the system generation options that affect the terminal user and the programmer. Other
options are removed during system generation to save the memory these options would otherwise
require.
The RSX-IIM-PLUS operating system runs on processors with 22-bit addressing; it provides
software features that take advantage of the hardware features of these processors. These
software features are outside the scope of this manual, but they include the virtual terminal,
which is used by the batch processing subsystem; multiuser tasks; and Resource Accounting.

The System in Operation 6-1

The variety of possibilities can be confusing to a new user, but the purpose is to make possible
an operating system closely suited to the needs of your installation.
You are not likely to encounter any absent system generation options. It is much more likely
that some task or utility you need will simply not be installed when you need it. In such a
case, you can usually have your system manager install the task for as long as you need it and
then remove it when you no longer need it.

6.2 Applications and Operating Systems
RSX-IIM-PLUS systems are real-time systems. This means that the system is designed to
respond rapidly, either to input from users or to input from application tasks.
RSX-IIM-PLUS systems are also multiuser systems. This means that more than one user can
have access to the system at any time.
The combination, a real-time, multiuser system, allows real-time activity-such as data
acquisition or control of an industrial process-to occur at the same time as program development
from interactive terminals.
Typically, commercial and industrial data-processing applications fall into one of three categories:
real-time control, applications processing, and general-purpose timesharing.
In the real-time control environment, the operating system is used as a tool. This is also true
of the applications environment. In these environments, rapid response is the more important
capability of an operating system. In the general-purpose environment, parts of the system are
used as tools and throughput. Throughput, the total volume of work performed in a period of
time, is the more important capability.

6.2.1 The Real-Time Control Environment
The real-time control environment is one in which the principal function of the operating
system is to handle rapid data movement with little human interaction. Typical examples of
such environments are steel rolling mills, oil refineries, and communication switching centers.
When certain conditions are met-a thickness, a temperature, a delay-the system must respond
rapidly by closing a valve, slowing a motor, or throwing a switch.
The operating system, of course, does not know about steel rails, or long-distance calls, or
milling machines. The principal function of the system in a real-time control environment is to
receive, verify, reply to, and move data messages rapidly and without error.

6.2.2 The Applications Environment
The applications environment is one in which the greatest part of the system's resources are
given over to continuous, high-volume data handling. Again, rapid, error-free handling of
data messages is the principal function of the system, but instead of controlling a process, the
messages update a database under the control of the applications task.
In the applications environment, most terminal users have no direct contact with the operating
system. Typically, the terminals they use are slaved to the applications task, and the terminal
users communicate directly with the task rather than with the operating system. The terminal
users enter data for processing by the applications task. The task opens and closes files, updating

6-2

The System in Operation

and altering information as it is entered. In the applications environment, there are few users
of the operating system itself.

6.2.3 The General-Purpose Timesharing Environment
The general-purpose timesharing environment is one in which program development and testing
is a major activity. Terminal use is prominent in this environment, which means that the system
spends a great deal of time waiting for terminal input. Assembling, compiling, and task building
make heavy use of the central processing unit (CPU). In this environment, there may be many
users at one time, but most of the time, they are thinking, looking up commands, or the like
between keystrokes.
In the general-purpose timesharing environment, the system's interactive facilities are heavily
used. These include the DIGITAL Command Language (DCL), the editors, the utilities, and the
program development tasks, such as the assembler or compiler and the Task Builder. Because
human input is so slow compared to input from machines, the system's real-time capabilities
are not as important as in the applications or real-time control environment.
Often, one system may be used to develop programs to be run on another system. These
programs might be intended for real-time control or as an applications task. On the other
hand, the programs may perform special computations, such as modeling, statistical analysis, or
forecasting, which are to be run on the same system they were developed on.
RSX-IIM-PLUS systems can be used in any of these three environments. Or, an installation
can combine any or all of these kinds of functions.
Every installation is a custom installation-a combination of hardware and software designed
to fulfill the needs of the installation. Therefore, the best sources of information about the
operating system are the system manager, in-house documentation, and other people who
use it.

6.3 The Purpose of the Operating System
The purpose of any operating system is to make the computer hardware easier to use.
The operating system is under the control of the Executive, a set of routines that coordinate all
activities in the system, including supervision of input and output, allocation of resources, task
execution, and operator communication.
The Executive is the kernel of the operating system. The operating system consists of the
Executive plus the utilities, the programming languages, device drivers, and other system
components. The installation consists of the operating system plus the applications tasks, as
well as the computer and all its hardware devices.
The operating system manages the software and hardware resources of the system.
management requires that the operating system perform the following kinds of tasks:
•

Keep track of all resources.

•

Enforce policy on who gets which resources, when, and how much.

•

Allocate the resources according to system policies.

•

Reclaim the resources when they are no longer needed.

This

The System in Operation 6-3

The operating system uses three control mechanisms that it applies to all system users: privilege,
priority, and file protection.

6.3. 1 Control Through Privilege
System users are divided into privileged and nonprivileged groups. Installations usually have
only a few privileged users. The system manager is always privileged. Privileged users have
access to every part of the operating system. Nonprivileged users can use most of the operating
system, but they cannot change it. For example, nonprivileged users can issue a SHOW TIME
command; privileged users can also issue a SET TIME command to change the system time.
Usually your lack of privilege is of no concern. Most privileged functions have to do with
system control and maintenance, not with common use of the system facilities. If you should
need access to a privileged function, you can usually arrange it through a privileged user.
In addition to privileged users, there are privileged terminals and privileged tasks. A privileged
terminal is any terminal with a privileged user logged in on it. Privileged commands can be
issued only from a privileged terminal.
Privileged tasks are tasks that perform operations normally considered to be the domain of the
Executive or that can affect the operations of the system as a whole. Nonprivileged users can
use privileged tasks. Many system tasks are privileged, but it is the task, not the user, that has
the privilege.
Only privileged users can permanently install tasks in the system. Nonprivileged users install
nonprivileged tasks with the RUN command, but these tasks are removed as soon as they have
finished running.

6.3.2 Control Through Priority
Privileged users can build, install, and run tasks at priorities of 1 to 250. Nonprivileged users
can only install and run tasks at the default priority of 50, but they can build tasks with any
priority.
A task's priority determines the preference given its requests for services from the Executive. In
particular, a task's access to memory and to the CPU are determined by priority. The highest
priority task that has access to all the resources it needs is granted control of the CPU.
In systems that combine real-time applications with less urgent work, the real-time applications
are given higher priority because they must be processed immediately to give the response
demanded in a real-time environment.
In timesharing systems, interactive tasks, such as editors, are generally installed at a higher
priority than tasks that run unattended, such as the Task Builder. This means that users at their
terminals are less likely to have to wait for a response.
How the system uses priority to control access to system resources is explained in Section 6.4.1.

6.3.3 Control Through File Protection
The system also controls access to information through file protection, which determines which
users and tasks can use or alter the contents of files. You can set the protection status of your
own files with the SET PROTECTION command.

6-4 The System in Operation

6.4 Operating System Resources
There are four basic resources under the control of the operating system, as follows:
Memory

Specifies the system's workspace, where active tasks, their data, and
the Executive itself are located.

CPU

Specifies the part of the computer that executes instructions or
computes.

Peripheral device

Specifies the input and output devices, including mass-storage disks,
line printers, terminals, and the like.

Stored information

Indicates the file system, the organization of files into directories and
directories into volumes.

Each task has different resource requirements. Involved scientific and statistical calculations,
"number-crunchers," use a great deal of CPU time and memory, but make few demands on the
system's devices or the file system. Conversely, printing a long listing can tie up an output
device like a line printer for hours, while using little memory and only a few seconds of CPU
time.

6.4. 1 Memory
The size of memory is measured in words. The unit of measure is a K, which stands for kilo
and is equal to 1024, or 210 •
Memory should not be confused with mass storage. Mass storage, such as disks or tapes, is
where files are kept when no immediate use is being made of them. Memory is the randomaccess workspace in which all instructions and data in current use by the system are kept. These
instructions and data can be accessed immediately.
Instructions are executed in memory after having been read from a file on a mass-storage device.
Instructions act on data in memory. The data has either been created in memory or read from
a file on a mass-storage device.
Part of memory-the amount depends on the choice of system generation options-is occupied
by the Executive and the operating system.
Included in the Executive's partition in memory is the dynamic storage region, commonly called
pool. The pool contains dynamic information on the current state of the system. The pool
space is generally available to the Executive and to privileged tasks, to use as it is needed. The
information in the pool enables the Executive to perform its functions. RSX-11M-PLUS systems
relegate some this of information to secondary pool.
All memory is divided into partitions, which are subdivisions dedicated to a particular task or
to system functions. All partitions have a name and a size. Some partitions are used by the
system, such as SYSPAR, the partition used by the Monitor Console Routine (MCR). If you
do not specify a partition when you install and run a task, it will be installed in the default
partition, named GEN.
An installed task has an entry in the System Task Directory (STD), but it is not resident in
memory nor does it compete for other system resources. For example, EDT is usually installed
even if no one is using it. It is dormant until some terminal user issues the EDIT JEDT command.
A dormant task uses no memory, but it is quickly available when needed.

The System in Operation 6-5

An active task is a task that has been requested to run. It is usually resident in memory, either
as a ready-to-run task or as a blocked task, which is defined as a task that is waiting for some
needed resource. Only tasks that are resident in memory can have access to the CPU.
When the Executive receives a request to activate a dormant task that is not in memory, it
allocates the required memory resources, brings the task into memory (if there is space available
in its partition), and puts the task into competition for system resources with other tasks
resident in memory. If there is no memory space available in the task's partition, the task is
still considered active and is placed in a queue by priority with other active, waiting tasks.

