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Document:	PS/8 Programming System Programmer's Reference Manual
Order Number:	DEC-08-MEXA-D
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Pages:	96
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I
IDENTIFICATION

I
0

Product Code:

DEC-08-MEXA-D

Product Name:

PS/8 Progral"'.mina System
Progra:-:uner 's Reference ~1anual

Date Created:

:uly, 1970

: lain tair:.er:

PDP-8 Software Development

This document contains advanced information
on the PS/8 Programming System, and is subject to change without notice.

PDP..B
LIBl=lAllllY

PREFACE

This document describes the PS/B Programrnina system for the
PDP-B/I or PDP-8/L with at least BK of core, one DECtape and an
ASR-33 Teletype.
Chapters 1 through 4 cover information required by the
average PS/B user.

The discussion assumes familiarity with aK PAL-D,

BK SABR, BK FORTRAN, the Symbolic Editor, ODT, the Absolute Binary
Loader, and the Linking Loader (all of which are covered in the
PDP-8 handbook Introduction to Programming 1970).
After a general introduction in Chapter 1, the structure and
operation of PS/B's filing system is described in Chapter 2 as
necessary background to using PS/B.

In Chapters 3 and 4, inter-

action with PS/B via the Teletype is detailed and many examples of
possible command strings are given.
User programs run while PS/B is on DECtape or disk can call
upon PS/B to perform directory operations and to use the I/O device
handlers for user input and output.
Information about the preliminary version of PS/B is presented
in Chapter 6, along with internal

in~ormation

of interest mainly to

the advanced programmer.
At the end of this document, appendixes summarize, in easily
referenced forr.1, the co!TlTI'.ands and error messages.
tl1e whole.

iii

An index concludes

{

0
•

Table of Contents

Chapter 1

Introduction

1.1

Hardware

1.2

System Software Components of PS/8

Chapter 2

~,iling

System

2.1

Types of l''iles

2.2

Device iJu.-nbers

2.3

Per~anent

2.4

User Device i;a.:nes

2.5

::--ile :~a.mes

2.6

Default and Assu.-ned i.xtensions

2.7

Dimensions

Chapter 3

1-~eyboard

Device ~a~es

Co::1..>Uands

3.1

Core Control 3lock

3.2

Co:::imands to the :r:eyboard ::onitor

3.2.1

3.3

.t;rror :ressages
The CorJ!lla.nd Decoder

3.3.1

I/O Specification

3.3.2

Option Syntax

3.3.3

,C;rror :;essa.ges

Chapter 4-

Library of syste:'l Progra:.is

4.1

Peripheral Interchange Progr~-n

4.2

Symbolic ~ditor

4.3

Binary Loader

4.4

8i.\ PAL/D c',..ssenbler

4.5
4.6

Conversion Progran
Linldng Loader
v.

:.-.

;1
t1
t

8K SABR Assembler

8K FORTRAN Compiler

tj
i

~'I

Chapter 5

Interfacing with the User Service Routine (USR)

5.1

The DEVICE and FILNAM Pseudo-Ops

5.2

Calls to the USR

5.2.1

Generalized Calling Sequence

5.2.2
5.2.3

Request Numbers
Fetch Handler

5.2.4

Lookup Permanent File

5.2.5

Enter Output File

5.2.6

Close Output File

5.2.7

Coillllland Decode

5. 2. 8
5.2.9

Chain to Program

5.2.10
5.2.11

Lock USR in Core
USR Dismiss from Core

5.2.12

Ascertain if Handler in Core

5.2.13

Reset System Tables

Signal User Error

5.3

Device Handlers

5.4

Demonstration Program

Chapter 6

,n
. ·.'.·.\
v

Preliminary and Supplementary Information

6.1

PS/8 and the Disk Monitor Compared

6.2

Limitations of the Preliminary Version

6.3

Directory Structure

6.4

Building and starting a PS/8 System

6.5

Using the System ODT

6.6

The Supplied Device Handlers

6.7

Writing Device Handlers

6.8

RK8 Disk Handler Listing
vi

Appendixes
A

Summary of Keyboard Commands

Special Character Commands

Error Hessages

C.1

From the Keyboard Honi tor

C.2

From the Command Decoder

C.J

From the Linking Loader

C.4

From the PS/8 Version of FORTRAN

vii

CHAPTER l
INTRODUCTION

The PS/8 Programming System is a keyboard-oriented prograrndevelopment system, expandable to accommodate any amount of core
memory from 8K up.

In addition to the language processors (FOR-

TRAN, 8K PAL-D, and SABR) the PS/8 system includes:
• Absolute and Relocatable Loaders
• A Symbolic Editor
• CONVRT (a program to provide file compatibility with
the present Disk Monitor System)
• PIP (Peripheral Interchange Program)
• An invisible ODT (Octal Debugging Technique) which
allows the programmer to debug programs without
giving up core space.
An important aspect of PS/8 is that user programs may call
upon the system for various services, including:
• Loading device handlers
• Searching file directories
• Creating and closing variable and fixed length output
files
• Decoding a line of Teletype input identifying I/O files
and options
• Program chaining, that is, the process of automatically
starting a subsequent program upon completion of a preceding one, often using results from the preceding one
in the execution of the subsequent one.
PS/8 provides true device-independence, i.e., user and system
programs can be written without concern for specific I/O devices.
Programs can then be run using the most effective I/O devices available at a given installation.

Further, if the system configura-

tion is altered, programs need not be rewritten to take advantage
of the new configuration.

The PS/8 system controls the copying of

data from any medium to any other medium.

Logical names can be

assigned to devices within the system to enable symbolic referenc-

ing of devices, making for easy-to-follow programs.
1-1

. 4 .

[I
!

With PS/8 it is possible for the user program to specify variable length buffers.

Large buffers ensure efficient use of storage

devices and a minimum of time spent in data transfer operations by
minimizing disk and tape motion.

PS/8 takes full advantage of the

new RK8 disk pack for fast bulk storage, yet full system services
are possible with a single DECtape.
This discussion of the PS/8 Programming System assumes that
the reader is familiar with 8K PAL-D, 8K SABR, 8K FORTRAN, Symbolic
Editor, ODT, and the operations of the Binary and Linking Loaders.
The reader need not be familiar with monitor systems, the Peripheral
Interchange Program (PIP) , and the program to convert the 4K Disk
Monitor ASCII files to PS/8-compatible files

(CONVRT) ; these are

thoroughly explained in this chapter.
1.1

HARDWARE
The PS/8 Programming System can operate using either disk or

DECtape as the system device.

To accommodate PS/8, the disk con-

figuration must have 96K or more words of storage and either a
DECtape or high-speed papertape reader/punch.
The minimum PS/8 configuration is a PDP-8/I or PDP-8/L with
at least 8K of core, one DECtape used as the system device, and
an ASR-33 Teletype.

A multiple DECtape system performs appreciably

faster than a single DECtape system.

The multiple DECtape system

reduces DECtape motion because it is possible to copy directly
(i.e., without intermediate searchino) from the system DECtape to
another DECtape (or vice versa) when editino or assemblina.
Up to fifteen devices may be interfaced to PS/8.

The devices

include:

up to 8 DECtape units (TC,0'1/TUSS or TC,0'8/TU56)

•

high-speed papertape reader and punch

•

up to four RK8 disks

•

up to four DF32 disks or RF,0'8 disks

•

a card reader

•

a line printer

1-2

1.2

•

Linctape (compatible with the PDP-12)

•

industry-compatible magnetic tape

•

any other device for which it is possible to write a
device handler in one, or at most, two pages.

SYSTEM SOFTWARE COMPONENTS OF PS/8
The main software components of the PS/8 system are:
1.

The Keyboard Monitor, which accepts commands from the
keyboard to create logical names for devices, run
system and user programs, save programs, and call in
debugging aids.
The Keyboard Monitor provides
communication with the PS/8 executive routines.

A library of system programs:

Peripheral Interchange Program (PIP) ,

Editor,

8K PAL-D Assembler,

Absolute Binary Loader,

8K SABR Assembler,

Linking Loader and 8K FORTRAN Subroutine library,

8K FORTRAN Compiler,

a conversion program (CONVERT) to provide file
compatibility with the Disk Monitor System,

and other standard system programs as they become available.
3.

The Command Decoder accepts a command string from the
keyboard, indicating input and output files and various
options. Following a keyboard command to run a system
program, one or more command lines indicate to the system
program what files are to be used as input, what to call
the output file(s) and how to perform the function.
The
Command Decoder communicates with the System Library
Programs .

Device handlers, that is, subroutines which accept a
standard calling sequence from all programs and perform
input and/or output operations on a device.

The User Service Routine (USR) which controls directory
operations for the PS/8 system.
The user program may
call upon the USR using standard subroutine calls.
Some
of the functions performed by the USR are:

•

1-3

.. #C

W..Q ___ ¥.--.#

ii#.

I
0
a.

loading device handlers,

searching file directories,

creating and closing variable and fixed length
output files,

decoding command strings from the Keyboard,

chaining from one program to another.

When PS/8 is operating, the Command Decoder, USR, and the
Keyboard Monitor are swapped into core from the system device as
needed and when their operation has been completed; the previous
contents of core are restored.

1-4

CHAPTER 2
FILING SYSTEM

Before going on to a study of how to operate the PS/8 system,
a discussion of the files and devices being manipulated is in order.
The filing system is basic to an understanding of the keyboard
commands and service calls.

Names for I/O devices and files on these

devices are used for symbolic reference in keyboard commands and
service calls.

2.1

TYPES OF FILES
Files may be permanent, tentative, or free:

A permanent file is one which is no longer expandable.
That is, it has a fixed size.

A tentative file is a file that has been opened for
output and has not yet been closed.
If a tentative file is no longer receiving output, it is said
to be inactive. An inactive tentative file will be
deleted by the USR (the User Service Routine) at the
first opportunity. Such an inactive tentative file
might have been created by a program which was
interrupted before completion. When a tentative
file is still receiving output, it is said to be
active. A directory device may have only one active
tentative file at a time. Upon closing, a tentative
file becomes permanent.

A free file is a contiguous area of unused storage
space which is available for output.

Two calls to USR (ENTER OUTPUT FILE and CLOSE OUTPUT FILE)
operate together for handling output files.

The ENTER operation

may be used to create an active tentative file.

This file may

have the same name as a permanent file.

2-1

§#¢

-·. ZL L,

_______ 44@44tti@4$_$.,

,_.zg __@A.14}%#.}_.4 ...... %..

·--·-4.-. -

Upon closing, the active tentative file becomes the new permanent

file and the old permanent file of the same name (if it existed) is
deleted.

If the user program fails or is interrupted before

executing the CLOSE operation, the tentative file becomes inactive
and is soon deleted automatically; the old permanent file of the
same name (if one existed) is untouched.
2.2

DEVICE NUMBERS
At system-generation time, the I/O devices in a given configura-

tion are each assigned a number between 1 and 17 (inclusive).

The

number is used to refer to the device in coding user programs which
interface with the USR of PS/8.

Each of the devices also has a

permanent (system) name.
2.3

PERMANENT DEVICE NAMES
The correspondence between permanent names and the standard

I/O devices follows.
Permanent Name

I/O Device

SYS:

Systems device (Disk if system haslarge disk
(RK8 or RF~8), otherwise DTA~)

DTAn:

DECtape n (n is an integer in the range 0 to
7, inclusive)

OSK:

The default storage device for files.
The
assignment of DSK: is specified at system
generation time.
In the preliminary software
the assignment is fixed as follows:

= the disk
= SYS: = DTA~:

For a single system DSK: = SYS:
For a DECtape system OSK:
TTY:

Teletype keyboard and printer

PTP:

High-speed papertape punch

PTR:

High-speed papertape reader

CDR:

Card reader

LPT:

Line printer

MTAn:

Magnetic tape n

LTAn:

LINCtape n (formatted for the PDP-12)

2-2

USER DEVICE NAMES
Each device may be given a user name by the keyboard
command ASSIGN.

The user name is composed of up to four alpha-

numeric characters of which the first must be alphabetic.

The

user name takes precedence over the permaner.t name; For example,
you may assign the user name IN to the device with the permanent
system name DTAl, via the command
ASSIGN DTAl IN
Future references to IN will refer to DTAl.

Thus, device-

independent programs are easily possible since a change in the
user name of a device using the ASSIGN command can change the
operation of a routine without changing the code.

User names

may be removed by the same ASSIGN command without a name argument.
For example,
ASSIGN DTAl
would remove the user's name for DTAl.

All user device names may

be deleted at once by the keyboard command DEASSIGN.
A device name may consist of up to four alphanumeric
characters.

All one and two character names are unique.

Due

to a system limitation, not all user device names of three and
four characters are uniquely represented in the system.

The device name is internally coded in one 12-bit word.
If the name is one or two characters long, the encoding is the
name itself.

If the name is three or four characters long,

the name is the sum of the two words in the name with the sign
bit set.

As a result, some three or four character names have

common encodings.

For instance, DTA3 and CSB4 have the same

encoding.
It is, therefore, recommended that user device names be
one or two characters only.

A three or four character name may

be tested for uniqueness by typing
ASSIGN name
2-3

; __

" ¥2,

-14

L@#A . L _ ,4---#.¢.

.M,41M4i4L }.. Mk .

If a
NOT AVAILABLE
message results

(indicating the device name is not in the system

tables), the name is unique.
Some devices

(such as disks and DECtapes) are directory

devices, that is, they are a collection of entities called
files.

The system keeps track of these files by means of a

Directory, which is a list of file names and their corresponding storage space on the device.

2.5

FILE NAMES

Files are referred to symbolically by a name of up to six
alphanumeric characters optionally followed by a period and an
extension of two alphanumeric characters.

The extension to a

file name is generally used as an aid for remembering the format

of the file.

2.6

DEFAULT AND ASSUMED EXTENSIONS

If an extension is not explicitly given for an input file,
a default extension will be appended by the Command Decoder if
the program which calls the Command Decoder so specifies.

the file with the default extension appended is not found, then
a search for the original file

(without any extension) is made.

When using the Command Decoder, most system programs make use
of this default extension feature.
only to input files.

Default extensions apply

In addition, some system programs append

extensions to their output files if the user does not specify
an extension.

These extensions are called assumed extensions.

Assumed extensions apply only to output files.

The keyboard

monitor uses an assumed extension of .SV when referencing
core-image files.
2-4

In the table which follows, extensions and their usage are
detailed.
Extension

Indicates

Usage

.sv

a core image (SAVE) file

'l'he assumed extension for the
R,RUN, SAVE, and GET Keyboard
Monitor.Commands.

.FT

a FORTRAN source file

Default extension for BK
FORTRMJ.

• SB

SABR source file

Default extension for BK SABR •

. PA

PALB source file

Default extension for BK PAL-D •

.BN

absolute binary file

Default extension for Binary
Loader.Assumed extension for
BK PAL-D binary output.

