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DEC-XV-USUTA-A-D

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Document:	SGEN XVM Utility Manual
Order Number:	DEC-XV-USUTA-A-D
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Pages:	50
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OCR Text

SGEN XVM UTILITY
MANUAL
DEC-XV-USUTA-A-D

digital equipment corporation · maynard. massachusetts

First printing, December 1975
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.
Digital Equipment Corporation assumes no responsibility for the use or
reliability of its software on equipment that is not supplied by
DIGITAL.

The postage prepaid READER'S COMMENTS form on the last page of this

document requests the user's critical evaluation to assist us in preparing future doc~~entation.

The following are trademarks of Digital Equipment Corporation:

DIGITAL
DEC
PDP
DECUS
UNIBUS
COMPUTER LABS
COMTEX
DDT
DECCOMM

DECsystem-lO
DEC tape
DIBOL
EDUSYSTEM
FLIP CHIP
FOCAL
INDAC
LAB-8

MASSBUS
m'lNIBUS
OS/8
PHA
RSTS
RSX
TYPESET-8
TYPESET-IO
TYPESET-II

- ,

CONTENTS

Page
PREFACE
CHAPTER

CHAPTER

vii
1

USING SGEN

1-1

1.1
1.2
1.3
1. 3.1
1. 3. 2
1.4

loS

CONTEXT
ORGANIZATION
ANSWERS TO SGEN XVM QUESTIONS
Teleprinter Command Mode
SGEN XVM Batehing Command Mode
ERROR MESSAGES
OPERATION

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

DETAILED DESCRIPTION OF OPERATION

2-1

2.1
2.1.1

2-1
2-1

2.1.2

ALTER SYSTEM PARAMETERS?
API?
~~l
(Y)
TAB SIMULATION?

2.1. 3

FILL CHARACTERS?