Checkpointing is the process of temporarily removing a partly executed task from memory to
make room for a higher-priority task. If the partition in which the task is to run is fully
occupied, checkpointing can clear the space.
The Executive accomplishes checkpointing in the following fashion. The prerequisites are that
the waiting task must have a higher priority than the task resident in memory, and the task
resident in memory must have been built, or installed, as a checkpointable task. If these
prerequisites are met, the Executive saves the resident task in its incompletely executed state
and writes it to a reserved checkpoint space on the disk. Then, the higher-priority task is
brought into the memory space that has thus been freed. When the higher-priority task has
finished running or when some other space in the partition becomes available, the checkpointed
task is returned to memory to continue its processing.
Checkpointing depends on differences in priority, but many tasks in the system run at the
default priority of 50. This means that tasks of the same priority can block each other. The
Executive gets around this problem through a variation on checkpointing called swapping. With
swapping, the Executive regularly lowers the priority of tasks resident in memory so that other,
waiting tasks will have a higher priority and can thus effect checkpointing. The checkpointed
tasks return to their regular priority. Once the new tasks are resident, their priorities will also
be lowered, enabling the first tasks to checkpoint them in tum.

6.4.2 The CPU
The CPU can only execute one instruction at a time, but it does that quickly. Almost everything
that is done on the system must pass through the CPU to get done, but you will probably never
address the CPU directly. Access to the CPU is under the control of the Executive. Tasks must
be resident in memory to gain access to the CPU. Only one task at a time can have control
of the CPU. Multiprogramming is possible because the task operation almost always involves
more than just the CPU.
The Executive's control of the CPU is accomplished through a significant event. A significant
event causes the Executive to reevaluate the eligibility of active tasks to run. When a significant
event occurs, the Executive scans the list of active tasks and runs the highest-priority task that
is ready to run. The most important significant events are as follows:
•

The completion of input or output. If a task is waiting for I/O or cannot continue its I/O
because the I/O device is unavailable, then it has no further need for control of the CPU.

•

The execution of a task.

6-6 The System in Operation

•

The execution of an Executive directive that causes a significant event. System directives
are services provided to the programmer by the Executive that make it possible for tasks
to synchronize their own execution, get device and system information, communicate with
other tasks, and generally communicate with and work through the system.

•

The execution of the round-robin scheduler. The round-robin scheduler is a form of
timesharing that overcomes the Executive's tendency to give the most CPU time to tasks
that appear first in the Active Task List (ATL). The round-robin scheduler rotates entries
in the ATL and then causes a significant event to occur after a given period of time. This
significant event causes the Executive to look for a higher-priority task to take over the
CPU. The time interval is usually one-tenth of a second.

Once again, the explanation is greatly simplified. Fortunately, the system can display a moving
picture of these processes as they occur.

6.4.3 Devices
Device control is another important element of the system. The SHOW DEVICES command
lists the devices on the system. Devices are often called peripherals because they are located
outside the computer. All input to the computer and output from it is handled by the peripheral
devices.
In this manual, we have given attention to three devices found on all RSX-IIM-PLUS systems.
These are: the terminal, the printer, and the mass-storage disk. The terminal is two devices
combined: the keyboard is an input device, and the screen or print head is an output device.
The printer is strictly an output device.
The terminal and printer are both record-oriented devices. This means they handle information
one record at a time. A record is one line of information. In other words, record-oriented
devices have a limited capacity for storing information. As soon as they have received one
record, they must process it before going on to the next record.
Mass-storage disks and DEC tapes are file-structured devices. This means that these devices,
which allow random access, are capable of working with the system's file services.
Many kinds of devices are supported on RSX-IIM-PLUS systems. Several DIGITAL terminals
and printers among record-oriented devices and a dozen or more file-structured disk and tape
devices are supported. This support consists primarily of device drivers that enable the system
to handle I/O to the devices.
These devices have different physical characteristics. On the simplest level, disks for one type
of disk drive will rarely fit on any other type of disk drive. Programmers do not need to concern
themselves with these physical differences. Programs accept input from devices and send output
to devices, but the coding is independent of the physical characteristics of the devices for the
most part. Tasks perform I/O on Logical Unit Numbers (LUNs), which the programmer or
operator can assign to specific devices before the program uses the devices.
In addition to the devices discussed here, the operating system can control industrial and
commercial devices, such as lathes or communications switching apparatus. The disk and tape
drives are complex machines that are controlled by the operating system through device drivers.
By the same token, lathes and switchboards can also be controlled by the operating system, but
users must write their own device drivers to suit these machines.

The System in Operation 6-7

Furthermore, in some environments, you may find software handling I/O as if the software
were a physical device. For instance, RSX-11M-PLUS supports virtual terminals, which are
software that appears to the system to be a physical terminal. In these cases, the devices look
the same to the operating system. All are treated as part of the system's resources under the
control of the Executive. Virtual terminals are used in batch processing, which is described in
Chapter 4.
DCL provides a number of ways to associate LUNs with physical devices.

See the

RSX-llM-PLUS Command Language Manual for more information. At this point, you need
only understand that almost all device use is transparent on RSX-11M-PLUS systems.

6.4.4 Stored Information
Control of stored information, or data processing, is the purpose and function of the computer.
Every key you strike, every task that runs, is information being processed. On a less abstract
level, the file system is the system's way of organizing stored information so that you can use
it.
Most of the information to be processed by the operating system is located on disks and tapes.
These disks and tapes are magnetic media, which means that the information on them is stored
in the form of magnetic impulses.
Because RSX-11M-PLUS is a disk-based system, most of the discussion that follows refers to
disks. A disk is a random-access medium, which means that all the information on it is equally
accessible. Most magnetic tape, however, is a sequential-access medium, which means that to
get to any particular record on the tape, you have to read the tape from the beginning until you
get to the record you want. Tape is economical but slow; disks are more expensive but faster.
The magnetic impulses are read and written by electromagnetic heads, much like the recording
and playback heads on a tape recorder. These heads and the movement of the disk are
controlled by a device controller. This is all hardware, however, and tells us nothing about the
organization of the information on the disk.
Users access information in files. The files are organized in directories, and these directories are
organized in volumes located on a mass-storage disk. The volume is the software equivalent
of the magnetic medium in hardware. However, although magnetic media differ, the operating
system considers all file-structured disk volumes to be identical because all file-structured disk
volumes are organized in the same format, called Files-11. Files-11 volumes are created through
the DCL command INITIALIZE.
An explanation of how the hardware and software handle I/O is beyond the scope of this
manual. Irt the simplest terms, the file system makes it unnecessary for you to worry about
the physical location of your files on the disk. Each Files-11 volume has an MFD, or Master
File Directory, which is a file of User File Directories (UFOs) on that volume. (See Figure 6-1.)
Each directory is a file containing the names of a user's files and pointers to each file header.
The file header contains information about the physical location of the file's contents on the
disk. The system finds files by using the information in the directories and file headers.

6-8 The System in Operation

Figure 6-1: Structure of Flies on a Volume

MFO
[0,0]

-- -

---

UFO
[200,1]

----

HIYA.MAC;1

UFD
[303,5]

----

FLY.TXT;1

-- ---

IZZY.TXT;1

I
OZY.TXT;1

-----

ZK-282-81

Tasks running on RSX-IIM-PLUS access data within files through one of two sets of routines:
File Control Services (FCS) and Record Management Services (RMS-ll). Both FCS and RMS-ll
organize information within files. RMS-ll was developed after FCS and allows more complex
file organization than is possible with FCS.

6.5 The SHOW MEMORY Command
The DCL command SHOW MEMORY displays information about the status of the system. In
particular, it displays information about the contents of memory and the task that currently
controls the CPU.
If you issue the SHOW MEMORY command from a hardcopy terminal, you get a snapshot of
memory at the moment you issued the command. Issue the command twice, so that you will
have two snapshots to compare.
If you issue the SHOW MEMORY command from a video terminal, you can see a moving
picture of tasks coming into memory and leaving it, and you can watch the changing control of
the CPU. If you have access to the computer room, you may find a video terminal permanently
running the memory display task, which is called RMD.

The SHOW MEMORY command requires that RMD be installed on your system. If the command
does not work, you should find out if the display is available elsewhere. Most systems have
a video terminal running the display somewhere near the computer. If not, ask your system
manager for assistance.

The System in Operation 6-9

Figure 6-2 is a sample SHOW MEMORY display. An explanation of the numbered elements
follows the figure.
Figure 6-2:

SHOW MEMORY Display

'"
8
•
e
RSX-11M-PLUS V4.0 BL15C (KERMIT) 1792K UP 000:03:33
TASK= RMHACP
e.FREE= DBO:OFL
DB2:100335.
DB1:238650. DRO:DMO
POOL=3628. :4280. :43. CDSECPOOL=1225. :1536.79%
3628. : 4280. : 43 .
1225 . : 1536. : 79%

CD
CD

IN: DTDFF . RRRHLMQBFSEF AA
27
ITL11.MMMRPAMATHVRUT
48 191K RC: 11 . TSSCOIGPSOCK. .
OUT: 10 AAAALR. R. ODV.HTV
{o
1M CCTCBE. E. E1.021
OK M PP.PBS. S. Q. 2
!! !»++>! !»!»»»»

CD
8-APR-87

PARS
SECPOL:P 4D
SYSPAR:D
DRVPAR:D
GEN
:D

M A'
S u.
R . . 4B
TE
1 3 D
3 T

<->

>++

11:24:17

0********112*****224*****336*****448*****560*****672*****784******}

:~~==~~=~========================================================= GD

896*****1008****1120****1232*****1344****1456****1568****1680*****
! !=!

NNP
TTO

ERRSEQ ~
25 .

.. 0

UEL
NP.
AM.
ZK-4120-85

o Specifies the operating system name and version number.
8 Specifies the DECnet node name (if the DECnet package is installed on your system) or the
system name selected in SYSGEN (if the DECnet package is not installed on your system).
•

Specifies the size in K words of the system's memory.

e Specifies the time elapsed in units of days, hours, and minutes since the system was last
bootstrapped.
CD Specifies the current date and time.

CD Specifies the name of the task that is currently executing. Sometimes this task name will
be *IDLE*, which signifies that no task is controlling the CPU.

e. Specifies the number of free blocks on four Files-II devices in your system. DMO indicates
that the device is dismounted. OFL indicates that the device is off line.