.RL

relocatable binary file

Default extension for Linking
Loader.Ji.ssumed extension for
BK SABR

NOTE
The BK FORTRAN Library file LIB.B.RL is
not (as a whole) relocatable, though each
subroutine of the file is.
.MP

file contains a loading
map

Assumed extension for Linking
Loader map.

.LS

an assembly listing

Assumed extension for BK PAL-D
and SABR listing output.

.TM

a temporary file

Extension for FORTRAN- and
SABR-generated files for
system use.

For example, if the user types:

RUN DSK PROG
the extension

.sv will be assumed and the file named PROG.SV

device DSK) will be run if found.

If the user types:

RUN DSK FROG.A
then FROG.A will be run.

2-5

.. h

.f#- ., . ,

(on

I
~I

DIMENSIONS

0
The terms block, record

and~

are defined thus:

1 block=l record=2 pages=256 10 words
In directory listings, calls to the USR, etc., reference
file length

in terms of blocks (or records).

2-6

CHAPTER 3
KEYBOARD COMMANDS

Conunands typed on the Teletype keyboard may be directed to the
Keyboard Monitor or to any of the system programs in the PS/8
library.

The Keyboard Monitor indicates it is ready to receive

a conunand by printing a dot.

The System Programs use the Conunand

Decoder to interpret user conunands.

The Command Decoder indicates

it is ready to receive a command by printing an asterisk.
Each command to the Keyboard Monitor or Command Decoder is
typed on the Teletype and corrected, if necessary, before ending
the line and initiating execution.
delete the last character typed.

The RUBOUT key may be used to
Pressing this key prints a

backslash ( \) character followed by the character which was deleted.
Successive pressings of the RUBOUT key each cause one more character
to be printed and deleted.

The first non-RUBOUT character typed

after the last rubout in a sequence causes a closing backslash to
be printed.

For example:

User types:

RUN DSK (RUBOUT)

Teletype shows:

RUN DSK \

Monitor sees:

RUN DTAl FILE

(RUBOUT)

(RUBOUT) DTAl FILE

KSD\ DTAl FILE

The key combination CTRL/U (produced by holding down the CTRL
key while typing U)

can be typed anywhere in an input line.

echoes on the Teletype as "tU".
be ignored.

CTRL/U

The line on which it occurs will

To the Keyboard Monitor, typing CTRL/C anywhere in an

input line causes "tC" to be printed and the line to be ignored.

the Command Decoder, typing CTRL/C prints "tC" and returns control
to the Keyboard Monitor.
The RETURN key is typed to enter a command to the computer and
to initiate its execution.

The ALT-MODE (also called ESCape or

PREFIX on some Teletypes) key may also be used to end a line.
key will print on the Teletype as a dollar sign ($).

3-1

.4.

... 4 .... P

"...... ML

... .-4 ) ..

This

I
If the LINE FEED key is .pres,s~d at any time while entering
a line, the line is echoed as the Keyboard Monitor currently
sees it.

For example:

(RUBOUT)

(Rt.H30UT)'

User types:

RUN DTA3

.Monitor
echoes:

RUN DTA2

The line is not terminated.

\3\

PRG

,G,

(LINE FEED

PROG

The user may terminate the line, append

or'change it.

J.l

CORE CONTROL BLOCK

A block of da.ta internal to PS/8 can be directly changed
by commands from the keyboard.

This block, called the Core

Control Block, contains information about the file such as i t.s
'starting address, the areas of core occupied by the file, and a
word called the Job Status Word.
The Job Status Word is saved and loaded with a file to

indicate what locations in core the file uses and how, as follows:

Meaning

Bit Number

Contents

The file does not load over locations
0-1777.

The file does not load over locations
10000-11777.

The program is not restartable, i.e.,
the file must be-reloaded before it
can be started again.

Locations 0-1777 need not be saved if
the Command Decoder is called. The
CD overlays them.
1

Locations 10000-11777 need not be
saved if the USR is called. The USR
overlays them.

A core control block is set up for each core image file

when the file is created by the Binary or Linking Loader or by
the SAVE keyboard command.

(A core image file is one which has

been dumped from core onto some device by the SAVE command.)
'3-2

()

3.2

COMMANDS TO THE KEYBOARD MONITOR
The Keyboard Monitor is ready to receive a command when a

dot is printed on the Teletype.

You may then type any of eight

commands to manipulate files and names; execution occurs upon
typing a carriage return.
command need be typed.

Only the first two characters of the

In the description of the eight commands

to the Keyboard Monitor which follows, optional arguments are
enclosed in parentheses.

The following abbreviations are used

for indicating arguments:

Abbreviation

Meaning

dev

any device name

pdev

a permanent device name

udev

a user device name

file

a file name

ext

an extension to the file name

ASSIGN pdev (udev)
The specified user device name is associated with the
permanent device name in the system tables. Only one
user name may be associated with a device at a time.
For example,
ASSIGN DTAl IN
causes all future references to IN to refer ·to DECtape
unit 1.
If the optional argument for the user name is missing,
the current user name associated with the device will
be cleared.

DEASSIGN
All current user names are disassociated from the
devices.

GET dev file (.ext)
This command handles only core image files.
The specified file is loaded into core and its core control block
is moved to the system scratch area.

If an extension is not specified, the extension SV (for
core image files) will be added to the file name. For
example,
3-3

• 2f122!!1\M

4QS. .

GET DTA3

will fetch the file OH.SV from DTA3.
4.

SAVE dev file

(.ext)

(aaaaa-bbbbb, ccccc, •.• )

(;sssss)

(=nnnn)

where:aaaaa-bbbbb, ccccc, •.• are the addresses of the areas of
core to be SAVE d
;sssss

is the starting address

=nnnn

is the Job Status Word

The program currently in core is saved on the specified device
with the specified file name.

As before, if an extension is not

specified, the extension SV is added to the file name.

If the

other three optional arguments are not given, the information they
convey is taken from the core control block.
If an error message is printed in response to the SAVE command, the program currently in core has not been changed as yet.
For example,
SAVE DSK OHLA.SV 55,10500-10577;10502

saves the program in core on the disk as a file named OHLA.SV.
The areas of core saved will be 0 - 177 of field O and 400 - 577
of field 1.

The starting address of the program is 502 in field 1.

The Job Status Word will be taken from the core control block.

START (sssss)
The program currently in core is started at location
sssss if it is specified. If the argument sssss is
missing, the program is started at the starting address specified in its core control block.

ODT
The system ODT which is completely invisible to the
user is loaded into core and started. ODT occupies
locations 0-1777 in field 0.
It accepts five digit
core.memory addresses.
If the CTRL/0 combination
is typed, ODT will terminate printing and return to
command mode.

3-4

RUN dev file (.ext)
This clmmand handles only core image files.
The specified
file on the specified device is loaded into core, its core
control block is moved to the system scratch area, and the
program is started. at its starting address.
If an extension is not specified, the extension SV is added
to the file name. For example:
RUN DTAl HMM
causes the file HMM.SV on DECtape 1 to be loaded into core,
its core control block to be moved to the system scratch
area, and the program to be started.

R file

(.ext)

This command handles only core image files from the system
device (SYS.). The specified file on the system device is
loaded into core and started at its starting address.
If
an extension is not specified, the extension SV is added.

R differs from RUN in that a core control block is not moved
with the file.

In order to SAVE a program which does not have its

core control block with it, all the optional arguments of the SAVE
command must be explicitly stated.

System programs are most often

called using the R command, since they need not be SAVEd.

To call

a user program to be later SAVEd, use either the RUN or GET command.

•

3.2.1

Error Messages
If an error is made in typing a command to the Keyboard Monitor,

one of the following messages is printed.

3-5

-·u 4A MP. -®L .. ..

.L4JW S

. J44¥t42W . J

..m.

. .WZ.--.,~

Message

Meaning

device NOT AVAILABLE

The device name specified (to a rlUN, GET,
SAVE or ASSIGN command) is not in any
system table •

xx.xx ?

11 xx.xx 11
is not a legal command; e.g., if
the user typed "HELL0 11 the system would
respond 11 HELL0? 11

filename NOT FOUND

The file name specified (to a RUN, GBT,
or R command) does not exist on the
device specified.

TOO FEW ARGS

You left out an argument to a command;
e.g., 11 nUN DSK 11 would produce this
message.

NOl 1

You attempted to START a program which
cannot be started for some reason.
For example, the program may modify
itself and hence must be reloaded before
starting it again.

SAVE ERROR

An I/O error has occurred while SAVEing
a program. The program is still intact
in core after this message is given.

ILLIDAL ARG

Bad syntax was detected in the optional
arguments of a SAVE command.

BAD ARGS

Two areas of core specified in the
optional arguments of a SAVE command
overlay each other.

USER ERROR 0 AT xxxx.x

An I/O error was detected while loading a program (RUN, GET or H commands).
11 xxxxx 11 is a meaningles:; vestigial
location.

MONITOR ERROR 2 AT

An attempt was made to output to a
WRITE LOCKED device, usually DECtape.

·J.J

THE COMMAND DECODER
As soon as the system program is running, it uses the Com-

mand Decoder to receive a list of output devices and files, a
list of input devices and files, and a list of options.

These

specifications you type on the line (or lines) following the R
command. The Command Decoder prints an asterisk to ask for a
command string.

3-6

()
The PS/8 command Decoder is used to transmit information about
specified inputs, outputs, and options to programs requiring that
infop-iation.

The command Decoder builds up its information in

Field 1 in certain specified locations.
3.3.1

Output Files
There is room for three entries in the output file list.

list begins at 17600 and appears as followsa

4 bit device number

Filename in stripped ASCII
(6 characters)

!-----+----~
j

Extension (2 characters)

c
3.3.2

Input Files
There is room for

entries in the input file table.

The

list is built up from 17617, and each entry appears as follows 1

8 bit file length

4 bit device no.
starting record
(block) no. on
snecified device

•
NOTE

The file length is returned as a negative
number, i.e., 377 in these bits is a length
of l block, 376 is a 2 block file, etc.
A file length of 000 means the specified file has a length
greater than or equal to 256 blocks.

3.3.3

Parameter Table
OPtions specified to the Command Decoder appear as bits in

the parameter table.

There are bits to correspond to A-z, 0-9.
3-7

_ 44 J a

_w -. ¢4t

4" .. 4¢4,0f44 -·'

The

I
~

0
The list is three words long, beginning at 17643.
To clarify the above, consider an

e~ample.

Assume the input

to the command necoder appeared as1

*SYSsBILE.PA
The

co~mand

PTR1,DTA41MASS/T

Decoder tables would appear as follows:

Output ~ile Listi
B bits

4 bits

000

.--------.-----·02

system device

14
05
!-------+-----·-00
00
20

10 words of zeros

----------·-·---

The input file list 'NOUld appear as follows1

veaningless for PrR
(non-directory device)

PTR is device
Meaningless for nond irectory device

File length of MAS~

CTA4 is device

starts at record 50 8

0050

:14 words of zeros
'----·---~· ·-·-·

•

------··

Since there were two inputs, two entries were used.
The option list would appear as follows1
·-----·--··-····-~---·--

17643

0000

A-L not on

0020

T bit on

0000

y,z,0-9 not on

3-8

l"l.
'-J•

NOTE
The 4 bit device numbers are not sacred.
They will depend on the configuration
soecified when the system is built.
3.3.4

I/O Specification

The expected string for I/O specification takes the form:
(output files)+(input files)
There may be 0 to 3 output files and 0 to 9 input files,
depending upon the requirements of the system program as later
discussed for each system program.

For example, the assembler

uses the first output file for binary, the second output file
for the listing.

The files are separated by commas.

output files are given, the backarrow

If no

+ may be omitted.

File specifications for input and output files take the
following forms:

device: filename

the specified file on the specified device

device:

the specified device used as a non-directory
device, e.g., referencing DSK: will cause
the whole disk to be used.

filename:

the specified file on an assumed device,
depending upon context:

(a null)

Meaning

Form

for output files and the first input
file, the device is assumed to be DSK:

for input files after the first, the
device is assumed to be. that of the
previous entry

(By a null is meant the absence of an explicit specification.)
The meaning depends
upon context:
1.

for output files, a null indicates no
ouput file exists for this position

for input files, a null indicates the
device of the most recent entry used
as a non-directory device.

3-9

I
A null specification is indicated in the following three

contexts:
1.

A comma as the first character on a line, for example:
*,LPT:+-SRC

1st output file = null (means no file)
2nd output file = LPT:
1st (only) input file = DSK:SRC

A comma following a comma or back arrow, for example:
*PTR:,,DTAl:X

1st input file
2nd input file
3rd input file

PTR:
null (means PTR:)
DTAl:X

A carriage RETURN following a comma, for example:
*A+-TTY: I

1st output file = DSK:A
1st input file
TTY:
2nd input file= null (means TTY:)

Examples of command strings specifying I/O:

*.DSK:BINARY, LPT: +-SOURCE The file named SOURCE is the
input file on the DSK: The
two output files' are one named
BINARY on DSK and another on
the line printer (device LPT:)

*INPUTl, INPUT2, INPUT3, PTR:,
This string of input files and
no output files might be typed
to one of the loaders (which
do not require output file
specification).
Three files
are taken from device DSK
then two are taken from the
paper tape reader.
*DTA2:A,B+-XYZ:C,D

The left arrow character
version of PS/B.

The input files C and D are
taken from device XYZ.
The
output files are a file on
DECtape 2 named A and a file
on device DSK named B.

(~)

is used in this preliminary

In later versions the left angle bracket (<)

will be interchangable with the left arrow.

3-10

3.3.5

option syntax.

The Command Decoder accepts options typed on the same line as
the previously described I/O specifications.

Options may be octal

numbers or single alphanumeric option characters.

Option charac-

ters are set off from I/O specification by the slash I for single
characters and by parentheses ( ) for a string of single characters.

The equal

off octal numbers.

sign= and square brackets [ ] are used to set
The following describes these constructions

in detail, although the actual meanings ascribed to the options
will be described later in connection with each system program.
1.

The / construction consists of a slash followerl by a single
option character. This construction may occur anywhere in
the input line, even in the middle of a name. For example,
*TTY:/L+DSK:A/BC is equivalent to TTY:+DSK:AC/L/B
and the options specified are "L" and "B".

The ( ) construction consists of an open parenthesis, followed by any number of option characters, followed by a
close parenthesis. This construction is also valid anywhere in the input line. For example,
*A:B+C:/Y(AXQ)Z(P) is equivalent to A:B+C:Z/X/A/Q/P/Y
and the options specified are "X", "A", "Q", "P" and "Y".

The = cons·truction consists of an equal sign followed by
an octal number up to seven digits long. This can only
occur once in a line and must be followed by a separator
character (comma, backarrow, or end-of-line character) or
by other options and a separator character. For example,
*FILE1=1002(123),FILE2,

•

(the 123 represents three separate options= "l", "2",
and "3") .
4.