2.1. 4
2.1. S
2.1. 6
2.1. 7

MIC [mie]
DEFAULT # BUFFERS[n]
# WORDS/BUFFER [nnn]
UC1S CONFIG?
~~l

2-3
2-3
2-4
2-4

2.1. 8

POLLER?
~~~
DEFAULT FILES PROTECTION CODE [n]
RESIDENT PATCH AREA ~fZE [nnn]
PAGE MODE SYSTEM?
~N)

2-6
2-6
2-6

2.1. 9
2.1.10
2.1.11
2.1.12
2.1.13
2.1.14
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.3
2.3.1
2.3.2
2.4
2.4.1
2.4.2
2.S
2.S.1
2.S.2
2.S.3

(N)

iii

2-3

(N)

XVM MODE?
~~~
SYSTEM MEMORY SIZE?
[nnnK]
60 CPS?
~~l
B. ALTER I/O DEVICES OR HANDLERS?
XXX?
(Y)
NEW HANDLERS:
OLD SKIPS:
NEW SKIPS:
C. ADD NEW DEVICE?
(N)
DEVICE CODE [ ]
NEW HANDLERS:
D.
CHANGE SKIP CHAIN?
(N)
DISPLAY SKIP CHAIN?
(Y)
SKIP MNEMONICS IN ORDER:
E.
ALTER DEVICE PARAMETERS?
(N)
~~l
7-CHANNEL MAGTAPE
LINE PRINTER SIZE
VT ON:
~~~

2-1

(N)
(Y)

2-S

2-7
2-7
2-7
(N)

(80, 120, or 132)

[nnn]

2-7
2-10
2-10
2-11
2-11
2-12
2-12
2-12
2-14
2-14
2-14
2-16
2-16
2-16
2-16

Contents (Cont)
Page
HALF ON?

2.5.4
2.6
2.6.1
2.6.2
2.6.3
2.7
2.7.1
2.7.2
2.7.2.1
2.7.2.2
2.7.2.3
2.7.2.4
2.7.2.5
2.7.2.6
2.8
2.8.1
2.8.2
2.8.3
2.8.4
2.8.5
APPENDIX A
A.l
1>•• 2

A.3
A.4
A.S

(y)
(N)

2-16

ALTER .DAT SLOTS?

(N)

2-18
2-18
2-18
2-18
2-19
2-19
2-21
2-21
2-21
2-21
2-22
2-22
2-22
2-23
2-23
2-23
2-23
2-23
2-23

# OF POSITIVE .DAT SLOTS [nn]
DISPLAY .DAT SLOTS
(Y)
NEW ASSIGNMENTS:
G.
CHANGE SYS FILES?
(N)
tQ AREA SIZE?
(NONE, NNNK)
TO BE KEPT:
ovrlay
(Y)
OVERLAY NAME [ ]
# OF BLOCKS [
BUFFS [nn]
.DAT SLOT nn?
(Y)
.DAT SLOTS
H. ADD SYS PROG?
(N)
PROG NAME [ ]
# OF BLOCKS [ ]
OVERLAY NAME [ ]
BUFFS [0]
.DAT SLOTS:

[nnnK]

DOSSAV XVM OPERATING INSTRUCTIONS

A-l

RESTORING SYSTEMS
SAVING SYSTEMS
ERROR CONDITIONS AND MESSAGES
TAPE STRUCTURE
DOSSAV XVM RESTRICTIONS

A-2
A-4
A-4
A-6
A-6
Index-l

INDEX
FIGURES

Page
Figure

2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8

Section A Questions:
Section B Questions:
Handlers
Section C Questions:
Section D Questions:
Section E Questions:
meters
section F Questions:
Section G Questions:
grams
Section H Questions:

System Parameters
I/O Devices and

Adding New Devices
Altering Skip Chain
Altering Device Para.DAT Slot Assignments
Changing System ProAdding System Programs

2-2
2-9
2-13
2-15
2-17
2-17

2-20
2-24

LIST OF ALL XVM MANUALS

The following is a list of all XVM manuals and their DEC numbers, including the latest version available.

Within this manual, other XVM

manuals are referenced by title only.

Refer to this list for the

DEC numbers of these referenced manuals.
BOSS XVM USER'S MANUAL

DEC-XV-OBUAA-A-D

CHAIN XVMjEXECUTE XVM UTILITY MANUAL

DEC-XV-UCHNA-A-D

DDT XVM UTILITY MANUAL

DEC-XV-UDDTA-A-D

EDITjEDITVPjEDITVT XVM UTILITY MANUAL

DEC-XV-UETUA-A-D

8TRAN XVM UTILITY MANUAL

DEC-XV-UTRNA-A-D

FOCAL XVM LANGUAGE MANUAL

DEC-XV-LFLGA-A-D

FORTRAN IV XVM LANGUAGE MANUAL

DEC-XV-LF4MA-A-D

FORTRAN IV XVM OPERATING ENVIRONMENT MANUAL

DEC-XV-LF4EA-A-D

LINKING LOADER XVM UTILITY MANUAL

DEC-XV-ULLUA-A-D

MACII XVM ASSEMBLER LANGUAGE MANUAL

DEC-XV-LMLAA-A-D

MACRO XVM ASSEMBLER LANGUAGE MANUAL

DEC-XV-LMALA-A-D

MTDUMP XVM UTILITY MANUAL

DEC-XV-UMTUA-A-D

PATCH XVM UTILITY MANUAL

DEC-XV-UPUMA-A-D

PIP XVM UTILITY MANUAL

DEC-XV-UPPUA-A-D

SGEN XVM UTILITY MANUAL

DEC-XV-USUTA-A-D

SRCCOM XVM UTILITY MANUAL
UPDATE XVM UTILITY MANUAL
VPISA XVM GRAPHICS SOFTWARE MANUAL

DEC-XV-USRCA-A-D
DEC-XV-UUPDA-A-D
DEC-XV-GVPAA-A-D

VTIS XVM GRAPHICS SOFTWARE MANUAL

DEC-XV-GVTAA-A-D

XVMjDOS KEYBOARD COMMAND GUIDE
XVMjDOS READER'S GUIDE AND MASTER
INDEX

DEC-XV-ODKBA-A-D

XVMjDOS SYSTEM MANUAL

DEC-XV-ODSAA-A-D

XVMjDOS USERS MANUAL

DEC-XV-ODMAA-A-D

XVMjDOS VIA SYSTEM INSTALLATION GUIDE

DEC-XV-ODSIA-A-D

XVMjRSX SYSTEM MANUAL

DEC-XV-IRSMA-A-D

XVM UNICHANNEL SOFTWARE MANUAL

DEC-XV-XUSMA-A-D

DEC-XV-ODGIA-A-D

PREFACE
This manual describes the XVM/DOS System Generator Utility Program,
SGEN XVM, and gives other information needed by the System Manager
for installation and maintenance of the XVM/DOS

syste~.

In the preparation of this manual, it was assumed that the reader is
familiar with the XVM Disk Operating System (XVM/DOS), including its
Monitor, and the several Utility Programs -- especially PIP, PATCH,
and UPDATE XVM.

The XVM/DOS USERS MANUAL describes the general oper-

ating procedures for XVM/DOS.
Chapters 1 and 2 of this manual describe SGEN XVM and its use.

Chap-

ter 3 describes the general sequence of operations to be followed
when using SGEN XVM.

It is recommended that the user read the entire

manual before installing XVM/DOS.

vii

CHAPTER 1
USING SGEN

1.1

CONTEXT

The XVM/DOS System Generator, SGEN XVM, allows the system manager to
modify an existing XVM/DOS system to suit the needs of a particular installation.
one.

SGEN XVM does not create a system, but modifies an existing

The XVMjDOS disk-restore DECtapes or magtape that Digital Equip-

ment Corporation distributes will produce a working XVM Disk Operating
System when restored to the disk via the DOSSAV XVM program 1 . The system manager can initiate a system generation operation in order to
tailor this basic system to his own needs by issuing the following series
of commands to the XVM/DOS Monitor:
$MICLOG SYS
A RK -14}
A DK -14
{ A DP -14

Required System Manager Password for the basic system
(for system generation on RK Disk cartridge){Required )
(for system generation on RF DECdisk)
ASSIGN
(for system generation on RP Disk Pack)
statement

$SGEN

Load command for SGEN XVM

When SGEN XVM is loaded, it automatically starts an interactive system
generation procedure.

Once system generation is complete, the system

manager should save the changed system via the DOSSAV XVM program.
should always retain at least two copies of the system:

the original

tape(s) from DEC, and a copy of the new system.
When the system manager wishes to do a subsequent system generation,
he should type the same command series given above,

substituting the

Monitor Identification Code which he supplied during the last system
generation.
1.2

ORGANIZATION

SGEN XVM is a core-image system program with no overlays.

When loaded

into core SGEN XVM tests to ensure that the system is currently logged
in and that the "A" handler of the RF15 DECdisk (DKA) or RK15 Disk
1Appendix A describes the DOSSAV XVM program.
1-1

Using SGEN
cartridge/or RP15 Disk Pack (DPA) is assigned to .DAT -14.
exits if these requirements are not met.

SGEN XVM

SGEN XVM then types out its

name, version number, and the device and unit number on which the new
system will reside.
SGEN XVM then proceeds with eight sequentially presented sets of questions that can modify three basic areas of the system:
parameters,

(2) I/O, and (3) system programs.

(1)

system

The eight sets of ques-

tions are identified by the letters A through H.

Each set is started

by a key question that describes the category of the questions in that
particular set.

Key questions start at the

lef~

margin, questions

within a set are tabbed one stop (8 spaces) to the right.
The user can save time by refusing to consider questions in a particular
set involving an area not to be modified.

He can do this by responding

to the key question of any set with a Carriage RETURN, which effects
the acceptance of a set of default answers.

This means that the param-

eters covered by the rejected set remain as in the previous system.
SGEN XVM provides restart pOints which coincide with the beginning of
each set of questions.

In general, a CTRL P from the keyboard at any

point before the end of the current set of questions causes a return
to the start of the current set of questions, and the deletion of all
answers previously supplied for the current set.

Before the user ter-

minates a particular set, he should then check all answers for that set.
If he later finds a mistake after a set is completed, he must abort the
operation and go through another complete system generation to correct
the error.

A CTRL C, at any time before the end of Section H terminates

the system generation, leaving the old system unchanged.
1.3

ANSWERS TO SGEN XVM QUESTIONS

1.3.1

Teleprinter Command Mode

To save time, SGEN XVM supplies a default answer in either parentheses
or square brackets with each question.

The default answer always shows

how the previous system looked or in some way indicates no change is
required.

A Carriage RETURN response indicates the user accepts the

default answer.

In the illustration of each question where the default

may be more than one, this manual indicates the possibility with brackets (}).

Thus:
API?

r(y)}

leN)

1-2

Using SGEN

Y and N are I-character answers for many of the Yes/No, On/Off class
of questions.

They are self-explanatory.