CD Specifies the number of words in the largest free block in pool, the number of free words
in pool, and the number of pool fragments, respectively.

6-10 The System in Operation

CD Specifies the number of free blocks, the total number of blocks, and the percentage of free
blocks in secondary pool, respectively.
4D Specifies the names of all partitions in the system, and whether each is a system-controlled
partition (indicated by a D after the name) or a secondary pool partition (indicated by a P
after the name).
•

Specifies the number of tasks in memory and how many words of memory they occupy
(IN). It also shows the number of tasks out of memory or checkpointed, and how many
words of memory they occupied when they were memory resident (OUT).

Specifies the tasks currently resident in memory. The symbols under the names of tasks
designate the size, type, and other attributes of the tasks.
You should understand that the display changes only once a second; it is possible that tasks
are in and out of memory or in and out of the CPU in less than that time. Nonetheless,
RMD displays graphically how the Executive controls the contents of memory and use of
the CPU.

Specifies the size and location of the partitions and tasks. The lines of asterisks are
proportional representations of the amount of memory each partition or task occupies.

e Specifies the system error count sequence recorded by the Executive.
There is a more detailed explanation of the meaning of this display in the RSX-11M-PLUS
Command Language Manual. For now, you should simply watch it changing. Notice which tasks
seem to occupy the most memory or use the most CPU time. There may be one large task
using most of memory and much of the CPU time. Or, a number of smaller tasks may be
sharing memory.
As explained earlier, tasks are usually named for the terminal from which they originate. In any
case, write down the names of some of the more prominent tasks from the SHOW MEMORY
display, and see if some knowledgeable system user can identify them for you. This will give
you a better idea of what is going on at your installation and of how the system manages its
resources.
If you are at a video terminal, press CTRL/Z to cancel the SHOW MEMORY display.

The SHOW MEMORY display helps the system manager observe the system running and find
bottlenecks; for example, a task running at a higher priority than it should takes too much CPU
time. As you learn more about the system, this display will become more meaningful to you.

The System in Operation

6-11

Glossary

abort

Stopping a program from running before it is finished is called aborting the program. When
nonprivileged users log out, LOGOUT aborts any programs they have running at the time.
Aborting a program does the program no harm, nor does it harm the system. If the program
keeps records of any kind, as a business system would, then aborting it may result in incomplete
records, but these can usually be brought up to date. Aborting programs of this sort may also
result in locked files.
account

Each system user has an account. This is a record of the user's User Identification Code (UIC),
name, password, default disk, default directory, and privilege status. System managers create
accounts using the Account File Maintenance Program, ACNT.
active task

All tasks that have been requested to run are included in the list of active tasks. This is a
priority-ordered list of all tasks resident in memory or checkpointed. Active tasks are in active
competition for system resources. Checkpointed tasks are out of memory and waiting for system
resources.
addressing

All computer operations depend on the ability to address specific memory locations. Put simply,
the longer the possible address, the more locations you can reference. In its original design,
the PDP-II used 16-bit addresses, which meant that programs could not use any more memory
than could be addressed in 16 bits. Later, optional memory management hardware extended
that addressing ability to 18 bits. Finally, the more recent PDP-II processors include memory
management hardware that extends the addressing ability to 22 bits. The greater the addressing
ability, the larger the possible program.
RSX-IIM-PLUS systems run on 22-bit processors and can address from 256 kilobytes (Kb) of
memory up to 3.8 megabytes (Mb) of memory. Since RSX-IIM-PLUS was specifically designed
for the 22-bit processors, it can take advantage of features available only on 22-bit processors.
See your processor handbook and the RSX-llM-PLUS and MicrojRSX Task Builder Manual for
more information on addressing capabilities.

Glossary-l

applications task

An applications task is any task that uses the operating system to run but is not part of
that system. Examples include games, office automation programs, graphics programs, control
programs, and so forth.
argument

Arguments add specific information to DCL command qualifiers.
A DCL command consists of a command and optional qualifiers. The qualifier alters the
operation of the command. For instance, the PRINT command has a /COPIES qualifier. This
qualifier accepts an argument that specifies the number of copies you want. In DCL, arguments
are preceded by a colon ( :) or an equal sign (=). The following example includes two qualifiers
with arguments.
$

This command prints three copies of the file IVAN.LAB and gives the name MELISSA to the
print job.
See the RSX-IIM-PLUS Command Language Manual for more information on DCL commands.
ASCII

ASCII stands for American Standard Code for Information Interchange. ASCII is the standard
format for readable text on computers. It is a code used to translate letters, numbers, and
symbols from a keyboard into machine code, and vice versa.
Thus, an ASCII file is a file that can be read both by people and by computers.
assembler

The MACRO-II assembler takes ASCII files written in the MACRO-II assembly language and
assembles them into a relocatable object module suitable for processing by the Task Builder.
assembly language

MACRO-II is the assembly language on RSX-IIM-PLUS.
Assembly language is used to generate binary machine code. See MACRO-II assembly language.
bad block

Bad blocks are blocks on a mass-storage device that are not usable because there is some
physical damage or flaw. The ANALYZE/MEDIA command is used to find bad blocks. You
can use disks that have bad blocks on them, but if there are many bad blocks, you should
consider replacing the disk.
batch log

A batch log is a file or printed listing documenting everything that happened to a particular
batch job.

Glossary-2

batch processing

Batch processing is a mode in which all commands to be executed by the operating system, or
data to be used as input to the commands, are placed in a file and submitted to the system for
execution.
Batch jobs can be scheduled to run at a particular time, such as at night when no one is using
the system.
See also Indirect Command Processor.
binary machine code

Binary machine code is the internal instruction format actually used by the computer. It is
called binary because only two characters-O and I-are used in this code.
The following is an instruction in MACRO-II assembly language:
MOV

RO,R1

This is an instruction to move the number in register 0 to register 1. The assembler translates
this instruction into the following binary machine code:
0001000000000001

You will rarely see binary machine code. While this is the only form that the computer can
actually use, it is difficult for humans to use. Thus, humans are provided with languages,
compilers, and the assembler, and these are used to generate binary machine codes.
block

A block is a unit of measurement for files. In almost all cases, a block is 512 bytes. Since
each character in text takes one byte, this means that one block in an English language text file
contains about 80 words of text.
The term "block" is also used to refer to various parts of the system that contain processing
information, such as a Task Control Block (TCB), which is used by the RSX-IIM-PLUS system
to control tasks.
boot

See bootstrap.
bootstrap

In computer terminology, a bootstrap is an operation that brings itself into a desired state by
its own action, as in the expression "She lifted herself by her bootstraps." In RSX-IIM-PLUS
systems, the bootstrap is a routine included in the PDP-II computer that includes enough
instructions to bring the rest of the operating system into the computer's main memory. A
bootstrap is often called a boot, and bootstrapping is often called booting.
buffer

Buffer refers to a temporary storage area in a program. In this book, the term refers to the
buffers created by EDT for your use in creating and modifying files. EDT always starts out in
a buffer named MAIN, but it has other buffers available, and you can create your own buffers.
See the EDT Editor Manual for more information on EDT and its buffers.

Glossary-3

central processing unit

See CPU.
character mode

EDT's character mode uses the video screen to operate on text one character at a time, in
contrast to line mode, which operates on one line at a time. Character mode editing commands
are entered by using the keypad.
See also line mode.
checkpolntlng

Checkpointing is the process by which the Executive makes memory space and processor time
available to tasks according to their priority. Also called Hrolling out.
H

If a higher-priority task is ready to run and no memory is available, then lower-priority tasks
will be temporarily removed, or checkpointed, to make room for the higher-priority task. The
lower-priority tasks are saved on the disk exactly as they were when interrupted. When memory
is available, the tasks are returned to memory and take up exactly where they left off.

Your task can be checkpointed without your knowing it. If your task seems slow or refuses to
accept input, it may be checkpointed. Checkpointing is an automatic process. Your task will
probably return to active status shortly after it is check-pointed.
circumflex

The circumflex character ("), also called an up arrow, is used on RSX-IIM-PLUS systems to
indicate that you have typed a control character.

eLi
CLI stands for command line interpreter. The CLI is a system feature that makes it possible for
you to communicate with the operating system from your terminal. RSX-IIM-PLUS provides
two CLls. For further information, see DCL and MCR.
command

A command, when executed, is an instruction to the software to perform a particular action.
For instance, the following command directs RSX-IIM-PLUS to perform a series of operations:
$

This command directs the system to find a file named IZZY.TXT and display the contents of
that file on your terminal.
In this book, you learn commands to DCL, the DIGITAL Command Language, and commands
to the EDT editor. See the RSX-IIM-PLUS Command Language Manual for more information on
DCL commands.
command line Interpreter

See CLI.
compiler

Each high-level language is implemented through a compiler. A compiler is a program that
takes a source program written in the high-level language and translates it into binary object
modules that can then be translated into tasks by the Task Builder.

Glossary-4

contiguous

A contiguous file consists of physically adjacent portions on a mass-storage device. Contiguous
files can be loaded into main memory in a single operation. The most common contiguous files
are task image files, but other files can also be contiguous. Contiguous files are indicated by a
letter C in the directory listing, as follows:
HIYA.TSK;2

40.

