Digital PDFs

DEC-T8-MRFB-D

September 1970

136 pages

Original

3.4MB

Document:	UserGde Feb70
Order Number:	DEC-T8-MRFB-D
Revision:	0
Pages:	136
Original Filename:	DEC-T8-MRFB-D_UserGde_Feb70.pdf

OCR Text

TSS/8
TIME-SHARING SYSTEM
USER'S GUIDE

For additional copies, order No. DEC-TS-MRFB-D from Program Library, Digital
Equipment Corporation, Maynard, Massachusetts 01754.

DIGITAL

EQUIPMENT

Price $3.00

CORPORATION • MAYNARD, MASSACHUSETTS

1st Printing September 1968
2nd Printing March 1969
3rd Printing (Rev) February 1970

Your attention is invited to the last two pages of this manual. The
Reader's Comments page, when filled in and returned, is beneficial
to both you and DEC. All comments received are considered when
documenting subsequent manuals, and when assistance is required, a
knowledgeable DEC representative will contact you. The Software
Information page offers you a means of keeping up to date with DEC's
software.

The 'l"aterial in th,s manual,s for information purposes and is subject to change without notice.

The following are trademarks of Digital Equipment
Corporation, Maynard, Massachusetts:
DEC
FLIP CHIP
DIGITAL

PDP
FOCAL
COMPUTER LAB

CONTENTS
Page
CHAPTER 1 INTRODUCTION
1.1

General Description

1-1

1.2

User Programs

1-1

1.3

User Files

1-2

1.4

TSS/8 User Console

1-2

1.4. 1

Power Control Knob

1-3

1.4.2

Printer

1-3

1.4.3

Keyboard

1-4

1.4.4

Paper-Tape Reader and Punch

1-4

1.4.5

Positioning Tape in the Tape Reader

1-5

1.5

Use of This Manual

1-5

CHAPTER 2

ELEMENTARY MONITOR COMMANDS

2.1

Calling Monitor

2-1

2.2

Logging In on TSS/8

2-2

2.3

Logging Out of TSS/8

2-4

2.4

System Library Program Control

2-4

2.5

Communication with other Users

2-5

2.6

System Status Reports

2-6

2.7

Resource Sharing

2-6

2.8

Error Messages

2-9

CHAPTER 3

DESCRIPTION OF TSS/8 SYSTEM LIBRARY PROGRAMS AND THE INTERACTIVE LANGUAGES

3.1

Introduction

3-1

3.2

General Characteristics of System Library Programs

3-1

3.2. 1

Controll ing the Execution of System Library Programs

3-3

3.2.2

Returning to Monitor

3-4

3.2.3

Additional Manuals

3-4

3.3

BASIC-8

3-5

3.3.1

Example of a BASIC-8 Program

3-6

3.3. 2

Summary of BASIC -8 Statements

3-7

3.3.3

Functions

3-8

3.3.4

Complex Functions

3-9

3.3.5

Summary of Edit and Control Commands

3-9

iii

CONTENTS (Cont)
Page
3.3.6

Error Messages

3-10

3.3.7

Implementation Notes

3-12

3.4

FOCAL

3-13

3.4. 1

FOCAL Command and Operation Summary

3-13

3.4.2

FOCAL Operations

3-15

3.4.3

Mathematical Functions

3-16

3.4.4

Control Characters

3-16

3.4.5

Reading FOCAL Paper Tapes

3-17

3.4.6

FOCAL Error Messages

3-17

CHAPTER 4

FORTRAN-D COMPILER

4.1

Introduction to TSS/8 FORTRAN

4-1

4.2

Calling and Using FORTRAN-D

4-1

4.3

FORTRAN I/O

4-2

4.4

Examples of FORTRAN Programs

4-3

4.5

Summary of FORTRAN-D Statements

4-5

4.6

FORTRAN-D Compiler Systems Diagnostics

4-6

4.7

FORTRAN-D Compiler Compilation Diagnostics

4-7

4.8

FORTRAN-D Operating System Diagnostics

4-8

CHAPTER 5

PAL-D ASSEMBLER

5.1

Introduction to PAL-D

5-1

5.2

TSS/8 PAL-D

5-1

5.3

Example of a PAL-D Program

5-2

5.4

Symbol List for TSS/8

5-3

5.5

Error Diagnostics

5-6

CHAPTER 6

UTILITY PROGRAMS

6.1

EDIT

6-1

6.1.1

Summary of Symbolic Editor Operations

6-2

6. 1 .2

EDIT Command Summary

6-3

6.2

LOADER

6-4

6.3

ODT (Octal Debugging Technique)

6-5

6.3.1

Programming Notes

6-6

CONTENTS (Cont)
Page
6.3.2

ODT Command Summary

6-6

6.4

CAT

6-7

6.4.1

Example of CAT Usage

6-7

6.5

SYSTAT (System Status)

6-8

6.5.1

Example of SYSTAT Usage

6-8

CHAPTER 7

PROGRAMS FOR PAPER TAPE AND DECTAPE CONTROL

7.1

PIP (Peripheral Interchange Program)

7-1

7. 1. 1

PIP Conventions

7-1

7.1.2

Using PIP to Load a Paper Tape to a Disk File

7-1

7.1.3

Using PIP to Punch Out a Disk File

7-2

7.1.4

Using PIP with the High-Speed Reader and Punch

7-2

7.1.5

Using PIP to Transfer BIN Format Files

7-3

7.1.6

Moving Disk Files

7-3

7.1.7

Deleting Disk Files

7-3

7.1.8

Transferring BASIC-8 Files

7-4

7.1.9

Transferring SAVE Format Fi les

7-4

7.1.10

Summary of PIP Options

7-5

7.2

COpy

7-5

7.2.1

Using and Calling COPY

7-5

7.2.2

Loading Files from DECtape

7-6

7.2.3

Saving Disk Files on DECtape

7-7

7.2.4

Listing Directories

7-7

7.2.5

Deleting Files

7-7

7.2.6

Deleting All Files on a Device

7-8

7.2.7

Summary of COPY Options

7-8

7.2.8

Example of COPY Usage

7-9

CHAPTER 8

ADVANCED MONITOR COMMANDS

8. 1

Introduction

8-1

8. 2

Control of User Programs

8-2

8.3

Defining Disk Files

8-3

8.3.1

Creating a Disk File

8-3

8.3.2

Opening and Closing a File

8-3

CONTENTS (Cont)
Page
8.3.3

Extending, Reducing, and Renaming a Disk File

8-4

8.3.4

Protection Codes

8-4

8.3.5

Error Conditions

8-6

8.4

Saving and Restoring User Programs

8-6

8.5

Utility Commands

8-8

CHAPTER 9

WRITING ASSEMBLY LANGUAGE PROGRAMS FOR TSS/8

9.1

Introduction

9-1

9.2

Console I/O

9-2

9.3

Fi les and Disk I/O

9-4

9.4

Assignable Devices

9-9

9.5

Program Control

9-12

9.6

Program and System Status

9-13

9.7

PDP-8 Compatibility

9-16

APPENDIX A

TSS/8 CHARACTER SET

APPENDIX B SUMMARY OF MONITOR COMMANDS

APPENDIX C

SUMMARY OF lOT INSTRUCTIONS

APPENDIX D OFF-LINE TAPE PREPARATION AND EDITING

APPENDIX E SYSTEM CONFIGURATION AND OPTIONAL HARDWARE

APPENDIX F

STORAGE ALLOCATION

APPENDIX G

GLOSSARY OF ABBREVIATIONS AND TERMS

TABLES
2-1

Monitor Error Messages

2-10

3-1

Summary of BASIC-8 Statements

3-7

3-2

Summary of BASIC Edit and Control Commands

3-10

3-3

FOCAL Command and Operation Summary

3-13

TABLES (Cont)
Page
4-1

Summary of FORTRAN-D Statements

4-5

4-2

FORTRAN-D Compiler Systems Diagnostics

4-6

4-3

FORTRAN-D Compiler Compilation Diagnostics

4-7

4-4

FORTRAN-D Operati'1g System Diagnostics

4-8

5-1

Symbol List for TSS/8

5-3

5-2

PAL-D Error Diagnostics

5-6

6-1

Summary of Symboli c Editor Operations

6-2

EDIT Command Summary

6-3

ODT Command Summary

6-6

ILLUSTRATIONS
1-1

User Console

1-3

1-2

Console Keyboard

1-4

E-1

Reader/punch

E-2

Transport

E-3

vii

PREFACE

The TSS/8 User's Guide is a console-oriented manual, written especially for the student, technician, engineer,
or scientist. This manual presents a functional overview of the operation of TSS/8 (sometimes called
Time Shared-8) from the user's viewpoint, with precise instructions on how to make efficient use of the TSS/8
system.
In particular, the first section is intended to introduce the new user to TSS/8 and provide some insights on how
TSS/8 enables a single computer to efficiently service the differing needs of many users simultaneously. In
later sections, Monitor commands are explained in detail, and illustrated by actual examples. Full descriptions
of a number of System Library Programs are also presented.
The user of this Guide can be certain that the system operates exactly as explained because each operation has
been verified on TSS/8, with the actual printout included herein.
Documents referenced (available from DEC's Program Library):
TSS/8 System Manoger's Guide, DEC-T8-MBZA-D
Introduction to Programming, C-18
Paper Tape System User's Guide, DEC-08-NGCC-D
FOCAL-8 Programming Manual, DEC-08-AJAD-D
BASIC-8 Programming Manual, DEC-T8-KJZA-D
Symbol i c Editor, Programmer's Reference Manual, DEC-08-ESAB-D
PAL-D Assembler, Programmer's Reference Manual, DEC-D8-ASAB-D
4K FORTRAN, Programmer's Reference Manua I, DEC-08-AFCO-D
KT08/I Time-Sharing Option, DEC-8I-H-8NA-D

CHAPTER 1
INTRODUCTION

1.1

GENERAL DESCRIPTION

TSS/8 (Time-Sharing System for the PDP-8/1 and -8 Computers) is a general-purpose, time-sharing system
offering up to 16 users (24 in certain applications) a comprehensive library of System Programs. These programs
provide facilities for editing, assembling, compiling, debugging, loading, saving, calling, and executing user
programs on-line. Two conversational, interactive systems, FOCAL-8 and BASIC-8t are also included.
By separating the central processing operations from time-consuming interactions with human users, the computer
can, in effect, work on a number of programs simultaneously. Cycling between programs and giving only a
fraction of a second at a time to each program or task, the computer can deal with many users seemingly at
once. The appearance is created that each user has the computer to himself. The execution of various programs
is done without their interfering with each other and without lengthy delays in the respanse to individual users.
The heart of TSS/8 is a complex of subprograms called the Monitor. Monitor coordinates the operations of the
various programs and user consoles, ensuring that the user is in contact at all times with his program. Monitor
allocates the time and services of the computer to the various users; it grants a slice of processing (computing)
time to each job, and schedules jobs in sequential order to make most efficient use of the system device (disk).
Monitor handles user requests for hardware operations (reader, punch, etc.), swaps (moves) programs between
memory and disk, and manages the user's private files.

1.2

USER PROGRAMS

When the user is working on a program with TSS/8, his work exists in the computer as though he had his own
4K (4096 word) PDP-8. Several users can run programs at virtually the same time, because TSS/8 Monitor controls the scheduling of execution times. Monitor brings a program into core from the disk, allows it to execute
for a short time, and takes note of the state at which execution is stopped. Monitor then brings the next user
program into core, and repeats the process. The user is allotted a 4K block of storage that contains his particular

tFOCAL-8 (FOrmula CALculator) is an on-line conversational program developed by DEC. BASIC-8 is a
slightly modified version of the algebraic language originally developed at Dartmouth College.