In the case of some questions,

however, a third I-character choice is required.

In such questions,

the third choice implies "Yes, but ask me questions about the details
of the subject".

For example, Section B, which concerns devices and

device handlers, first asks about each device, deferring questions
about its handlers until necessary.

Thus, the question:

PR? ($)
asks whether the user wants the Paper Tape Reader.

"N" says "NO, delete

the Paper Tape Reader and all of its handlers and skips from the system".

Response "$" or Carriage RETURN says, "YES, keep the Paper Tape

Reader and all its handlers and skips as they are".

Response "Y" says,

"YES, keep the Paper Tape Reader, but ask me questions about its handlers and skips".

ALT MODE alone is echoed "$", and substitutes for "$".

For the Y/N/$ type of question, which accepts a I-character answer, a
left arrow (or underline) implies the default and gives a visible answer on the printout.

(Carriage RETURN is not a printing character.)

Some questions cannot be answered by a simple yes/no multiple choice
type of question; for example, the specification of the monitor identification code (MIC)

(section 2.1.4).

For such questions the present

value (or default) is supplied in square brackets rather than parentheses.

The user may type a single Carriage RETURN to continue with

the present value, or a new value followed by a Carriage RETURN.

The

exact form a new value must take is given in the sections on the
appropriate questions.
Some questions allow multiple answers; for example,
IN ORDER"

(section 2.4.2).

"SKIP f1NEMONICS

In such instances, the user may type sev-

eral answers on one line, separating each answer from the next by a
comma.
Other answers are explained in the relevant parts of Chapter 2.
1.3.2

SGEN XVM Batching Comreand Mode

Like other XVM/DOS Monitor system programs, SGEN XVM may be used in the
XVM/DOS Batching Command Mode.

In fact,

which make the batching process easier.
the following reason:

some features have been added
These features are required for

For those answers whose defaults are specified

in parentheses, SGEN XVM reads teleprinter input in Image Alphanumeric

1-3

Using SGEN

Mode.

Hence, it does not require a Carriage RETURN to complete a .READ.

System considerations, however, require that Batching Mode tapes or
decks be in lOPS ASCII.

This means that each line of input must be ter-

minated by a Carriage RETURN.

Since lines containing one Carriage RE-

TURN only cannot be generated by the Editor, the default answer must
always be specified by a left arrow (+) or an underline (_).

One-

character answers in teleprinter mode have their Batching Mode equivalents as follows:
Teleprinter

Batching

Carriage RETURN

or
Left arrow (+)
or
Underline (_)
All of the above types of answers go with questions where the default

is specified in parentheses.

The user should have XX •. X~in the batch-

ing command string in all cases where the default is not specified
in parentheses (i.e., no default, or one in brackets).
1.4

ERROR MESSAGES

SGEN XVM checks all answers for syntax and acceptability to the XVM/
DOS software.

It also does some limited checking for acceptability

within the current hardware configuration.

Whenever SGEN XVM finds a

wrong answer, it types an error message two tabs to the right of the
left hand margin (16 spaces in).

SGEN XVM does not check for multiple

errors; any answers that follow an erroneous answer on the same line
are not processed, and must be retyped.
1.5

OPERATION

When SGEN XVM starts operation, it saves an image of the three parameter blocks from the system device plus the Storage Allocation Table.
These blocks contain the old image of the three system information
blocks:

SGNBLK, SYSBLK and COMBLK.

SGNBLK contains information about

the default settings of key .SCOM registers, the .DAT and .UFDT, an

1-4

Using SGEN

ordered skip chain, the names of all the handlers, and certain information about the devices that the system recognizes.

Together, SYSBLK

and COMBLK occupy two continguous blocks on the system device.
describe the system programs.

They

These information blocks are illustrated

in the XVM/DOS System Manual.
f..'lost of SGEN XVM I S operations consist of building new images of SGNBLK,
COMBLK and SYSBLK and the Storage Allocation Table.

On completion of

the last set of questions (the "H" set), SGEN XVM disallows corrunands
from the teleprinter, writes out the new system block images, and deletes any discarded handlers from the lOS User File Directory.

(Up to

that point, the current system has remained unchanged.)

It is up to

the user to insert added handlers and system programs.

Handlers can

be added via PIP XVM.

PATCH XVM can be used to add core-image system

programs for which SGEN XVM has allocated space.

1-5

CHAPTER 2
DETAILED DESCRIPTION OF OPERATION
This section describes the options available to the SGEN XVM user, and
explains some of the planning necessary for determining an optimum
configuration for a particular installation.
paragraph denotes a new set of questions.

Each first order (2-digit)

Each second order (3-digitl

paragraph presents an individual question and a description of its
meaning and use.
2.1

ALTER SYSTEM PARAMETERS?

(N)

The "A" section defines those system parameters that do not fall under
I/O or system program categories.

Some are default parameters which

can be modified by commands to the Nonresident Monitor.
only be modified by SGEN XVM.

Others can

Figure 2-1, Section A Questions, illus-

trates this section.
2.1.1

API?

{(Yl)

~Nl

This asks whether the user wishes the default to be API (Automatic
Priority Interrupt System) on or off. A "Y" response makes "API ON"
the default condition. An "N" answer makes "API OFF" the default.
The Nonresident Monitor's API ON/OFF command can change the state of
API temporarily.
2.1.2

TAB SIMULATION?

{(Yl)
~(Nl

This asks whether or not the Resident Monitor teleprinter handler
should simulate the TAB function by outputting spaces.

This question

should be answered with a "Y" response if the console terminal is a
LA36 or a KSR-33.
KSR-3S.

It should be answered "N" if the console is a

The Nonresident Monitor's TAB command can temporarily over-

ride this setting.

2-1

Detailed Description of Operation
~;GEN

XVM V:I. MOO

SYSTEM UPDATE ON DPO
A. ALTER SYSTEM PARAMETERS? eN) Y
API'!' (N) Y
TAB SIMULATION? (Y) Y
FILL CHARACTERS? (Y) Y
t1ICCSYS]
DEFAULT I BUFFERS[3] 4
WORDS/BUFFERCSOO]

UC15 CONFIG? eN) Y
POLLEW!' (N) Y
DEFAULT FILES PROTECTION CODE[2]
RESIDENT PATCH AREA SIIELO]
PAGE MODE SYSTEM? CN) Y
XVM MODE SYSTEM? eN) Y
SYSTEM MEMORY SIZE
1',0

:=';GEN

X')I"l

1.):1.

cp~:n'

[24KJ 96K

(Y)

r::jOOO

SYSTEM UPDATE ON OPO
A. ALTER SYSTEM PARAME'rERS? eN) Y

TAB SIMULATION? (Y)
FILL CHARACTERS? (Y)

DEFAULT I BUFFERSL3: 2
I WORDS/BUFFERCSOO]
l.JC:I. ~:5 CONI'" I C:i'i'

«(!:;

DEFAULT FILES PROTECTION CODE[2] 1
RESIDENT PATCH AREA SIZELO]
PAGE MODE SYSTEM? (N)
XVM MODE SYSTEM? (N)
SYSTEM MEMORY SIZE

[24K] 32K

Figure 2-1
Section A Questions: System Parameters
2-2

Detailed Description of Operation

2.1. 3

FILL CHARACTERS?

( (Y))
(N)

This question asks whether or not the Resident Monitor teleprinter
handler should insert fill characters in the output to the console teleprinter.

A "Y" response causes several Null Characters to be output

following each Carriage RETURN.

This question should be answered with

the "Y" response if the console terminal is a 30 cps. LA3.0.

It should

be answered "N" if the console terminal is a KSR-33, a KSR-35, or a
slower LA3.0.

The Nonresident Monitor FILL command can temporarily

override this question.
2.1. 4

MIC [mic]

This question prints the current Monitor Identification Code (MIC) in
square brackets.

A Carriage RETURN entry retains the old MIC.

If the

user wishes to change the current MIC, he should type exactly three
printing characters, followed by a Carriage RETURN.

If possible, the

user should avoid MIC codes that equal User Identification Codes (UICs)
current to the system.
UIC's:

In particular, he must avoid the following

???, PAG, BNK, lOS, CTP and SCR.

SGEN XVM does not accept non-

printing characters as part of an MIC.
2.1.5

DEFAULT # BUFFERS[n]

This command requests a default number of buffers to be allocated for
user programs and non-core image system programs.
square brackets is the old number.

The number in

If the user wishes to retain the

old default number, he should type a Carriage RETURN.

SGEN XVM accepts

any set of six or fewer octal digits followed by a Carriage RETURN as