The [ ] construction can only occur immediately after an
output file name and consists of an open bracket, an
octal number between 1 and 377 8 , and a close bracket.
The open bracket is produced by holding down.the SHIFT
key while typing K (i.e., SHIFT/K). The close bracket
is produced by holding down the SHIFT key while typing
M (i.e., SHIFT/M). This construction is used to provide
an upper limit on the number of records (256 words) of
the output file so the system can optimize file storage.

llflt,

3-11

., (_&@.. . "4

.i@..4!4.L.

-- ..:..-~-

... ,A -

I
'

This option need not be included in a command string
although some users may find it to their advantage. For
example,

*BINARY [12),LISTING[200]+SOURCE/8,
The output files, above, are a file.named BINARY on device DSK:
(maximum length 12 8 blocks) and a file named LISTIN (only six characters are significant) on device DSK:

(maximum length 200 8 blocks).

The input file is SOURCE on device DSK: and the option specified is

"8".

3.3.6

Error ~essages

If the command string to the Command Decoder has an error,
one of the following messages may be printed on the Teletype:
Message·

Meaning

ILLEGAL SYNTAX

This command line does not make
sense.

TOO MANY FILES

More than three output files or
nine input files were specified.

device DOES NOT EXIST

The device specified could not
be found in the system tables.

filename NOT FOUND

The specified filename does not
exist on the specified device.

3-12

CHAPTER 4
LIBRARY OF SYSTEM PROGRAMS

The R command to the Keyboard Monitor may be used to call the
system programs using the following names as arguments.

{Each system

program is also briefly described and mutual interaction outlined) :
Name

System Program Description

PIP

Peripheral Interchange Program - PIP is used to
transfer files from one device to any other, to
concatenate files, to list directories, and to pack
files so that free space becomes a contiguous block.

EDIT

Symbolic Editor - the PS/8 Editor is a modified
version of the Disk Monitor System Editor with
four added commands.
It is used to create, add
to, or delete from source files before assembling
or compiling (see Chapter 6).

ABSLDR

Absolute Binary Loader - used to load object
programs in absolute binary format (assembled by
BK PAL-D) into core memory for execution.

PALS

BK PAL-D Assembler - accepts source programs
written in the BK PAL-D Assembly language and
outputs object programs in absolute binary format.
Options to the Command Decoder used by PAL may
specify calling the Absolute Binary Loader upon
completion of the assembly - an example of program
chaining.
(For a complete description of PAL, see
Programming Languages, Chapter 14).

CONVRT

DECtape conversion program - as input it accepts
ASCII files on DECtapes compatible with the Disk
Monitor System.
It outputs the PS/8 version of
the ASCII files onto DECtapes compatible with
PS/8.

(The following three system programs work together as the
BK FORTRAN system.

The first two also work separately as stand-

alone programs.)
LOADER

Linking Loader - loads the output of the BK SABR
Assembler and BK FORTRAN Compiler, automatically
stepping throuqh the available fields for each
input file until it finds one with enough space
to load the file.
The loader features an automatic search of the system library, loading only

4-1

IAP

those programs which are referenced.
(For a
complete description, see Programming Languages,
Chapters 14 and 15).
SABR

8K SABR Assembler - may be used as a stand-alone
assembler to produce relocatable binary code for
the Linking Loader or to serve as pass 2 of an
8K FORTRAN compilation.
(For a complete
description, see Programming Languages, Chapter
14.)

FORT

8K FORTRAN - used to compile the user's FORTRAN
program and automatically call K SABR to assemble
it.
Options to the Command Decoder exist which
will cause the Linking Loader to load the assembled
program and any referenced programs of the 8K
FORTRAN Library.
This operation is another
example of program chaining.
(For a complete
description, see Programming Languages, Chapter 14.)
On the line

fol~owing

the R command calling the system program,

a command string is typed by which the Command Decoder indicates
input/output specifications to the particular system program.

The

number and type of input and output files are dependent upon the
system program which receives them.

Much repetition of file names,

extensions, and device names has been eliminated by the existence
of default options.

For example, system programs append default

extensions to input names.

If such a file is not found, a search

is made for a file without an extension.
Command strings to the various system programs and additional
features of the PS/8 versions of these programs are discussed in
the following sections.

4.1

PERIPHERAL INTERCHANGE PROGRAM
After the keyboard command R PIP to call the program, the next

•

line to the Command Decoder should specify one output file and
zero to nine input files.

The input files are transferred to the

output file under control of the option switches:

4-2

Effect

Option

Transfer in ASCII mode (default mode).

Transfer in Binary Mode (used for files in absolute
and relocatable binary format) •

Transfer in Image mode (the /I option is used for
transferring core-image files and other files which
do not fall into the ASCII or binary categories.
For example, the FORTRAN library file SYS: LIB8.RL
must be copied using the /I option.
NOTE:

Merging of core-image files is meaningless.

Zero the directory of the output device before
beginning the transfer. Before you can use a
DECtape with the PS/8 system, you must create a
zero directory on it using the /Z option with
no input files specified.

Delete the old copy of the output file(s) before
beginning the transfer.
If this option were not
specified, the old copy (copies) would not be deleted
until the transfer was completed.

Eliminate trailing blanks (ASCII mode only) •

Convert tabs to spaces (ASCII mode only) •

Save n extra words per file entry in the directory to contain descriptive information about
the file (with /Z only).
If no input files are specified, no data transfer occurs.

For example, the option /Z may be used.to zero a directory and /D
to delete a file if no input files are specified.
NOTE:

It is recommended that you do not use the "=n" option in

preliminary versions of this software.
Examples of command strings:
Example 1

.R PIP
*DTAl:FILEl+DTA2:FILE

4-3

-A .. ¥. ML ., _ . .4

_.¢44#({.Pl .. 2$,A# @.$ .· . . . . £,M

& _

transfers the file FILE on DTA2 to DTAl in ASCII
mode and calls it FILEl.
Example 2

*BIN.BN,C,SV/D+A.BN,B.BN/B

deletes the file BIN.BN on device DSK: and combines
files A.BN and B.BN (both from DSK:) in binary mode
to form a new BIN.BN. Also deletes file C.SV from
DSK: The old copy of DSK:BIN.BN would have been deleted after completion of the transfer if /D had not
been specified.
Example 3

*DTAl:/Z+

zeros the directory of DTAl:
Example 4

*PTP:+cDR:/C

moves information from the device CDR: to the device
PTP: in ASCII, deleting trailing blanks.
Example 5

*DTA3:PAL8.SV+PAL8.SV/I

transfers the file PAL8.SV from DSK: to DTA3: in
Image mode.
Example 6

*DTA4:LIB8.RL +SYS:LIB.40.RL/I

transfers the 8K FORTRAN Library to DECtape 4
from the system device. Loading the Library can
be speeded up (by reducing DECtape motion) if the
Library is transferred to a DECtape other than the
system DECtape(on a DECtape system) before loading.
PIP also performs other operations for the options given below~
Option

Effect

Lists the directories of the input devices onto the
output file starting at the file specified. Note
that in this case the input file itself is not
transferred, only the directory.

Lists directories in short form (file names only).

Lists directories in Extended form (the lengths
for the free files are also listed.

Moves the contents of the input device(s) specified
onto the output device, eliminating all free
files. This combines all of the f~ee space
into one contiguous block instead pf many
fragmented blocks, ahd packs all the programs
one after another.
4-4

More examples of command strings follow:
.R PIP
*LPT:/L+DSK:,DTA2:BLAH

Example 7

transfers the listing of the entire directory of
device DSK: and the directory of device DTA2:
starting with the file BLAH onto the device LPT:
*DIRECT+DTA7 :/E

Example 8

transfers an extended listing of the directory of
device DTA7: onto the file DIRECT of device DSK:.
A PIP directory listing might appear thus:

.a;

ABSLDR.SV
PIP
.SV
LIB4,0 . RL
BLAH

<EMPTY)

4
1.0
41
17

These octal numbers represent
the length of the files in records and are listed for the
"L" and "E" options only.

1
511

Free files like these are only
listed if the "E" option is
specified.

6J-- ..

517 FREE BLOCKS

C'
,

4.2

SYMBOLIC EDITOrt

The Editor is called by the command R EDIT.

Then the line

to the Command Decoder should specify one output file and .0 to 9
input files.
If the input is null, then the R Editor command is illegal.

Instead, the A command is used for input from the Tele-

type.

The command string may include the following options:

Option

Effect

Upon closure of the output file by the E or Q
Editor conunands, return control to the Command
Decoder and leave the Editor in core. Without
the /A option, control returns to the Keyboard
Monitor after an E or Q command.

Convert two or more spaces to a tab.

Delete the old copy of the output file (if one
exists) before opening the edit output file.
4-5

For example,
*DTA2:FILE+DTAl:BLECH/D

This will delete FILE on DTA2 before opening
the new file FILE.

The Editor is a modified version of Disk Monitor System
Editor described in Chapter 6.

The following commands and error

messages are in addition to those described therein.
Command

Meaning

Close the presently open output file first copying
the editor buffer and the rest of the input file
into the output file.

Delete the next (n-1) pages and read the nth page
into the text buffer. For example, SY will kill
(delete) the next four pages, then read and leave
in the fifth page.

End the file with the last page already processed
by the P command.
Compare this with the E command,
which ends the file by passing the rest of the
file to the output device.

Print the decimal number of unused core locations
which remain in the text buffer (maximum capacity
approximately 5000 source characters). To estimate the relationship between locations and characters, the value 1.7 characters per location may be
used.

CTRL/R

(an alternative way to merge files)
return control to the Command Decoder to receive more input
and output file specifications and options while
retaining the present contents of the text buffer.
A carriage return sends control back to the Editor.
Compare this with CTRL/C followed by the START
command, which loses the contents of the buffer.

If control returns to the Command Decoder during output operations, the specified output device lacked enough space for the
output.

You may specify a different output device, and complete

the output operation upon typing the carriage return which sends
control back to the Editor.

Otherwise, if an error occurs during

data transfer, the Editor prints the message:
4-6

? n 1'C

where n refers to

an error code in the following table.

Meaning

failed in reading the device

fatal write-error

output file close-error

output-file open-error

4.3

ABSOLUTE BINARY LOADER
Call this Loader with the keyboard command R ABSLDR.

Then type

a number of lines to the Command Decoder, each containing input files
only (no output files) and options.

A line ending in a carriage

return indicates that there is more input to come.

The last line

of input files is indicated by the /G option or ended with an
ALTMODE character.

If extensions to the input file names are not

specified, the default extension .BN is added.

The input files are

loaded according to the options specified and a core control block
is set up.
Option

Effect

Load all the binary programs in the specified input
files (instead of loading only the first program in
each file) .

Set bit 10 of the Job Status Word (this implies that
the program does not care if locations 0-1777 are
destroyed when the Keyboard Monitor is called).

Set bit 11 of the Job Status Word (this implies that
the program does not care if locations 10000-11777
are destroyed when the Keyboard Monitor.is called).

Treat the input file (only one permitted) on this
line as a core image to be loaded and overlaid with
the input of subsequent lines~ This option may be
used only in the first command string (not yet implemented) .

Start program when loading is complete. The start
address may be specified using the remaining options.
Otherwise, the starting address will be location 200.
If /G is not specified, control returns to the Keyboard Monitor so that the core loaded may be saved
or started.

4-7

(where n is an integer).
Force loading of all files
specified on this line into field n.

Set the starting address to n, (where n is an octal
number up to five digits octal). For example,

*BINl,DTAl:BIN2.MY~(8G)=l3~~~

Load the file BINl.BN (or BINl) from DSK: and BIN2.MY
from DTAl:, setting bit 10 of the Job Status Word and
start at location 13~~~.
Examples of Command Strings:
Example 1
.R ABSLDR
*DTA3:FOCAL /S
*ODT/l/G=l7~~~

Assuming that you had placed the binary of DEC's FOCAL
program on DTA3: in the file FOCAL.EN (or FOCAL) and you had a
binary version of the DECUS program XOD in the file ODT.BN (or
ODT) on device DSK: this sequence would load all the programs
in the FOCAL file into core (FOCAL is actually two or three binary programs, hence the /S is necessary) then load XOD into

field one and start the combined program at location 7000 in
field 1.
Example 2
.R ABSLDR
*DTA1:8KFORT,PTR:$t
.SAVE SYS FORT

(the $ stands for ALTMODE)

This would load the file 8KFORT.BN (or BK FORT) from device DTAl: and also a tape from device PTR:.
asks if the tape is in the reader.

The up arrow t

In order to initiate the

reading of the tape, type any character on the Keyboard in
response to the up-arrow.

The combined programs are left in

core and control returns to the Keyboard Monitor.

The resulting

program has a starting address of 00200 and may be saved (as in
this example) or started using the START command.

When putting

a binary tape into the reader for input to the ABSLDR, it is not
necessary to have leader ( 20 0 8 ) code under the read .head.

The

tape may be positioned so that the blank tape at the beginning
is under the read head.

4-8

4.4

8K PAL/D A.:35~:-lliL.:;i\

The keyboard command to call SK PAL-D is R PALS.

The line

to the Command Decoder consists of an optional binary output
file follrn·.1 ed by an optional listing output file,
files,

and various options.

A null output file indicates no

output of that type is to be generated.
~,TTY:

0 to 9 input

For example,

+OSK: ISIT

indicates no binary is to be generated, only a listing on the
Teletype.
If extensions to the file name are omitted, the following
extensions are assigned:
Extension

File Type

input

.PA

(default extension

binary output

.BN

(assumed extension)

listing output

.LS

(assumed extension)

The following options may be included anywhere in the
command string.
Option

Effect

Omit the symbol table normally generated with the
listing (applicable only if a listing file is
specified).

Generate the symbol table but not the listing (also
applicable only if a listing file is specified).

Call the Absolute Loader at the end of assembly and
load the binary file (only applicable if a binary
file is specified).

Equivalent to /L/G - i.e., call the Absolute Loader,
load and go.

Generate an ODT-compatible symbol table.

(Options
to the
Binary
Loader)

When the /L or /G option is specified, any options
to the Binary Loader may be included in the cor.u:iand
string for PALS.
4-9

Examples of Command Strings:
Example 1
.R PALS
•PTP:,LPT:+SOURCE

assembles SOURCE.PA (or SOURCE), putting the binary output
on the paper tape punch and the listing and symbol table
(in that order) on the line printer.
Example 2
*, BLAH+ECCH/S
assembles ECCH.PA (or ECCH}, putting the listing only into
file BLAH.LS on device DSK:
No binary output is generated.
Example 3
*BIN+INPUT.XY/G=6~~

assembles INPUT.XY putting the binary output into BIN.BN,
and then calls the Binary Loader, which loads BIN.BN and
starts it at 00600.
("=600" is an option to the Loader
specifying the start address.)