1-1

program; this 4K block will be swapped from core onto a 4K area of disk storage when it is necessary for Monitor
to bring in another program to run.
After the user's program has been executed, for a period of time it is placed at the end of the queue (line) of
user programs waiting to run. If only one program is ready to run, it is allowed to do so withaut interruption
until another program is ready.
If a user wishes to maintain a permanent copy of his program, it is necessary to save a copy within the file area
of the disk (an area separate from the swapping area). Later sections of this manual describe the procedures to
create and update such fi les •
1 .3

USER FILES

A TSS/8 user is any person logged in on TSS/8. Each user has an account number and password assigned to him
by the installation manager or the person responsible for his particular TSS/8; the account number and password
allows the user access to the computer. His account number is also used to identify whatever fi les the user may
own within the TSS/8 file system.
The disk (a large external memory device used for storage of programs and data) is divided into logical areas
called files. A user can create files and store them in the file storage area of disk. The user can also specify
which groups of users may access his files and for what purpose (read, write, or both).
Parts of the disk are used to store System Files; those programs which are accessible to anyone using the computer.
A major portion of this manual deals with haw to use System Files, generally referred to as System Library
Programs.
With the appropriate Monitor commands, the user can create new files and manipulate old files (extend, reduce
or delete them). These commands are explained in Chapter 8. Most individual System Library Programs are
able to handle user files as input or output with commands issued at the user's consale.

1.4

TSS/8 USER CONSOLE

The user's console is a model 33 ASR Teletype® (Figure 1-1). The consale keyboard (Figure 1-2) allows the
user to communicate with his programs and Monitor. The paper-tape reader and punch are for paper-tape input
and output, while the teleprinter provides a typed copy of user input as well as program and Monitor output.
The Teletype controls are described here as they apply to the operation of the computer. Off-line operations
are explained in Appendix D.

® Teletype is a registered trademark of the Teletype Corporation.
1-2

---

-----

--,

..
"d
I

OFF

REL.

B. SP.

START STOP - - - ! I i...
FREE -

OFF

LINE

Figure 1-1

1.4.1

0 LOCAL

User Console

Power Control Knob

The following is a description of settings on the power control knob.
Function

1.4.2

LINE

The Teletype is energized and connected to the computer
as an input/output device, under computer control.

OFF

The Teletype is deactivated.

LOCAL

The Teletype is activated for off-I ine operation.

Printer

The printer provides a typed copy of input and output at a maximum rate of 10 characters per second.

1-3

1 .4.3

Keyboard

The console keyboard is similar to a typewriter keyboard. However, certain operational functions are shown
on the upper part of some of the key tops. These functions are activated by holding down the CTRL key while
depressing the desired key. For example, when using the Symbolic Editor, CTRL/FORM causes Editor to enter
command mode.
Although the left and right square brackets are not visible on the keyboard key tops, they are shown in Figure 1-2
and are generated by typing SHIFT/K and SHIFT/M, respectively. Also, the ALT MODE key is identified as
ESC (ESCape) on some keyboards.

C)C)C)C)G)C)OG)G)G)C)O®
@G)G)tV~®OG)CV~®@@
8G)~@G)evQQCD~c)@88

8G)G)G)G)G)CDCDC)Oo8
SPACE

Figure 1-2 Console Keyboard

1.4.4

Paper-Tape Reader and Punch

The paper-tape reader is used to input (to a user program) data punched on eight-channel perforated paper tape
at a rate of 10 choracters per second (maximum). The reader control settings are shown in Figure 1-1 and
described below:
Control

Function

START

Activates the reader; reader sprocket wheel is engaged and operative.

STOP

Deactivates the reader; reader sprocket wheel is engaged but not
operative.

FREE

Deactivates the reader; reader sprocket wheel is disengaged.
NOTE
The high-speed reader and punch are described in
Append;x E.

1-4

1.4.5

Positioning Tape in the Tape Reader

The following procedure describes how to properly position paper tape in the low-speed reader.
a.

Raise the tape retainer cover.

Set reader control to FREE.

Position tape to fit in the carrier and over sprocket wheels.

Close the tape retainer cover.

e. Tape should be able to be drawn through low-speed reader in either direction while the control is
set to FREE.

1.5

USE OF THIS MANUAL

At this paint, the user has a general understanding of time-sharing and how it is done. The following chapters
describe haw to use the system, and include summaries of the various System Library Programs available and haw
to use them. Chapter 2 describes the elementary Monitor commands every user will require. Chapter 3, Section 3.1 describes the System Library. Section 3.1 assists the user in learning to gain access to (in computer
jargon "to access") files and control execution, and includes a list of more detailed manuals on each of the
TSS/8 System library Programs. A glossary of terms and an Index appears at the end of this manual.

1-5

CHAPTER 2
ELEMENTARY MONITOR COMMANDS

TSS/8 offers the user a variety of hardware and software resources. The TSS/8 Monitor controls the allocation
and use of these resources. Many of the functions of the Monitor are invisible, and of no concern to the user,
for example, the way it allows many users to run prograrras on a single computer. In other instances the user
explicitly tells Monitor what he would like to do and the resources he wishes to utilize. He does so by typing
one or more of the commands described in this chapter or Chapter 8 (Advanced Monitor Commands).
The Monitor commands described in the first half of this chapter are those the user needs to log into the system,
to uti lize the TSS/8 System Library Programs, and to logout of the system. All TSSAl users must be fami I iar with
these commands. The commands described in sections 2.5, 2.6, and 2.7 are not needed to run TSS/8 System
Library Programs such as BASIC and FOCAL, but are frequently useful. The Monitor commands described in
Chapter 8 are primarily useful for creating assembly language programs and files.
NOTE
All Monitor commands must be terminated by typing the
RETURN key. All words within a Monitor command
line are separated by one or more spaces.

2.1

CALLING MONITOR

The user enters commands to System Programs, such as BASIC and FOCAL, in exactly the same way that he
enters commands to Monitor (i .e., by typing them in at the keyboard); therefore, the system must have some
way of distinguishing between the two cases. It does so by defining two modes of console operation: Monitor
mode and program mode. When a user's console is in Monitor mode, all input is interpreted as being commands
to Monitor. Otherwise, all input is assumed to be to the user program.
A special character, CTRL/B, (obtained by striking B with the CTRL key held down; and echoed on the Teletype
as tB) is used to unconditionally place the user's console in Monitor mode. Typing CTRL/B tells the system that
the command to follow is to be interpreted as a command to Monitor, regardless of the mode that the Teletype is
in. Generally, the command which follows the CTRL/B will be the S command.

2-1

fBS

Return to Monitor mode.

fBfBS

Return to Monitor mode from a program which is typing
out. (The two CTRL/B's stop the typeout, allowing the
S command to be typed.)

It is not necessary to precede each Monitor command with CTRL/B. Once in Monitor mode, a cOl1sole stays in
that made unti I a command is typed which starts a user program. To signify that it ;s in Monitor mode, the
system types a dot (.) on the left margin of the console printer paper. This dot indicates that the characters
typed in next will be treated as a Monitor command. Thus, the CTRL/B capability is important when a user is
runni ng a program and wishes to type a Monitor command. He may, for example, be using one language
(or System Program) and want to change to another, as shown below •

• R FOCAL
CCNGRATULATIO~S! !
YOU HAVE SUCCESSFULLY LOADED

SEALL I RETAIN

LOC~

SHALL I RETAIN

SINE~

EX~~

'FOCAL~1969'

A TSS-8/1 COMPUTER.

ATN ?:NO

COSINE ?:NO

PROCEED.

*
fBS
.R BASIC
NEv.' OR OLD--

Monitor always responds to tBS by typing a dot at the left-hand margin.

2.2

LOGGING IN ON TSS/8

To prevent unauthorized usage and to allow Monitor to maintain a record of system usage, TSS/8 requires that
each user identify himself to the system before using it. Before attempting to log in, the user should ensure that
the console LINE/OFF/LOCAL knob is turned to the LINE pasition (see section 1.4.1) before striking the
RETURN key. If the console is connected to TSS/8 and is not already in use, Monitor rolls the console paper
up two lines and prints a dot at the left margin of the paper.
The dot indicates that TSS/8 is in Monitor mode and that Monitor is waiting for the user to issue a command.
LCGIN

Request access to TSS/8.

2-2

The LOGIN command allows the user to access the TSS/8 system.
The user types LOGIN followed by a valid account number and password. Providing the console is free (not
already logged in), the command, account number, and password will not be pnnted on the console paper as
the keys are typed. If the command name letters are being printed, stop typing the command; instead, strike
the RETURN key, log out using the LOGOUT command (see section 2.3), at this point a successful LOGIN can
be accorr.plished. The LOGIN command is formatted as shown below:

.LOGI"J 1234 ABCD

(only the dot is printed)

where. is printed by Monitor, LOGIN is the command name, 1234 represents the account number, and ABCD
represents the password.
NOTE
A command name and each parameter (except the last)
is always followed by a space, and the command line
is always terminated with the RETURN key.
When a user types something other than a valid LOGIN command on a console, Monitor respands in one of the
following ways.
Explanation

Response
HELLO?
LC'GI:'-J PLEASE?

(user typed HELLO)
(user typed ASSIGN D 3)
(user typed LOGIN ABCD ABeD)

ILLEGAL RE.QUEST
.LOGIN' 4771 DEt'iC
ALREADY LeGGED I:'-J

(user typed va Iid LOGl N on an already logged in
console)
(user typed an incorrect account number or password)

UNAUTHORIZED ACCOU~T

In the first example, HELLO is not a command, so it is repeated with a question mark by Monitor. In the
second example, ASSIGN D 3 is a valid command but it is not appropriate until after the user logs in; therefore,
Monitor asks the user to log in. In the third example, Monitor finds that the LOGIN command is improperly
formatted (the first parameter must be from one to four numbers). The console printout tells the user that he has
made an ILLEGAL REQUEST. When the console is already logged in and the user types the LOGIN command,
the characters typed echo at the console, and Monitor informs the user that the console is occupied with the
message ALREADY LOGGED IN? If the user attempts to use an incorrect account number or password, Monitor

2-3

replies UNAUTHORIZED ACCOUNT. Thus, Monitor can distinguish an invalid command from a valid command;
it can also distinguish whether the valid command is appropriate when issued, whether the command is properly
formatted, and whether the account number and password are acceptable. In all the examples above, Monitor
ignores the command and prints another dot.
When Monitor finds the LOGIN command properly formatted and the account number and passwords acceptable,
it responds by identifying the version of the system being used, the job number it has assigned to the user, the
number of the console being used, and the time-of-day in hours, minutes, and seconds. For example:

TSS/8.19

JOB 03

K01

08:45:21

USUALLY THE SYSTEM MA~AGER WILL ENTER
HERE A COMME~T OR NOTE TO THE USER CONCER~ING
THE SYSTEM

A~D

Monitor then prints another dot and waits for the user to issue the next command. The job number assigned is an
internal number by which the system identifies each on-line user.

2.3

LOGGING OUT OF TSS/8

The LOGIN command tells Monitor that the user is ready to begin an on-line session. The LOGOUT command
indicates that the user is finished and ready to leave his Teletype.
DiscoMect the user from the system and record the
amount of time he has used.

LGGOUT

Monitor responds to LOGOUT by typing the amount of computer time used in the session and the total real time
of the session. For example:
.LOGOUT
RUN TIME 00:00:34 ELAPSED TIME 00:35:41
PLEASE TUR~ OFF YOUR TTY

Computer time used in this example was thirty four seconds, while the elapsed time between LOGIN and
LOGOUT was thirty five minutes and forty one seconds.

2.4

SYSTEM LIBRARY PROGRAM CONTROL

Once logged in, the user can call any of the TSS/8 Library Programs described in Chapters 3 through 7. To
call such a program, the user types the command R {meaning run} followed by one or more spaces and the pro-

2-4

Call in and start a Tss/8 System Library Program.

For example:

.R BASIC
NE\!: OR OLD

Monitor fetches the BASIC language processor from the System Library and starts it. BASIC begins its dialogue
by asking if the user wishes to work on a new program or retrieve an old one from disk storage. Notice that
once BASIC begins, the console is no longer in Monitor mode. Dots are no longer printed at the margin. All
input is considered to be commands to BASIC.
If the user types a program name which cannot be found in the System Library, Monitor responds with an error
message and returns the console to Monitor mode •
• R BASICK
FILE NOT FOUND?

The exact contents of a Tss/8 System Library may vary from installation to installation.

2.5

COMMUNICATION WITH OTHER USERS

Although Tss/8 gives each system user the impression that he is the only user of the system, it is actually
supporting many users at a time. Often, it is useful to communicate with another user, or with the system
operator; this is done through use of the TALK command.
TALK

Type out a message on another Tss/8 Teletype.