the octal number.

The Master Tapes which Digital Equipment Corpora-

tion distributes indicate three (3) as a default number.

The user

must consider the trade-off of the available core in his installation
(systems with little memory might need a smaller number of buffers)
versus the convenience of a large number of buffers.
This parameter does not affect core-image system programs, which always get as many buffers as they need.

Users whose programs need a

different number of buffers may use the BUFFS Nonresident Monitor
command to allocate the exact number of buffers needed.

2-3

Detailed Description of Operation
2.1.6

# WORDS/BUFFER [nnn]

This requests the number of words per buffer, and prints the old number (in octal) in square brackets.

A decision regarding an efficient

size for the buffers requires some knowledge of the disk handlers which
use them.

The handlers break buffers from the pool into three parts:

(1) File Information (about 408 words),

(2) the Block List -- addresses

of pre-allocated blocks (between 4 and 3748 addresses, inclusive), and
(3) the data buffer (4008 words).
words long.

Thus, buffers must be at least 4448

The disk handlers do not use extra words in buffers longer than 1034 •
8
This, therefore, may be an upper limit on buffer size, unless other
programs need more space in their buffers.

The larger the Block

List -- that is, the larger the buffer -- the faster is the output.
Smaller Block Lists may give more efficient allocation of disk space,
and certainly save core.
Any number typed is interpreted as an octal number.
2.1.7

UC15 CONFIG?

r(y)}
'l(N)

The XVM-200 is a dual processor system made up of an XVM processor
and a PDP-II processor.

Normally, the two processors run together as

an integrated single system.

It is possible to use the system as in-

dependent systems running independently on each processor.

In order

to enable this operation, it is necessary to control the interaction
between the two processors.
and the one which follows.

This control is provided by this question

This question asks whether the UC15 option hardware should be enabled
for use.

If the "Y" response is given, the interprocessor communication

link will be allowed to interrupt the XVM processor.
ponse is given, these interrupts will be disabled.

If the "N" resThe "Y" response

is required for correct operation of all DEC supplied UNICHANNEL software.

The "N" response is appropriate for XVM/DOS systems without

UNICHANNEL hardware or for independent operation of the two processors.
The Nonresident Monitor UC15 command can temporarily override the
response to this question.
SGEN XVM uses the response to this question to determine whether the
following question should be a.sked.

2-4

If the answer is "Y", the following

Detailed Description of Operation
question (Section 2.1.8) is asked.

If the answer is "N", the follow-

ing question is not asked and SGEN XVM skips to the question in Section
2.1.9.
2.1.8

POLLER?

fey)}

leN)

The XVM/DOS monitor discovers errors detected by the PDP-II UNICHANNEL
processor via an automatic polling mechanism.

The monitor periodically

polls the UNICHANNEL software system (XVM/PIREX)
any errors which may have occurred.

for information about

If an error has occurred, an ap-

propriate message will be passed on to the user.

If the user is not

using the DEC supplied UNICHANNEL Software system, he may wish to disable the error poller.

This question provides the user with that cap-

ability.
If the "Y" response is given to this question, the poller will be
enabled; the XVM/DOS monitor will periodically poll the UNICHANNEL
processor and report any errors so discovered back to the user.

the "N" response is given, the poller will be disabled and this process
will not occur.

It should be noted that this all depends upon the

UCI5 option hardware being enabled.

If the UCI5 is disabled, the poller

does not run, regardless of the state of the poller enable/disable
switch.

Because of this, SGEN XVM will only ask,

previous question,

"POLLER?" if the

"UC15 CONFIG?", has been answered affirmatively.

"POLLER?" should be answered "Y" for all normal UNICHANNEL systems.
The "N" response should be given only if the following three conditions
are met:
1.

The UNICHANNEL (PDP-II)

is running some non-standard, user

supplied software (replacing XVM/PIREX) .
2.

This non-standard UNICHANNEL software will not respond correctly to error status requests.

For more information on

error status requests, see the XVM UNICHANNEL Software
Manual.

The UNICHANNEL and XVM processors will be interacting with
each other via the interprocessor communication (interrupt)
link.

If this were not the case, a "N" response would be

given to the question,
tion,

"UC15 CONFIG?", and the current ques-

"POLLER?", would not be asked.

2-5

Detailed Description of Operation
The user should be cautious about disabling the poller.

Doing so dis-

ables virtually all error messages regarding devices connected to the
UNICHANNEL.

If a device should go off-line, the XVM/DOS monitor will

be unable to detect or report it.

This condition will only be remedied

by the user visually checking the device and discovering the problem.
The Nonresident Monitor POLLER command can temporarily override the
response to the question.
2.1.9

"POLLER?".

DEFAULT FILES PROTECTION CODE

en]

This requests the default file protection code, and prints the old code
in square brackets.
Code

The possible codes and their meanings are:

Unprotected, with the exception that the file may not
be deleted and the number of blocks may not change, if
the directory is protected.

Code

Write protected, if directory protected.

Code

Read/ Write protected, if directory protected.

SGEN XVM checks the validity of the number entered.
The default protection code for User File Directories is always 1,
protected, and may not be changed by SGEN XVM.
A user may temporarily change the default protection by means of the
Nonresident Monitor Command PROTECT.
2.1.10

RESIDENT PATCH AREA SIZE [nnn]

This requests the Resident Monitor's Patch area size and prints the
old number in square brackets.

The Resident Monitor's Patch Area is

a number of reserved registers (no bigger than 1¢¢¢8) located just
above the Resident Monitor.

The System Loader does not refresh it,

except on Bootstrap loads, restarts, and any of the QFILE GET commands.

The area may be used for patching the system or for communi-

cation among several programs in different core loads.
SGEN XVM interprets any number typed in response to this question as
an octal number.
2.1.11

The refore, the digits 8 and 9 are not accepted.

PAGE MODE SYSTEM?

(Y)}
\'<1\1)

--'"

This requests the default addre s sing mode.
addr e ssing the default mode.

A "Y" response makes page

An "N" response makes bank mode the
2- 6

Detailed Description of Operation
default.

Users may temporarily change the mode via the PAGE ON/OFF

or BANK ON/OFF Nonresident Monitor commands.
2.1.12

XVM MODE?

r(y)}
UN)

This requests the default operating mode for the execution of user pro-

grams under XVM/DOS.

A "Y" response makes XVM ON (17-bit indirect

addressing) the default mode.

A I!N" response makes XVM OFF (IS-bit

indirect addressing) the default mode.

The Nonresident Monitor XVM

command can temporarily override the response to this question.

The

System must have the XM1S option in order to take advantage of 17-bit
indirect addressing.
2.1.13

SYSTEM MEMORY SIZE?

[nnnK]

This requests the default system memory size (MEMSIZ) for the system.
The memory size should be expressed as a two to three digit, decimal
number followed by the letter "K".

The "K" is an abbreviation for

1,024.

Thus a memory size of 65,536 words is expressed as "64K", not

"6SK".

Legitimate memory sizes are in the range 24K through 12BK in-

clusive in increments of BK.

The Nonresident Monitor MEMSIZ command

can temporarily override the response to the question,

"SYSTEM MEMORY

SIZE?".
An attempt to enter an illegitimate memory size will result in the
error message:
"ILLEGAL MEMORY SIZE"
The "system memory size" question will then be repeated.
2.1.14

60 CPS?

((Y)}
(N)

This requests the line frequency at the installation.

Installations

with 60hz line frequency require a "Y" answer; those with 50hz require
an "N" response.
2.2

ALTER I/O DEVICES OR HANDLERS? (N)

This set of questions allows the user to delete or retain devices and
all their handlers, and allows a third option of retaining the reference to the device, and then retaining, deleting or adding handlers