4.5

CONVERSION PiiOGRAM

Call the conversion program with the command R CONVRT.
The line to the Command Decoder consists of an optional output
file, one input file, and up to two options.
are handled by CONVRT.

Only ASCII files

The output file, if specified, will be an

ASCII file compatible with PS/8.

If an output file is not specified,

the /L option alone must be used.

The input device must be a DECtape

compatible with the Disk Monitor System and be specified by the
form DTAn: where n is an integer in the range 0 to 7 (0 is DECtape unit 8).

If an error is made, a message explaining the

fault is printed on the Teletype.

After the completion of the

task(s) or the occurrence of an error, CONVRT will recall the
Command Decoder, accept another command string, and perform the
specified task.
The following are the two available options:
4-10

Effect

Option

Look up the input file using the directory and storage
map already in core.
If there is no directory in core
when this option is given, the message INPUT FILE NOT
FOUND will be printed.
If this option is not specified,
the directory of the input device will be read into core
for each conversion.

Generate a directory listing of the input ASCII files
of the device on the Teletype.
Examples of Command Strings:
Example 1
*SYS:YES~DTAS:YES

converts the ASCII file YES on DECtape 5 to a PS/8-compatible
file YES on the systems device.
Example 2
*DTA2: /L
prints on the Teletype a directory listing of the ASCII files
on DECtape 2, then recalls the Command Decoder.
Example 3
*SYS:GOPS.AS~DTA3:GODM(DL)

Generates a directory listing of the ASCII files of DTA3 on
the Teletype, then converts the Disk Monitor file GODM on
DECtape 3 to a PS/8 file GOPS.AS on the system device using
the directory already in core.

4.6

LINKING LOAD~n

This Loader is called by the command R LOADER.

The next

line to the Command Decoder consists of 0 to 1 output files, 0
to 9 input files and various options.
per file is permitted.
is .RL.

Only one binary program

The default extension for input files

A carriage return initiates the specified tasks.

tasks may be specified on the following lines.

Other

The last line is

ended by an ALT-MODE character or contains a /G (start program
or go) option.
4-11

The options are as follows:
Option

Effect

Start the program after processing the rest of the
conunand string. Execution starts at the symbol
MAIN unless othenvise overridden by an option.

Output a map of loaded programs onto the output
file specified.
If no output file is specified,
the map is put onto the Teletype. The default
extension for the map output file is .MP. The map
is printed after the rest of the line is processed.

Like /M but only outputs undefined symbols.

Like /M but only outputs counts of free pages in
each field.

(where n is an integer in the range 0 to 7 inclusive). Search through the available fields starting
at field n for space large enough to load each input file.
Only one binary program may be in each
input file.
If not specified, the Loader starts
looking at field 0.

Restart loading process (forget all previously
loaded programs).

(where n is an octal number up to 5 digits lona)
Specifies the starting address of the program if
it is other than the entry point MA.IN.

0:
.

Load the specified file (only one file permitted
on the line) as a library, i.e., the loader expects a directory at the front.
The Loader automatically searches the SK FORTRAN Library and

loads those programs which are referenced after processing the
last command string (ending with ALT-MODE or containing /G).

a loading map is requested on the last line, it is generated
after the Library is searched.
NOTE
The SK FORTRAN Library is in the file LIBS.RL
on the device SYS:
Despite its extension RL,
it is not as a whole relocatable since it begins with a directory.
Instead each of its
elements is relocatable.
The Library as a
whole can be specified as input to the Linking
Loader only by using the /L {Library) option.
For example,
*SYS:LIB8.RL/L
4-12

tells the Linking Loader to load the Library
as a Library, i.e., load only the necessary
elements of the Library into core.
Examples of command strings to the Loader:
*PROG,DTA2:SUBR1,SUBR2/G
loads DSK:PROG.RL,DTA2:SUB1.RL,

DTA:SUB2.RL loads the Library

from SYS:LIB8.RL and starts the program at the entry point "MAIN".
The same process could also have been done as follows:
*PROG

Load DSK:PROG.RL

*TTY:+-/U

Get a list of undefined symbols on
the Teletype

(a list of undefined symbols
goes here)

*DTA2:SUBR1,SUBR2

Load DTA2:SUBR1.RL,SUBR2.RL

*LPT:/M+-$

Put a loading map on the Line Printer
load the Library from SYS:LIB8.RL and
exit.
($ stands for ALTMODE)

.SAVE DTA2 FORTPG

Save the core image on DTA2 as FORTPG.SV

.START

Start the core image at its starting
address (entry point "MAIN")

The Linking Loader gives error messages in the form "ERROR
nnnn".

The meaning of the different values of nnnn are:

Error Code

Explanation

0001

Symbol table overflow (more than 64 subprogram
names).

0002

Program will not fit.

0003

Program with largest common storage was not
loaded first

0004

Checksum error in input tape .

4-13

... #UL.AA .4. 4

.. .$

.. ,14.

. __ ¥£3

- .... Wl#..--4& .

£..."'

?l!IJ~j!g

__ _(. __

--X--,.,-o

.. --. .. -....LL42$ .... ,.,,... L--_, ___ m.,..,@"·

Error Code

Explanation

0005

Illegal relocation code,

0006

An output error has occurred while outputting
a storage map

0007

An input error has occurred while reading a
binary file.

0010

No starting address has been specified and there
is no entry point named "MAIN".

greater than
0010

4.7

An internal error has occurred. Please send the
typeout and history to Digital Equipment Corporation.

8K SABB ASSEMBLER

Call this Assembler using the R SABR command.

The line to

the Command Decoder consists of 0 to 3 output files: the first
for binary, the second for the listing, and the third for Linking
Loader output for the /M, /U, or /P options when chaining to the
Linking Loader occurs.
and various options.

Next on the line are 1 to 9 input files
A null binary file is assumed to be SYS:

FORTRL.TM if the /L or /G option is specified.

Otherwise, a null

binary output file indicates no binary output is to be generated.
Similarly, null listing file indicates no listing is to be generated.
The default extensions for SABR are as follows:
File Type

Extensicn

input

.SB

(default extension)

binary output

.BN

(assumed extension)

listing output

.LS

(assumed extension)

The following options may be included in the command string:
4-14

Option

Effect

Omit the symbol table (applicable only if a listing
file is specified).

Output the symbol table but not the rest of the listing (applicable only if a listing file is specified).

Call the Linking Loader at the end of the assembly
and load the specified binary file.
If a binary output file is not specified, then the
temporary file FORTRL.TM is loaded into core and
deleted from the file device.

Equivalent to /L/G, that is, call the Linking Loader,
load and go.
If a binary output file is not specified, then FORTRL.TM is loaded and deleted.
If a
starting address is not specified (using the options
to the Linking Loader) , control is sent to the location labeled "MAIN".

Indicates that the input file is an SK FORTRAN
output file.

(Options to When the /L or /G option is specified, any options to the Linking Loader may be included in
the Linking Loader the command string for SABR except the /L
(Library) option of the Linking Loader.
Examples of command strings:
Example 1
.R SABR
*FORTRN.TM/F/G
DSK:FORTRN.TM is assembled as a FORTRAN output file and
the relocatable binary is loaded and started at MAIN.
Example 2
*SYS:TEERL,TTY:+TEE /S
The input file TEE.SB (or TEE) on DSK: is assembled.
The
relocatable binary goes to the output file TEERL.RL on
SYS:, the listing without a symbol table goes to the Teleprinter.
The following error messages have been added to the PS/8
version of SABR:

4-15

Message

Meaning

The definition of the S error message has been
extended to include any system error, such as
overrunning an output file.

The D error signifies that a Device Handler
returned a fatal error.

The U message is printed if no symbol table is
being produced and there is at least one undefined symbol in the program.

The L error indicates that the /L or /G options
were requested but LOADER.SV does not exist on
device SYS:
See Chapter 14, Progranuning Languages, for other messages.

4.8

8K i?OrtTrtAN COHPIL:C...~

The line to the Command Decoder consists of O to 3 output
files

the first for binary, the second for the listincr and the

third for Linking Loader output for the /~1, /U, or /P options
when chaining to the Linking Loader occurs.
to 9 input files and various options.

Next on the line are 1

The default extension for FORTRAN input file is .FT. The Compiler produces an output file named FORTRN.TM on the system
device, for input to the BK SABR Assembler.
matically calls SABR after compiling.

The Compiler auto-

The FORTRN.TM file is

usually deleted by SABR unless the following option is specified.
/K

Keep the file FORTRN.TM as a permanent file.
In addition to this option, any options to SABR may

be included in the command string to the Compiler.

SABR out-

puts a file in relocatable binary format into the specified
binary output file.

If a binary output file is not specified

and the/Lor /G option (to load binary) is, then the binary
output goes to a file FORTRL.TM on device SYS:

Otherwise, a

null binary output file indicates no binary output is to be
generated.

A SABR listing is not generated if a listing output

is not specified.

4-16

C"
'

FORTRAN will only assemble one main program or subroutine
per call.

A job with multiple programs in it must be run by

compiling each routine separately and combining them with the
Linking Loader.
Examples of command strings:
Example 1
.R FORT
*DTAl:TEST /G
The input file TEST.FT (or TEST) on DTAl: is compiled,
output into FORTRN.TM on device SYS:, then SABR is
called. SABR uses FORTRN.TM as input and outputs the
assembled file into FORTRL.TM, deleting the old FORTRN.TM.
The Linking Loader then loads FORTRL.TM, deletes FORTRL.TM
upon loading, and sends control to the location labeled
MAIN (the beginning of the main program).
Example 2
*,,LPT:~BLAH/L/M

compiles and assembles file DSK:BLAH.FT (or BLAH),
putting binary in SYS:FORTRL.TM, calls the Linking
Loader, loads and deletes SYS:FORTRL.TM, puts a full
loading map on device LPT:. The Loader then asks for
another command string. If .the line had terminated with
an ALT-MODE, control would have returned to the Keyboard
Monitor after loading.

Example 3
*BINARY,LPT:/N+MATRIX.AB/K
The input file MATRIX.AB on DSK: is compiled and output
into SYS:FORTRN.TM. SABR is called and it assembles
SYS:FORTRN.TM, putting the relocatable binary output
into DSK:BINARY.RL and the symbol table only (see SABR
section for details) on device LPT:. The /K option
will cause SYS:FORTRN.TM to be kept as a permanent
file.
Example 4
*DTAS :SOURCE /L
In this line to FORTRAN, /L means load but do not go.
Example 5

*OO'A5:LIB40:/1./G

C.\

In this line to the Linking Loader, /L means load
file DTA4:LIB40 ait a !!;ibrary. /G means go (start
execution) •

4-17

, ¥¥4A#A .ALO ..·. .

. A4. P

. 44 ., Q

" ¥.. _$ -

•~

The following error messages have been added to the PS/8

version of FORTRAN (all error messages described in Chapter 15
of Programming Languages are also valid) :
Message

Explanation

I/O

A device handler has signalled a
fatal I/O error

NO ROOM FOR OUTPUT

The file FORTRN.TM cannot fit on
device SYS: .

SABR.SV NOT FOUND

Self-explanatory.
The compiler
will not run without SABR.

NO END STATEMENT

The input to the compiler has been
exhausted.

COMPILER MALFUNCTION The meaning of this message has
been extended to cover various
"impossible" monitor errors.

4-18

,f
l

CrlAPTcn 5
INTERFACING WITH Trl~ USErt SEHVICE nOUTIN.::. (U.::i.ri.)

The heart of the PS/8 system is the program called the
User Service Routine (USR) .

USR handles all directory opera-

tions for the PS/8 system, such as calling device handlers
into core, creating files,searching file directories,decoding
command strings fromthe Teletype and chaining to SAVEd programs.
An important aspect of PS/8 is that the user program may call

upon USR for these services as well, using standard subroutine
calls.
USR in turn calls upon the device handlers, that is, pagerelocatable subroutines which accept a standard calling sequence
and perform input and/or output operations on a device.

Any de-

vice can be interfaced to the PS/8 syster:t or a user program by
means of a device handler.

Thus, user and system program can be

written without concern for specific input/output devices, since
the details of device operation are coded in the device handlers.
In order to write a program which interfaces ,,·i th USR, the
standard calling sequences for the device handlers and the CSR
subroutines must be used.

5.1

'l'HE DEVIC.t:: AND FILNAA ?Si.UDO-OPS

In specifying arguments to the USR, it is sometimes necessary to indicate device names or file names.

It is for this

purpose that two pseudo-ops, named DEVICE and FILNAM, have been
added to the instruction repertoire of the PAL-8 Assembler.

Both

of these pseudo-ops, when used, must be followed by a single blank
or tab character and a name.

For the DEVICE pseudo-op, the name

should be a legal PS/8 device name; two words are generated by
the pseudo-op.

The FILNAM pseudo-op takes a legal PS/8 file

name; four words are generated.

The name should be followed by

one of the characters blank, tab, or carriage-return.

For

example,
DEVICE
FILNAM

5.2

DTA7
PIP.SV

/NAME OF SYSTEM PROGRAM "PIP"

CALLS TO TH~ USrl

Location 7700 in field 1 is the entry point to USR.

Upon

execution of a JMS 7700 with the instruction field= 10, user
locations 10000-11777 are written out onto the system device (if
necessary) and USR is read into these locations.

USR cannot be

called from locations 10000-11777 because these locations will
not be in core while USR is fetching arguments.

USR fetches

the request number fromthe location following the JMS 7700.

The monitor performs the requested task, fetching and
storing additional arguments as necessary.
otherwise directed) reads the

dQ~ped

It then (unless

user locations back and

resumes execution of the user program.

s.2.1

Generalized Calling Sequence

The generalized calling sequence for requests to USR is as
follows.
TAD argument

(Where argument is data to be passed to
USR - applicable in only some cases.)

CDF n

{Where n is the number of the current
instruction field.)

CIF 10
5-2

(Where n is 200 if the USR has been
locked in core and not yet dismissed
and n=7700 othe:cwise. See the description of the USR request LOCK USR IN CORE.
This word sends control to the USR.)

request number

(Where the request number, an integer
from 1 to 17 8 indicates the function to
be performed. )

argument

(The next few words contain arguments
whose number and type depend on the function to be perrormed

JMS I

argument
error return

(If an error return is possible for
this request, then this location is an
error return.
Otherwise, it is the
normal return.)

normal return

(If an error return is possible for
this request, this location is the
normal (non-error) return.)

Request Numbers

5.2.2

The request numbers and their USR functions are sunmarized
below.
Request Number
1

Function
FETCH HANDLERS:
Fetch handlers into core if not already in
core and pass entry point address to the
calling program.

LOOKUP PERMANENT FILE:
Pass the starting block number and the length
of the specified permanent file on the specifield device to the calling program.

ENTER OUTPUT FILE:
Create a tentative file on a specified
device for output.

l/l"ft.