For example, to teIl the systenl operator (Teletype O) to tum on the high-speed punch, a user types the following
(where the initial dot was typed by Monitor):

.TALK 13 PLEASE TUR:.J ON THE HIGH SPEED PUNCH

This command causes the following to be typed on console 0:

** K137**

PLEASE TURN ON THE HIGH SPEED Pu~CE

where K07 is the number of the physical console which sent the message. Any Teletype can initiate a message
to any other Teletype. However, if the destination Teletype is printing at that time, the message will not be
sent. The initiating Teletype will, in this case, get the message BUSY as a response.
2-5

2.6

SYSTEM STATUS REPORTS

The command SYSTAT initiates a typeout of the full status of TSS/8; how many users are on-line, what they are
doing, etc.
SYSTAT

Report system status.

The command SYST AT is equivalent to typing R SYST AT. The format of the status report is described in the
section on SYSTAT in Chapter 6.
To learn the amount of computer time used since logging in, the user issues the TIME command:
TIME

The elapsed processor time of the user since he logged in
is printed.

TIME 0

The time of day is printed.

TIME C1

The amount of processor time used by job C 1 since login
is printed.

For example:

.TIME
00:00:09
.TIME 0
09:29:32
.TI~E 02
00:00:10

2.7

RESOURCE SHARING

All TSS/8 users, when logged in, have free access to the System Library, the disk storage capobi I ity, and the
TSS/8 computer. Monitor automatically handles resource requests on a rotating basis. Monitor also maintains
a pool of available devices which must be assigned to be used. These are devices, such as the high-speed
paper-tape reader, which by their very nature cannot be assigned to several programs simultaneously. Therefore,
Monitor grants individual users exclusive access to these devices when needed. Thus, users still share the
device, although not simultaneously.

2-6

All Tss/8 systems include a high-speed, paper-tape reader in the pool of available devices. Many systems also
include a high-speed, paper-tape punch, and one or more DECtapes. These assignable devices are normally
used with System Library Programs PIP and COpy to store programs or data on paper tape or DECtape.
When a device is assignable (present on the system) and available (not being used), the ASSIGN command may
be used to assign the desired unit or units to the console issuing the command. The valid ASSIGN commands are
formatted as shown below:
ASSIGN R

Assign the high-speed paper-tape reader.

ASSIGN P

Assign the high-speed paper-tape punch.

ASSIGN D

Assign a DECtape unit.

where R, P, and D are device designators for reader, punch, and DECtape, respectively. If other devices are
assignable, the system manager will inform the user of the appropriate device designators. The following is an
example of using an invalid device designator .

• ASSIGN X
ILLEGAL REQUEST

Monitor ignores the request, responds with the appropriate message, and prints another dot.
When a valid ASSIGN command is issued, Monitor checks for the availability of the device and respands
accordingly. For example:
.ASSIGN R
R ASSIGNED

(reader is assignable, available, and assigned)

.ASSIGN P
JOB 02 HAS P

(punch is unavailable because job number is using
it, and thus not assigned)

When the system contains multiple units of a device, the user simply specifies the device; Monitor assigns an
available unit and responds with the unit number. For example:
.ASSIGN D
D 2 ASSIGNED

If all DECtape units are busy, Monitor prints the message shown below:

.ASSIGN D
DEVICE NOT AVAILABLE

2-7

A specific unit can be requested, leaving a space between the device designator and the device number .

• ASSIGN D 4
D 4 ASSIG;\;ED

{assignment was accomplished}

NOTE
If the user assigns a device with a nonexistent device
number, that device will not be assigned; an error
message does not result because that device is not busy.
An error message only results when the device is already
assigned •

The ASSIGN cornn'lOnd can assign only one device at a time. Therefore, when multiple devices are to be
assigned, each must be assigned separately. The following will not accomplish the desired assignments, either
with or without the illegal commas .

• ASSIG~ R~ D 2~ D 1
R
ASSIGNED
Monitor accepted the first device designator {and unit number if any} and ignored the rest of the command. If
device R is unavailable, Monitor prints the appropriate message. The following completes the desired assignments {assuming available devices} .

• ASSIGX D 2
D 2 ASSIG:\ED
• ASS I Gr\ D 1
D 1 ASSIG:.\'ED

When the user has finished working with an assigned device, the RELEASE command must be used to terminate
the assignment and allow other users access to the device. (When a user logs out of TSS/8 any devices he still
has assigned to him are automatically released.)

RELEASE

Terminate a previous device assignment and make the
device available to other users.

An assigned device is released when the user types the RELEASE command, a space, the device designator {and
unit number if required}, and the RETURN key as shown below •

• RELEASE R
.RELEASE D 3

2-8

In the previous example, the reader and OECtape unit number 3 are released. Monitor prints a dot on the next
line if the release is accomplished; otherwise, it prints a message. If, for example, a request is made to release
a device which has not been assigned to the issuing console, the following happens:

.RELEASE P
ILLEGP.L REQUEST

Monitor printed ILLEGAL REQUEST after it checked and found that the specified device was not assigned to the
console issuing the command.
NOTE
All commands must be formatted properly; ILLEGAL
REQUEST is printed if the user fails to separate the
device designator and unit number with a space.
When multiple device units exist on the system, each must be individually released. For example:

.RELEASE D 1
.RELEASE D 2
.RELEASE R

Monitor does not check when releasing a device as it does when checking to assign an available device. The
user could have two device units (for example, two DECtape units) assigned and Monitor would not know which
to release; therefore, device numbers are necessary with a RELEASE command. However, where only one unit
of a specific device (one reader, one punch, etc.) is on the system, the device designator alone is sufficient.
Examples follow.

2.8

.RELEASE D
ILLEGAL REQUEST
.RE.LEASE R

(accompl ished)

.RFLEASE D

(0 1 is released)

(due to multiple OECtope units)

ERROR MESSAGES

An appropriate error message is printed whenever: a Monitor command cannot be performed at the time it was
requested, a typing error was made, or the command is illegal (nonexistent). Following each error message,
Monitor ignores the request and prints another dot, after which the user can issue another command.

2-9

Table 2-1
Monitor Error Messages
Explanation

Command
Sl ?

The Systell1 Interpreter does not understand the command.
Sl = command

The user attempted to use a console which is not logged
in.

UNAUTHORIZED ACCOUNT

The user attempted to log into the system with an invalid
account number or name.

ALREADY LOGGED IN?

The user tried to log in on a console which is already in
use.

FULL

The TSS/8 system is full. Another user cannot log in
until one of the present on-line users logs out.

TYPE tBS FIRST

The user attempted to use a system command whi ch
cannot presently be honored due to the status of the
user's prograll1. The message may appear even after the
user has typed tBS, since his program may continue until
the I/O in progress at the time of the halt is completed.
The user should wait a few seconds and then type his
command a second time.

ILLEGAL REQUEST

The user requested an illegal command. This error
usually results when some parameter has been given an
incorrect value or the request refers to a facil ity nat
owned by the user.

BUSY

The user attempted to talk to a console which is
currently typing out or is being typed on.

2-10

CHAPTER 3
DESCRIPTION OF TSS/8 SYSTEM LIBRARY PROGRAMS
AND THE INTERACTIVE LANGUAGES

3.1

INTRODUCTION

The TSS/8 System Library contains a comprehensive set of user programs for a wide range of applications.
Language processors, such as BASIC-8, FOCAL, and FORTRAN, allow the user to code and run programs
in interactive languages. A complete assembly language system allows programs to be written in PAL-D.
Various utility programs perform special functions. The System Library consists of the following programs:

BASIC-8 - an easily learned algebraic language originally developed at Dartmouth College.

FOCAL - DEC's own conversational language for on-line problem solving.

FORTRAN-D - a modified version of FORTRAN.

d. EDIT - a keyboard oriented Symbolic Editor, used to create and modify source programs and data
files.
e.

PAL-D - a two-pass Symbolic Assembler.

LOADER - a Binary Loader used to load assembled programs for execution.

ODT - Octal Debugging Technique for testing and modifying assembly language programs.

PIP - Peripheral Interchange Program for transferring files between the TSS/8 disk and paper tape.

COpy - a utility program used to transfer files between the TSS/8 disk and DECtape.

CAT - used to list all the files which a user has stored in his library.

SYSTAT - (System Status) a util ity program that prints the status of the whole TSS/8 system.

A more detailed description of each of the above System Programs is presented in the following chapters.

3.2

GENERAL CHARACTERISTICS OF SYSTEM LIBRARY PROGRAMS

A fundamental feature of the TSS/8 Monitor is its ability to save programs or other data for each user in his own
private library. These individual user libraries are maintained on the system disk. Individual entries in the
library are called files, whether they contain programs or data. Within the library itself, there is no distinction
between types of files by their conte"ts.

Each file is identified with a file name by which it is known, and

called into use.

3-1

The user does not directly create and update the files in his library. He uses the System Library Programs for
this purpose. For example, he can use the SAVE command in BASIC. The SAVE command takes the BASIC
program named and saves it as a file in the user's library for future use. Similarly, EDIT can be used to modify
an existing file, resulting in the creation of a new file. Therefore, although TSS/8 Monitor provides the actual
file storage capability, most file manipulation is done while System Library Programs are being run.
The System Library Programs which operate on these files, must know which file to use, when to create a new
file, and what to call it. Each Library Program has its own method of determining whether a user wishes to use
an old file or create a new one; this is explained in the sections on individual programs.
Example 1:
.R BASIC
NEW OR OLD--OLD
OLD PROGRAM NAME--PRIME
READY

Example 2:

.R FORT
INPUT:TYPE
OUTPUT: BTYPE

For most of his work, the user requires access to only his own library. However, it is often a useful feature to
be able to obtain a program from another user's library; allowing a single file to be shared by several users. To
access a program from another user's library, the user must tell the system in which individual Iibrary the fi Ie is
stored. The user tells the system by entering the account number of the library's owner. (In the absence of an
account number, the user's own Iibrary is the assumed source.) To get a fi Ie from the System Library, type an
asterisk immediately after the file name.
Example 1:
.R BASIC
NEI,: OR OLD--OLD
OLD PRCGRAM NAME--HOSSR*
READY

Example 2:

.R PALD
INPUT:NOTPIP 5440
OUTPUT:BINI

3-2

NOTE
Most examples in the discussions of individual System
Library Programs use file names within the user's own
library. The user is free (file protect permitting) to
use files from other users' libraries.
Access to another user's files is gained only with his permission. A user may "protect" his files against other
users (see Appendix F), i.e., prevent them from gaining access to his files, even though they know his program
name and account number. Library Programs never permit a user to write in another user's files. Specifying a
file which is protected, or specifying a nonexistent file, is an error that is detected immediately. An error
message is typed and the same request made again.
The user places his output in a single file; however, it is often useful to input several files together. (For
example, the user may wish to assemble two parts of a PAL-D program together.) To specify more than one
input file, separate the file names by commas. No Library Program allows more than three input files.
FORTRAN is limited to two; BASIC allows only one.
BASIC is a self-contained programming system, with an editor, compiler, and run-time system. It also has a
distinctive disk file format. Files created by BASIC are not compatible with files created by other Library
Programs. All other Library Programs depend on each other; therefore, all Library Programs use the same format
for their disk files. Consequently, files created by the Editor can be used as input to PAL-D or FORTRAN-D,
and numerical files created with the use of the Editor can be read by FORTRAN programs as data files.
Up to this point, only files that exist within the Time-Sharing System, i.e., on the Tss/8 disk, have been
described; however, Tss/8 provides two other means of file storage: paper tape and DECtape. The Library
Program PIP can be used to transfer files between paper tape and disk. The Library Program COpy allows files
to be transferred between disk and DECtape.

3.2.1

Controlling the Execution of System Library Programs

Tss/8 provides the user with two options for stopping the system. CTRL/c (C with the CONTROL key held
down) allows the user to stop his BASIC program and return to the beginning of that program without returning to
the Tss/8 Monitor. For example, if the user begins to run a BASIC program that has an endless loop, he can
type CTRVC to stop it. BASIC responds to tC with READY. All other Library Programs respond in a similar
manner.
CTRL/B is used to stop the Library Program most recently called. CTRL/B followed by S and carriage return
(RETURN key) unconditionally returns the user to the Monitor level; the user can now call another Library
Program. If the system is typing out, two CTRL/Bs and the S (tBtBS) are required to stop the system.