01-APR-87 00:01

control character

A control character is a special form of command to the system entered by pressing the CTRL
key and a letter key together. The most important control character is CTRL/C, which aborts
any task running on your terminal. Other useful control characters include CTRL/Z, which
means "end-of-input," and CTRL/O, which skips over unwanted output on your terminal.
Control characters are sometimes echoed on your terminal with a circumflex (") followed by
the character, as follows:
AZ
CPU

CPU stands for central processing unit. It is the hardware that handles all the calculation and
routing of input and output (I/O), as well as the execution of tasks. The CPU is the part of the
computer that actually computes.
crash

A crash is the system's response to an unstable condition. Rather than continuing to operate
and allowing the system to do itself damage, it ceases operation. In general, all you will need
to do is boot the system again; however, persistent crashes are a sign of trouble.
cursor

The cursor is a flashing indicator used on video terminals to point to the screen position where
the next character will appear. It is called a cursor because it shows the "course" the printed
or typed line will follow. The VT100- and VT200-series terminals allow you to choose a solid
block «::1;;> or an underscore line (_) as a cursor. See your terminal manual for information.
data

Data is a general term used for any representation of facts, concepts, or instructions in a form
suitable for communication, interpretation, or processing.
In the demonstration in this manual (see Section 5.3), when the HIYA task asks for your name,
it is asking for data. It then processes this data by inserting the name you give into a greeting.

Many commands are tasks. When they prompt you for command elements, they are asking
you for data to process.

DCl
DCL stands for DIGITAL Command Language. DCL provides a means of communication
between the user and the RSX-IIM-PLUS operating system. DCL is designed to be easy to use.
Commands are generally English words. If necessary elements are not typed in, DCL prompts
for them. DCL also provides help for the user.
DCL is used on most DIGITAL operating systems. There are differences from system to system,
but for everyday use, DCL is quite similar on all systems.
Compare with MCR.
Glossary-5

dedicated

In the computer industry, a system resource-an I/O device, task, or the entire system-is said
to be dedicated when it is assigned to a single application or purpose.
default

A default is a value or operation that is automatically included in a command unless you specify
otherwise.
In most cases, default settings will be what is normal or expected. Many times, you will not
even notice that defaults are being used, but the default settings can always be overridden.
You can always find the defaults for any command in the RSX-IIM-PLUS Command Language
Manual and in the help files.
In RSX-IIM-PLUS and the RSX family in general, a wide range of defaults is used. The idea is
that the less the user has to specify in any given situation, the easier the system is to use and
the smaller the chance of error.
delete

Removing a file header from a directory and deallocating its reserved space is called deleting
the file. The file cannot be accessed after a delete operation because it cannot be found. The
disk space occupied by the file is available to any user.
You can use the SET PROTECTION command to protect your files against deletion.
The terminal key marked DELETE or <Xl deletes previously typed characters.
EDT, the DIGITAL Editor, provides commands for deleting text from buffers.
delimiter

A delimiter is a character that separates, terminates, or organizes the elements of a command or
file specification. An example of a delimiter is the semicolon (;) that appears before the version
number or the slash (/) that sets off a qualifier from a DCL command.
The RETURN key is a delimiter that marks the end of a command field or command. Other
delimiters are punctuation marks, such as the colon (:) and comma (,). Spaces or tabs are also
common delimiters. These small elements play an important part in keeping matters organized
on the system.
device

A device is any peripheral hardware connected to the processor and capable of receiving, storing,
or transmitting data. Devices found on RSX-IIM-PLUS systems include terminals, line printers,
disk drives, and tape drives.
In examples, all devices have names in the same form: two letters, a number, and a colon (:).
Terminals are called TTl:, TT2:, and so forth. The line printer is usually LPO:. The first device
of any type is always number O.
device controller

Each physical device included in the system is associated with a hardware device controller
that consists of electronic circuits. The device controller serves as the interface between the
processor and the device hardware.

Glossary-6

device driver

Each device included in the system has a device driver, which is the software interface between
the Executive and the device controller.
DIGITAL Command Language

See DCL.
directive

Some requests for system functions are called directives. This manual refers to Executive
directives, which are requests to the Executive for system services, and indirect command
directives, which are instructions to the Indirect Command Processor.
directory

A directory is a file that briefly catalogs a set of files stored on disk or tape. The directory
includes the name, type, and version number of each file in the set. Every user has a default
directory.
Directories can have names of up to nine characters, such as [SCHMENDRK] or [JESSEJOE], or
they can have names consisting of two numbers, such as [303,26] or [7,11]. Directories with
two numbers can generally be referenced either as [7,11] or [007011]. There is no distinction
between the two kinds of directories.
The DCL command DIRECTORY displays information about files in directories.
disk

The disk is the major type of mass-storage device on RSX-11M-PLUS systems.
high-speed, random-access devices.

Disks are

disk-based system

On a disk-based system, such as RSX-11M-PLUS, the tasks and other functions that make up
the operating system are stored on a disk and loaded into memory as they are needed by users.
The disks are removed when they are no longer needed. The RSX-11M-PLUS system is kept
on a disk because of the disk's speed and capacity. The disk with the system on it is called the
system disk.
dormant task

A dormant task is installed but is not yet requested to run.
See also task state.
DSR

Dynamic Storage Region. See pool.
Dynamic Storage Region

See pool.
echo

When characters that are typed on a terminal keyboard are also displayed on the terminal,
the process is called echoing. Terminals are dual devices that send input and receive output.
Echoing is one form of receiving output from the system.

Glossary-7

editor

An editor is a system task for creating and altering text files. RSX-IIM-PLUS systems include
EDT, the standard DIGITAL editor.
error message

Error messages are sent by the system when some action you have requested fails. Each error
message identifies the command or system function that detected the error. For instance, error
messages from the TYPE command are labeled TYP.
The great majority of error messages result from mistakes in typing or mistakes in syntax. Often,
you can correct the error by retyping the command.
Error messages are explained in the documentation.
Executive

The Executive controls the operating system. The Executive coordinates all activities in the
system, including task execution, user communication, supervision of input and output (I/O),
and resource allocation. The name RSX stands for Resource Sharing Executive.
explicit prompt

The 3-letter prompt that identifies the command line interpreter or other system task is called
an explicit prompt. For example:
DCL>DIGITAL Command Language
MCR>Monitor Console Routine
PIP>Peripheral Interchange Program
FCS

FCS stands for File Control Services, which is a set of routines that can be used in tasks to
open and close files, read from files, write to files, extend, or delete files. FCS provides a set of
macros to simplify the user's interface to the system I/O structures.
High-level language statements that operate on files on RSX-IIM-PLUS systems are implemented
through these routines or a similar set of RMS-ll routines.
field

The term field usually refers to a portion of a command or command element. For example,
the file name and file type are two fields of the file specification.
file

A file is a set of data arranged in a structure significant to the user; it is one of the basic units
of information on RSX-IIM-PLUS.
A file is any named, stored program or data, or both, to which the system has access. Access
can be of two types: (1) read-only, which means the file cannot be altered, and (2) read-write,
which means the contents of the file can be altered. See read and write.
See also volume.
File Control Services

See FCS.

Glossary-8

file header

Each file has an associated file header block that includes information needed by the file system
to find and use the file. Some of the information in the file header block is displayed by the
DCL command DIRECTORY.
file-structured device

A file-structured device is a device, such as a disk or tape, that can accept data organized into
files. See also volume. Compare with record-oriented device.
file specification

The file specification, sometimes called a filespec, is the unique identification of a file that gives
its physical location and, generally, an indication of its contents.
All file specifications are in the following form:
DBO:[USER]FLY.TXT;l

The device name DBD is represented here by two letters and a number followed by a colon ( : ).
Next is the directory, enclosed in square brackets, such as [USER].
File names can include 1 to 9 of the letters A to Z and the numbers D to 9, but no other
characters. The name, such as FLY, should give some indication of the contents.
The file type starts with a period (. ) and includes from zero to three characters. It usually gives
some indication of the type of file, such as TXT.
The version number is set off by a semicolon (;).
See the RSX-llM-PLUS Command Language Manual for more information about file specifications
and their component parts.
Some file types commonly used on RSX-IIM-PLUS systems are as follows:
File Type

Use

BAS

BASIC-II source program. System default.

BAT

File containing batch processing commands. System default, RSX-IIM-PLUS only.

BP2

BASIC-PLUS-2 source program. System default.

CBL

COBOL source program. System default.

CMD

Indirect command file. System default.

COR

Source Language Input Program (SLP) file used to correct a source file. System
convention.

OAT

File containing data, as opposed to code. System convention.

FTN

FORTRAN source program. System default.

LOG

Log of batch processing session. System default.

LST

Listing file. System default.

Glossary-9

File Type

Use

MAC

MACRO-II source program. System default.

MAP

Task Builder map file. System default.

MLB

Macro library. System default.

OBI

Object module output from assembler or compiler. System default.

ODL

File containing Overlay Description Language (ODL) to be used by the Task
Builder. System default.

OLB

Object module library. System default.

SYS

Bootable system image. System default.

TMP

Temporary file. System convention.

TSK

Task image file. System default.

TXT

Text file. System convention.

ULB

Universal library.

Some of these file types are system defaults, which are automatically supplied and sought by
the software. You can override these defaults, but in most cases they are convenient. Other file
types are system conventions. These are also not required, but they are commonly used and
recommended for your use.
Flles-ll

Files-II is the name of one of the file structures used on RSX-IIM-PLUS. Volumes from other
operating systems can be converted to Files-II structure with FLX, the File Transfer Utility
Program.
form feed

A form feed is a nonprinting character that causes a line printer or hardcopy terminal to move
the paper up to the next full page. You can include a form feed in text by inserting a CTRL/L
while editing. You will see <FF> in your text. When the file is printed, the line printer
moves to a new page.
functionality

Functionality is a computer industry term that means nothing more than what the hardware or
software can do. Feature is a synonym for functionality.
global

Global means affecting the entire file, the entire system, or the entire task, depending on the
context. In this book, you have learned about global substitutions, that is, changing all instances
of one string in a file.