CLOSE OUTPUT FILE:
The currently open tentative output file is
closed to further output and becomes a permanent file.
Any previous permanent file of
the same name on the device is deleted and
unused blocks become free files.
5-3

I
~I

Request Number
5

Function
COMMAND DECODE:
The Command Decoder is called and passes I/O
specifications and options typed on the Teletype to the calling program.

CHAIN TO PROGRAM:
Load the specified program from the system
device and start it.

SIGNAL USER ERROR:
Print on the Teletype the error message indicated by the calling program.

LOCK USR IN CORE:
USR is loaded into core and is not overlaid
again until the USR DIS:nss command is given.

USR DISMISS FROM CORE:
USR is overlaid with the user's core (unless
the Job Status Word specifies otherwise).

ASCERTAIN IF HANDLER IN CORE:
Ascertains whether a given device exists,
if so whether its handler is in core, and
if so what the entry point is.
If the
handler is not in core, it is not loaded
by this request.

RESET SYSTEM TABLES:
The USR tables are set to indicate that all
device handlers (except the system device
handler and its co-resident handlers) are
not in core.
This request may also be used
to delete all active tentative files.

14-17

These request numbers are reserved for
future expansion.

The specific calling sequence for each USR request and the
details of its function are next discussed.

It is assumed that

the instruction field and data field are already set up for the
call (see "Generalized Calling Sequence").

5-4

5.2.3

Fetch Handler

This request may be made by two different calling sequences:
1.

The number of the I/O device to be used is passed to
USR in the accumulator (often abbreviated AC) .

The device number is obtained by searching the User
Device Name table and, if no match is found, the
System Device Name table. The number of the device
is the index number of its match in the first table
in which it is found.

The first calling sequence:
TAD device number
CALL, JMS I

(Where the number becomes the loworder four bits of the AC.)
(Where n=200 if USR is locked in
core and n=7700 otherwise.)
(Request number)

ENTRY, loading address (The loading address of the handler
has the following format:
Bit No.

Contents

0-4

page number in which to
load handler (i.e., 1
here mEans start at location 200)

5-10

ignored

0 if space available for
handler is one page, 1
if space available for
handler is two pages.

On return, the USR overlays this
location with the address of the
entry point of the handler.)
error return

(If the device name is 0, if the
device does not exist, or if the
handler will not fit in the allotted
space, control returns here.)

normal return

(At this point the handler and any
co-resident handler~which share the
same page, are in core in field 0,
and any handlers which were formerly
resident in the same page (or pair
of pages for a two-page handler) are
marked as not being in core.)
5-5

I
~

'.I

'!'he second calling sequence:
(Not necessary if AC already cleared)

CLA
CALL, JMS I

(Where n=200 if the USR is locked
in core and n=7700 if otherwise.)
(Request Number)

DEVICE device name
(Where either the user or perma(takes two locations) nent device name is given as the
argument of the DEVICE pseudo-op.
The second word (DEV+l) will be
overlaid by the USR with the device number for future reference
by the calling program.)

DEV,

loading address

(of the device handler. Operation is the same as for the
first calling sequence.)

error return

(If the device name is not found
in either table, if the device
does not exist, if the device name
is 0, or if the handler will not
fit in the allotted space, control returns here.)

normal return

(The same as for the first sequence.)

0
~ookup

Permanent File

(The device handler for the file's device must be in core
when this request is made.)
TAD

device number

CALL, JMS I

(The device number is in the
low-order bits of the AC.
If
bits 8-11 of the AC are zero,.
a system error is signalled
and control returns to the
Keyboard Monitor.
(Where n=200 if the USR is
locked in core and n=7700
otherwise.)
(Request number)
5-6

0
II.
I

C'
'

5.2.5

pointer to file name

(If the device is a directory
device, the file named (by
the FILNAM pseudo-op or equivalent) in the specified location is searched for among the
permanent files and if found
its starting block number overlays this location. For a nondirectory device, this location
is cleared to zero.

reserved for file length

(For a directory device this
location is overlaid with the file
length. For a non-directory device this location is cleared.)

error return

(If the file is not found for a
directory device.)

normal return

(The starting block number and
file length are now available to
a calling program for a directory
device. This return is also taken
for a non-directory device.)

Enter Output File

(The device handler for the file's device must be in core
when this request is made.)
TAD

JMS I

device number and length

3
pointer to file name

,.,..,.·

"''

(The device number is in bits
8-11 of the AC.
For a directory device the length of the
desired file is indicated in
bits 0-7.
If the length is
zero, the largest free file on
the device is used.
If the
length is non-zero, the smallest free file at least as
large as the length is used.)
(Where n=200 if the USR is
locked in core and n=7700
otherwise.)
(.:i.,"quest '11L.'llber)

(For a directory device this
location is overlaid with
starting block number of the
specified file.
For a nondirectory device this location
is cleared.)
"i-7

I
~, ·I.,·;

·l.
I

reserved .for file length

(For a directory device this
location is overlaid with the
length of the created tentative
file.
For a non-directory device this location is cleared.}

error return

(If the device is read-only,
if an active tentative file
already exists on the device,
or if there is not enough room
for the file on the device.}

normal return

(At this point for a directory
device an active tentative file
is open on the device and the
file's starting block number and
actual length is available to
the calling program for reference.
Control is sent here for a nondirectory device as well.)

:.I

r-1

~:,

5.2.6

Close Ou!£ut File

0
(The device handler for the file's device must be in core
when this request is made.)
TAD

device number

JMS I

(Where n=200 if the USR is locked
in core and n=7700 otherwise.)
(Request Number}

pointer to the file
name to be deleted

(For a directory device the
file pointed to here is deleted)

length of new permanent file

(This location should be loaded
with the number of records which
were actually used for the file.
If the file has exceeded the space
allotted in the ENTER OUTPUT FILE
operation an error message is
printed and control returns to
the Keyboard Monitor.)

error return

(If no active tentative file or
permanent file of the specified
name exists on the device, then
control returns here.)
5-8

I
1·"•

(At this point if the device is
a directory device, the new permanent file has replaced the old
permanent file (if one existed)
and the directory has been updated to reflect this change.)

normal return

NOTE
The normal way to use the ENTER and CLOSE operations
is to point to the same file name in both calling
sequences. This results in a very protective mode
of operation - i.e., if a file A.B exists on a device and you ENTER a file A.B, the old file is not
deleted.
If your program bombs out or is interrupted
before it can execute the CLOSE operation, the old
file A.B is still intact and the new one will disappear in time.
If in the arguments of the CLOSE operation you specify the file name A.B, then the old file
will be deleted at this point and the new one will
take its place. When using the ENTER and CLOSE operations in any other manner you must exercise extreme
caution, because it is possible to wind up with two
permanent files in the same directory with the same
name, a situation for which the Monitor operations
are not defined.

Command Decode

JMS I

(Where n=200 if the USR is locked
in core and n=7700 otherwise.)

(Request number - interpret command string typed on the Teletype.)

(If the user of the Teletype does
not specify an extension for an
input file the default extension
is added to the filename.
If the
file is not found, a search for
a file without an extension to
the filename is made.)

default extension

return
Example
A program calls the Command Decoder and specifies .XY
as the default extension to be used for filenames.
types:
BLAH A.BC,DTAl:HELLO,GOODBYE
5-9

AP...

AA¥

The user

The input files that the system program sees are:
1.

DSK:

DTAl:HELLO.XY if it exists; otherwise DTAl:HELLO
(if both do not exist an error is printed).

DTAl:GOODBY.XY if it exists; otherwise DTAl:GOODBY.

A.BC

The output file is DSK:BLAH.

(Default extensions do not

affect the output side of the list.)

5.2.8

JMS

Chain to Program

(Where n=200 if the USR is locked
in core and n=7700 otherwise.)
(Request Number)

starting block number

(This starting block number of
the program chained to can be
obtained by a Lookup PermanentFile cperation. The program on
the system device which begins
at the specified starting block
is loaded into core.
The program is started at an address
one greater than the starting
address specified in the core
control block.)

(no return)

5.2.9

JMS

3ignal User ~rror

error number

(Where n=200 if the USR is locked
in core and n=7700 otherwise.)
(Request Number)
(The message "USER ERROR n AT
LOCATION xxxxx" is printed on
the Teletype.
The address xxxxx
points into the offending calling
sequence, not to its beginning.
The integer n has the following
meanings:
5-10

5.2.10

JMS I

t:rror

User specified CLOSE operation with a length larger
than the lenqth qiven to himthis may indicate that the
user has destroyed some of
his permanent files.
2

I/O error reading or writing a directory block.

LOOKUP, ENTER, or CLOSE
attempted on device whose
device handler was not in
core.

Illegal operation specified
to Monitor, or device number~ specified in a LOOKUP,
ENTER, or CLOSE operation.

Lock USR in Core

(Call USR) .

(7700

(Request Number)

return
This command causes USR to come into core and stay there
unless it is dismissed by the Monitor dismiss command.

When

USR is in core, it should be called by a JMS to location 200
in field 1.

All other aspects of calling USR are the same.

If USR is called by a JMS I

(7700 while locked in core,

the core which it saved upon coming in may be destroyed.
While USR is in core, locations 20-37 in field 1 are available
for user scratch area.

5.2.11

JMS I

USR Dismiss from Core

(This command is a no-operation
if you mistakenly write JMS I
(7700.)
5-11

(0200

4 . .,._£

4-.l L+ .. MA.§ . . ::.'- .. ¥.¥ ..

-LJ?.4$?41?Y.f. A .. _.,,,,#-2¥.,_ ...J-,.,..

4-...,

_ (_

--.*-- ... L __

I
(Request Number.)

return:

This command also restores the user's core (unless the
Job Status Word specifies otherwise.)
dismissed, it is called by JMS I
I

After USR has been

(7700 again instead of JMS

(200.

Ascertain if Handler in Core

5.2.12

This request may be made by two different calling
sequences:

The number of the I/O device to be used is passed
to USR in the AC.

The device number is obtained by searching the User
Device·Name table and, if no match is found, the
System Device Name table.
(The number of the device
is the index number of its match in the first table
in which it is found.f

The first calling sequence:
TAD device number
CALL, JMS I

12
ENTRY, loading address

(Where the number is the loworder four-bi ts of the AC.)
(Where n=200 if the USR is
locked in core and n=7700
otherwise.)
(Request Number)
(The loading address of the
handler has the following
format:)
Bit No.

Contents

0-4

page number in which
to load handler (i.e.,
1 here means start at
location 200)

5-10

ignored

0 if space available
for handler is one page,
1 if space available for
handler is two pages.

5-12

I
0 I

On return, the USR overlays this
location with the address of
the entry point of the handler
if the handler is in core.
If
the handler exists out of core,
the USR clears this location.)
error return

(If the device name is 0, or if
the handler does not exist, control returns here.)

•

normal return

(If the device exists but is not
in core, control returns here.)

The second calling sequence:
CLA

(Not necessary if AC already cleared.)

CALL, JMS I

(Where n=200 if the USR is locked
in and n=7700 otherwise.)

(Request Number).

DEV, DEVICE

device name

(Where either the user or permaent device name is given as the
argument of the DEVICE pseudoop. The second word (DEV+l) will
be overlaid by the USR with the
device number, for future reference by the calling program.)

loading address

(of the device handler. Operation the same as for the first
calling sequence.)

error return

(If the device name is not found
in either table or if the handler
does not exist, control returns
here.)

normal return

(The same as for the first sequence.)

5.2.13

JMS I

Reset System Tables

(Where n=200 if the USR is locked
in core and na7700 otherwise.)

.M .. 4441_.. 4.$$

@.#..@ .. - _4Q

. 4 ..

. ; .

_ J¥Q4L 4

.#....__ .::zz ru.c: Q.

AJ .( .., .

zj.,

,,,¥WA¥ . .. 4 , 4-. i.@¥iiil1!9i94¥-J.A Q2

UQA -

I
The return, if all the active
tentative files are to be
deleted, otherwise ~.

(If this location is non-zero,
all files upon which output operations have not yet been terminated
will be destroyed.
In any case,
all handlers other than for the
system device, PTR, and PTP will
not longer be in core.)

The return if previous word ~.

(At this point, all the handlers
other than for the system device,
PTR, ~nd PTP are no longer in core,
though the active tentative files
are intact.)

5.3

DEVICB HANDLERS

Once a device handler is in core (loaded by USR call 1),
it may be called to perform read and/or write operations on
the device using the following standard calling sequence.

CDF

CIF

(Where n is the number of the
current instruction field.)

JMS I entry

(Where entry is a location containing the address of the entry
point of the device handler.)

function word

(Where the function word has
the following format)
Bit Number

buffer address

Contents

0 if a read operation
1 if a write operation

1-5

the number of pages
to be transferred

6-8

the field· in which
the buffer resides

9-11

device dependent function which need not
be programmed

(of the location at the beginning
of the buffer)
5-14

·'

starting block number

(Block number at which the operation will take place.
For a call
to the PTR, if this location is
0, the handler will print an uparrow and wait for a character
to be typed . )

error return

(Control returns here if an error
occurs. The accumulator will be
negative if the error is fatal,
(e.g., parity error, impossible
request) and positive if the
error is non-fatal (e.g., paper
tape reader ran out of tape.)

normal return

(Control returns here if the
transfer was successfully completed.)

For example, the calling sequence to the high-speed reader
device handler from instruction field 10 might be as follows:
CDF 10
CIF 0
JMS I
0200

INPUT

3000
30
HLT

/SET DATA FIELD TO 10
/INSTRUCTION FIELD NOW 0
/SEND CONTROL TO DEVICE HANDLER
/FUNCTION WORD INDICATES A READ
/OPERATION OF TWO PAGES (256 WORDS)
/INTO FIELD 0.
/BUFFER BEGINS AT LOCATION 3000
/OF FIELD 0.
/READING BEGINS AT RECORD 30 (MEANINGLESS
/FOR PAPER TAPE READER).
/IF AN ERROR OCCURS, HALT
/OTHERWISE, CONTINUE WITH PROGRAM

All device handlers are loaded into field 0.

The device

handler for the system device is always resident at location
7607 in field 0.

Before using the USR requests to Lookup,

Enter, or Close a file on a device, its device handler must be
in core.

C'
'

5-15

5.4

DEMONSTRATION PROGRAM

What follows is a user program which interfaces with the
USR to handle I/O for the task of copying a tape read by the
high-speed reader onto DECtape unit 1.

The program first locks

the USR in core and loads the device handlers for the highspeed reader and DECtape 1 into core.

Next, i t creates an

output file named YES.NO on the DECtape and reads a record
from the reader into core.

Then the record is written on

DECtape, counters are incremented and the next record is
read and written, etc.
If a non-fatal error occurs

(e.g., end of tape), the

error handling routine will write the last record of output
on the DECtape and close the output file.

The program then

rings the Teletype bell and returns to the Keyboard Monitor.