3-3

RUBOUT is another useful character that deletes the last typed character. Some Library Programs respond bv
printing \ or" while others print the rubbed out character. If the RUBOUT key is typed while entering file
names for input or output to a library Program, RUBOUT deletes the whole line. The request for input or output
is then repeated.

3.2.2

Returning to Monitor

The user can stop the execution of a System Library Program at any time by typing CTRL/B followed by S and the
RETURN key. The System Library Programs can also initiate a return to the Monitor. When the System Library
Programs initate a return, tBS is printed just as though the user had terminated the program. For example,
BASIC-8 returns to Monitor when the user types the BYE command:
READY
BYE

tBS

FORTRAN returns to Monitor after completing execution of a program. CAT and SYSTAT return after typing
their particular data output. PAL-D returns after completion of an assembly, LOADER at the end of a normal
load, and EDIT after completion of an EDIT. FOCAL, BASIC, ODT, PIP, and COPY never return to Monitor;
these programs must be terminated by the user.
NOTE
Some System library Programs return to the Monitor when
a fatal error condition is detected.

3.2.3 Additional Manuals
Many of the System Library Programs are documented in their own individual manuals. Those programs for
which manuals exist, are:
BASIC-8

DEC-T8-KJZA-D

FOCAL

DEC -08-AJAD-D

EDIT

DEC -08-ESAB-D

FORTRAN-D

DEC-Q8-AFC 0- D

PAL-D

DEC-D8-ASAB-D

ODT

DEC-Q8-COCO-D

Only a brief description of these programs is given here. Tables of commands are included for reference; however, for detailed instructions on the usage of these programs, the user is referred to the individual manual.

3-4

3.3

BASIC-S

BASIC-S is the TSS/S version of the time-sharing language BASIC. It allows even the beginning computer user
to write and run meaningful programs. BASIC-S is described at greater length in the BASIC-S Manual (Order
No. DEC-TS-KJZA-D). To call BASIC, type:
.R BASIC
After the user logs into TSS/S, and calls the BASIC program, BASIC then prints NEW OR OLD--. The user then
types the appropriate adjective: NEW (if the user is about to type a new program), or OLD (if the user wants
to access a program that was previously fi led).
BASIC asks NEW PROGRAM NAME-- (or OLD PROGRAM NAME--) and the user types any combination of six
letters or less. If the user is recalling an old program file from memory, he must use exactly the same name as
when he originally instructed BASIC to save it.
BASIC prints READY to signal the start of the editing phase; the user then begins to type the new program. If
the user types a line consisting of only a line number followed by the RETURN key, that line is deleted. Make
certain that each line begins with a line number greater than 0 and less than 2047 and contains no non-digit
characters. To enter the line to the computer be sure to strike the RETURN key at the completion of each
line.
If, while typing a statement, the user makes a typing error and notices it immediately; he can correct it by

striking the RUBOUT key (right-hand side of the keyboard), or the back arrow key (SHIFT/O). Striking either
key deletes the character in the preceding space and prints a left arrow (+} for each rubout. The user can then
type in the correct character. Striking the RUBOUT key a number of times erases one character from the
current line, (spaces are characters) to the left for each RUBOUT typed.
NOTE
BASIC sometimes takes several seconds to accomplish
a rubout.
While BASIC is in the editing phase, certain additional commands (which must not have line numbers) are available and are described below:
a. If the user types SAVE followed by one or more spaces, followed by a name, and strikes the
RETURN key, the current program is saved for future use under that name.
b. If the user types UNSAVE, followed by a name, and strikes the RETURN key, the program with the
name given is deleted from the user's permanent file.
c. If the user types CATALOG, and strikes the RETURN key, a listing of all the program names in
his permanent file is typed.

3-5

NOTE
Names of temporary files are also shown. These are of
the form, BASnn, and can be ignored.
d. If the user types LIST followed by two line numbers separated by a comma, a listing of the particular
part of his current program that lies between those line numbers is typed. If the comma and second line
number are omitted, only the sil1gle line indicated is listed. If no line numbers follow the word LIST
(but only the RETURN key), the whole program is listed.
e. If the user types DELETE followed by two line numbers separated by a comma, all lines between and
including the two indicated are deleted. If the comma and second line number are omitted, only the
single line specified is omitted.

f. When the user is ready to leave the Teletype, he signs off by typing BYE. BYE concludes
operations and TTS/8 Monitor deletes any tempory files assigned to the user.
g. After BASIC is called, the user can load a BASIC program from paper tape by placing the tape in
the console tape reader and typing TAPE. The tape is read in without printing on the console paper.
All RUBOUT characters are ignored.
h. After loading a tape, type KEY to return to normal keyboard mode. (Characters typed while in
TAPE mode do not echo on the console paper.)
If information (other than the RETURN key) is to follow the control word, at least one blank must precede the
additional information.

3.3.1

Example of a BASIC-8 Program
LIST
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
1 60
1 70

REM - PROGRAM TO COMPUTE I~TEREST OX A
PRINT "INTEREST DJ PERCENT";
INPUT J
LE.T J=J/100
PBI~T "Ar-:'OCNT OF LOAN";
I~Pl·T A
PRI~T "~Ul"BER OF YEARS";
I~PUT N
PRINT ":\JUl".BER OF PAYME~TS PER YEAR";
I~PUT M
LET ~=N*K
LET I=J/M
LET B=1+I
LET R=A*I/(1-1/BT~)
PR DJT ·'l",ONTJiL't PI>YME.:--JT ="Fi.
PRDJT "TOTAL I~TEREST ="R*N-A
END

3-6

LCA~

READY
RUN
INTEREST IN PERCENT? 8
AMOUNT OF LOAN? 25000
NUMBER OF YEARS? 20
NUMBER OF PAYMENTS PER YEAR? 12
MONTHLY PAYMENT = 209.1103
TOTAL INTEREST = 25186.46

READY
3.3.2

Summary of BASIC-8 Statements

Tabl e 3-1 is a summary of BASIC-8 statements.
The following is a list of symbols used in Table 3-1.
v = variable
f = formula
r = relationship
a = arguments

n = Ii ne number
s = integer subscript value
d = data, either real or integer

Table 3-1
Summary of BASIC-8 Statements
Explanation

Statement
LET v = f

Assign the value of the formula to the specified
variable.

DATA d, ••• , d

DATA statements are used to supply one or more
numbers to be accessed by READ statements.

READ v, ..• , v

READ statements, in turn, assign the next available
number in the DATA string to the variables listed.

PlUNTa, ••. ,a

Type the values of the specified arguments, which
may be variables, text, or format control characters.

GOTOn

Transfer control to the line number specified and
continue execution from that point.

~F (f rf) THEN n }

If the stated relationship is true, then transfer control
to the I ine number specified; if not, continue in
sequence.

FOR v = f1 TO f2 STEP f3

Used for looping repetitively through a series of steps.
The FOR statement initializes the variable to the value
of formula 1. If the increment is positive and the
variable ~formula 2, the instructions following are
executed unti I the NEX T statement is encountered.

IF (f r f) GO TO n

3-7

Table 3-1 (Cont)
Summary of BASIC -8 Statements
Statement

Explanation

NEXT v

The NEXT statement increments the variable by the
value of formula 3 (if omitted, the increment value is
+ 1). The variable is again tested as described above,
and this process continues until the loop is repeated the
specified number of times. When the variable becomes
larger than formu la 2, control goes to the statement following the NEXT. If the increment (formula 3) is negative, then the instructions between the FOR and NEXT
statements are executed until the variable becomes less
than the value of formula 2.

DIM v (s)

Enables the user to enter a table or array with the
specified number of elements.

END

Last statement to be executed in the program. This
statement must be present.

RANDOMIZE

When placed at the start of a program, causes a
different set of random numbers to be generated each
time that program, using RND (X), is run.

GOSUB n

Transfers control to the subroutine beginning at the
line number indicated.

RETURN

RETURN simplifies the execution of a subroutine by
providing an automatic return from the subroutine to
the next sequential statement following the appropriate
GOSUB (the GOSUB which sent control to the subroutine).

INPUT v, ••• , v

Causes typeout of a ? to the user and waits for user to
respond by typing the value of the variable(s).

STOP

Equivalent to GO TO [line number of END statement] •

REM

Permits typing of remarks within the program.

RESTORE

Sets pointer back to beginning of string of DATA values.

3.3.3

Functions

BASIC performs several mathematical calculations for the programmer eliminating the need for tables of
trigonometric functions, square roots and logarithms. These functions have a three-letter call name, (the
argument (X) can be a number, variable or formula) and are written as follows:

3-8

Functions
SIN

(x)

Meaning
sine of x in radians

COS (x)

cosine of x in radians

TAN (x)

tangent of x in radians

ATN (x)

arctangent of x in radians
x
e where e=2.712S1S

EXP

(x)

LOG (x)

ABS

(x)

SQR (x)

natural logarithm ofx, log x
e
absolute value of x, Ixl
square root of x,

..rx-

3.3.4 Complex Functions
a. SG N (x) - the SG N or sign function returns the value +1 if x is a positive number, 0 if x is 0,
and -1 if x is negative. For example: SGN (3.42) =1, SGN (-42) =-1.
b. I NT (x) - the I NT or integer functi on returns the va lue of the greatest integer not greater than x.
For example: INT (34.67) =34, INT (-34.42) =-35.
c. RND (x) - the RND or random number function produces a random number between 0 and 1. The
numbers are reproducible in the same order for later checking of a program. The value of x is ignored.
If a truly random number generator (causing different random numbers every time the program runs) is
desired, place the RANDOMIZE statement at the beginning of the program, before the initial use of
RND (x).
d. User defined functions - The user may create his own functions by using the DEF statement. The
statement defining the function must appear before any reference to that function, its form is:
DEF F NA (x) = (some formula) where the function name must be a three-letter sequence beginning
with F.

3.3.5

Summary of Edit and Control Commoods

Several commands for editing BASIC programs and controlling their execution enable the user to: delete lines,
list his program, save programs on a file-structured storoge device (disk), delete or replace old programs on
the storage device with new programs, call in programs from the storage device, etc. These commoods are
summarized below.

3-9

Table 3-2
Summary of BASIC Edit and Control Commands
Action

Command
BYE

Exit to TSS/8 Monitor to conclude operations

DELETE n

Delete line number n (or simply type the line number and RETURN key).

DELETE m, n

Delete line numbers m through n.

LIST

List program.

LIST n

list line number n.

LIST m, n

List program from line number m through n.

NEW

BASIC will ask for a new program name.

OLD

BASIC wi II ask for the 01 d program name and wi II rep lace current contents of
user core with the program of the given name from the storage device.

RUN

Compile and run program currently in core.

SAVE name

Save the BASIC program currently being worked on under the name given. t

UNSAVE name

Delete the named program from the storage device.

tC (CTRL/C)

To stop a running program, type CTRL/C (C with the CONTROL key held
down). BASIC will return to editing mode and type READY.

t SAVE commands overwrite an existing file of the Same name.

3.3.6

Error Messages

There are four types of BASIC error messages. The messages and their various interpretations are shown below.

3.3.6.1

Editing Phase Diagnostics - Retype the line to correct it.
Error Message

Explanation

SYSTEM 1-0 ERROR

BASIC was unable to perform the desired disk I/O.

//ERROR ft1

The user did not type in OLD or NEW when the information was requested.

//ERROR ft2

The new or old name is not a valid name.

//ERROR ft3

The neW name given is currently an active program.

//ERROR ft4

The old program name requested cannot be found.

//ERROR 11

The SAVE or UNSAVE name given is not a valid name.

WHAT?

The editor cannot understand the command given.

//ERROR 2ft

Invalid line number format or outside the range

0< line number < 2047.

3-10

3.3.6.2

Compilation and Execution Diagnostics - Most messages are followed by the notation ON LINE nnnn,

where nnnn is the line number on which the error was detected. (BASIC prints READY and the user is back in
the editing phase.)
Explanation

Error Message
PROGRAM TOO LARGE

The program is too large to be executed. Make it
smaller.

MISSING END STATEMENT

All programs must have an END statement.

DATA POOL OVERFLOW

The user used too many constants and/or variables in the
program.

ILLEGAL STATEMENT

A statement was used which is not one of the legitimate
BASIC statements.