2-7

Detailed Description of Operation
and skips for a particular device.

The printout given in Figure 2-2

illustrates the use of this section.
Section B refers to all devices currently in the system by a 2-character
device code.

The device codes for those device handlers included in the

original supplied by the Digital Equipment Corporation are:
CD
DK
DP
DT
LK
LP
MT
PP
PR
RK
VP
VT

Card Reader (CR03B or CR15 or CRll)
RF15 Disk Control
RPl5 Disk Pack Control
DECtape (TCl5 DECtape Control)
LK35 Keyboard
Line Printer (either LPl5C or LPl5F or LPll/LSll)
Magtape
Paper Tape Punch (PClS)
Paper Tape Reader (PClS)
RK05 Disk Cartridge Control
VP Point Plotting Display
VTl5 Graphic Display Console
Writing Tablet
XYll Plotter

(TT, which means console terminal, is not included in this set of questions, because DOS uses the console terminal as its command device.)
The device handler names used in Section B are printed as 3-character
names.

In reality,

handler names are four characters long, but this

section truncates the last character, a period (.).

The first two

characters must be the 2-character device code for the handler's device.
The third character must be alphabetic.
SGEN XVM starts this set of questions by asking whether the user wishes
to delete discarded handlers from lOS.

Deletion saves space on the

system device.
SGEN XVM then begins asking key questions for each device currently on
the system:

xx'?

($)

(where XX stands for any device code)

or
HANDLERLESS DEVICE ($)
If the user answers with a Carriage RETURN or "$", SGEN XVM retains
the device and all its skips and handlers as they were in the previous
system.

If the user answers "N", SGEN XVM deletes all information

about that device and its handlers, and all its skips from the Skip

2-8

Detailed Description of Operation

Eo ALTER I/O DEVICES OR HANDLER S? (N) Y
DELETE DIS CARDED HANDLERS? (Y) Y

TO BE KEPT:
( !I; )

!j;

FP'i' ($)
DT'i' ( !t»
[l1,,'i' ( ~; ;.

~I,

FW~

DI"AT'

(Y)

DI"IYi'

(Y)

DI\C'~

(Y)

Y
Y

NEW HANDLEF:S t

>mm
::=-

D!3BF :::'70'7()O:l.?

NEW

~)I\ I P!:;

DP'i'

( ~I; )
<: ~I; )

i"iT?

I...F?
CD?
l)P T
\)T T

( ~I; )

(Y;'

,1,
N
~!;

( ~I:
·1' ;.

~I;

( !I; )

;\;

<: ;1,· )

Vi,JT

( .+
:p )

L.K: ·T

( ;1:· )

F(I-{?

(·,1,· ;'

'I;

XY?

(·,1;)

'/;

HANDLERLE SS DEVICET

($)

Figure 2-2
section B Questions: I/O Devices and Handlers

2-9

Detailed Description of Operation
Chain.

(Deletion of handlers from the handler UFD, lOS, does not occur

until the termination of Section H.)
If the user answers "Y", SGEN XVM asks specific questions about the
handlers and skips for the device in question.

A "HANDLERLESS DEVICE" is a set of one or more skips not
associated with any handler. An example of a handlerless
device is the set of LT19 skips used to prevent illegal interrupts from LT19 Terminals. Handlerless device questions
should be treated in the same manner as normal device questions except that no handler questions are asked.
2.2.1

XXX?

(Y)
(where XXX stands for any handler name)

SGEN XVM asks this question for each handler the device has in lOS.
A "Y" response retains the handler; an "N" response deletes it.

SGEN XVM does not allow the user to delete the "A" handler
for the system device (DKA., RKA. or DPA.).
2.2.2

NEW HANDLERS:

When SGEN XVM has asked a question for each of the device handlers
currently in lOS, it asks whether the user wishes to add any new handlers.

It makes no sense to "add" a handler name which has just been

deleted.

If the user wishes to change a handler, he may use PIP XVM

to transfer a new one to lOS.

PIP XVM automatically deletes the old

one if the user transfers a new one with the same name.
names should follow the rules outlined in Section 2.2.

New handler
When the

user has no more handlers to add, he should simply type a Carriage
RETURN.
Adding handler names only makes them "logically" present.

The user

must call PIP XVM to transfer the handlers to the lOS UFD, in order to
make handlers physically present.

SGEN XVM warns the user about missing

handlers at the end of Section C.

File names for handlers in lOS

must have the same name as the handler global and the entry point label
and a "BIN" extension (e.g.,

.GLOBL DKA.

2-10

,DKA. DAC CALP, or DKA. BIN).

Detailed Description of Operation
2.2.3

OLD SKIPS

Presumably, the user changes old skips only in the case where they were
incorrectly inserted.

In any case, after the user has indicated he has

no more handlers to add for the current device, SGEN XVM prints the
skips for thi& device that are in SGNBLK (whether or not these skips
are in the skip chain).
devskp

SGEN XVM prints skips in the following format:

= nnnnnn? (Y)

A Carriage RETURN or "Y" accepts the old skip; an "N" deletes the skip.
2.2.4

NEW SKIPS:

When SGEN XVM has exhausted the skips for the cur.. ent device as they
were in the old system, it requests any new skips.
be typed in the following format:
devskp

New skips should

= nnnnnn

where devskp has no more than six characters, and nnnnnn is a legitimate device skip.

SGEN XVM performs (in octal) the following tests to

determine if a skip is a legitimate lOT:
1.

Must be an lOT.

Bit 14 must be zero -- the skip may not clear the accumulator.

(i.e., must be of the form 70nnnn).

Either of these two tests will cause the error message ILLEGAL lOT to
be displayed and the lOT.
In addition, the low order octal digit must
be a 1 -- it must be a skip lOT and not some other kind.
This check
may be overridden by the user by typing "Y" to the question:
"NOT A STANDARD SKIP lOT"
"DO YOU WISH IT ACCEPTED?

(N)"

Any other answer causes the skip to be ignored.
If a skip is rejected for any of the above reasons, SGEN XVM re-prompts
with the ">" symbol which requests another skip.
Users should not insert skips which can in any way modify the contents
of the accumulator.

Such skips will cause unpredictable timing depend-

ent action in XVM/DOS.

For a similar reason users are also cautioned

2-11

Detailed Description of Operation

against using skip lOTs which in any way modify device status information.
When the user types a Carriage RETURN after the ">", SGEN XVM proceeds
to the next device.

Negative skips (that is, those which skip on "OFF",

not "ON") should be preceded by a minus sign (-), to indicate that they
are negative:
devskp
2.3

= -nnnnnn

ADD NEW DEVICE?

(N)

When SGEN XVM has finished with Section B, it asks whether the user
wishes to add a new device.

Section C differs from other sections

in that restarts (CTRL p) only delete information added for the current
device.
That is, if the user adds devices AA, BB, and CC, but types CTRL P
during the CC operation, SGEN XVM returns to a point just after the
completion of the BB device insertion.
When the user has no more devices to add -- that is, when he answers
the key question with an "Nil or carriage RETURN, SGEN XVM reminds him
of all the handlers he has added to the system, but which are not yet
present in lOS. He can add them later, via PIP XVM. The printout
shown in Figure 2-3 illustrates the use of this Section.
2•3. 1

DEVI CE CODE [ ]

Here, the user may type any two alphameric characters that SGEN XVM
cannot interpret as an octal number.

It is recommended, however, that

the user give only alphabetic characters, as any numerals might be
confused with a unit number.

SGEN XVM does not accept any input other

than two alphameric characters.

There is no default for this question;

SGEN XVM assumes that if the user answered the Section C question with
a "Y", he has a device code to add.

SGEN XVM makes no assumption about

which device it is.
2.3.2

NEW HANDLERS:

Here, the user should add all the handlers he will use for the new
device.

The names should follow the rules for handler names outlined

in paragraph 2.2.
2-12

Deta i led Des cript i on of Operation

c . ADD NEW DEVICE? CN) Y
DEVICE COD CE ] AD

>'/0:1.30:1.

("'/0130:1." !SN'

SYMBOL'

>t, D~:;F"",? O:1. 30:1.
.:.

ADD NEW DEVICE? eN)
MISSING HANDLERS :

Figure 2-3
Section C Questions: Adding New Devices

2-13

Detailed Description of Operation
A carriage RETURN typed after the prompt symbol causes SGEN to proceed
to the next question.
2.3.3

NEW SKIPS:

The new skips for the device should follow the format outlined in Paragraph 2.2.4.

SGEN XVM adds all new skips to the end of the Skip Chain.

The user may change the order of the Skip Chain in Section D.
When the user has no more skips to add, he types a Carriage RETURN after
the prompt symbol.
C.

SGEN XVM repeats the key question for Section C.

ADD NEW DEVICE?

(N)