Glossary-l 0

global symbol

A global symbol is a value defined in one object module that can be used in other object
modules. Many global symbols are defined in the system library. Global symbols are identified
and defined by the Task Builder.
See local symbol.
hang

When a terminal or task appears to be going nowhere or doing nothing, it is said to be hanging.
Hung terminals are sometimes described as static, dormant, or locked.
Sometimes, you can correct a hung terminal by pressing CTRL/Z or CTRL/C, or by turning the
terminal off and on. You should also check to be sure the NO SCROLL or HOLD SCREEN key
has not been pressed.
hardcopy terminal

Terminals that print output on paper are called hardcopy terminals; they are also called printing
terminals. Hardcopy terminals preserve a permanent record of everything that is printed or
typed on them.
hardware

Hardware is all the parts of the computer system you can touch. The terminals, the computer,
the disk drives, and the line printer are all hardware. Your system may have special hardware.
Hardware and software must be in harmony for the system to work at full efficiency.
See software.
help file

A help file is a text file in a form suitable for use with the HELP command. Many help files
are included as part of the RSX-IIM-PLUS system, but you can also write your own help files.
high-level language

High-level languages, for example, BASIC-PLUS-2, FORTRAN-77, and COBOL-BI, are
transportable programming languages. Programs in these languages are not tied to a particular
kind of computer. They are called high-level because programs written in these languages
usually provide a higher level of information about what the program will do than assembly
language provides.
Each programming statement in a high-level language is translated into several machine-language
instructions.
Implicit prompt

The right angle bracket prompt (> ) is called the implicit prompt. It indicates that a command
line interpreter (CLI) is ready to receive input. When you type a command to the system and
enter it, the implicit prompt does not return until the action of the command has completed. If
you press the RETURN key, you will get an implicit prompt, but there will be another prompt
outstanding, which will appear when the task has completed. The presence of the implicit
prompt is not required to enter commands, but if it is not present, the terminal may not be
ready to accept command input.

Glossary-II

The following example shows what can happen if you do not wait for the implicit prompt to
return following a command:

0>'

•

TKB -- *FATAL*-FILE HIYA.OBJ;1 HAS ILLEGAL FORMAT

8>
0>

CD>

o The MACRO command was issued to assemble the file HIYA.MAC.
•

Before the implicit prompt returned, indicating completion of the MACRO command, the
user attempted to LINK HIYA. This failed because the file HIYA.OBJ was not yet complete.

A prompt was issued following the failed LINK command.

o The MACRO command completed, which caused another prompt to be issued. The LINK
command issued in response to this prompt is completed successfully.

A prompt was issued that indicates completion of the LINK command.

Indirect Command Processor

The Indirect Command Processor passes commands to the operating system automatically. In
addition, the Indirect Command Processor permits you to use programming techniques, such
as loops, counters, labels, and symbol substitution, to set up more elaborate procedures. Any
series of commands you have to enter over and over with few or no changes is a candidate for
Indirect processing.
See batch processing.
Input

Whatever you supply to the system is input. Most input is typed in, but both batch processing
and Indirect processing supply input to the system without typing once they are started.
input file

Many system utilities and commands take existing files and produce new files. For example,
the COpy command takes a file from one place and copies it to another. EDT can edit a file
and make a new one from it. In these cases, the file being copied is called the input file and
the file being created is called the output file.
Install

When you copy the operating system or an application from its distribution media to the system
disk, you are installing it.
Installing a task has a different meaning. An installed task is named in the System Task
Directory (STD), which is a list of Task Control Blocks (TCBs) that contain information about
each task. Taking a task out of the STD is called removing it.
A task cannot run unless it is installed.
Users automatically install and remove their tasks through the RUN command. Privileged users
can also install and remove tasks explicitly.

Glossary-12

Installation

The installation is the full computer system at your location. The installation includes the
operating system, the programming languages, and applications tasks, as well as the computer
and its hardware devices.
Each installation has a different collection of hardware and software that has been selected and
customized for the needs of that particular installation. For this reason, not every capability or
function mentioned in the system documentation is available at every installation.
Interactive system

RSX-IIM-PLUS is an interactive system. This means that you and the operating system
communicate directly by using the terminal. The RSX-IIM-PLUS operating system immediately
acknowledges and acts upon commands you enter at a terminal.
journallng

Journaling is an EDT feature that allows you to recover work that is lost from a system
interruption.
While you are using EDT, it records each keystroke you make. If the system fails while you
are editing, this record is preserved. You can then restore your file to where it was before the
failure by using the /RECOVER qualifier to the EDIT command. See the EDT Editor Manual for
more information.
K

K is a unit for measuring the size of memory or similar resources. K is short for kilo and is
used roughly to mean 1000. K is equal to 210, or 1024, in formal usage.
kernel

The irreducible minimum of the Executive is called the kernel. It is the core of the operating
system. The kernel runs in kernel mode, which has no hardware protection at all and no
restrictions on machine use. In most cases, however, Executive and kernel are synonyms.
label

A label is one or more characters used to identify a source language statement or a line in a
program. In the HIYA.MAC demonstration program for this manual (see Section 5.2.1), the
label MSGl: identifies the line that contains the first message sent by the program.
The term label is also used to identify a particular Files-II volume.
language library

Most high-level languages have a unique set of routines for program support that are collected
in a separate library. Some of those routines are similar to routines commonly found in the
system library. Some routines found in a language library are required by the compiler to
properly implement some high-level instructions, such as WRITE or PRINT. Others are required
by the Task Builder to link the program correctly.
library

A file containing one or more relocatable routines that can be incorporated into a task is called a
library. A system library is supplied, but you may also create user libraries for your installation
or application.
See also language library, object library, resident library, system library, and user library.

Glossary-13

license

Each copy of the operating system is sold to run on a particular PDP-II processor and no other.
This is called a license. There are several varieties of license to suit particular situations.
line mode

EDT has two main modes of operation: line mode and character mode. Line mode operates
on a line or group of lines and is well suited to manipulating large blocks of text. Line mode
editing commands are English words.
See also character mode.
line number

EDT automatically assigns numbers to the lines of the file you are editing. The numbers are
useful in finding and manipulating the contents of the file. In line mode, you can see the
numbers on your terminal; in character mode, you do not. In any case, the numbers disappear
when you leave the editor.
line pOinter

A line pointer marks where you are in a file. For example, EDT uses an invisible line pointer
to mark your place in the file you are editing.
line printer

The line printer is an output device that prints files one line at a time. It is used to print
large amounts of output in a hardcopy form. In some cases, the line printer will actually be a
high -speed hardcopy terminal.
In general, the line printer is under the control of a system task called the Queue Manager.
You send files to the line printer with the PRINT command.
link

See Task Builder.
listing

This is a common computer term for output printed on the line printer. It also refers to the text
file of a program as produced by a compiler.
load

When a task is loaded, it is located in main memory and is therefore available for use.
Most tasks on RSX-IIM-PLUS stay on the system disk until needed, at which time the system
loads them into memory.
local symbol

A symbol that cannot be referenced outside its defining object module is called a local symbol.
Local symbols are identified and defined by the assembler or compiler.
In MACRO-II programs, the term local symbol is also used for a label that cannot be referenced
outside its local symbol block.
See also global symbol.

Glossary-14

locked files

Occasionally, when a program terminates abnormally (for example, when you issue the ABORT
command), files that the program was using are locked. You may not discover the locked files
until you try to run the program again and find that you cannot.
Locked files are indicated by the presence of a letter L in the directory listing, such as the
following:
LCPJUL87.MAI;1

267.

01-AUG-87 09:27

You can use the DCL command UNLOCK on locked files. You should be aware, however,
that RSX-IIM-PLUS locks files for your protection. You should check to make sure the data in
locked files is sound after you unlock them. How you check such data naturally depends on
what the files are for, but if a text file has been locked, you can read it over after it has been
unlocked.
If you continually have trouble with locked files, there may be some problem with the program
that uses the files.
log

A log is a record of performance. In this manual, the term refers to a file produced by a batch
processor in which is recorded all terminal activity resulting from a QMG batch job. A QMG
batch job consists of one or more user batch jobs, each of which has a separate section of the
log. Batch processing is included on RSX-IIM-PLUS systems only.
logical unit number

See LUN.
login

Logging in identifies you to the operating system and informs the system that you have certain
privileges and are using a particular terminal. You can log in on RSX-IIM-PLUS with either
the HELLO or LOGIN command. They are identical. You will also need an account to log in
to and a password.
logout

Logging out informs the operating system that you have finished using a particular terminal.
You can log out with the LOGOUT or BYE command. Logging out aborts any task you have
running from your terminal and eliminates your access to a disk or tape.
LUN

LUN is an acronym for logical unit number. A LUN is a number associated with a physical
device during a task's I/O operations. Each task can establish its own correspondence between
LUNs and physical device units. See the RSX-IIM-PLUS Command Language Manual for more
information.
macro

A macro, in MACRO-II assembly language, is a single assembly language instruction that
generates a predefined set of machine language instructions.
MACRO-II derived its name from its capacity to define macros. A MACRO-II user can, in
effect, create high-level instructions by writing macros. Many macros are available in the system
macro library.

Glossary-IS

MACRO-ll assembly language

Most of the system tasks and utilities on RSX-11M-PLUS are written in MACRO-II assembly
language. The language is called MACRO-11 because it allows programmers to define macros.
A macro is a series of instructions that collectively perform some operation, which can be called
by a single name.
MACRO-II includes a number of functions designed to make programming easier. These
functions include directives to divide programs into sections, conditional assembly directives, a
comprehensive system macro library, and user-defined macro libraries.
See the RSX-IIM-PLUS Guide to Program Development, the RSX-IIM-PLUS and Micro/RSX System
Library Routines Reference Manual, the PDP-II MACRO-II Language Reference Manual, and your
processor handbook for more information.
main memory

Main memory is a series of storage locations from which the CPU fetches its data. The contents
of main memory can be easily altered. It can also be randomly accessed. When a task is run,
it is loaded in main memory. The task has no access to the CPU if it is not in main memory.
Compare with mass-storage device.
moss-storage device

A mass-storage device is a device, such as a disk, where data files and other types of files are
stored when they are not being used. The RSX-IIM-PLUS system and its components reside
on a mass-storage device most of the time.
MCR

MCR stands for Monitor Console Routine, the prime interface with the system. MCR commands
go directly to the system utilities and installed tasks. Most MeR commands use initials or special
characters in strict syntax, rather than English words.
Compare with DCL.
media

See medium.
medium

The medium is the physical device, such as a disk or magnetic tape, that contains the data. The
plural of medium is media.
See also volume.
memory management

Memory management is a process that supports the running of large programs on PDP-II
computers. All current DIGITAL computers include memory management hardware. The
RSX-IIM-PLUS operating system includes software that works with this hardware.
The instruction set of the PDP-II computer forms 16-bit virtual memory addresses, so a
program can directly address only 64 Kb of memory. The actual physical address space on
PDP-lIs is 4096 Kb, or 4 Mb. Memory management is a combination of PDP-II hardware and
RSX-ll software that permits programs to translate 16-bit virtual addresses into 22-bit physical
addresses. With 22-bit addresses, programs can address all of memory.