ILLEGAL LINE FORMAT

The structure of the statement does not agree with the
BASIC syntax.

NOT CONSTANT IN DATA

The user attempted to use something other than a constant in a DATA statement.

DEF STATEMENT MISSING

A function needing a DEF statement exists in the
program.

FOR WITHOUT NEXT

There is an unmatched FOR statement in the program.

NEXT WITHOUT FOR

The NEXT statement indicated has no preceding FOR
statement.

ILLEGAL CHARACTER

The user attempted to use an illegal character in the
statement being processed.

ILLEGAL CONSTANT

The format of a constant in the statement being processed
is not valid.

INVALID NAME

A name is being used which does not agree with the
BASIC requirements.

INVALID LINE NUMBER

The format of the line number, being used in a GO TO
or IF statement, is not acceptab Ie.

ARRAY USED BEFORE DEFINED

The user attempted to use an array prior to its appearance
ina DI M statement.

EXPRESSION SYNTAX

The expression being processed does not agree with the
BASIC rules (this will probably be due to unmatched
parentheses) •

STACK OVERFLOW

The user programmed a situation in which either DO
statements, subroutines, or functions are nested too
deeply; or the user has a function which calls itself.

OUT OF DATA

An attempt was made to READ more data than was
supplied by the user.

ILLEGAL INPUT FORMAT

The form of a constant, which the user is attempting to
INPUT, is not valid.

DIMENSION TOO LARGE

Too large an array to fit in the core available.

UNDEFINED LINE NUMBER

The line number appearing in a GO TO or an IF-THEN
statement does not appear in the program.
3-11

3.3.6.3

Non-Fatal Execution Errors - Non-fatal errors are for notification purposes and indicate that the user

performed a computational range error. The errors all cause the message XX IN nnnn to be printed, where nnnn
is the line number and XX is as described below:
Error Code

Explanation

/'1

ZERO DIVIDE - An attempt was made to divide a number
by zero. The largest possible number is used for the
result.

OVERFLOW - The result of a calculation was too large
for the computer to handle. The largest possible number
is used for the result.

UNDERFLOW - The result of a calculation was too
small for the computer to handle. Zero is used for the
result.

An attempt was made to compute the logarithm of zero
or a negative number. Zero is used for the result.

An attempt was made to compute the square root of a
negative number. The square root of the absolute value
is used for the result.

An attempt was made to raise a negative number to a
fractional power. The absolute value of that number
raised to the fractional power is used.

3.3.6.4 System Error - If a failure occurs in the disk I/O portion of the BASIC system, the message SYSTEM

I/o ERROR is printed and control returns to the editing phase.
3.3.7

Implementation Notes

The TSS/8 BASIC language is compotible with Dartmouth BASIC except as noted below:
a.

There are no matrix operations.

There are no character string instructions.

The ON statement has not been implemented.

The TAB function is not available in PRINT statements.

e. BASIC-8 has no features which allow reading or writing data on the disk. (Although programs may
be saved on the disk for future use.)
f.

All array (subscripted) variables must appear in a DIM statement.

g. The function INT (X) gives the greatest integer in X. Therefore, INT (-2.3) gives the value -3;
INT (2.3) gives the value +2
h. Negative numbers can t.vt be raised to integer powers. The absolute value is used and an error
message printed. The reason for this is the unary minus has a lower priority during execution than
exponentiation. For example, -23 = +8 with an error message given.

3-12

User defined functions are restricted to one line.

i. Maximum size of a BASIC-8 program is about 300 lines, depending on the number of variables,
number and size of arrays, and number of nested subroutines and FOR-NEXT loops.

3.4

FOCAL

FOCAL (Formulating On-line Calculations in Algebraic Language) is an on-line, conversational, service program for the PDP-8 family of computers, designed to help scientists, engineers, and students solve numerical
problems. The language consists of short imperative English statements which are relatively easy to learn. It
is used for simulating mathematical models, for curve plotting, for handling sets of simultaneous equations, and
many other kinds of problems.
For a detailed introduction to the FOCAL programming language, consult the FOCAL Programming Manual
(Order No. DEC-08-AJAD-D).
To call FOCAL, type:
.R FOCAL
FOCAL enters its initial dialogue, and asks if its extended functions are to be retained. The extended functions
are exponential, sine, cosine, arctangent, and logarithm. If the FOCAL program to be run uses any of these
functions, the user responds YES. If not, the user responds NO to free more space for the user program. Without
the extended functions, there is room for approximately 1800 characters of program. If the extended functions
are retained, there is room for approximately 1100 characters.

3.4.1

FOCAL Command and Operation Summary

Table 3-3
FOCAL Command and Operation Summary
Command

Abbreviation

Example of Form

Explanation

ASK

ASK X, Y, Z

FOCAL types a colon for each
variable; the user types a value
to define each variable.

COMMENT

If a line begins with the letter C,
the remainder of the line will be
ignored •

CONTINUE

Dummy lines.

3-13

Table 3-3 (Cont)
FOCAL Command and Operation Summary
Command
DO

ERASE

FOR

Abbreviation
0

Example of Form

Explanation

DO 4.1

Execute line 4.1; return to command following DO command.

DO 4.0
DO All

Execute all group 4 lines; retum
to command following DO command, or when a RETURN is encountered •

ERASE

Erases the symbol table.

ERASE 2.0

Erases all group 2 lines.

ERASE 2.1

Deletes line 2. 1 .

ERASE All

Deletes all user input.

FOR i=x,y,z;(commands)

Where the command following is
executed at each new value.
x=initial value of i
y=value added to i until i is
greater than z.

Starts indirect program at lowest
numbered line number.

GO?

Starts at lowest numbered line
number and traces entire indirect
program unti I another ? is encountered, until an error is encountered, or until completion of
program.

GOTO

GOT03.4

Starts indirect program (transfers
control to line 3.4). Must have
argument.

IF (X)ln, ln, ln

Where X is a defined identifier,
a value, or an expression,
followed by three line numbers.

IF (X)ln, In; (commands)
IF (X)ln; (commands)

If X is less than zero, control is
transferred to the first line number.
If X is equal to zero, control is
to the second Ii ne number.

If X is greater than zero, control
is to the thi rd Ii ne number.
MODIFY

MODIFY 1.15

Enables editing of any character
on line 1.15 (see below).

QUIT

Returns control to the user.

RETURN

Terminates DO subroutines, returning to the original sequence.

3-14

Table 3-3 (Cont)
FOCAL Command and Operation Summary
Command

Abbreviation

Example of Form

SET

SET A=5/B*C;

TYPE

TYPE A+B-C;

Explanation
Defines identifiers in the symbol
table.
Evaluates expression and types out

= and result in current output
format.

WRITE

3.4.2

TYPE A-B, c/E;

Computes and types each expression separated by commas.

TYPE "TEXT STRING"

Types text. May be foil owed by
I to generate a carriage return
and line feed, or 11 to generate
a carriage return.

WRITE
WRITE ALL

FOCAL types out the entire indirect program.

WRITE 1.0

FOCAL types out all group 1
lines.

WRITE 1.1

FOCAL types out line 1.1.

FOCAL Operations

The following is a description of symbols used in FOCAL operation.
Explanation
To set output format,

To type symbol table,

TYPE %x.y

Where x is the total number of
digits, and y is the number of
digits to the right of the decimal
point.

TYPE %6.3, 123.456

FOCAL types: =+123.456

TYPE %

Resets output format to floating
point.

TYPE $

Other statements may not follow
on this line.

After a MODIFY command, the user types a search character, and FOCAL types out the contents of that line
until the search character is typed. The user may then perform any of the following operations.
a.

Type in new characters. FOCAL will add these to the line at the point of insertion.

Type a CTRL/L. FOCAL will proceed to the next occurrence of the search character.

Type a CTRL/BELL. After this, the user may change the search character.

d. Type RUBOUT. This deletes characters to the left, one character for each time the user
strikes the RUBOUT key.

3-15

Type", Deletes the line over to the left margin, but not the line number.

Type RETURN. Terminates the line, deleting characters over to the right margin.

g. Type LINE FEED. Saves the remainder ci the line fran the point at which LINE FEED
is typed over to the right margin.

3.4.3

Mathematical Functions

A listing of mathematical functions follows:
Function

Symbol

Interpretation

Square Root

FSQT(x)

where X is a positive number or expression greater than
zero.

Absolute Value

FABS(x)

FOCAL ignores the sign of x.

Sign Part

FSGN(x)

FOCAL evaluates the sign part only I with 1.0000 as
integer.

Integer Part

FITR(x)

FOCAL operates on the integer part of x, ignoring
any fractional port.

Random Number
Generator

FRAN(x)

FOCAL generates a randan number. The value of x is
ignored.

tExponential
Function (eX)

FEXP(x)

FOCAL generates e to the power x. (2.7182a><)

tS'me
tc oslne
.

FSIN(x)

FOCAL generates the sine of X in radians.

FCOS(x)

FOCAL generates the cosine of x in radians.

tAre Tangent

FATN(x)

FOCAL generates the arc tangent of x in radians.

tlogarithm

FlOG(x)

FOCAL generates log

(x).

3.4.4 Control Characters
Control characters and their explanation follows:

%
!

,
$

( )

[]

<>
II

? ?

Output format delimiter
Carriage return and line feed
Carriage return
Type symbol table contents
Parentheses
}
Square brackets
Angle brackets
Quotation marks
Question marks
Asterisk

(mathematics)
(text string)
(trace feature)
(high-speed reader input)

tThese are known as extended functions.

3-16

SPACE key (names)
}
RETURN key (lines)
ALT MODE key (with ASK statement)
Comma (expressions)
Semicolon (commands and statements)

3.4.5

(nonprinting)

Reading FOCAL Paper Tapes

To ensure that FOCAL paper tapes are read without error, they should be read silently. To do this, type tB
(CTRL/B) followed by UNDUPLEX just prior to reading the tape in. This Monitor command suppresses the printing of the program as it is read. As each line is read, a line feed and FOCAL's asterisk are typed, indicating
that the line is properly stored. After the tape has been completely read, type tB DUPLEX to restore FOCAL to
its normal mode. An example is shown below:

*ERPSE ALL
*tBlJ~DUPLEX

* *tBDCPLEX

*WRITE ALL
C-FOCt:.L,1969
01.05
01.06
01.10
01.20
01.30
01 .40

C PROGRAV- TO CALCULATE THE HYPOTENUSE OF A
C RIGHT TRIANGLE GIVEN THE TWO SIDES
ASK "SIDES OF TRIANGLE ARE" A,B
SET C=FSQT(At2+Bt2)
TYPE "hYPCTENUSE IS" C.. !
GOTO 1.1

*
3.4.6 FOCAL Error Messages
Code

?oo.oo
?OO.OO
?01.4O
?01.78
?01.96
?01.:5
?01.;4
?02.32
?02.52

Explanation
Manual start given from console.
Interrupt from keyboard via CTRL/C.
Illegal step or line number used.
Group number is too large.
Double periods found in a line number.
Line number is too large.
Group zero is an illegal line number.
Nonexistent group referenced by DO.
Nonexistent line referenced by DO.

3-17

Code

?02.79
?03.05
?03.28
?04.39
?04.52
?04.6O
?04.:3
?05.48
?06.06
?06.54
?07.22
?07.38
?07.:9
?07.;6
?08.47
?09.11

?10.:5
?11.35
?20.34
?23.36
?26.99
?28.73
?30.05
?31.<7

Explanation
Storage waS fi II ed by push -down list.
Nonexistent line used after GOTO or IF.
Illegal command used.
Left of = in error in F OR or SET.
Excess right terminators encountered.
Illegal terminator in FOR command.
Missing argument in display command.
Bad argument to MODIFY.
Illegal use of function or number.
Storage is filled by variables.
Operator missing in expression or double E.
No operator used before parenthesis.
No argument given after function call.
Illegal function name or double operators.
Parentheses do not match.
Bad argument in ERASE.
Storage was fi lied by text.
Input buffer has overflowed.
Logarithm of zero requested.
Literal number is too large.
Exponent is too large or negative.
Division by zero requested.
Imaginary square roots required.
Illegal character I unavai lable command I or unavai lable function used.