If the user has another new device, he may add it now.
NOTE
A "HANDLERLESS DEVICE" is created by: (1) entering any two
unused (alphabetic) characters for the device code (this
device code is not retained); (2) answering the new handlers as a question followed by a carriage RETURN; (3) entering the skips in the format outlined in paragraph 2.2.4.
2.4

CHANGE SKIP CHAIN?

(N)

When the user has responded to the key question for Section C with an
"N" or a Carriage RETURN, SGEN XVM proceeds to Section D, which allows
the user to change the Skip Chain order and delete skips.
may not add any skips in this section.

The user

The printout of Figure 2-4

illustrates the uses of this Section.
2.4.1

DISPLAY SKIP CHAIN?

(Y)

In most instances, the user wishes to see all skip mnemonics and acronyms in the old system, plus those he has just added.
"Y" or Carriage RETURN.

SGEN XVM types:

If he answers

DEFAULT SKIP CHAIN ORDER,

followed by the old Skip Chain with any new skips at the end.
2.4.2

SKIP MNEMONICS IN ORDER:

Users have two basic options for this part: accept the whole chain as
is, or retype the entire chain, in a new order.

2-14

The user may type a

Detailed Description of Operation

D. CHANGE SKIP CHAIN? eN) Y
DISPLAY SK IP CHAIN? CV)
DEFAULT SKIP CHAIN ORDER:
SPFAL
DTDF
DSSF
RKSF
DPSJ
MTSF
SPDI
WTSK
SDDF
CRSI
CRSD
LPSF
CLSF
RSF
PSF
KSF
KSFl
TSF
DTEF
DPSE
MPSNE
MPSK
SP E
CRSF
LSSF
XYSF
KSF2
KSF3
KSF4
KSF5

SKIP MNEMONICS IN ORDER:
)SWTSK

)S SD DF
)SCRSI
)SCRSD
)SLPSF
>SCLSF
)SRSF
)SPSF
)SKSF
>SKSFl
)STSF
)SDTEF
)SDPSE
)$MPSNE
)SMPSK
)SSPE

SK IP MNEMONICS IN ORDER:

)SCRSF

)'SPFAL

)SLSSF

)'DTDF

)SXYSF

)'DSSF

)'KSF2

>S RK SF

)SKSF3

)SDPSJ

)SKSF4

)SMTSF

)SKSF5

)SSPDI

Figure 2-4
Section D Questions: Altering Skip Chain

2-15

(con~)

Detailed Description of Operation
single Carriage RETURN in response to the "SKIP MNEMONICS IN ORDER:"
question, and obtain the old chain order, with any new skips at the
end of the chain.

If he types any mnemonic, however, he must account

for all of the skips.

When the user responds to the SGEN XVM request

for the next skip (»

with an ALT MODE, SGEN XVM types "$" and the first

skip in the old chain that has not already been selected.

When the

user responds to the ">" with a Carriage RETURN, SGEN XVM deletes all
unlisted skips, freezes the new order, and continues on to Section E.
Two warnings are in order:
the chain.

(1) Negative skips should be at the end of

Illegal interrupts may otherwise occur when the peripheral

device is down.

(No standard XVM/DOS devices have negative skips.)

(2)

Beware of changing the relative order of the chain, as supplied by

DEC.

For instance, the clock interrupt must come before the printer.

2.5

2.5. 1

ALTER DEVICE PARAMETERS?
7 -CHANNEL MAGTAPE

(N)

O~O

The user should choose the proper default.

"N" gives 9-channel.

The

printout for this section is shown in Figure 2-5.
2.5.2

LINE PRINTER SIZE (80, 120, OR 132)

[nnn]

Acceptable responses to this question are 80, 120, or 132, or a Carriage RETURN.

A Carriage RETURN retains the old line size, printed in

square brackets.
2.5.3

VT ON:

((Y)\
((N»)

This requests the default setting for the CTRL X option.
VT ON the default.

An "N" makes VT OFF the default.

A "Y" makes

SGEN XVM does

not ask this question or the next one if the VTA handler is not in
the system.
2.5.4

HALF ON?

((Y)l.

((N»

This requests the default setting for the half-screen setting for the
CTRL X option.

An "N" response makes HALF OFF the default.

ponse makes HALF ON the default.

2-16

A "Y" res-

Detailed Description of Operation

E. ALTER DEVICE PARAMETERS? eN) Y
7 CHANNEL MAGTAPE?

(Y)

LINE PRINTER LINE SIZE(80. 120 . OR 132)[80J 132
lJT ON? eN) Y
H('~LF

ON? ( N;'
Figure 2-5

Section E Questions: Altering Device Parameters

F. ALTER .D AT SLOTS? eN) Y
OF POSITIVE .DAT SLOTSC20J

DISPLAY .DAT SLOTS?

D(,:-,T

....

:;. .•t::'..1

DElv' I CE
~:~ y' (.':-!

····1 4
.... .,.1. "X

~:)y (~I

·..·1 ::::

\,.'

~:;yt,

UI t .."
\

'd ' I C
UI C

UI C
UI C

....

:I. :I

Ci"i,(:·,
~:~ y' (:i

....

:I ,)

Cf'~i('1

UI C

,.,

[lPL
~::, y. (.)

,"~

.....{.

.,., ~5

NDNE

UI C

..../j

GY(.,

.... "X
\ ..'

.... ::.~

'"("r !'""
TTt·,

r: L.:U
uI C
u Ie

.... :I.

~:; y (,

~:) ''( ~:,

~:;Y"~

UI C

( ..

.. .,.-

''}

::.::

!:,.{(.)

~;y{.)

!:;Yr::)

I::'

~:)yt)

,.,l .

'::: '.j (:)

'':;-

!:;y (.)

:I. 0
·1
.I. :I.
,.,

nY,00

,.J

," ,

UI
~::,

I•••.

....

, ,.' ,
I ~:)

UI C

UI c

Li Ie
UI C

UI c

UI C

LlI c

LIT c

!:;y (~

UIe

:i. .,':.
:I ~':~

TT t)
TTl',

:I. ··V/1

NONE

I. ~'.)
1 c:,

PPt)

UJ C
LI I C
LlI C
uI C
UI C

I'Ht,

;:.::0

~ru~

i'l D i··~E::

U :r [
uI C

>A LP -:1.2,6/[[1 5
("CD" ISN'T IN SYSTEM)

EX:

>A DK(UIC) ;,I.O/TTA 4

)A LP -12,6/[DB 5
)(.) !:;Y <UIC> .....q

:>
Figure 2-6
Section F Questions: .DAT Slot Assignments
2-17

Detailed Description of Operation
2.6

ALTER .DAT SLOTS? (N)

This section allows the user to alter the number of positive, or user
.DAT slots. which is a permanent change to the system (until the next
System Generation), and to make the default assignments to both the
.DAT slots and the .UFDT slots.

The operator may temporarily change

the assignments via the ASSIGN (A) command to the Nonresident Monitor.
(See Figure 2-6.)
2.6.1

# OF POSITIVE . DAT SLOTS

[nn]

This asks the number of positive .DAT slots for the new system, and
indicates the old number in square brackets.
.DAT slots is fixed at 15.
77, inclusive.

The number of negative

SGEN XVM accepts any octal number from 1 to

Each .DAT slot adds two registers to the size of the

Resident Monitor and two parameters to SGNBLK -- one for the .DAT slot
entry, and one for the .UFDT entry.

Users with a great deal of core

should still be careful about too many .DAT slots.

That might cause

SGNBLK overflow and an abort from the system generation.

Further,

FORTRAN OTS users must reassemble FIOPS STOP and .FLTB in order to use
more than 208 .DAT slots.

(See FORTRAN IV XVM OPERATING ENVIRONMENT

MANUAL for instructions.)
2.6.2

DISPLAY .DAT SLOTS (Y)

If the user wishes to change any assignments, he may request their
current assignments by answering "Y" or Carriage RETURN.

This has the

effect of a REQUEST command to the Nonresident Monitor.
2.6.3

NEW ASSIGNMENTS:

The user may make new default assignments to the .DAT and/or .UFDT by
using the same format of ASSIGN (A) commands he would use to the Nonresident Monitor.

When the user has no more new assignments, he should

type Carriage RETURN when SGEN XVM types a new angle bracket (».
Typing 'UIC' in a .UFDT slot means the UIC currently logged in is given
to that .UFDT slot.

Typing 'SYS'

in a .UFDT slot means either BNK or

PAG will be assigned to that slot by the loaders (depending on the
addressing mode of the load).

Any other three letters are retained

unless changed via an ASSIGN command.

2-18

Detailed Description of Operation
2.7

CHANGE SYS FILES?

(N)

With the exception of the first question, which refers to the size of
the tQ area, this refers to the core-image system programs currently
listed in SYSBLK and COMBLK.

This section allows no additions.

The

printout given in Figure 2-7 illustrates the use of this section.
2.7.1

tQ AREA SIZE?

(NONE, NNNK)

[nnnK]

This question allows the user to set the tQ area size.

The Resident

Monitor will tQ dump (to the tQ area) the minimum of the current system memory size and the tQ area size.

The tQ area size should normally

be set to the expected system memory size.

However, some users, espe-

cially those with large amounts of memory (more than 32K) , may wish to
select an tQ area size smaller than their memory size.

This saves

disk space while sacrificing the upper portion of all memory dumps.
While the system will allow tQ dumps to any size tQ area, GET/PUT
operations will be performed only if the Q area is at least as large
as the system bootstrap (24K or 32K).

Detailed Description of Operation

G. CHANGE SYS FILES? (N) Y
~Q

AREA SIZECNONE,NNNK)[NDNCJ 32K

TD DE I<EPT;
D C! ~::; :1. ~:.=.; ? (~!;) ~l;
\:,UEN? (~I;) t
UPD(ITE--i'- Cl-:;' N

F' I F' 'i:- (~I;) tEDIT? (~I;) -,I;
i-'-j (H::: I'W 'i'

(-:I;:;'

P iyr C I--/""i:-

('I;;'

-,I;
~I;

G!F I LE';'"

C l-;'

.,'

Figure 2-7
Section G Questions: Changing System Programs

2-20

Detailed Description of Operation
2,7.2

TO BE KEPT:
syspro?

($)

After the tQ area size has been defined, SGEN XVM asks questions about
each core-image system program currently on the system, in the order
that it finds them in COMBLK.

A response of "$" or Carriage RETURN