Glossary-16

mnemonic

A mnemonic is an aid to memory. It is pronounced ne-MON-ic. PIP is a mnemonic for
Peripheral Interchange Program.
Most mnemonics are acronyms.
mode

Mode refers to a possible condition or state of operation. For example, EDT can operate in line
mode or character mode.
monitor

Command line interpreters (CLls) are sometimes called terminal monitors. They monitor the
activity on your terminal when nothing else is happening. Commands at monitor level are
directed to the operating system. Pressing CTRL/C gives you access to monitor level from
within a task.
See also DCL and MCR.
Monitor Console Routine

See MCR.
multiprogramming

A multiprogramming system, such as RSX-IIM-PLUS, can run more than one task at a time
without interference among tasks.
multiuser

A multiuser system, such as RSX-IIM-PLUS, permits a number of users to work on their
terminals simultaneously with little or no interference among users. Users on a multiuser system
have their own files and their own share of time on the system. Commands such as LOGIN
and LOGOUT are part of the protection offered on a multiuser system, as is the ability to make
one of the disks or tapes your private device through the command MOUNT jNOSHAREABLE.
nonprlvlleged

Most RSX-IIM-PLUS users are nonprivileged. Nonprivileged users run programs, or tasks, on
the system, but they have no means of directly affecting the system and its operations. In most
cases, users do not need to be privileged. See also privileged.
object library

An object library is a file containing a collection of compiled or assembled routines that can
be included in a user program's task image. Object libraries commonly reside on disk devices
and are only present in memory when routines within a library are called by a program being
compiled or assembled.
object module

An object module is a program, or part of a program, that has been converted from the
programming language in which it was written to a format the computer can use. This
conversion is performed by a language processor, which is called an assembler or compiler.
Object modules are files with the file type OBJ. An object module must be processed by the
Task Builder to make a task file, which is the executable program.
For more information see the RSX-IIM-PLUS and MicrojRSX Task Builder Manual.

Glossary-17

."
octal number

A number in the base 8 numbering system is called an octal number. Only the numerals 0 to 7
are used in this system. If a number includes an 8 or a 9, it cannot be an octal number. Octal
numbering is used in computer systems because it is easy to convert to the binary numbers that
are actually used by the computer.
ODT

ODT (the On-Line Debugging Tool) provides special code that you link into your task image
to help debug a program. ODT commands and operators allow you to execute your program
gradually by setting breakpoints at selected locations or by stepping through the program one
instruction at a time. See RSX-IIM-PLUS and Micro/RSX Debugging Reference Manual for more
information.
off line

Equipment and devices that are unavailable for use are considered to be off line. For example,
turning off a line printer puts the printer off line.
on line

On line means ready for use. Peripheral devices can be on line or off .line.
On-Line Debugging Tool

See ODT.
operating system

An operating system is a set of computer programs that work together to manage computer
resources for efficient operation. An operating system is used for communicating with the
computer, for developing programs, and for scheduling the efficient use of the computer
hardware, including memory, CPU, terminals, line printers, and communications devices.
The RSX-IIM-PLUS operating system is part of the RSX-ll family of DIGITAL operating
systems.
output

Output is whatever the system or a program returns to you. For example, all the prompts from
DCL are system output. If you use the TYPE command to display a file, your command is
input, and the contents of the file displayed at your terminal is output.
output file

Many system utilities and commands take existing files and produce new files. For example,
the COpy command takes a file and creates a copy of it. EDT can edit a file and make a new
one from the original. In these cases, the file being copied is called the input file, and the file
being created is called the output file.
parse

Parsing is breaking a command string into its elements to interpret it.
A PRINT command without a file specification, or with illegal characters in the file specification,
will not parse correctly.

Glossary-18

partition

A partition is a predetermined, contiguous area in memory in which tasks are loaded and
executed. Each partition has the following characteristics:
•

A name

•

A defined size

•

A fixed starting address

The default partition is named GEN. If you do not specify a partition, your tasks will run in
GEN. Other partitions are reserved for other system functions, such as DRVP AR, the partition
for device drivers.
password

A password is a protective mechanism to identify a particular user. Only you should know
your password. Anyone who knows your password can log in to your account and do what
they like.
peripheral device

Any auxiliary device that can provide the system with input, or accept output from the system,
is called a peripheral device or a peripheral. Terminals, line printers, and disks are all peripheral
devices.
pool

The Dynamic Storage Region (DSR) is commonly called the pool. The pool is part of the
Executive's partition in memory. The pool contains the Executive's database.
print head

The print head is the moving mechanism on a hardcopy terminal that prints characters on the
paper. On many hardcopy terminals, the print head rests just to the right of the next character
position when it is not printing. The print head is an output device.
priority

Priority is a rank assigned to a task to determine its precedence in obtaining system resources
when the task is run. Priority is usually set when the task is built. Priority can also be set
when the task is installed or when it is run.
The default priority is 50. Only privileged users can build, install, or run tasks at any other
priority. Once a privileged user has built or installed a task to run at a higher priority, however,
nonprivileged users can run it at that higher priority.
Priority numbers range from 1 to 250 10 with the higher number having priority.
privilege

Privilege determines the level of system access allowed to a user or a task.

Glossary-19

privileged

On RSX-IIM-PlUS systems, most users are nonprivileged. This simply means that they are
not allowed to perform operations or issue commands that will affect the system as a whole.
Nonprivileged users can find out what time it is with the SHOW TIME command, but only
privileged users can change the time with the SET TIME command.
You become privileged by logging in to a privileged account. The same applies to becoming
nonprivileged. The system manager is usually privileged.
prompt

A prompt is a sign that signals that the system is ready to accept input from you.
For example, when you enter the TYPE command without specifying a file name, the TYPE
command prompts you as follows:
File(s)?

By default, DCl prompts with a dollar sign ($ ).
In line mode, EDT prompts with an asterisk (.).
protection

One of the major features of a multiuser system is its ability to tell one user's files from
another's. On RSX-I1M-PlUS systems, each file has a protection code that specifies what kind
of access different users can have to the file and what they may do to the file when they access
it. File protection is based on the User Identification Code (UIC). You can display your UIC
with the SHOW UIC command. The UIC is a two-number code, such as [303,5].
There are four kinds of users, as follows:
SYSTEM

Specifies the operating system itself and privileged users, those with
group numbers of 10 or less.

OWNER

Specifies the user with the same UIC as the file owner. You can display
the file owner, and the file's protection, with the /FUlL qualifier to the
DIRECTORY command.

GROUP

Specifies users with the same group number, which is the first number
of the pair in the UIC.

WORLD

Specifies everybody else.

There are also the following four kinds of access to files:
READ ACCESS

Indicates a user can read, copy, print, or type the file. If the file is a
task image file, READ access means you can run the program.

WRITE ACCESS

Indicates a user can add new data to the file by writing to it.

EXTEND ACCESS

Indicates a technical provision so that tasks can change the amount of
disk space allocated to the file.

DELETE ACCESS

Indicates a user can delete the file.

You can display the protection and ownership of any file with the DIRECTORY/FULL command.
You can change the protection of files you own with the SET PROTECTION command.

Glossary-20

pseudo device

Although it is not any particular physical device, a pseudo device is an entity treated as an
input/output device by the user or system. The pseudo device name is a stand-in name
through which the actual physical device is reached. (This is similar to addressing a letter to
the Governor of North Carolina without knowing the name of the person holding the office.)
The pseudo-device convention makes it possible to refer to a device on any RSX-ll system
without knowing its physical name and number. Thus, pseudo device LB is always the disk
containing the operating system itself and TI is always the terminal you are using, no matter
what its number is or whether it is local or remote or hardcopy or video.
qualifier

A qualifier for a DCL command is always preceded by the slash character (/). The qualifier
alters the action of a command. Most often, qualifiers override defaults. For instance, the
following command uses the default, which is to print one copy:

•

Adding the /COPIES qualifier overrides the default and prints the number of copies you specify,
such as the following:

•

In this case, /COPIES is a command qualifier that alters the operation of the command itself.
The number 2 is an argument to the /COPIES qualifier.

DCL also uses file qualifiers, which alter the effect of a command for one file associated with the
command, but not others. For example, the following command prints one copy of IZZY. TXT
and FIZZY.TXT because that is the default, but it prints two copies of OZZY.TXT:

•

See the RSX-llM-PLUS Command Language Manual for more information on DCL qualifiers.

queue

A queue is a waiting line. In the computer industry, a queue is a list of items to be processed
according to system or user priorities. On RSX-IIM-PLUS systems, queues are under the control
of the system task called the Queue Manager (QMG).
Queue Manager

The Queue Manager, also called QMG, is a system task that controls queues of jobs directed to
batch processors, line printers, or other output devices. In general, the Queue Manager keeps
the jobs separate and in order.
random access

Random access refers to a type of access to memory or mass-storage devices in which any
location can be accessed directly and without regard for which location was accessed previously.
This term is in contrast to sequential access, such as on a tape, where you have to start at the
beginning and move toward the end until you reach the location you want.