3-18

CHAPTER 4
FORTRAN-D COMPILER

4.1

INTRODUCTION TO TSS/8 FORTRAN

FORTRAN-D compi les and runs programs written in the PDP-8 version of FORTRAN. Programs {usually created
and stored with the Symbolic Editor} are compiled in a single pass and executed {automatically} immediately
following compilation. The PDP-8 FORTRAN Manual {Order No. DEC-08-AFCO-D} provides exact instructions
for writing programs in FORTRAN.

4.2

CALLING AND USING FORTRAN-D

To use FORTRAN-D, type:

• R FORT

FORTRAN requests the name of the input file, i.e., the file containing the FORTRAN program to be compiled
and run. The user responds with the fi Ie name, then strikes the RETURN key. FORTRAN then requests the
name of an output file in which to store the compiled version of the program. For normal usage, just the
RETURN key need by typed. FORTRAN places the compiled code in a fi Ie of its own, then proceeds to run the
program.
If a file name is entered for output, FORTRAN creates a permanent file in which the compiled binary program

is saved. It is then possible to rerun this program without recompiling it. To run an already compiled program,
call the FORTRAN operating system directly by typing:

.R FOSL
FOSL requests the name of an input file. Enter the name of the file containing the compiled binary.
Examples:

.R FORT
INPUT:MTRIX
OUTPUT:

4-1

FORTRAN compiles and executes the program MTRIX but does not save the compiled binary •

• R FORT
I:-.JPUT:MTRIX
OUTPl'T:BlYTRIX
FORTRAN compiles and executes the program MTRIX and then leaves the compiled binary in the file named
BMTRIX.

.R FOSL
INPUT:Btl:TRIX

The FORTRAN binary program BMTRIX is executed without first being compiled.
NOTE
All FORTRAN programs return to the Monitor when
they hove completed execution.

4.3

FORTRAN I/O

Differing versions of PDP-8 FORTRAN offer slightly different features. TSS/8 FORTRAN-D differs in the way it
is called into use (described above), and in its more powerful I/o capability (described below). FORTRAN-D
allows three data formats:
Integer format
E

Exponential format

Alpha format, the ASCII value of a choracter is stored as an integer value.

The standard device for READ and WRITE statements is the Teletype, which is assigned device code 1. Because
the Teletype is so frequently used, FORTRAN-D includes two special input/output instructions, ACCEPT and
TYPE. These instructions imply use of the Teletype; therefore, the device code need not be specified. ACCEPT
is especially convenient if data is to be entered at the keyboard because this instruction automatically supplies
a line feed when the RETURN key is typed. Also, the user can correct an erroneously typed value by striking
the RUBOUT key.
A FORTRAN-D program can also utilize the high-speed reader and punch for I/O. These devices are assigned
code 2. Because the high-speed reader and punch are shared by all TSS/8 users, it is necessary to assign them

if they are to be used. Assign the appropriate devi ces and mount tapes in the reader before runni ng
FORTRAN-D. When running several FORTRAN-D programs, reassigl1 the devices before each run.

4-2

TSS/8 FORTRAN also allows programs to read and write data files on the disk. These data files are completely
separate from the program files. Data files are read and written by standard READ and WRITE statements withi n
the FORTRAN-D program. The device code for the disk is 3. Because programs using the disk are treated
differently by FORT (the FORTRAN-D compiler), it is necessary to identify programs which use the disk. These
programs are identified by a DEFINE DISK statement as the first statement in any such FORTRAN-D program including a READ or WRITE statement with device code 3.
Just as FORT itself must ask for the name of its input and output files, so must a FORTRAN program ask for the
names of its disk files. FORTRAN-D programs do this by typing INPUT: and OUTPUT: a second time. The user
responds by typing the name of the files to be read or written by the program. FORTRAN-D asks for both input
and output for all programs which include a DEFINE DISK statement. If only input (or output) is to be used, the
user responds to the other by striking the RETURN key.
The following program is an example of a FORTRAN-D program whi ch utilizes the disk for data storage. The
program reads an already existing file (DATAl) of 10 values from the disk and writes their square roots into a
new file (DATA2).

4.4

EXAMPLES OF FORTRAN PROGRAMS

Example 1:

C
C
C

FOP.TRA~ PBOGRA~ TO READ 10 VALUES FBOM A DISK FILE.
COKPUTE THEIR SQUARES. A~D WRITE THE SQUARES OUT TO
A SECCND DISK FILE.

DEFI:-JE DISK
DIMENSIO:.\l A(10)
C

10
20

DO 20 1=1.10
READ 3.10.A( I)
FOR~AT
(E)
CO:-JTINUE

DO 30 1=1.10
A(l)=A(U**2
CONTI:-JUE

DO 40 1=1 J 10
WRITE 3.10.A(I)
CONTINUE

STOP
END
.R FORT
INPCT : SQCARE
OUTPCT:

4-3

INPUT: DATAl
OUTPUT: DATA2
tBS

Example 2:

.R ED IT

INPeT:MTRIX*
OUTPUT:
R

10
15

MATRIX MULTIPLIER
DIMENSI00.: A(36), B(36), C(36)
TYPE 200
TYPE 201
READ 1 , 1 , I
FORMAT ( I )
TYPE 202
DO 10 M=l,I
DO 10 N=l,I
INDX=M+I*(N-1 )
READ 1 , 2 , A ( I :-.JDX )
FORt'AT (E)
COJTINUE
TYPE 15
FORMAT C/ )
TYPE 202
DO 20 M=l,I
DO 20 N=l,I
INDX=r-'+I*(N-1 )
REAr; 1 ,2, B ( I NDX)
C (INDX )=0
CCNT1NUE
DO 30 M=l,1
DO 30 :-.J=l,1
DO 30 K=l,1
1C=N+I*(M-1 )
1A=M+1HK-1 )
1B=K+I*OJ-1 )
C ( I C) =C ( I C) +A ( IA HB ( IB)
C00.:T1:-.JUE
TYPE 15
DO 40 M=l,I
TYPE 21
DO 40 :\1=1,1
I:\1DX=:\1+1*(M-1 )
TYPE. 2, C ( INDX)
CO:\1TI:\1UE
FORMAT C/ )
TYPE 15

4-4

200
201
202

FORlVIAT
FORMAT
FORMAT
END

(/,"MATRIX MULTIPLIER",/)
("IJIME:JSIO:J IS:")
(I,"ENTER Ml>TRIX",1)

rBS

.R FORT
I:JPUT:MTRIX*
OUTPCT:
MATRIX MULTIPLIER
DIMENSIO:\T IS:3
E:JTER MATRIX
12 23 34
11 21 13
10 20 30
E:\TTER MATRIX
1.21.23.1
.01 121 12.
111 1.2 343
0.378863E+4
0.145641E+4
0.33LJ219E+LJ

0.283820E+4
0.256979E+4
0.2LJ6800E+LJ

0.119751E+5
0.474510E+4
0.105610E+5

rBS

4.5

SUMMARY OF FORTRAN-D STATEMENTS

Table 4-1
Summary of FORTRAN-D Statements
Explanation

Statement and Form
Arithmetic Statements
v=e

v is a variable (possibly subscripted); e is an expression.

Control Statements
GOTOn

n is a statement number.

GO TO (n ,n ,··· ,nn),i
1 2

n , .. . ,nn are statement numbers; i is a nonsubscripted
1
integer variable.

IF (e) n ,n ,n
1 2 3
DO n i=k ,k ,k
1 2 3

e is an expression; n 1 ,n ,n are statement numbers.

CONTINUE

Proceed

PAUSE

Temporarily suspend execution.

n is the statement number ofa CONTINUE; is is an integer variable; k1 ,k ,k are integers or nonsubscripted
2 3
interger variables.

4-5

Table 4-1 (Cont)
Summary of FORTRAN-D Statements
Explanation

Statement and Form
STOP

Terminate execution.

END

Terminate compilation; last statement in program.

Specification statements
DIME NSION v 1(n ) ,v (n },· .. , vn (nn)
1 2 2
DEFI NE device

v 1 ' ... , vn are variab Ie names; n 1 ' ... , nn are integers.

FORMAT (5 ,5 , ..• ,sn)
1 2
COMMENT

s is a data field specification.

Device is DISK or TAPE, system I/O device.

Designated by C as first character on line.

Input/Output Statements
ACCEPT f,list

f is a FORMAT statement number; list is a list of
variables.

TYPE f, list

f is a FORMAT statement number; list is a list of
variables.

READ u , f , list

u is an integer, representing device from which data
is to be read.
f is a FORMAT statement number; list is a list of
variables.
u is an integer, representing device onto which data
will be written.

WRITE u,f, list

f is a FORMAT statement number; list is a list of
variables.

4.6

FORTRAN-D COMPILER SYSTEMS DIAGNOSTICS
Table 4-2
FORTRAN-D Compiler Systems Diagnostics
Error
Code

Explanation

0240

System fi Ie error. One of the FORTRAN components cannot be found or the
disk is full, preventing FORTRAN from proceeding. Try recalling FORT.

3100

Illegal operator on compiler stack t

3417

Pre-precedence error t

6145

Could not find FOSL on system device; if the error occurs, it may be necessary
to reload FORT and FOSL.

6223

Error while loading .FT.

t Error may be due to a compiler error or a machine malfunction.

4-6

Table 4-2 (Cont)
F ORTRAN-D Compi ler Systems Diagnostics
Error
Code

Exp Ianat ion

6226

Same as above

6257

Same as above

6724

No END statement on source device

6746

Same as above

7114

Same as above

tError may be due to a compiler error or a machine malfunction.
4.7

FORTRAN-D COMPILER COMPILATION DIAGNOSTICS
Table 4-3
FORTRAN-D Compiler Compilation Diagnostics
Error
Code

Explanation

Mixed mode arithmetic expression

Missing variable or constant in arithmetic expression

Comma was found in an arithmetic expression

Too many operators in this expression

Function argument is in fixed-point mode

Floating-point variable used as a subscript

Too many variable names in this program

Program too large, core storage exceeded

Unba lanced right and left parentheses

Illegal character found in this statement

Compiler could not identify this statement

More than one statement with same statement number

Subscripted variable did not appear in a DIMENSION statement

Statement too long to process

Floating-point operand should hove been fixed-point

Undefi ned statement number

Too many numbered statements in this program

Too many parentheses in this statement

Too many statements have been referenced before they appear in the program

DEFINE statement was preceded by some executable statement

Statement does not begin with a space, tab, C, or number
4-7

4.8

FORTRAN-D OPERATING SYSTEM DIAGNOSTICS
Table 4-4
FORTRAN-D Operating System Diagnostics
Error
Code

Explanation

Checksum error on FORTRAN binary input

Illegal origin or data address on FORTRAN binary input

Disk input-output error t

High-speed reader error

Illegal FORTRAN binary input device

Attempt to divide by zero

Floating-point input data conversion error

Illegal op code

Disk input-output error t

Non-FORMAT statement used as a fORMAT

Illegal FORMAl specification

Floating-point number larger than 2047

Square root of a negative number

Exponential negative number

Logarithm of a number less thon or equal to zero

Illegal device code used in READ or WRITE statement

System device full, could not complete a WRITE statement

Stack underflow error tt

Stack overflow error tt

tMay be caused by machine malfunction or operating system error.

ttMay be caused by source program or loacting error; to correct, do the followi ng in descendi ng
order.
Q.

Use Diagnose to determine where the error occurred.

Recompile the source program.

Examine source program {in particular the arithmetic statements and subscripted
variables} •

4-8

CHAPTER 5
PAL -0 ASSEMBLER

5.1

INTRODUCTION TO PAL-D

The Tss/8 Assembly System is composed of the PAL-D Symbolic Assembler, LOADER, and ODT. The PAL-D
Assembler is used to translate the user's source program into an object program {binary or machine code}.
LOADER is used to transfer the user's object program from the disk into core for debugging or execution. ODT
(Octal Debugging Technique) is used to dynamically debug the object program which has been loaded into core
using LOADER.
The PAL-D Assembler is fully documented in the PDP-8 PAL-D Assembler, Programmer's Reference Manual
(Order No. DEC-D8-ASAB-D), and its operation under Tss/8 is covered in an appendix in that document.
PAL-D source programs ore usually written on-line using the EDIT program, which stores them in disk files. The
Assembler checks for assembly languoge syntax errors and for undefined user symbols but does not check for
logic errors. To call the PAL-D Assembler, type:
.R PALD

PAL-D responds by requesting INPUT: Type and enter the nome of the source program or programs to be
assembled. A maximum of three files con be assembled together. PAL-D then requests OUTPUT; Type in the
name of the new file in which PAL-D will store the assembled program in executable binary form. PAl-D then
requests OPTION: For a normal assembly, strike the RETURN key.. If on assembly listing is not desired, respond
to OPTION: with N.
PAL-D then proceeds to ossemble the program: any errors in the program are indicated; the program symbol
table is printed; and finally, an assembly listing of the source program is printed. When the listing is completed
and the assembly finished, control is returned to Tss/8 Monitor.