instructs SGEN XVM to retain all information about the last-named system program.

A response of "Y" instructs SGEN XVM to retain the pro-

gram's name in SYSBLK and COMBLK, but implies that the user wishes to
change some of the information about the program, as listed in SYSBLK
and COMBLK.

An "N" deletes the program from the system.

SGEN XVM does

not allow the Nonresident Monitor (DOS15) to be deleted.
2.7.2.1

ovrlay

(Y)

(where "ovrlay" is the name of any
currently listed overlay)

If the user responds to a system program name with a "Y", SGEN XVM
first lists each of the program's overlays, if any.
answers.

These are Yes/No

A "Y" Carriage RETURN response retains that overlay, and an "N" response
deletes it.
2. 7. 2. 2

OVERLAY NAME [ ]

If the user wishes to add any overlays to the current system program,
he should type the names at this point. SGEN XVM rejects names which
are more than six characters long, or are the same as any Nonresident
Monitor or PATCH XVM command.

If the named overlay is already listed

in SYSBLK, SGEN XVM requests the next overlay.

If not, SGEN XVM re-

quests:
2.7.2.3

# OF BLOCKS [ ]

The user should type the number of blocks required for the new system
program.

If the number is legal, SGEN XVM tests whether there are as

many contiguous free blocks on the system device as are necessary to
hold the new overlay.

SGEN XVM starts testing at block 0 of the system

device, and stops as soon as it finds enough blocks.

SGEN

XVM

then

updates its image of the Storage Allocation Table (SAT) to indicate
that those blocks are occupied.

2-21

Detailed Description of Operation

Note that when disk space is limited, and the user wishes to add several system programs and overlays or a large tQ area, SGEN XVM may
not allocate disk space efficiently.

In an extreme case, the user

may need to first transfer the files of several UFDs (or even all of
lOS, except the system device's "A" handler) off the disk via PIP XVM,
and then do one pass through SGEN XVM to delete all unwanted system
programs.

Then the user must do enough succeeding passes to ensure

that system programs are added in order of size, with the largest first.
Finally, the user should transfer the UFDs back, via PIP XVM.

This

allows the UFD files, which need not be in contiguous blocks, to use
the noncontiguous blocks.
2.7.2.4

BUFFS

[nn]

This question indicates the number of buffers previously allocated for
this system program, and asks whether the user wishes to change the
number.

SGEN XVM has no way of checking whether the number of buffers

allocated is compatible with the program.

That is the user's responsi-

bility.
2.7.2.5

.DAT SLOT nn?

(Y)

After the user has indicated the number of buffers for this program,
SGEN XVM asks him to check the .DAT slots required.
the old ones.

If the user types "Y" or Carriage RETURN,

retains the listed .DAT slot.
2.7.2.6

It first lists
SGEN XVM

An "1'1" deletes the listed .DAT slot.

.DAT SLOTS

After checking the old .DAT slots, the user should add any new ones
the program needs.
in Section F.

The .DAT slots added must be legal, as determined

All positive .DAT slots may be obtained by typing "ALL".

If the user has added an overlay, he should add any .DAT slots needed
by the overlay but not listed by SGEN XVM for the system program.

2-22

Detailed Description of Operation
2.8

ADD SYS PROG?

(N)

This section allows users to add the names of new core-image system
programs and their overlays to SYSBLK and COMBLK.

Restarts in this

section delete only the current system program, just as they do for
neW devices, Section C.
The printout given in Figure 2-8 illustrates the use of this section.
2.8.1

PROG NAME [ ]

Names must conform to the rules for system program names outlined in
paragraph 2.7.2.2.
2.8. 2

There is no default for this question.

# OF BLOCKS [ ]

This question works just like that for overlays, described in paragraph
2.7.2.3.
2.8.3

There is no default for this question.

OVERLAY NAME [ ]

Any overlay names must conform to the rules for system program names
outlined in Paragraph 2.7.2.2.

If the overlay name is not already

listed in SYSBLK, SGEN XVM requests:
# OF BLOCKS [ ]

2.8.4

BUFFS [0]

The user should enter the octal number of buffers needed for the new
system program.
2.8.5

.DAT SLOTS:

The user should list the octal numbers of all .DAT slots needed by the
new system program, or any of its overlays.

The response "ALL)" ob-

tains all positive .DAT slots.
After the user has entered all necessary .DAT slots, he should type a
carriage RETURN in response to the " >" symbol typed by SGEN XVM.
returns him to the start of Section H.

2- 23

This

Detailed Description of Operation
If the user types Carriage RETURN or "N" to the key question for
Section H, SGEN XVM disallows CTRL P or CTRL C, modifies the system
and re-bootstraps the monitor.

H. ADD SYS PROG ? (N) Y
PROG NAME r ] ADMON
:11: OF

n LCJCI{~:; [ ::I

OVERLAY NAME[ ] ADMON1
:11: OF

n LnCI<~:;[::I

B UFF ~:; [() ::I

:-5

>11 .12. 1:3" :1.4

H. ADD SYS PROG ? (N)
MO DI FY IN G S Y S T EM(~P , ~ C IGN OR ED)

Figure 2-8
Section H Questions: Adding System Programs

2-24

APPENDIX A
DOSSAV XVM OPERATING INSTRUCTIONS
DOSSAV XVM (DOSSAV) is the save/restore system for XVM/DOS.
DOSSAV saves and restores to/from DECdisk, Disk Cartridges, Disk Packs,
DECtape and magtape.

A DECdisk system can be saved on and restored

from DECtape, magtape, Disk Cartridge and Disk Pack.

A Disk Pack or

Disk Cartridge system can use DECtape and magtape.
Once loaded, DOSSAV asks for all necessary information such as input
and output device, unit numbers, and, in the case of magtape, track
and density.
GENERAL INSTRUCTION:
The user must type a Carriage RETURN after all entries,
character typed to restart after errors.

including the

For XVM UNICHANNEL systems,

start up XVM/PIREX as indicated below.
To load XVM/PIREX, place the ABS11 paper tape in the XVM's pdper tape
reader.
tion.

Place the ENABLE/HALT switch on the PDP-II in the HALT posiPress the STOP and RESET switches on the XVf'.1 simultaneously.

Set the ADDRESS switches on the XVM to 177¢¢. Press the READIN switch
on the XVM. When readin operation is completed and the XVM has halted,
set the PDP-II switch register to:
1¢¢¢¢¢ for 8K local memory on the PDP - II
12¢¢¢¢ for 12K local memory on the PDP-II
and depress the PDP-II LOAD ADDR switch, then set the ENABLE/HALT
switch on the PDP-II to ENABLE, and finally depress the PDP-II START
switch.
Remove ABSI1 from the paper tape reader, and reload it with the XVM/
PIREX paper tape.
ABSI1 program

Press CONTINUE on the XVM.

(which has two segments:

A-I

This will cause the

a PDP-11 segment, and an XVM

DOSSAV XVM Operating Instructions
segment) to read in XVM/PIREX (which is a PDP-II absolute binary tape)
via the XVM segment and load it into PDP-II lower memory via the PDP-II
segment.
When the XVM/PIREX paper tape has been read in, the XVM will halt, and
the PDP-II will be running XVM/PIREX.
from the reader.

Remove the XVM/PIREX paper tape

At this point the UNICHANNEL Peripheral Processor has

been loaded and is waiting for an I/O request from XVM/DOS.
A.l

RESTORING SYSTEMS

The following examples illustrate how to put the systems distributed by
DIGITAL on DECtape or magtape onto a DECdisk, Disk Pack or Disk Cartridge.
The user responses are underlined.

The RK~5 based systems start up

XVM/PIREX as described in GENERAL INSTRUCTION, above, before starting
up DOSSAV.

DOSSAV resides on a paper tape, which must be (HRM) loaded

at 57720 (restart 54000).1
1.

To restore a DECdisk system from DECtape (1 of 2 on Unit 1
and 2 of 2 on Unit 2)
DOSSAV XVM Vnxnnn
INPUT DEVICE? DTi
UNIT NO? -1L
OUTPUT DEVICE? DK)
DATE CREATED: 06 Jun 73
TAPE DONE. HOUNT ANOTHER

/Note that if DK is typed no
unit number is requested.
/At this point,
/type 2 on the key/board followed by carriage
RETURN.

To restore a DECdisk system from magtape (on Unit ¢):
DOSSAV XVM Vnxnnn
INPUT DEVICE? MT,
UNIT NO? gJ.
OUTPUT DEVICE: DK)
DATE CREATED: 06-JUN-73
NOTE
All XVM/DOS System Restore magtapes distributed by DIGITAL are 800 BPI. DOSSAV
always assumes odd parity. For 9 track
units, DOSSAV assumes 8~~ BPI.

IDOSSAV may be loaded at any of the following locations.
1772~g'
3772~, 5772~3 or 7772¢8.
A binary loader precedes DOSSAV on tne
paper tape and this loader moves DOSSAV to bank 2 where DOSSAV
actually runs. The restart must be 54~008·

A-2

DOSSAV XVM Operating Instructions
3.

To restore a Disk Pack system from DECtape (1 of 2 on Unit 1
and 2 of 2 on Unit 2):
DOSSAV XVM Vnxnnn
INPUT DEVICE? DT)
UNIT NO? 1)
OUTPUT DEVICE?
UNIT NO? iU