Glossary-21

range

Range is the expression of the exact number of lines of text that EDT will operate on. The
simplest form of range is WHOLE, which means the entire buffer, but you can use expressions
such as 20 THRU 30, which means from line 20 to line 30. Type HELP RANGE while in EDT
for more information, or see the EDT Editor Manual.
read

When a task is accepting data, it is said to be reading. This is a standard computer term. When
you enter a TYPE command, the system must read the designated file from the disk before
displaying it at the terminal.
real time

RSX-IIM-PLUS is a real-time system. This means it can respond rapidly, almost without any
delay, to any outside event. Real-time systems are often used to control industrial processes, but
the real-time nature of RSX-I1M-PLUS means it can respond rapidly under most circumstances
to timesharing users as well as industrial processes.
Record Management Services

See RMS-l1.
record-oriented device

A record-oriented device is a device such as a line printer or terminal that deals with information
one record, or one line, at a time. See file-structured device.
reentrant

A program or routine that can be entered at the same time by more than one task is called
reentrant.
remove

A task is removed when its name and address are taken out of the System Task Directory
(STD). A task must have been installed before it can be removed.
resident

A task or other file is said to be resident (or memory resident) if it is normally stored in the
main memory of the computer. Typically, tasks that must take over control of the CPU quickly
(such as those designed to respond to real-time events) are resident tasks.
resident library

A resident library is a block of executable instructions that normally resides in memory. The
routines in a resident library are already linked (task built) and can be shared by several tasks
at the same time. Resident library routines are not included as part of your program's task
image, but they are directly accessible by your program.
RMD

RMD is the Resource Monitoring Display invoked by the SHOW MEMORY command. RMD
displays the current contents of memory, currently active task, and other system information.

Glossary-22

RMS-ll

RMS stands for Record Management Services. RMS is the more sophisticated and flexible of the
two sets of routines supplied on RSX-llM-PLUS systems for file operations; the other is FCS.
RMS routines open and close files, read from files, write to files, and extend and delete files.
Most programming languages have their own methods of dealing with files that use these
routines. In general, RMS routines are not used directly.
round-robin scheduler

The round-robin scheduler is a form of timesharing that gives tasks of equal priority equal access
to the CPU. The Executive tends to give CPU time to process the first task in the System Task
Directory (STD). The round-robin scheduler rotates the entries in the STD. The round-robin
scheduler also causes a significant event after a given time interval. The significant event causes
the Executive to search the STD for a task that is eligible to run. The first task in the STD gains
access to the CPU. After a time interval, the round-robin scheduler again rotates the entries in
the STD and causes another significant event. The new first task in the STD gains access to the
CPU and so forth. In this way, tasks of the same priority have an equal share of CPU time.
See significant event.
routine

A routine is an ordered set of instructions that performs an operation. A routine can be an
entire program or a part of a program.
RSX-ll system

The name RSX stands for Resource Sharing Executive. The RSX-ll family of DIGITAL operating
systems has been in use and under subsequent development for more than 12 years. RSX-ll
systems are real-time systems with features that also allow many users to share the system.
Current members of the RSX-ll family include the following:
RSX-llM

The oldest active member of the family. RSX-llM is a real-time system
with many timesharing features. It runs on any PDP-II computer.
RSX-llM is intended primarily for the smaller, older PDP-lIs.

RSX-llS

A specialized real-time system used for process control on systems with
no mass-storage peripherals.

RSX-llM-PLUS

Also a real-time system, but with many additional timesharing features.
It is designed for the current line of PDP-lIs. RSX-llM-PLUS systems

make the best use of the features available on modem PDP-lIs.
Micro/RSX

An RSX-llM-PLUS system designed specifically for the MicroPDP-l1.
It has many features to make it easier to use and install, but it is still a

real-time system for multiple users.
VAX-II RSX

A system that runs under VMS and emulates an RSX-style system.

P/OS

The Professional Operating System, an RSX-llM-PLUS system designed
specifically for the Professional 300 series of desktop computers. It has
many new features designed for a single user with little interest in or
knowledge of computers.

Glossary-23

scroll

When more than a screenful of output is sent to a video terminal, the output usually scrolls up.
New output appears at the bottom of the screen and eventually disappears off the top, just as
if it were on a scroll that is being unrolled at the bottom and rolled at the top.
Use the NO SCROLL or HOLD SCREEN key on your terminal if the output scrolls too fast.
sequential access

This term refers to a method of access to memory or mass-storage devices where the records or
files are read one after another in the order they appear in the file or volume. A magnetic tape
is an example of a sequential access device. If you are half way through a tape and want to
read a record that is one-third of the way through the tape, you must go back to the beginning
and read through until you get to the record that you want.
See also random access.
significant event

A state that is declared whenever there is a change in system status. Whenever there is a
significant event, the Executive reviews the eligibility of tasks to execute because the change
that caused the significant event to be declared may mean that a priority task that was blocked
is no longer blocked.
For instance, a significant event is declared when a task completes its execution or when a task
cannot continue I/O because an output device is unavailable. The round-robin scheduler causes
a significant event to occur regularly.
software

All computer programs are software. Software is all the parts of the computer you cannot
touch. Software is the collection of tasks, procedures, and rules associated with the operation
of a particular computer system. The operating system is software. EDT is editing software.
Office automation is software. The purpose of software is to make the computer easier to use.
Compare with hardware.
source file

A source file is a text file; it is a program in some programming language that is to be translated
into an object module by the MACRO-tt assembler or a compiler. A source file cannot be run
or task built. The Task Builder uses the object module to produce a task file; the task file is a
runnable program.
STD

STD stands for System Task Directory. The STD is a list of all tasks installed on the system.
You can display the STD through the DCL command SHOW TASKS/INSTALLED.
string

A string is a sequence of characters. When you search for a word in EDT, you are searching
for a string. The sequence of characters that forms a command is sometimes called a command
string. Strings are not always what they seem. The string " Jena" is different from the string
"Jena" because the first string includes a space. Similarly, the string "7" is different from "007"
even though they are equal numbers.

Glossary-24

subroutine

A subroutine is a set of instructions, or a routine, that can be called by other routines. A
subroutine performs a secondary function in a larger program.
swapping

Swapping is a system generation option. It is a variation on checkpointing where tasks of
equal priority have their swapping priorities systematically raised and lowered so that they can
checkpoint each other and all gain access to the CPU and memory.
Sy

SY is the pseudo device that stands for the user's default device. Your system can be located
on any of a number of different physical devices. Using SY in commands ensures that the
command will go to your current default device even though you have changed devices since
you wrote the task.
symbol

A symbol is a representation of something by reason of relationship, association, or convention.
In a programming context, a symbol (sometimes called a variable) is an entity that must be
defined, or given a meaning, so that it can be used.
symbol table

Each task has a symbol table constructed by the assembler or compiler and completed by the
Task Builder, which identifies and defines all symbols used in the task.
syntax

Syntax refers to the structure or format that a command must follow. Misspelled words are the
most common syntax errors. You can always find the complete syntax for any command in the
RSX-llM-PLUS Command Language Manual.
system disk

The disk that contains the operating system is called the system disk. You can find the system
disk on an RSX system by referencing pseudo device LB.
system generation

System generation is the process of tailoring an operating system for a particular hardware
configuration with modifications and additions to the software configuration as well.
system library

All the relocatable routines used by the operating system are defined in the system library. These
routines perform various common functions, such as formatting input and output, managing
memory, and converting binary numbers to decimal.
system task

A task that performs a system-level function is called a system task. Most parts of the operating
system, such as EDT or DCL, are system tasks.
See also applications task.

Glossary-25

system task directory

A list of all the tasks installed on the system. Users can display the STD by using the DCL
command SHOW TASKS/INSTALLED.
task

The task is the fundamental executable programming unit on RSX-IIM-PLUS. Almost everything
that runs on an RSX-IIM-PLUS system-EDT, DCL, or applications-is a task.
task build

Task build is another term for "link." See Task Builder.
Task Builder

The Task Builder is a translator that uses an object module to produce a runnable task. It
allocates the space the task needs to run and makes sure that the symbols used by the program
are properly related to one another. This is also called linking. The LINK command invokes
the Task Builder.
For more information, see the RSX-IIM-PLUS and Micro/RSX Task Builder Manual.
task Image file

A task image file is a file that contains a runnable program, or task. Most task image files have
the file type TSK and also include a letter C in their directory listing, which indicates that they
are contiguous and not spread out over the disk. The following is a directory listing for a task
image file:
HIYA.TSK;2

40.

01-APR-87 00:01

task state

An installed task may be in one of the following task states:
Dormant

Indicates that the task is installed, but it has not yet requested to run.

Active

Indicates that the task has requested to run. It remains active until it exits,
terminates, or is aborted.

An active task may be in one of the following substates:
Ready-to-run

Indicates that the task is competing with other tasks for CPU time on the
basis of priority.

Blocked

Indicates that the task is unable to compete for CPU time, or it is unable
to run because a needed resource is not available.

terminal

A terminal is a hardware device with two functions: sending input to the system and receiving
output from the system. Terminal input usually comes from a typewriter-like keyboard. Output
appears on terminals in two ways, which depends on the terminal type, as follows:
•

Hardcopy terminals keep a permanent record of output on paper.

•

Video terminals have a video screen for receiving output.