5.2

TSS/8 PAL-D

Because of the necessary hardware changes made for the Time-Shared System, PAL-D has been revised in the
following ways:

5-1

a. PAL-O, under TSS/8, allows 245 (decimal) user symbols in addition to the permanent symbols (listed
in section 5.4). All symbols reside in locations 5200 through 7777. The permanent symbol table has
been revised to include a \I instructions peculiar to the Time-Sharing System.

b. A CTRL/C (tC) from the Teletype terminates the assembly, and halts PAL-O, sending the user bock
to the TSS/8 Monitor.

5.3

EXAMPLE OF A PAL-O PROGRAM
.R PALL
I :--JPUT: TYFE2
OUTPUT: B 10J2
OPTIOK:
COL':JT
CRLF
LCCP
OUT
REG
START

0415
0417
0406
0425
0416
0400
/PROGRAM TO TYPE OUT "0123456789"
"'0400
START~
CLA
JMS CRLF
TAD (-12)
DCA COL'0JT
/ASCII CODE FOR ZERO (0)
TAD (260 )
DCA REG
TAD REG
LOOP~
JMS OUT
ISZ REG
ISZ COUNT
JMP LOOP
JfVS CRLF
HLT
COU~T~
0
REG~
0

0400
0401
0402
0403
0404
0405
0406
0407
0410
0411
0412
0413
0414
0415
0416

7200
4217
1377
3215
1376
3216
1216
4225
2216
2215
5206
4217
7402
0000
0000

0417
0420
0421
0422
0423
0424

0000
1375
4225
1374
4225
5617

CRLF~

0425
0426
0427
0430
0431
0432
0574
0575
0576
0577
rBS

0000
6046
6041
5227
7200
5625
0212
0215
0260
7766

OUT~

0
TAD (215)
JMS OUT
TAD (212)
J~S OUT
JMP I CRLF
0
TLS
TSF
JMP • -1
CLA
JMP I OUT

5-2

/ASCII FOR CARRIAGE RETUR:--J
/LINE FEED

5.4 SYMBOL LIST FOR TSS/a
Table 5-1
Symbol List for TSS/a
Mnemonic

Operation

Code

Event Time

MEMORY REFERENCE INSTRUCTIONS
AND
TAD
ISZ
DCA
JMS
JMP

0000
1000
2000
3000

4000
5000

Logical AND
Twos complement add
Increment & skip if zero
Deposit & clear AC
Jump to subroutine
Jump

I GROUP 1 OPERATE MICROINSTRUCTIONS
NOP
lAC
RAL
RTL
RAR
RTR
CML
CMA
CLL
CLA

7000
7001
7004
7006
7010
7012
7020
7040
7100
7200

No operation
Increment AC
Rotate AC & link left one
Rotate AC & link left two
Rotate AC & link right one
Rotate AC & link right two
Complement link
Complement AC
Clear link
Clear AC

1
3
3
3
3
3

2
2
1
1

IGROUP 2 OPERATE MICROINSTRUCTIONS
HLT
OST
SKP
SNL
SZL
SZA
SNA
SMA
SPA

7402
7404
7410
7420
7430
7440
7450
7500
7510

Halts the computer
Inclusive OR switch register with AC
Skip unconditionally
Skip on nonzero link
Skip on zero link
Skip on zero AC
Skip on nonzero AC
Skip on minus AC
Skip on plus AC (zero is positive)

ICOMBINED OPERATE MICROINSTRUCTIONS I
CIA
STL
GLK
STA
LAS

7041
7120
7204-

Complement & increment AC
Set link to 1
Get link (put link in AC, bit 11)

7240

SetAC~-l

7604

Load AC with switch register

5-3

4
3

1
1
1
1

Table 5-1 (Cont)
Symbol List for TSS/8
PSEUDO-OPERATORS
DECIMAL
EXPUNGE
FIELD
FIXTAB
I

Mnemonic

OCTAL
PAGE
PAUSE
TEXT
XLIST
Z

Code

Operation

Event Time

lOT MICROINSTRUCTIONS

Program Interrupt

6000

(See Time-Sharing System User's Guide
DEC-T8-MRFB-D)

KSF
KCC
KRS
KRB

6031
6032
6034
6036

KSB
SBC
KSR

6400

Skip if keyboard/reader flag = 1
Clear AC & keyboard/reader flag
Read keyboard/reader buffer
Clear AC & read keyboard buffer,
& clear keyboard flag
Set keyboard break
Set buffer control flags
Read keyboard string

lOT

Keyboard Reader

6401
6030

1
2

3
2,3

Tel epri nter/punch

TPC

6041
6042
6044

TLS

6046

SAS

6040

TSF
TCF

Skip if teleprinter/punch flag = 1
Clear teleprinter/punch flag
Load teleprinter/punch buffer,
Select & print
Load teleprinter/punch buffer,
Select & print, and clear
Teleprinter/punch flag
Send a stri ng

1
2

3
2,3

High-Speed Reader (Type PC02)
RSF
RRB
RFC
RRS

6011
6012
6014
6010

Skip if reader flag = 1
Read reader buffer & clear flag
Clear flag & buffer & fetch character
Read reader stri ng

1
2

Skip if punch flag ::= 1
Clear flag & buffer
Load buffer & punch character
Clear flag & buffer, load & punch
Punch string

1
2

High-Speed Punch (Type PC03)
PSF
PCF
PPC
PLS

PST

6021
6022
6024
6026
6020

5-4

3
2,3

Table 5-1 (Cont)
Symbol List for TSS/a
Mnemonic

Operation

Code

Event Time

DECtape Transport (Type TU55) and Control (Type TC01)
DTXA
DTSF
DTRB

6764
6771
6772

Load status register A
Skip on flags
Read status register B

6411
6412
6413
6414
6415
6420
6421

User run time
Time of day
Return clock rate
Date
Quantum synchronization
Skip on TSS/a
User
Set switch register
Check status
Assign device
Release device
Duplex
Console

Program Control
URT
TOO
RCR
DATE
STM
TSS
USE
SSW
CKS
ASD
REL
DUP
CON

6430
6200
6440

6442
6402

6422

File Control
WHO
SIZE
RFILE
WFILE
ACT
REN
OPEN
CLOS
PROT
CRF
EXT
RED
FINF

6616
6614

6603
6605
6617
6600
6601
6602

6604
6610
6611
6612
6613

Who
Segment size
Read file
Write file
Account number
Rename file
Open file
Close file
Protect file
Create file
Extend file
Reduce file
File information

5-5

3
1

5.5

ERROR DIAGNOSTICS
Table 5-2
PAL-D Error Diagnostics
Error
Code

Explanation

Two PAL-D internal tables have overlapped - This situation can usually be
corrected by decreasing the level of literal nesting or number of current
page literals used prior to this point on the page.

System device error - An error was detected when trying to read or write onto
the system device; after three failures, control is returned to the Monitor.

Systems device full - The capocity of the systems device has been exceeded; assembly is terminated and control is returned to the Monitor.

Illegal character - An illegal character was encountered other than in
a comment or TEXT field; the character is ignored and the assembly
continued •

Illegal redefinition of a symbol - An attempt was made to give a previously defined symbol a new value by means other than the equal sign;
the symbol was not redefined.

Illegal equals - An equal sign was used in the wrong context.
Examples:
TAD A +=B
A +B=C

the expression to the left of the equal sign is not
a single symbol or, the expression to the right of
the equal sign was not previously defined

Illegal indirect - An off-page reference was made; a link could not be
generated because the indirect bit was already set.

The program terminator, $, is missing.

Current nonzero page exceeded - An attempt was made to
a.

override a literal with an instruction, or

override an instruction with a literal; this can be corrected by

(1) decreasing the number of literals on the poge or
(2)

decreasing the number of instructions on the poge.

Phase error - PAL-D has received input files in an incorrect order;
assembly is terminoted and control is returned to the Monitor.

Symbol table exceeded - Assembly is terminated and control is returned
to the Monitor; the symbol table may be expanded to contain up to 1184user symbols by saving a file named .SYM on the system device.

Undefined symbol - A symbol has been processed during poss 2 that was
not defi ned before the end of poss 1.

Page 0 exceeded - Same as PE except with reference to poge O.

5-6

CHAPTER 6
UTILITY PROGRAMS

6.1

EDIT

TSS/8 Editor provides the user with a powerful tool for creating and modifying source files on-line. Its precise
capabilities and commands are detailed in the PDP-8 Symbolic Editor Programming Manual (Order No.
DEC-oB-ESAB-D). EDIT allows the user to delete, insert, change, and append lines of text; and then obtain
a clean listing cI the updated file. EDIT also contains commands for searching the file for a given character.
EDIT considers a file to be divided into logical units, called pages. A page of text is generally 50-60 lines
long, and hence corresponds to a physical page of program listing. A FORTRAN-D program is generally 1-3
pages in length; a program prepared for PAL-D may be several pages in length. EDIT operates on one page of
text at a time, allowing the user to relate his editing to the physical pages of his listing. EDIT reads a page
of text from the input fi Ie into its internal buffer where the page becomes available for editing. When a
page has been completely updated, it is written onto the output file and the next page of the input file is made
available. EDIT provides several powerful commands for "paging" through the source file quickly and conveniently.
NOTE
The end of a page of text is marked by a fonn feed (CTRL/L)
character. Form feed is ignored by all TSS/8 language
processors.
To ca II the Edi tor, type:
.R EDIT

EDIT responds by requesting INPUT: Type and enter the name of the source file to be edited. If a new file
is to be created using EDIT, there is no input file. In this case, strike the RETURN key. EDIT then requests
OUTPUT: Type in the name of the new, edited, file to be created. The name of the output file must be different
from the name of the input file. If EDIT is being called to list the input file, there is no need to create an
output file; strike the RETURN key. When EDIT sets up its internal files and is ready for a command, it rings
the bell on the Teletype.

6-1

For example:
.R EDIT
INPUT: vlXZOLD
OuTPUT: XYZNEW

(Bell rings at this point.)

6. 1. 1

Summary of Symbolic Editor Operations
Table 6-1
Summary of Symbol ic Editor Operations
Special Characters
Carriage Return
(RETURN Key)
Back Arrow (-)

Function
Text Mode - Enter the line in the text buffer.
Command Mode - Execute the command.
Text Mode - Cancel the entire line of text, continue typing on
same line.
Command Mode - Cancel command. Editor issues a ? and
carriage return/line feed.

Rubout (\)

Text Mode - Delete from right to left one character for each rubout
typed. Does not derete past the beginning of the line. Is not in
effect during a READ command.
Command Mode - Same as back arrow.

Form Feed
(CTRL/FORM Combination)

Text Mode - End of inputs return to command mode.

Period (.)

Command Mode - Current line counter used as argument alone or in
combination with + or - and a number (., .+5L).

Slash (/)

Command Mode - Value equal to number of last line in buffer. Used
as argument (/-5,IL).

Line Feed ( l )

Text Mode - Used in SEARCH command to insert a CR/LF combination
into the line being searched.

Right Angle Bracket (»

Command Mode - List the next line (equivalent to .+lL).

Left Angle Bracket «)

Command Mode - List the previous I ine (equivalent to . -1 L).

Equal Sign (+)

Command Mode - Used in conjunction with. and / to obtain their
value ( .=27).

Tabulation
(CTRL/TAB Key Combination)

Text Mode - Produces a tabulation which, on output, is interpreted as
spaces if bit 1 of the switch register is set to 0, or as a tab character/
rubout combination if bit 1 is set to 1.