0
5-16

c
/Tl-!IS PHOGRAM TRANSFERS A TAPE FROM DEVICE "PTH"
/(USUALLY THE HIGH SPEED PAPER TAPE HEADER)
/TO A FILE N.AMED "YES.t-JO" ON DEVICE D!Al
!<USUALLY DECTAPE 1>
/THIS PROGRAM IS NOT RESTARTABLE BECAUSE THE
/MONITOR GALLS WHICH IT USES ARE ALTEHED
/BY THE MONITOR AND NOT> RESTORED.

*200
CIF
JMS
10
CIF'
JMS

10
I <7700
10
I

C200

1
DEVICE PTR

/SET INST FIELD TO 1
/CALL USR
/LOCK USR INTO CORE
/CALL USR AT ITS LOCKED-IN
/ENTRY POINT
/FETCH HANDLER

/ASSEMBLER WILL GENERATE DEVICE. NAME HERE
INPUT,
1000
/LOAD HANDLER IN PG 1000 a· NOT
I IN CORE OVERLAYD \JI TH HANDLER ENTRY
HLT
/ERROR RETURN - PTR NOT FOUND
/OR HANDLER IS 2 PAGES LONG
CIF' 10
JMS I <200
/CALL USR AGAIN
1
DEVICE OTAl
DTA=.-1
OUTPUT,

2001

HLT
C IF 10
TAD DTA ·
JMS I <200

3
FSTRT,

POINTR

Fl.EN,

0
HLT

/ASSEMBLER WILL PU1 UEVICE#
/OF "DTAl" IN LOC "DTA"
/LOAD HANDLER INTO PAGES
/2000 AND 2200 <OVERLAYED WITH REAL
/ENTRY POINT>
/DTAl DOES NOT EXIST??!!
/DEVICE # OF "DTAl" INTO AC
/ENTER OUTPUT FILE
/POINTS TO FILE NAME - OVERLAYED WITH
/STARTING BLOCK # OF CREATED FILE
/OVERlAYED WITH LENGTH OF CREATED FILE
/ERROR RETURN

/WE ARE NOW READY TO DO THE TRANSFER.ING OF DATA
LOOP,
JMS I INPUT
/CALL "PTR" DEVICE HANDLER
0200
/TRANSFER 2 PGS TO FIELD 0
3000
/BUFFER IS AT LOC 3000
!REC,
0
I INPUT BLOCK NUMBER
JMP INERR
/INrfUT ERROR DETECTED
TAD FSTRT
TAD CLENGT
/COMPUTE BLOCK TO WRITE INTO
DCA ECCH
JMS I OUTPUT
/CALL '"DTAl" HANDLER
li200
/\.:RI TE 2 PAGES F'ROM F1 VLD 0
/BUFFER IS AT 3000
3000

5-17

-- . M. #¥- _ A -.. 4.

. . . . . 4.. ,¥4#.\jl#..J . .4,?A .41.,#._ PA.. A. ..

. . 4.M

I
0
ECCH,

0
HLT

/BLOC1{ TO OUTPUT INTO
/OUTPUT ERROH
/THERE .!'.RE NO SOFT OUTPUT ERRORS
I SZ IREC
/BUMP THE INPUT BLOCK #
!<WE SHOULD DO THIS. DJ!:SPITE THE FACT THAT PTR
/IS NOT FILE STRUCTURED!)
ISZ CLENGT
/BUMP COUNT OF RECORDS OUTPUT
I SZ FLEN
/BUMP COUNT OF BLOCKS IN OUTPUT FILE
. JMP LOOP
/LOOP IF EVERYTHING IS OK
HLT
/OUT OF ROOM FOR OUTPUT
IN ERR,

SPA CLA
HLT
TAD FSTRT
TAD CL EN GT
DCA ECCH2
JMS I OUTPUT
420121

/WHAT JUND OF ERROR WAS IT?
/BAD KIND
/OUT OF TAPE, COMPUTE OUTPUT .·
/BLOCK FOR LAST RECORD

3000
0
HLT
ISZ CLENGT
en, 10
TAD DTA
<iMS I <200

/WRITE LAST BUFFER OUT

ECCH2,

/ERROR
/BUMP COUNT OF BLOCKS OUTPUT
/GET THE DEVICE # OF "DTAl" IN AC
/CLOS~

OUTPUT fTLE

/FUiNTS ·Ta·· FIL::;· N;u·1~ -

S.HOULD SE
THAT USED IN
/THE "ENTER" OPERATION
/NUMBER OF.BLOCDS OUTPUT
/SOMETHING ;BAD HAPPENED.

POINTR

I SAME NAME AS

CLEl'JGT, 0
HLT
TAD <207
6046
612Jl.!l
JMP • -1
CLA
JMP I ( 7600
PO INTR:.

FI LNAM

/RING THE BELL
/WA IT FOR TELETYPE TO STOP

/RETURN TO KEYBOARD MONITOR

YES• NO

/ASSEMBLEH WILL GENERATE 4-WORD FILENAME HERE

5-18

c
CHAPTER 6
PRELIMINARY AND SUPPLEMENTARY INFORMATION

The information contained in the following sections is preliminary and is subject to change without notice.
follows is not necessary for the average use.r.

Much of what

It is documented

for use by the advanced programmer who may wish to alter the
system internally.

6.1

PS/8 AND THE DISK MONITOR COMPARED

PS/8 differs from the 4K Disk Monitor in the following ways:

•

PS/8 has BK FORTRAN and a system ODT while the DM system
has 4K FORTRAN and a system DDT.

•

PS/8 makes more effective use of extended memory than the
DM system.

For example, core image files may include code

in more than one memory field.

•

PS/8 is truly device independent.

The device handlers

are a part of the system and are loaded by the User
Service Routine.
In the Disk Monitor (DM system) the handlers for
devices other than the system device must be coded
into the program.

•

In PS/8 it is possible to specify variable length reads
and writes to the device handlers.

The DM system trans-

fers one block at a time.
•

PS/8 files occupy contiguous blocks and the file directory
entries are listed simply in order of occurrence of files
on the device.

DM files may be segmented and the direc-

tory includes a storage allocation map.

6-1

.. 4

#.~KY.6

.. 7_.)

___ ;;:

I
l.

~.Ji

•

The USR performs directory operations on file structured
devices (Directory Lookup, Enter, Close.)

!'.

DM system

programs must perform these operations themselves.

•

PS/8 will RUN and SAVE programs on devices other than
system device.

•

PS/8 is capable of program chaining.

6.2

LIMITATIONS OF THE PRELIMINARY VERSION

The PS/8 system which is being made available now is still
a preliminary version and does not have all the features of the
completed version as yet.

What follows is a list of the present

limitations on PS/8:
1.

As yet, building the system is simply a process of
reading in all the tapes of the system since no
configuration editor exists. Device handlers
other than those provided as a part of PS/8 can
not yet be integrated into the system. Since the
system is not edited to fit the configuration, reference to a non-existent device will cause the computer to enter an infinite loop waiting for the
device to respond.

Various option which the Command Decoder passes
to the system programs are not yet implemented:
0Etion

Not Yet ImElemented for

PIP

/G
/L
/0

PIP
CO NV RT
ABSLDR

The Card Reader Handler (CDR) is not useable.

Putting source and binary output on the Teletype
punch is not recommended as it may come out interspersed with error messages and system prompt
characters. Listings may be put on the punch.
If you wish to load absolute binary tapes from
the Teletype with ABSLDR, you should use the /S
option to avoid confusion.
(Type CTRL/Z after
all the tapes are read.)
Relocatable binary
tapes should not be read from Teletype readers
since they may contain CTRL/Zs and CTRL/Cs.

6-2

When loading a multi-segment absolute binary tape
from the high-speed reader using ABSLDR, use the
/S option.

File directories as yet are one block instead
of six blocks. As a result the maximum number
of files which can exist on a·directory device
will be between 34 and 48, depending on the
fragmentation of the storage area.

7. Avoid using files longer than 256 blocks.

6.3

DIRECTORY STRUCTURE

File directories list the files in their order of occurrence
on the device, since each file is in one contiguous area on the
storage device.

The directory occupies up to six blocks starting

at block one of the device.

Each block has the same format: a

directory-block header of five words followed by entries for
each file giving the file name and length.

Each directory block

is linked to the following block (if one exists) by a word in the
directory-block header.
The organization within the directory block header is as
follows.
Word

Contents

The number of entries in this directory block expressed
as a negative number.

The starting block number for storage of files listed
in this block.

Link word: The block number of the next directory
block if there is a next.
If this is the last
directory block in use, this word contains zero.

Flag word: The address of the file entry for the
tentative file if one exists.
(Only one tentative
file can exist on a device at a time.)

The number of extra words per directory entry. The
number is specified as an option to PIP using the
construction "=n" where n,4. The directory entries
may then be altered to include information as to date
and author of the file.
6-3

I
I!

I
,1

!1
'1

From words 5 to 377 are the file entries of the directory
block.

The three different types of files -- permanent, tenta-

tive, and free - have three different entry forms, all loosely
a file name followed by the file length.

A permanent file entry consists of a four-word name
(the name is six characters with an extension of two
characters) followed by a one-word length expressed
as a negative number.

A tentative file entry consists of a four-word name
followed by a one-word length of zero.
The zero
indicates that the length is not yet set, because
the file is not yet closed to further output. A
tentative file is always followed by a free file,
whose entry is described next.

A free file entry consists of one word of zero (indicating no name) followed by a one-word length expressed as a negative number.
Such an entry indicates
the space available for output.

BUILDING AND STARTING A PS/8 SYSTEM

The standard DEC Binary Loader should be loaded into field 1.

Use the following Bootstrap to move the Loader to the proper
memory locations.
0002
0003
0004
0005
0006
0007
0010
OOll
2)

Starting at location 0002:

1410
34ll
2007
5002
7402
7600
7577
1577

Place the Binary tape for the PS/8 system in the reader.

The number of the RK8 system tape is DEC-P8-MSDA-PB.

Load

address 011777; depress START.

The PS/8 system tape will

be read at this point.

The system tape is composed

of two binary tapes.

(NOTE:

The computer will halt after each seg-

ment is read in.) After the first segment has been read, the
computer will halt with a
second segment

AC.

Depress CONTinue to read the

If the AC is non-zero at any halt, a checksum error

has occurred, and it is necessary to restart the building procedure.

6-4

Load address with 4000 (data field and instruction field set
to ~), and depress START.

Some system I/O will take place,

after which the machine will halt with -1 (7777) in the AC.
3)

At this point, place the Command Decoder binary tape in

the reader.

(Tape No. DEC-P8-SWXA.)

Make certain any switch

The binary tape

will be read in, and the machine will halt with AC=O.
load address 4000 and depress START.

Again,

System I/O will take

place, and the Monitor will respond with a

(dot).

This

signifies that the Kayboard Monitor is in core, and is ready
for input.

At this point, the system Absolute Binary Loader

will be used to load the system program, according to the
following specifications.
Program Name:

PIP

Tape No. DEC-P8-PWXA

Place the PIP binary tape into the reader.
. R ABSLDR (CR)
*PTR:=l3000(89}$

Load as follows:

CR=carriage return
$=ALT MODE

When t appears, strike any character on the keyboard, and the
tape will be read in. The Monitor responds with . (dot} •
. SAVE SYS PIP(CR)
At this point, PIP is written onto the system device.

Program Name:

FORTRAN

Tape No. DEC-P8-KFXA

Place the FORTRAN binary tape into the reader, Load as follows:
. R ABSLDR (CR)
*PTR:/S$
When t appears, strike a keyboard character to read in the tape.
Monitor responds with. (dot) •
. SAVE SYS FORT(CR)
At this point, FORT is written onto the system device.

""""'

Program name: SABR
Tape No. DEC-P8-ARXA
Place the SABR binary tape into the reader. Load as follows:

6-5

I
0

• R ABSLDR (CR)
*PTR:/S$
When t appears, strike a keyboard character to read in the tape.
The tape is read, and Monitor responds with • (dot) •
• SAVE SYS SABR(CR)
At this point SABR is written onto the system device.
Program Name:

Linking Loader

Tap~

No. DEC-PS-LLXA

Place the Loader binary tape in the reader.

Load as follows:

• R ABSLDR (CR)
*PTR: (9)$
When t appears, strike a keyboard character to load the tape.
Monitor responds with a . after loading the tape •
• SAVE SYS LOADER(CR)
At this point, the Loader is written onto the system device.
Program Name:

LIBS

Tape No. DEC-PS-SFXA

Place the LIBB.RL tape in the reader.
NOTE:
It is necessary to place the tape in the reader so that
the first non-zero character to be read is directly to the right
of the read head. If this restriction is not followed, the
library may not be loaded properly. Load as follows, using PIP
and the LIBS setup tape •
• R PIP (CR)
*SYS:LIBB.RL TTY:,PTR:/I(CR)
Notice that this expects a file from the TTY first.
The machine will
appear to hang up. At this point, type in+ z (CTRL/Z). When t
appears, strike a keyboard character to read in the LIBS.RL tape.
After reading, PIP responds with *
~

*tc
responds with a .

(dot).

Type CTRL/C in response to the *

At this point, place the LIBS setup binary in the reader,
No. DEC-PS-SYXA. Load as follows:

Monitor

'I'

Tape

• R ABSLDR (CR)
*PTR:/G$
When t appears, strike a keyboard character to read the tape. At this
point, LIBB.RL is written, the bell is rung to signify completion of
the operation, and the Monitor returns with • (dot). ·

Program Name:

EDITOR

Tape No. DEC-PS-ESAA

Place the EDITOR binary tape in the reader.

Load as follows:

• R ABSLDR (CR)
*PTR: (9) $
When t appears, strike a keyboard character to read the tape.
EDITOR will be read in, and Monitor responds with • (dor) •

The

• SAVE SYS EDIT(CR)
At this point, the EDITOR is written on the system device.
Program Name:

PALS

Tape No. DEC-PS-ASXA

Place the PALS binary tape in the reader.

Load as follows:

. R ABSLDR (CR)
*PTR: (9) $
When t appears, strike a keyboard character to load the tape.
tape will be read, and Monitor will respond with • (dot) .

The

• SAVE SYS PALS(CR)
PALS will now be written on the system device.
Program Name:

CONVRT

Tape No. DEC-PS-SUTA

Place the CONVRT binary in the reader.

Load:

.R ABSLDR(CR)
*PTR: (9)$
When t appears, strike a keyboard character to load the tape.
loading, Monitor responds with • (dot) .
• SAVE SYS CONVRT(CR)
CONVRT is now written on the system device.
That completes the building of the present PS/S system.

6-7

WWW. .

. . . 3A.W#4 . 4,

.4#L4414 _

After

I
I
I~

Starting PS/8

A PS/8 system using a DECtape as the system device may be
started by toggling

the DECtape Bootstrap Loader:

Location

Contents

7613
7614
7615
7616
7617
7620
7621
7622
7623

6774
1222
6766
6771
5216
1223
5215
0600
0220

7754
7755

7577
7577

and then starting the Loader at location 7613.
A PS/8 system using an RK8 disk as the system device may
be started by toggling in the Bootstrap Loader for the disk:
Location

Contents

0030
0031

6733
5031

Load address and start at location 30.