Glossary-26

text ftle

Text files are those files that are readable by people, for example, files created by using EDT.
Text files are often called ASCII files.
throughput

The total volume of work performed by a computer system over a given period of time is called
its throughput, that is, how much has been put through the system.
TI

TI is the terminal input pseudo device; TI is your terminal. You can use TI in place of your
terminal's device name (TTn:) in commands. The terminal you are using will always be TI
regardless of whether it is the same number or type you were originally using.
timesharing

A timesharing system is a system in which each user gets equal computer time in tum. This
system contrasts with a real-time system, where the allocation is based on need and priority.
Although RSX-IIM-PLUS is fundamentally a real-time system, the round-robin scheduler
provides a form of timesharing called timeslicing.
See also round-robin schedule and real time.
transparent

A function of an operating system is called transparent when the user can use the function
without seeing it. For instance, the DIRECTORY command uses the system task PIP, the
Peripheral Interchange Program, but the user need not issue any commands directly to PIP to
use PIP.
This is a computer industry term.
UFO

See directory.
UIC

Each RSX-IIM-PLUS user has a two-number identification code enclosed in brackets that can
be used (with password) for logging in. The number is in the form [g,m], where g gives the
user's group number and m gives the user's member number. Users working together often
have the same group number because the default file protection setup permits group members
to use each other's files without hindrance.
user batch job

A user batch job is a complete terminal session consisting of commands to be processed: each
command is preceded by a dollar sign ($). The user batch job begins with $}OB, which logs
the job in, and ends with #EO}, which logs the job out. A file can contain only one user batch
job.
More than one user batch job can be passed to a batch processor with a single SUBMIT
command. The SUBMIT command creates a QMG batch job that consists of one or more user
batch jobs. The batch log is a record of the QMG batch job.
See the RSX-IIM-PLUS Batch and Queue Operations Manual for more information.

Glossary-27

User File Directory

See directory.
User Identification Code

See VIC.
user library

The DCL command LIBRARY allows you to incorporate your own unique set of special routines
into a library that you create yourself. In this way you can store your own commonly used
routines and recall them when you need them. See the RSX-IIM-PLUS Command Language
Manual for a description of the LIBRARY command.
utility

A utility is a general-purpose task included in the operating system to perform common
functions, such as editing or queue management.
video terminal

A video terminal is a terminal that accepts output on a video screen.
virtual terminal

A virtual terminal is a software terminal created by the Executive that passes commands and
data to the operating system, for example, from batch jobs. As far as the system is concerned,
a virtual terminal has the same behavior as a physical terminal.
See also terminal.
volume

The volume is the largest unit of the file structure. A volume contains files and can reside on
any medium. Disks are physical media containing files arranged in volumes. In other words,
the medium is the physical disk and the volume is the arrangement of the information on the
disk. In most cases you can think of the medium and the volume as being the same, but you
should be aware of this distinction.
wildcard

A wildcard character is an asterisk (*) or percent sign (%) used to replace parts of a file
specification that are not entered in a command.
word

The word in PDP-II terminology is a 16-bit unit of data. A word consists of two 8-bit bytes.
The CPU and memory are organized around this word length.
Each ASCII character uses a byte.
(512 bytes) each.

The blocks used in measuring file size are 256 words

write

When a task is sending output, it is said to be writing. When you issue a TYPE command, the
system must read the file from the disk and then write that file to the terminal.

Glossary-28

Index
A
ABORT command, 1-16, 5-14
Address
relocatable, 5-6
ADVANCE function
EDT editor, 2-7
Application, 6-2
Arrow keys
EDT editor, 2-6

B
BACKSPACE key, 1-7
BACKUP function
EDT editor, 2-7
Batch log, 4-7
Batch processing, 4-1, 4-5 to 4-7
Binary machine code, 5-5
BOTTOM function
EDT editor, 2-7
BROADCAST command, 3-9

C
Central Processing Unit
See CPU
CHANGE command
EDT editor, 2-6
Change mode
See Character mode
Character mode
EDT editor, 2-3 to 2-6
CHAR function
EDT editor, 2-7
Checkpointing, 6-6
CLI, 1-5
COBOL command, 5-12
Command, 1-1
abbreviating, 1-11

COMMAND function
EDT editor, 2-10, 2-19
Command line interpreter
See CLI
Compiler, 5-3
Control key
See CTRL key
COpy command, 3-4
EDT editor, 2-17
CPU, 6-5, 6-6
Crash, 1-19
CREATE command, 2-1, 3-5
CTRL key
CTRL/C, 1-4
CTRL/O, 1-16
CTRL/R, 1-9
CTRL/U, 1-9
CTRL/Z, 1-9, 1-10
Cursor, 1-4
CUT function
EDT editor, 2-9

D
DCL, 1-1, 1-11, 3-1, 5-1
Default, 1-14 to 1-15, 3-10
DEL C function
EDT editor, 2-8
DELETE/ENTRY command, 3-14
DELETE command, 3-5 to 3-6, 3-7
EDT editor, 2-15
DELETE key, 1-7, 1-9
DEL L function
EDT editor, 2-8
DEL W function
EDT editor, 2-8
Device, 1-6, 1-13, 3-11, 6-7 to 6-8
peripheral, 6-1, 6-7

Index-l

Device (cont'd.)
pseudo, 3-11
DIGITAL Command Language
See DCL
Directives
Indirect Command Processor, 4-3 to 4-4
Directory, 1-13
DIRECTORY command, 1-13, 3-6 to 3-7

E
Echo, 1-6
EDIT command, 3-7
/OUTPUT qualifier, 5-9
EDT editor, 2-2
deleting text, 2-8, 2-15
inserting text, 2-8
moving text, 2-9, 2-17
undeleting text, 2-9
EDTINI.EDT file, 2-2
EOL function
EDT editor, 2-7
Error message, 1-1
Executive, 5-1, 6-3, 6-6
EXIT command
EDT editor, 2-10

F
File, 2-1, 3-1
contiguous, 5-7
EDTINI.EDT, 2-2
name, 3-1
object, 5-6
protection, 3-4, 6-4
source, 5-6
startup command, 2-2
task image, 2-1, 5-7
text, 2-1
Filespec
See File specification
File specification, 1-13 to 1-15
File type, 2-1
FIND command
EDT editor, 2-16
FIND function
EDT editor, 2-9
FIND NEXT function
EDT editor, 2-9
FORTRAN command, 5-12

Index-2

G
GOLD function
EDT editor, 2-3

H
HELLO command, 1-5
HELP command, 1-11, 1-12, 3-9
EDT editor, 2-6, 2-12
High-level language, 5-11 to 5-12
HOLD /ENTRY command, 3-15
HOLD SCREEN key, 1-16

I
ICP, 4-1 to 4-2
INCLUDE command
EDT editor, 2-19
Indirect Command Processor
See ICP
Input, 1-4
INSERT command
EDT editor, 2-14
INSTALL command, 5-8

K
Keypad
EDT editor, 2-3, 2-4

L
LA120 terminal, 1-1
Labels (ICP), 4-4
LINE function
EDT editor, 2-7
Line mode
EDT editor, 2-5, 2-11
LINK command, 5-3, 5-6
Logging in, 1-5 to 1-6, 1-6
LOGIN command, 1-5 to 1-6
LOGOUT command, 1-19

M
Machine code
binary, 5-5
macro, 5-12
MACRO-II assembler, 5-4, 5-11
MACRO command, 5-4
MCR, 1-5, 5-1
Media, 6-8
Memory,6-5
partition, 6-5

Monitor Console Routine
See MCR
MOVE command
EDT editor, 2-17
Multiuser system, 6-2

N
NO SCROLL key, 1-16

RESET function
EDT editor, 2-9
RETURN key, 1-4
RMD,6-9
RUN command, 3-10, 5-8, 5-12
/TASK-NAME qualifier, 5-13

Qualifier
DCL,3-1
QUIT command
EDT editor, 2-10

SECT function
EDT editor, 2-7
SELECT function
EDT editor, 2-9
SET command, 1-17
SET DEFAULT command, 3-10
SET PASSWORD command, 3-10
SET QUEUE command, 3-14
SET TERMINAL command, 1-17
SHOW command, 1-10
SHOW DEFAULT command, 1-15, 3-11
SHOW DEVICES command, 3-11
SHOW MEMORY command, 6-9
SHOW QUEUE command, 3-14
SHOW TASKS command, 1-18, 5-5
SHOW TERMINAL command, 1-17
SHOW TIME command, 1-10, 3-12
SHOW USERS command, 1-18, 3-12
Significant event, 6-6
Source file, 5-3, 5-4, 5-6
Source language, 5-3
Special symbols
ICP, 4-3
Startup command file, 2-2
STOP / ABORT command, 3-15
SUBMIT command, 4-6
Subroutine, 5-9
SUBSTITUTE command
EDT editor, 2-18
Substitution mode
ICP, 4-3
Symbol
global, 5-6, 5-10
local, 5-6
Syntax, 1;14

Range
EDT editor, 2-11 to 2-14
Real-time system, 6-2
RENAME command, 3-8
RESEQUENCE command
EDT editor, 2-14, 2-15

TAB key, 5-9
Task, 5-1, 5-2
active, 6-5
dormant, 6-5
name, 5-12
resident, 6-5

o
Object module, 5-3, 5-5, 5-10
system library, 5-10
OPEN LINE function
EDT editor, 2-8
Operating system, I-I, 5-1
multiuser, 6-2
real-time, 6-2

p
PAGE function
EDT editor, 2-7
Password, 1-5, 3-11
PASTE function
EDT editor, 2-9
Peripheral Interchange Program
See PIP
PIP, 5-1
Priority, 6-4
Privilege
privileged task, 6-4
privileged user, 6-4
Program, 5-2
Prompt, 1-4, 1-10
explicit, 1-5
Pseudo device, 3-11
PURGE command, 3-7

Index-3

Task (cont'd.)
running, 5-2
Task Builder, 5-6 to 5-8
Task image, 5-3
file, 5-7
Terminal, 1-1, 1-6
hardcopy, 1-1
video, 1-1
VT100, 1-1, 1-3
VT220, 1-1, 1-4
Timesharing, 6-3
TOP function
EDT editor, 2-7
TYPE command, 1-14, 3-8

U
UFD
See Directory
UIC, 3-11
UND C function
EDT editor, 2-9
UND L function
EDT editor, 2-9
UND W function
EDT editor, 2-9
User File Directory
See UFD
User Identification Code
See UIC
Utility, 5-1

V
VT100 terminal, 1-1, 1-3
VT220 terminal, 1-1, 1-4

w
Wildcard, 3-1 to 3-3
WORD function
EDT editor, 2-7
WRITE command
EDT editor, 2-19

Index-4

Introduction to RSX-IIM-PLUS
AA-FD03B-TC

READER'S
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Introduction to RSX-IIM-PLUS
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