DATE CREATED:
06-JUN-73
TAPE DONE, MOUNT ANOTHER

At this point, type 2 on the
keyboard followed by a Carriage RETURN.

To restore a Disk Pack system from magtape (on Unit 1):
DOSSAV XVM Vnxnnn
INPUT DEVICE? MT)
UNIT NO? 1)
TRACK (7 or-9)? 7,
DENSITY (2,5,8)? -g)
OUTPUT DEVICE? DP)
UNIT NO? ~
DATE CREATED:
06-JUN-73

To restore a Disk Cartridge system from DECtapes on Units 1,
2, 3, and 4:
DOSSAV XVM Vnxnnn
INPUT DEVICE? DT)
UNIT NO? 1"
OUTPUT DEVICE? RK)
UNIT NO? 0)
DATE CREATED: 06-JUN-73
TAPE DONE, MOUNT ANOTHER

2)
TAPE DONE. MOUNT ANOTHER
3~

The user mounted the next tape on
unit number 2, then types 2,· to
continue)
The user mounted the next tape on
unit number 3, then types 3) to
continue)

TAPE DONE. MOUNT ANOTHER

(The user mounted the next tape on

unit number 4, then types 4.) to
continue)

DOSSAV XVM Vnxnnn
INPUT DEVICE?

(Operation complete)

To restore a Disk Cartridge from magtape Unit 1:
DOSSAV XVM Vnxnnn ,
INPUT DEVICE? MT~
UNIT NO? 1.,
TRACK (7 or 9)? 7)
DENSITY (2,5,8)? 8)
OUTPUT DEVICE? RK;
UNIT #? f!d.
DATE CREATED: 06-JUN-73
DOSSAV XVM Vnxnnn
INPUT DEVICE?

(Operation complete)

A-3

DOSSAV XVM Operating Instructions

It is possible to restore to the DECdisk a software system which was
created for a machine smaller (different number of DECdisk platters)
than the one being restored to.
ments of the SATsI.

DOSSAV does all the necessary adjust-

Therefore, the restore tapes issued by DIGITAL

for a I-platter system can be restored to any system.

Note that this

should only be done with the master tape(s) which have block 1775

8
That block is needed during the restore for five or more DECdisk

free.

platters.

It is not possible to restore a software system which is

larger than the hardware.

(For example, one cannot restore a 3-platter

system onto a I-platter configuration.)
The system can then be bootstrapped from the appropriate disk.

See the

XVM/DOS Keyboard Command Guide.
A.2

SAVING SYSTEMS

Once the user has tailored the system to his specific configuration, he
will want to save that system for future restorations.
simply reverse the procedure above.

To do that,

To illustrate, consider Example 1

above and the changes necessary to it to create a restore tape.
To save a DECdisk system to DECtape (on Units 1 and 2):
DOSSAV XVM Vnxnnn
INPUT DEVICE? DK )
OUTPUT DEVICE? DT )
UNIT NO? 1;
--TAPE DONE. MOUNT ANOTHER

At this point, type 2 on the keyboard followed by a Carriage RETURN.

Note that DOSSAV XVM allows for as many DECtapes and magtapes as are
necessary to hold the system.
A.3

ERROR CONDITIONS AND MESSAGES

Recoverable errors during command string decoding:

If a question is

answered incorrectly, DOSSAV outputs an appropriate error message and
then repeats the question.

These error messages are:

ILLEGAL DEVICE

An illegal device mnemonic was typed (something other than DP, DK, RK, DT, or MT) or
an illegal combination of devices was typed
(i.e., input = DT and output = MT).

BAD TRACK

Something other than 7 or 9 was typed.

1 SATS :

Storage Allocation Tables - i.e., bit maps.
l \-4

DOSSAV XVM Operating Instructions
BAD DENSITY

Something other than 2 (200),
8 (800) was typed.

Recoverable errors during operations:

If it is possible to recover

from an error, DOSSAV attempts to do it.
to the console.

5 (556), or

The error message is output

After the problem has been corrected, any character

on the keyboard followed by a Carriage RETURN resumes operation.

TAPE NOT READY

The DECtape or magtape unit is off line
or not write enabled.

DISK NOT READY

DECdisk is write locked.

DISK PACK NOT READY

The Disk Pack or Disk Cartridge unit is not
ready.

Unrecoverable errors:
cannot recover.
restarts.

Primarily hardware errors, from which DOSSAV

After the error message has been output, DOSSAV

DOSSAV retries five times on parity error, before issuing

an unrecoverable error message.
DECTAPE ERROR
MAGTAPE ERROR
DISK ERROR
DISK PACK ERROR
ATTEMPT TO RESTORE SYSTEM TO WRONG DISK
To protect users who have access
to more than one type of disk and
who may have several sets of
restore tapes, all restore tapes
are created with the mnemonic of
the disk type in the first SAT.
DOSSAV checks this code against
the output device code. If they
differ, this message is output.
BLK 1775 OCCUPIED. NO 2ND SAT CREATED

A DECdisk system created for 4 or
fewer platters is restored to a machine
with 5 or more platters and block 1775
is already used. Therefore, no second
SAT is created. A master tape was not
used to make the restore.

A-S

DOSSAV XVM Operating Instructions

XX ERR IGN
where

xx = DK or DP or RK.

This error is typed on the console,
and the XVM halts. This reports
that " Read/Write check" errors
occurred more than 128 times during
a save or restore process. The bad
block number is present in the XW 1
AC. Users can continue the save or
restore process by pressing the
continue switch on the console of the
machine.

A.4

TAPE STRUCTURE

The restore tapes are structured as follows:
tem is the first block put on the tape.

the first SAT of the sys-

This SAT, which is never re -

stored to the disk, has two words modified: word 2 contains the creation
date (MMDDYY,YY is years since 1970) and word 376 contains the device
mmemonic (.SIXBT, right justified).

All the occupied blocks referenced

by this SAT are then put sequentially on the tape.
there is one, is then put on, and so on.

The second SAT, if

This structure enables use of

magtape, which is a sequential only device.
A.5

DOSSAV XVM RESTRICTIONS
1.

It is not possible to save or restore magtapes with even
parity.

DOSSAV fails when two DECtapes are on line with the same
unit number.
It is necessary to restart under such circumstances .

A- 6

INDEX
ABS11 program, A-1
Addressing mode, 2-6
Answers, 1-2
API (Automatic Priority
Interrupt) System, 2-1
ASSIGN (A) command, 2-18

Bank mode, 2-6
Batching command mode, 1-3
Blocks containing system
information, 1-4
Blocks, number of, 2-21, 2-23
Bootstrap, 2-19
Buffer allocation, 2-3
Buffer size, 2-4
Buffers, number of, 2-22, 2-23

Carriage RETURN, 1-2, 1-3
COMBLK (system information
block), 1-4
Command mode teleprinter, 1-2
Configuration, 2-4
Core-image system programs,
2-3, 2-21, 2-23
CTRL C, 1-2, 2-24
CTRL P, 1-2, 2-24

.DAT slots, 1-2, 2-22, 2-23,
number of, 2-18
Default assignments, 2-18

Half-screen setting, 2-16
Handlers, 2-7, 2-10, 2-12
added or deleted, 1-5
new, 2-12
Hardware, 2-4

Image alphanumeric mode, 1-3, 1-4
Information blocks, 1-5

Key question, 1-2

Line frequency, 2-7
Line printer size, 2-16
Loading, 1-1
XVM/PIREX, A-l

Magtape channels, 2-16
Magtape structure, A-6
Memory size, 2-7
MIC (Monitor Identification
Code), 2-3
Mnemonics, skip, 2-14
Mode,
batching command, 1-3
image alphanumeric, 1-3
operating, 2-7
Mode of addressing, 2-6
Monitor Identification Code

Default parameters, 2-1

Default settings of Key .SCOM
registers, 1-4
Devices, 2-7
assignment, 1-2
code, 2-12
handlers, 2-10
insertion, 2-12
parameters, 2-16
Disk handlers, 2-4
DOSSAV XVM operating instructions, A-I

(MIC),

2-3

Names,
of overlays, 2-21, 2-23
of system programs, 2-23
New device, 2-12
New handlers, 2-12
New skips, 2-11, 2-14
9-channel magtape, 2-16
Number of blocks, 2-21, 2-23
Number of buffers, 2-22, 2-23
Number of .DAT slots, 2-18
Null characters, 2-3

Error messages, 1-4, A-4

File protection code, 2-6
Fill characters, 2-3

Old skips, 2-11
Operating mode, 2-7
Output, teleprinter, 2-3
Overlays, 2-21, 2-23
Index-1

INDEX (Cont.)
Page mode, 2-6
Paper tape reader, 1-3
Parameter blocks, 1-4
Parameters, system, 2-1
Parentheses usage, 1-2, 1-3
Patch area, 2-6
PDP-ll UNICHANNEL processor, 2-5
PIREX paper tape, A-I
Polling mechanism, 2-5
Processors, 2-4
Program information, 2-21
Programs, 2-23

tQ area size, 2-19
Questions, 1-2

Resident Monitor's patch area,
2-6
Restart points, 1-2
Restoring systems, A-2
Restrictions, A-6

Save/restore system, A-I
7-channe1 magtape, 2-16
SGNBLK (system information
block), 1-4
Size of tQ area, 2-19
Skip chain, 2-14
Skip mnemonics, 2-14
Skips, 2-11, 2-14
Square brackets usage, 1-2,
1-3
Storage Allocation Table (SAT),
1-4, 2-21
SYSBLK (system information block) ,
1-4
System parameters, 2-1
System programs, 2-23

Tab simulation, 2-1
Tape structure, A-6
Teleprinter command mode, 1-2
Teleprinter output, 2-3
Terminate the system generation,
1-2

UNICHANNEL hardware, 2-4, A-2

VTA handler, 2-16

Index-2

SGEN XVM Utility Manual
DEC-XV-USUTA-A-D
READER'S COMMENTS
NOTE:

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with software should be reported on a Software
Problem Repcrt (SPR) form.

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