6.5

USING THE SYSTEM ODT

The ODT available under PS/8 is a debugging tool similar
to the stand-alone ODT program (DEC-08-COCO) .
lowing properties and restrictions:

It has the fol-

(The user should be fami-

liar with stand-alone ODT before reading this part.)
6-8

It does not occupy any core outside of the two system pages
(07600 and 17600).

It requires locations 4, 5, and 6 in any field in which a
breakpoint will be used for breakpoint processing.

ODT wipes out the USER DEVICE NAME table.
Therefore you
should not use it to debug programs which require user
device names.

ODT should not be used to debug programs which use interrupts.

Do not set breakpoints:
in the Monitor
in device handlers
between a CIF and the following JMP instruction

Addresses can be five digits long on input and will always
be printed as five digits.

The following commands are available:

Meaning (if preceded by number N)

Open and examine location N.

Re-examine last examined location

Deposit N in opened location,
(if one exists); close location

Close location

Deposit N in open location, close
location, open and examine location + 1.

Open and examine
location +l.

Deposit N in open location, close
location, open location + 1

Close location, open
location+l

~
(SHIFT/O)

Open and examine location N (same
as /)

Open location pointed
to by last-examined
location

Open and examine location addressed by N

Open and examine location addressed by
last examined location

(SHIFT/N)

~·.

Meaning if not preceded by number

Command

Set breakpoint at location N

Clear breakpoint

Continue from breakpoint N times

Equivalent to lC.

Start program at location N

N ignored

Display AC as of last
breakpoint

N ignored

Display Link as of
last breakpoint

6-9

-···· ,, . 4.i

k44I

4#_.,

__Jg.,,_¥-~_!)!

•¥~

Meaning if not preceded by number N

Command

Meaning if preceded
by number N

N ignored

Next
Display Search Mask.
location is the lower limit
of search, next after that
is the upper limit.

N ignored

Display Data Field as of
last breakpoint

N ignored

Display Data Field for indirect (
and4-) references
and searches.

N ignored

Display TCF instruction on
ODT.
(This should be a NO-OP
if the TTY flag is to be on.)

Same c;s OW.
Search field F under
Mask M for N from
location (M+l) to location (M+2) ; print
all matches.

6.6

THE SUPPLIED DEVICE HANDLERS

0
Special Operation
for Record 0

Terminating
Conditions

Type an up-arrow
on the TTY and
wait for user to
mount his tape
and type a character.

End of paper Typing CTRL/
tape causes C while
tape is
CTRL/Z to
be entered, moving rethe buffer
turns to
is padded
Monitor.
with zeros
and the nonfatal error
return is
taken.

Device

Normal Operation

PTR:

Read characters
from paper tape
and pack them
into a buffer.

PTP:

Unpack characters None
from buffer and
punch them on paper
tape.

LPT:

Unpack characters
from buffer and
print them on
line printer.
Simulate any
format control
characters not
in the private
hardware.

None

Print a form feed. CTRL/Z in
buffer terminates
printing
form feed.

6-10

User Interaction via TTY

CTRL/C returns to
Monitor.
CTRL/C returns to
Monitor.

Special Operation
for Record 0

Device Normal Operation

Terminating
Conditions

User Interaction Via TTY

CDR:

Not usable in present version.

TTY:

Transfer characters between buff er and Teletype.

None

Input: Read- CTRL/Z tering a CTRL/Z minates infrom the TTY put.
causes CTRL/ CTRL/O terZ to be put minates
in the buf- printing
fer, the
of current
buffer pad- output bufded with
fer.
zeros and
CTRL/C rethe nonturns to
fatal error
Monitor.
return taken.
Output: seeing a CTRL/Z
in the buffer or seeing a CTRL/O
from the keyboard causes
a normal return to be
taken.

DTAn:

Transfers words
via data break
between buffer
and DECtape.

None

SYS:

Transfers words
via data break
between buffer
and systems
device.

None

Type
Devi::::e

AC<O for hard
(fatal) err'3r

Error Condition

Soft

PTR:

Ran out of tape
Attempt to write

PTP:
LPT:

Attempt to read
Attempt to read
Printer error (power low)

CDR:

Not yet available

Hard
Hard
Hard
Hard

6-11

... IM.....

.,.$.14.@.4 ..

AC~O for soft
(recoverable) error

,,,t.£4_.4 ._..

.. ...-A,..; .. "~

'
~.I

.,. . .•!.•
.I

Device

Error Condition

TTY:

CTRL/Z typed during input
operation
(tries three
times first) •

Type
AC 0 for hard
AC 0 for soft
(recoverable) error
(fatal) error

'
d

1:1
\·-1

r1
I
I

Soft

Write lock error during output operation (tries three
times) •

Hard

Unit not selected - handler
hangs until unit is selected.

SYS:

Not an error

Sarne as DTAn for DECtape system.
For RK8 disk system:
Track address error (tries
recalibration three times)
All other errors (tries three
.times)

6.7

Hard
Hard

WRITING DEVICE HANDLERS

All device handlers must be page relocatable - i.e., they
must be able to execute in any page (except page 7600 and possibly page ~) . This means that they must not contain any
fullword references to locations in the handler itself.

certain programs this is a restriction, but it can usually be
overcome.

For instance if a table lookup has to be done it

can be done by the following methods:
METHOD 1
Not Page Relocatable

METHOD 2
Page Relocatable

METHOD 3
,Page Relocatable

TAD N
TAD BASE
DCA TEMP
TAD I TEMP

TAD N
TAD TBASE
DCA
HLT

JMS .+l
BASEl, ~
TAD N
TAD BASE
TAD BASE 1

BASE, TABLE-1

TBASE,TAD TABLE-1

TABLE,

TABLE I

5 locs + 1 temp

5 locs

DCA TEMP
TAD I TEMP

BASE, TABLE-BASEl-1
TABLE
8 locs and 1 temp.

6-12

The third method shown is less efficient than the other two,
but has the advantage that it can be used in a two-page handler
when TABLE might be in a different page from the code.
There are two restrictions on the·entry point of a device
handler.

They are:

If the handler is a two-page handler, the entry point
must be in the first page.

If the handler is for a random access device which will
be used as a directory device,the entry point of the
handler relative to the beginning of its page must not
be zero or equal to the address of any other handler of
a directory device (other than the system device) relative to its page. EXAMPLE:
If you want to write a
handler for magnetic tape, and you want the magnetic
tape to be a directory device then you should make the
entry point of the handler before location 10 of the
page because the DECtape handlers have entry points
of 10 through 17 in their pages.
The problems involved in writing a handler O.epend upon whether

the device is character-oriented or uses data-break for information
transfer.

A character-oriented device requires a handler which packs

and unpacks characters into and out of the buffer.

Also the handler

must be capable of interacting easily with the user, who must usually
perform such manual functions as typing characters and loading tapes.
By comparison, the handler for a data-break device is simple, since
setting up the current address, the word count, and the actual
transfer is all that is necessary.
The standard character-packing format used in PS/8 is a
three-character into two-word format as follows:
Word 2

Word 1
Char

IChar 1
Bits 0-3.
3

j I

Char 3

IChar 2

Bits 4-7.

•

This format was chosen because two out of the three characters are visible at a glance, and also because the packing and
unpacking routines for this format are smaller than for any
other format:
The following is a typical routine used for packing characters into an input buffer:
6-13

I
~I

I
.,;.I

PACK, JMS RCHAR
DCA I POINTR
TAD POINTR
DCA TEMl
ISZ POINTR
JMS RCHAR
DCA I POINTER
JMS RCHAR
RTL
RTL
DCA TEM2
TAD TEM2
AND ( 7 49191
TAD I TEMl
DCA I TEMl
TAD TEM2
RTL
RTL
AND (7400
TAD I POINTR
DCA I POINTR
ISZ POINTR
ISZ COUNTR
JMP PACK

/INPUT A CHARACTER

(O·'··.
,

The following is a typical routine used for unpacking characters from an output buffer:
UNPACK, TAD I POINTR
JMS PUNCH
TAD I POINTR
AND (7400
DCA TEMl
ISZ POINTR
TAD I POINTR
JMS PUNCH
TAD I POINTR
ISZ POINTR
AND (7400
CLL RTR
RTR
TAD TE Ml
RTR
RTR
JMS PUNCH
ISZ COUNTR
JMP UNPACK

/OUTPUT A CHARACTER

6-14

c
A final word of warning - try to make these handlers as foolproof as possible.

For example, if a device is read-only the

handler should give a hard error on write operations and vice-versa.
Also try to guard against the possibility that the user will specify an operation which wraps around core (e.g., write three pages
from location 7400) or will specify 0 as a page count (if you can,
accept 0 as the same as 40 8 - a full core load).
What follows is a sample handler - it handles the paper tape
reader and punch.

6-15

. -· .!lil#... L ..

* 7400

7400

7400
7401
7402
7403
7404

0000
7320
4235
1 712
4 30 4

7405
740 6
740 7
7410
741 1
741 2

0 342
3313
2312
0232
1 71 2
4304

741 3
741 4
741 5
741 6
741 7
7420
7421
7422
7423
742 4

0342
71 1 2
7012
1313
7012
7012
4304
7700
2312
00 70

7425
7426
7427
7430
7431
7432
7433
7L!34
7435
7436
7437
74 40
7441
7442
74 4 3
7444
7445
7446
7447
7450
7451

6034
1311
7650
6031
5272
6203
5634
7600
0000
6214
1232
3301
1600
0224
1 372
32 71
7010
1 600
2200
7510
5370

7452
7453
74 5 4
7455
745 6
745 7
7460
7461
7462

0222
7040
3375
1 600
2200
3312
1 600
7650
7430

PTP,
PTPLP,

PTP232,

PT7700,
PTPEND,
PT70,

PTPCIF,
PSETUP,

/HIGH SPEED PAPER TAPE HANDLER FOR PS/8 MONITOR
/PACKS 3 CHARACTERS IN 2 WORDS ON INPUT, UPACKS
/ON OUTPUT
/PAGE RELOCATABLE
0
/ENTRY FOR PAPER TAPE PUNCH
CLA CLL CML
/SET LINK TO INDICATE PIDJCH
JMS PSETUP
TAD I PTPCA
JMS PTPPCH
/FIRST CHAR IN LOW ORDER 8 BITS
/OF iWRD 1
AND PT7400
DCA PTR
ISZ PTPCA
232
TAD I PTPCA
JMS PTPPCH
/SECOND CHAR IN LOW ORDER 8 BITS
/OF WORD 2
AND PT7400
CLL RTR
RTR
TAD PTR
RTR
RTR
/THIRD CHARACTER NOW IN AC
JMS PTPPCH
7700
/CLEARS AC AND NEVER SKIPS
ISZ PTPCA
70
/FOR WE'RE PUNCHING PG 7600 KEEP THIS
/LITERAL
KRS
TAD PTM203
SNA CLA
KSF
JMP PTPI SZ
CDF CIF 0
JMP I .+l
7600
0
RDF
/GET FIELD OF CALLING PROC
TAD PTPCIF
DCA PTPXIT
/SET UP RETURN
TAD I PTP
AND PT70
TAD PCDF
DCA PTPCDF
RAR
/GET LINKCl=PTP,0=PTR)
TAD I PTP
/GET FUNCTION WORD
I SZ PTP
SPA
/CHECK CORRECT MODE
JMP PTPERR
/SIGNAL "UNRECOVERABLE DEVICE
/ERROR"
AND PT7700
CMA
/SET UP -CWORD COUNT)/2-1
DCA PTPWC
TAD I PTP
/SET UP START ADDRESS
I SZ PTP
DCA PTPCA
TAD I PTP
S'.\JA CLA
SZL

6-16

i:,;·

7463
7464
7465
7466
7467
7470·
7471
7472
7473
7474
7475
7476
7477
7500
7501
7502
7503
7504
7505
7506
7507
7510
7511
7512
7513
7514
751 5
7516
751 7
7520
7521
7522
7523
7524
7525
7526
7527
7530
7531
7532
7532
7533
7534
7535
7536
7537
7540
7541
7542
7543
7544
7545
7546
7547
7550

5271
1373
6046
6031
5266
6032
0000
7471
2375
5635
12 71
7141
7620
2200
2200
7402
7004
5600
0000
6026
6021
5306
5704
7575
0000
0000
7300
1313
3200
4235
4345
3313
4345
3304
4345
7006
7006
3345
1345
0342
1313
1313
3712
1345
7006
7006
0342
1304
2312
7400
3712
5223
0000
12 71
7650
5745

PTPCDF,
PTP I SZ,
PTPRTN,

PTPXIT,

PTPPCH,

PTM203,
PTPCA,
PTR,

PTRLP,

PT7400,

PTRGCH,

JMP PTPCDF
TAD PTP336
6046
6031
JMP • -1
6032
0
PTPEOF=PTPCDF
I SZ PTPWC
JMP I PSETUP
/LOOP FOR BUFFER SIZE<l28 WORDS)
TAD PTPEOF
CLL CIA
SNL CLA
I SZ PTP
ISZ PTP
HLT
/EXIT CDF HERE
HAL
JMP I PTP
0
PLS
/NOTICE LACK OF OVERLAP
PSF
JMP • -1
JMP I PTPPCH
-203
0
0
/ENTRY FOR PAPER TAPE READER
CLA CLL
TAD PTR
DCA PTP
JMS PSETUP
/SET UP ADDRESS, COU:-JT, FIELDS
JMS PTRGCH
/READ FIRST CHAR OF 3
DCA PTR
JMS PTRGCH
DCA PTPPCH
JMS PTRGCH
RTL
RTL
DCA PTRGCH
/THIRD CHAR SPLIT
TAD PTRGCH
A'.\JD PT7400
TAD PTR
TAD PTR
DCA I PTPCA
/HIGH ORDER 4 BITS TO WORD 1
TAD PTRGCH
RTL
RTL
AND PT7400
TAD PTPPCH
I SZ PTPCA
7400
DCA I PTPCA
/LOW ORDER 4 BITS TO WORD 2
JMP PTPEND
0
TAD PTPEOF
S:'JA CLA
JMP I PTRGCH

6-17

7551
7552
7553

60 1 4
3271
2271

RFC
DC.A PTPEOF
PTT I ME, ISZ PTPEOF

7554
7555

5360
3374

JMP PGCHLP
DCA PTPTMP

7556

1210

TAD PTP232

7557
7560
7561
7562
7563
7564
7565

5745
1 3 74
3712
6011
5353
6012
3374

JMP I PTRGCH
PCCHLP, T!~D PTPTMP
DCA I PTPCA
RSF
JIV!P PT TIME
RRB
DCA PTPTMP

7566
7567
7570
7571

1 71 2
5745
7332
5277

TAD
JMP
PTPERR, CLA
JMP

7572
7573
75 7 4
7575

6201
0336
0000
0000

PCDF,
GDF
PTP336, 336
PTPTMP, 0
PTPWC,
0
EJECT

0
/LOOP WILL OIJERFLO\\' IN
/APPROX. 66 MS
/IF IT DOES, WE HA1JE RU'.\J OUT OF
/TAPE
/ZERO CHAR AT E'.\JD OF TAPE AND
IS E'.'JD

/tZ

/READER NOT READY - CHECK TIMDJC
/READER READY - READ CHAR
/BUFFER READER BY ONE CEAR TO
/ELIMI'.'JATE
/GARBAGE CEAR AT E'.\JD OF TAPE
I PTPCA
I PTRGC!-i
/AND RETUR'.\J
CLL CML RTR /ROTATED LEFT TO FORM CODE
/FOR "PERMA'.\JE'.\JT IIO ERROR" O'.\J
PTPXI T-2
/THE DEIJ·
0
/"t"

:O
6.8·

RK8 DISK HANDLER

6731
6733
6732
6741
6752
6742
6745
6747
6753
6755
760 7
7610
7611
7612
7613
761 4
7615
761 6
761 7
7620
7621
7622
7623

0000
7346
3333
6214
1340
3326
160 7
3334
2207
7240
160 7
3330
2207

DCLA=6731
DLDR=6733
DLDC=6732
DRDS=6741
DRWC=6752
DCLS=6742
DSKC=6745
DSKE=6747
DLWC=6753
DLCA=6755
*7607
SH:'VDLR, 0
CLA CLL CMA RTL
/SET # OF TRIES O>J ERROR
DCA SYSCNT
RDF
TAD SCIF
I SA VE CALLING FIELD FOR RETURN
DCA SF I ELD
TAD I SH'.\JDLR
/GET FU'.\JCTION 11.'0RD
DCA SFUN
ISZ SHNDLR
CLA CMA
TAD I SHNDLR
/GET BUFFER LDC
-1
DCA SLOC
ISZ SHNDLR

6-18

7624
7625
7626
7627
7630
7631
7632

160 7
1347
3331
1334
7004
0250
3332

7633
7634
7635

7006
1 341
3255

7636
7637
7640
7641
7642
7643
7644
7645
7646
7647
7650
7651
7652
7653

1330
6755
1332
1250
7640
1250
1250
6753
7240
6742
7600
1334
0310
6732

7654
7655
7656
7657
7660
7661
7662
7663
7664
7665
7666
7667
7670
7671
7672

1 331
0000
6745
7410
5304
6747
5256
2333
5267
7330
5325
6741
0342
2335
5271

7673
7674

7650
5236

7675
7676
7677
7700
7701
7702
7703
7704
7705
7706
7707

7240
6742
7200
6731
6745
5301
5236
6747
7410
5263
2331

STRY,

TAD
TAD
DCA
TAD
RAL
AND
DCA

I SHNDLR
SOFSET
SREC
SFU'.'J
S7600
SBLKCT

RTL
TAD SDLDR
DCA SINST
SLOOP,

S7600,

TAD SLOG
DLCA
TAD SBLKCT
TAD S7600
SZA CLA
TAD S7600
TAD S7600
DLWC
CLA CMA
DCLS
7600
TAD SFUN
AND S70
DLDC

/SOFSET=0
/STORE RECORD #

/SBLKCT=TOTAL WORD COU:.JT
/TO BE READ
/SINST=6733 <READ) OR
/6735 <V.'RITE)
/LOAD CURRENT ADDRESS REG.
/HALF - OR FGLL - RECORD READ?
/FULL
/HALF
/LOAD WORD COUNT REG.
/CLEAR ALL FLAGS
/CLEAR AC

/LOAD DATA FIELD OF BUFF.
/INTO COMD. REG.

TAD SREC
SINST,

/READ OR WRITE
DSKC
/SKIP ON DONE
SKF
JMP SNEXT
DSKE
/SKIP ON ERROR
JMP SINST+l
SERR OR, ISZ SYSCNT
/BUMP TRY COUNTER
JMP .+3
CLA CLL CML RAR /THREE TRIES, YOU'RE OUT
JMP SRTRN+l
DRDS
AND S40
/LOOK AT "SECTOR NOT FOUND" BIT
ISZ SZERO
JMP .-1
/DELAY TO LET UNIT QUIET DOWN
/<KLUDGE)
SNA CLA
JMP SLOOP
/ERROR OTHER THA'.\J "SECT. '.\JOT
/FOUND" - RETRY
CLA CMA
DCLS
CLA
DCLA
/RECALIBRATE DISK <SEEK TRACK 0)
DSKC
JMP • -1
JMP SLOOP
/RETRY
SNEXT,
DSKE
/DONE - IS ERROR FLAG UP?
SKF
JMP SERROR
/YES - ERROR
ISZ SREC
/BUMP RECORD #

6-19

I
~.I

·~

I
I

,,,1

0
7710
7711
7712
771 3
771 4
771 5
771 6
771 7
7720
7721
7722
7723
7724
7725
7726
7727
7730
7731
7732
7733
7734
7735
7736
7737
7740
7741
7742

0070
1330
1337
3330
1332
7120
1336
74 70
5323
3332
5236
7200
2207
220 7
7402
560 7
0000
0000
0000
0000
0000
0000
7400
0400
6202
6733
0040

s70,

70
TAD SLOG
TAD S400
DCA SLOG
TAD SBLKCT
CLL CV.L
TAD s 7400
SZL S:JA
JMP .+3
DCA SBLKCT
JMP SLOOP
CLA
SRTR:J,
I SZ SHNDLR
ISZ SHNDLR
SFI ELD, HLT
JMP I SH:\JDLR
SLOG,
0
SREC,
0
SBLVCT, 0
SYSC>JT, 0
SFU'.'J,
0
SZERO,
0
s 7 400,
7400
S400,
400
SCIF,
CIF 0
SDLDR,
DLDR
S40,
40
0

6-20

/BUMP CURRE'.'JT ADR

/IS

~ORD

COU:JT EXHAUSTED?

/BUMP \..'ORD COU'JT
/DO :JEXT RECORD

/RESTORE CALLI'JG INST.

FIELD

I
I

C.
'

APPiiliDIXES

SUHHARY OF fu:.LBOAiill COHHANDS

Command

Short
Form

---

Necessary
Arguments

Optional
Arguments

Operation
Performed

ASSIGN

permanent
device
name

user device
name

Associate user name with
specified device.
If
no user name specified,
disassociate user name
from specified device.

DEASSIGN

device
name,
filename

extension
(if not SV)

Disassociate all user
names from all devices.

GET

device
name.
filename

extension
(if not SV)

Load specified core
image file into core
and move its core control block into the
system scratch area .

SAVE

device
name,
filename

extension
(if not SV)

Dur.1p program in core on
specified device in a
file with the specified
name.

addresses of
areas of core
to be saved
(join by hyphen, separate by
comma)

I f the information given

by optional arguments is
not specified, it is
taken from the core control block.

starting address (preceded by ; )
Job Status
Word (preceded by =)
START

start
address

Start program in core.
I f a start address is

not specified, use the
on in the core control
block.
ODT

Load and start ODT.
A-1

I.
I
I

I
t:.

c
.

RUN

device
name,
filename

extension
(if not SV)

Load the specified core
image file and its core
control block and start
it.

Rt
(space)

filename

extension
(if not SV)

Load and start the specified core image file.

SPECIAL CHARACTErt C01·1MANDS

(KM stands for the Keyboard Monitor; CC stands for the
Command Decoder.)
Where Used

Effect

CTRL/C

anywhere

returns to KM

CTRL/U

CD,KM

deletes current

RUBOUT

CD, KM

deletes a character from the end of
the input line

Carriage
return

CD, KM

ends input line

ALT-MODE
(or PREFIX or
ESCape)

CD, KM

ends input line

Line
Feed

CD, KM

prints a clean copy of current command line (free of RUBOUT corrections)

CTRL/O

TTY handler
ODT

stops output

CTRL/Z

TTY handler

end of file

Character

B-1

l~ne

of input

- - - - - - - ··=--\

I
i,I

•I

·1·.!·.

I
~i

II
'1

·1

:o. ·. .
,,

0
I

ERROR MESSAGES

C.l

From the Keyboard Monitor

Message

Meaning

device NOT AVAILABLE

The device name specified (to a RUN,
GET, SAVE or ASSIGN command) is not
in any system tables.

xxxx ?

"xxxx" is not a legal command; e.g.,
if the user typed "HELLO" the system
would respond "HELLO?"

filename NOT FOUND

The file name specified (to a RUN,
GET or R command)does not exist on
the device specified.

TOO FEW ARGS

You left out an argument to a command;
e.g., "RUN OSK" would produce this
message.

NO!!

You attempted to START a program
which cannot be started for some
reason. For example, the program
may modify itself and hence must be
reloaded before starting it again.

SAVE ERROR

An I/O error has occurred while

SAVEing a program. The program is
still intact in core after this message is given.
ILLEGAL ARG

Bad syntax was detected in the
optional arguments of a SAVE command.

BAD ARGS

Two areas of core specified in
the optional arguments of a SAVE
command overlay each other.

USER ERROR ~ AT xxxxx

An I/O error was detected while

loading a program (RUN, GET or
R commands) xxxxx is a meaningless vestigial location.
~ONITOR

ERROR 2 AT xxxx

An attempt has been made to
output to a WRITE LOCKED
device, usually DECtape.

C-1

I
!

ti.,

From the Command Decoder

G.2

Message

Meaning

ILLEGAL SYNTAX

This corrunand line does not make
sense.

TOO MANY FILES

More than three output files or
nine input files were specified.

device DOES NOT EXIST

The device specified could not
be found in the system tables.

filename NOT FOUND

The specified filename does
not exist on the specified device.

G.3

From the Linking Loader

The Linking Loader gives error messages in the form "ERROR
nnnn".

The meaning of the different values of nnnn are:

Error Code

Explanation

0001

Symbol table overflow (more than 64 subprogram
names)

0002

Program will not fit

0003

Program with largest common storage was not
loaded first

0004

Checksum error in input tape

0005

Illegal relocation code

0006

An output error has occurred while outputting
a storage map

0007

An input error has occurred while reading a
binary file

0010

No starting address has been specified and
there is no entry point named "MAIN"

0010

An internal error has occurred. Please send
the typeout and history to Digital Equipment
Corporation.
C-2

0
l

From the PS/8 Version of FORTRAN

The following error messages have been added to the PS/8
version of FORTRAN (all error messages described in Chapter 15
of Prograrruning Languages are also valid) :
Message

Explanation

I/O ERROR

A device handler has signalled a
fatal I/O error.

NO ROOM FOR OUTPUT

The file FORTRN.TM cannot fit on
device SYS: .

SABR. SV NOT FOUND

Self-explanatory.
The compiler
will not run without SABR.

NO END STATEMENT

The input to the compiler has
been exhausted.

COMPILER MALFUNCTION

The meaning of this message has
been extended to cover various
"impossible" monitor errors.

C-3

... ifB. S.!t#Eiit.J4#;:;:_ ,_if\(§¢.. n

....

1.... -·-·

I. ··
"I·
I

INDEX
Absolute Binary Loader,

Device independence, 1-1

4-1, -7, -10

Device ncme, 3-7

ALTMODE, 4-7, -11, B-1

permanent, 2-2

"Ascertain if Handler in Core"

user, 2-3

5-4, -12

Device number, 2-2, 5-5, -12

ASSIGN, 3-3, A-1

DEVICE pseudo-op

Assumed extension, 2-4

5-1, -6, 5-13
Directory, 4-3, -4

Binary Loader, Absolute

Directory-device, 2-4

4-1, -7, -10
Block, 2-6
Calling Sequence, 5-10
"Enter Output File", 5-3, -7

Service calls, 5-2

Entry Point

Device handlers, 5-13

Handler, 5-3, -4, -12

"Chain to Program"

Error message, C-1

5-4, -10

Extension, 2-4, 3-5, 4-9, 5-9

Chaining,

"Fetch Handler", 5-3, -5

. 1-1, 5-4, -10

File length, 36, 39, 40, 42

"Close Output File"

5- 3 , - 6, - 7 , -10

5-3, -8

File name, 2-4, 3-7

Conunand Decoder, 1-3,

File types, 2-1

3-6, 4-6, 5-4, -9, C-2

Filing system, 2-1

Commands

FILNAM pseudo-op, 5-1, -6

Keyboard Monitor, 3-3, A-1

Free file, 2-1, 5-4

Command Decoder, 3-6

FORTRAN, 4-2, -15, C-3

Special Character, B-1

FORTRAN library,

Conversion program, 4-1, -10

2-5, 4-4, -12

CONVRT, 4-1, -10

Function word, 5-14

Core Control Block,
3-2, -4, -5, -7

GET, 3- 4 , A-1

Core image file
2-5, 3-4, 4-3

Handler, device,

Co-resident handler, 5-5

1-3, 5-1, -11, 5-14
Handler entry point, 5-3, -4, 5-12

DEASSIGN, 3- 4 I A-1

Default extension, 2-4, 5-9
Device handl.er, 1-3, 5-1, -11,

I/O specification, 3-7, 5-4
Input/output specification,

-14

3-7, 5-4

Co-resident, 5-5 ·

- ##4_ ...... Ah_,

x ..

4f!. #4¥@.

I
~

I
fl
I

Job Status Word
3-2, -4, 4-7, 5-11

Special character commands,
B-1

START, 3-5, A-1
Keyboard Monitor
1-2, 303, A-1, C-1

Starting block number,
5-3, -6, -8, -10, -15
Symbol table, 4-10, -14

Linking Loader,
4-2, -11, C-2
"Lock USR in Core"
5-4' -11
"Lookup Permanent File"
5-3' -6

Symbolic Editor, 4-1, -5
Syntax, option, 3-8
System device
1-2' 2-3' 3-5
Tentative file,
2-2, 5-3, -4, -8, -14

Null specification, 3-7
"USR Dismiss from Core"
ODT, 3-5, 4-10, A-1

5-4, -11

Option syntax, 3-8

User Device Name, 2-3, 3-3

Options, 3-8, 4-3 to -17

User Service Routine,
2-1, 5-1, -11

Page, 2-6
PAL-D Assembler, 4-1, -9
Peripheral Interchange Program,
4-1, -2

Permanent device name,
2-2, 3-3
Permanent File,
2-1, 5-3, -4, -9
Pseudo-op, 5-1, -6
R Command
3-5, 4-1, -2, A-1
Record, 2-6

Request numbers, 5-3

"Reset System Tables",
5-4, -13
RUBOUT, 3-2
RUN,

3-5, A-1

SABR Assembler, 4-2, -14
SAVE, 3-4, -5, A-1, C-1
Service calls, 5-1
Signal User Error, 5-4, -10

0
I