6-2

6. 1.2

EDIT Command Summary
Table 6-2
EDIT Command Summary

Command

Format(s}

READ

Read text from the input file and append to buffer until a form
feed is encountered.

APPEND

Append incoming text from keyboard to any already in buffer until
a form feed is encountered.

LIST

list the entire buffer.

list line n.

m,nL

list lines m through n inclusive.

Output the contents of the buffer to the output file, followed by
a form feed.

Output line n, followed by a form feed.

m,nP

Output lines m through n inclusive followed by a form feed.

TERMINATE

Close out the output fi Ie and return to TSS/a Mon itor.

Output the entire buffer and a form feed, kill the buffer and
read the next page.

Repeat the above sequence n times.

KILL

Ki II the buffer (i.e., delete all text lines).

DELETE

Delete line n of the text.

m,nD

Delete lines m through n inclusive.

PROCEED

INSERT

Meaning

Insert before line 1 all the text from the keyboard until a form
feed is entered.
nI

Insert before line n until a form feed is entered.

Delete line n, replace it with any number of lines from the keyboard until a form feed is entered.

m,nC

Delete lines m through n, replace from keyboard as above until
form feed is entered.

MOVE

m,n$kM

Move lines m through n inclusive to before line k.

GET

Get and list the next line beginning with a tag.

Search the entire buffer for the character specified (but not echoed)
after the carriage return. Allow modification when found. TSS/a
Editor outputs a slash (/) before beginning a SEARCH.

CHANGE

6-3

Table 6-2 (Cont)
EDIT Command Summary

6.2

Meaning

Command

Format(s)

SEARCH
(Cont)

Search line n, as above, allow modification.

m,nS

Search lines m through n inclusive, allow modification.

END

Output the contents of the buffer. Read in any pages remaining in
the input file, outputting them to the output file. When everything
in the input file has been moved to the output file, close it out and
return to the TSS/8 Monitor. E is equivalent to a sufficient number
of N's followed by a T command.

CTRL/C

Stop listing and return to Command Mode.

LOADER

TSSi8 LOADER is used to load programs in BIN format from a disk file into the user's core area for execution.
These files in BIN format can be created by PAL-D in the course of an assembly or they can be loaded from
paper tape using PIP (see the PIP writeup for special instructions on loading BIN format tapes).
To call LOADER, type:
.R LOADER

LOADER responds by asking for INPUT: Respond by entering the name of the file or files to be loaded. Although
many System Library Programs allow multiple input files, the LOADER uses this feature to special advantage.
Because it loads the files in the order they are typed, LOADER can be used to load patches and overlays. After
it has requested INPUT, LOADER requests OPTION: For normal operation strike the RETURN key; LOADER is
able to load into any part of core below nso. If the program to be loaded is to be debugged, respond to
OPTION: with D. This will cause ODT to be loaded along with the input files and started. ODT indicates
that it is ready by printing a second line feed. ODT uses locations 7000 through 7577; and if loaded along
with a program which uses any of these locations, the result of the load is unpredictable.
Example 1: Normal Operation

.R LOADER
INPUT: MAIN~
OPTION:

PATCHl~

PATCH2

rES

6-4

Example 2: Load ODT with Input File

.R LOADER
INPUT:PROG1
OPTION: 0

As seen in the first example, LOADER returns control to Monitor when it is finished. The user can then start
the program by using the Monitor command START. For example, LOADER can be used to load and run the
short program given as an example in the section on PAL-D (see Chapter 5, Section 5.3) .

. R LOADER
INPUT: BIN2
OPTION:
rBS
.START 400
0123456789
rBS

NOTE
The BIN format files loaded by LOADER include a checksum.
If LOADER detects a checksum error while loading, it types
"LOAD ERROR" and terminates the load.

6.3

ODT (Octal Debugging Technique)

ODT is a powerful octal debugging tool for testing and modifying PDP-8 programs in actual machine language.
It allows the user to control the execution of his program and, where necessary, make immediate corrections to
the program without the need to reassemble.
The complete command repertoire of ODT is documented in the ODT Manual (Order No. DEC-OB-COCO-D).
OOT (on TSS/B) is the high-core version which resides in locations 7000 through 7577. The paper-tape output
commands of regular ODT are not available in TSS/8 OOT. To call ODT, type:
.LOAD 2 ODTHI 0 7000
.START 7000

If ODT is to be used to debug a program being loaded with LOADER, ODT can be loaded and started directly

by specifying the Debug (D) option to LOADER.

6-5

6.3.1

Programming Notes

aOT executes an SRA (Set Restart Address) as part of its initialization process. As a result, typing CTRL/C
always returns control to aOT. If the program being debugged sets up its own restart address, typing CTRL/C
transfers control to the new restart address. It is necessary to type tBS followed by START 7000 to force control
back to aOT.
Every time aOT regains control, it puts the Teletype in duplex mode. Users debugging programs which do not
operate in duplex mode, should be aware of this fact.
aOT saves the state of the delimiter mask, when it regains control via a breakpoint. The state of this mask
is restored on a Continue (C) command, but not on a Ga (G) command.

6.3.2

aOT Command Summary
Table 6-3
aOT Command Summary
Meaning

Command
nnnn/

Open register designated by the octal number noon.

Reopen latest opened register.

RETlRN

Close previously opened register.

LINE FEED (ll

Close register and open the next sequential one for modification.

Up Arrow (t)
(SHIFT/N)

Close register, take contents of that register as a memory reference
and open it.

Back Arrow (-)
(SHIFT/a)

Close register open indirectly.

Illegal Character

Current line typed by user is ignored, aOT types ?CR/LF.

nnnnG

Transfer program control to location nnnn.

nnnnB

Establish a breakpoint at location noon.

Remove the breakpoint.

Open for modification, the register in which the contents of AC were
stored when the breakpoint wos encountered.

Proceed from a breakpoint.

nnnnC

Continue from a breakpoint and iterate past the breakpoint nnnn times
before interrupting the user's program at the breakpoint location.

Open the search mask register, initially set to 7777. It may be changed
by opening the search mask register and typing the desired value after the
value typed by aOT, then closing the register.

l (line feed)

Close search mask register and open next register immediately following,
containing the location at which the search begins. It may be changed by
typing the lower limit after the one typed by aOT, then closing the register.

6-6

Table 6-3 (Cont)
OOT Command Summary
Command

Meaning

l (line feed)

Close lower search register, open next register containing the upper
search limit initially set to 7000 or 1000 (location of OOT). It may
be changed by typing the desired upper limit after the one typed by
OOT and closing the register wi th a carriage return.

nnnnW

Search the portion of core as defined by the upper and lower limits
for the octal value nnnn.

6.4

CAT

TSS/8 Monitor maintains a library of disk files for each user. The System Library Program CAT is used to obtain
a catalog of the contents of this library. For each file, CAT types the size of the file in units of disk segments.
The size of a disk segment may vary among installations. Generally, it is 256 (decimal) words of disk storage.
The protection code for the file is also given. (See the section on the PROTECT Monitor command (Chapter 9)
for a precise explanation of protection codes.) If the program was created by any of the System Library Programs,
it has a protection code of 12, meaning that other users can read the file, but only the owner can change it.
To call CAT, type:

.R CAT

6.4.1

Example of CAT Usage

.R CAT
DISC FILES FOR USER
NAME
BAS016
BAS 116
PRIME
MATRIX
SOLVE
PROG
TYPE2
BIN2
TEMP27

SIZE

1
8

3
11
2
15

312

PROT

DATE

12
12
12
12
12
12
12
12
12

TOTAL DISC SEGMENTS:

14 NOV 69

14 NOV
14 NOV
14 :-JOV
14 NOV
14 NOV
14 NOV
14 NOV
14 :-JOV
14 NOV
43

rBS

6-7

69
69
69
69
69
69
69
69
69

6.5

SY ST AT (System Status)

It is frequently useful to know the status of the system as a whole; how many users are on-line, where they are,
what they are doing, etc. The SYSTAT program provides this capability. To call SYSTAT, type:
.SYSTAT
.R SY5TAT

SYSTAT responds by printing on the first line: the version of the TSS/8 Monitor being run, the time, and the
date. SYSTAT reports the uptime which is the length of time in hours, minutes, and seconds since the system
was last put on-line.
SYSTAT lists all on-line users. Each user is identified by his account number. The job number assigned to him
and the number of the console he is using are indicated, as is the particular System Program he is running. The
exact running state of each user, whether he is actually running (RUN), typing in (KEY) or out (TTY), doing
input/output on another system device (10 or FIP), or not running (t8), is indicated. The amount of computer
time used by each user since he logged in is given.
If more users are on-line than the system has core fields to hold them, the fact that the system is swapping is
reported. The number of free core blocks used internally by TSS/8 Monitor for Teletype buffering and various
other purposes is typed out. Then SYSTAT reports any unavailable devices, i.e., devices which are assigned
to individual users. The job to which they are attached and their status (AS if they are assigned but not active,
AS+INIT if they are assigned and active) is also indicated. Finally, the number of available segments of disk
storage is reported.

6.5.1

Example of SYSTAT Usage

.R SYSTAT
STATUS OF TSS/8.19 DEC PDP-8 III AT 10:27:33
UPTIME 84:12:33

13 OCT 69

JOB

WHO

WHERE

WHAT

STATE

RU~TIME

1
2
3
4
5
7
11
12
14
15
17

5440
10
3141
4771
4772
333
7
1221
2000
222
5440

K00
K14
K15
K16
K17
K04
K21
K06
K03
K12
K11

SYSTAT
COpy
EDIT
FORT
PALD
BASIC
FOCAL
BASIC
PIP
FOCAL
FORT

RUN
KEY
KEY
RUN
TTY

01:00:12
00:00:21
00:00:03
00:09:42
00:00:13
01:37:12
00:00:57
00:03:51
00:16:23
00:22:17
00:22:19

SWAPPING

28K

FREE CORE=238

6-8

RUN
1B

RUN
KEY
TTY

BUSY DEVICES
DEVICE

JOB

v.'HY

3
3

AS+I:'-JIT
AS
AS
AS+I:'-JIT

D0
D5

412 FREE DISC SEGMENTS
rBS

6-9

CHAPTER 7
PROGRAMS FOR PAPER TAPE AND DECTAPE CONTROL

7. 1

PIP (Peripheral Interchange Program)

All TSS/8 System Library programs discussed in previous sections operate only on files which are on the disk.
Disk is a convenient storage medium for many files; however, it may be more useful to keep some programs on
paper tape. PIP provides a convenient means of transferring files between disk and paper tape, for those users
who wish to preserve copies of their files off-line.

7.1.1

PIP Conventions

PIP may be considered a link between disk file storage and paper-tape devices. To punch out a desired file,
PIP obtains that file from the disk and punches it on paper tape. Similarly, to load a paper tape, PIP inputs
the tape from the reader, then outputs it to a disk file.
The way files are named is important to PIP. Files on disk are always narned.

Paper tapes, on the other hand,

have no names as far as the system is concerned (although the user can label the physical tape in any manner
he chooses). Paper tapes never have file names; therefore, PIP uses the absence of a file name to indicate a
paper tape (absence of a file name is indicated by striking the RETURN key).
The way in which INPUT: and OUTPUT: is indicated provides the means for determining the direction of file
transfer. If PIP is to get its input from the disk, the input is a file name; if the input is from a paper tape no
fi Ie name is given. Similarly, if PIP is to output to the disk, the file name is indicated; if output is to paper
tape, no name is given. To call PIP, type:

.R PIP

7. 1. 2

Using PIP to Load a Paper Tape to a Disk Fi Ie

To move a paper tape to disk, strike the RETURN key when PIP requests INPUT: Since PIP must output to the
disk, respond to OUTPUT: by typing a file name. When PIP requests OPTION: type T to indicate that the

7-1

paper tape is being loaded from the Teletype reader. For example:
.R PIP
INPUT:
OUTPUT: FILEl
OPTION:T

The paper tape, in the low-speed reader, is read in and stored in the system as ALE1.

7.1.3

Using PIP to Punch Out a Disk File

To move a disk fi Ie onto paper tape, the use of file names is reversed since PIP must input a disk file and output
it to paper tape. The option remains the same. For example:
.R PIP
INPUT:FILEl
OUTPUT:
OPTION:T

The contents of FILE1 are then punched out at the Teletype.

7.1.4

Using PIP with the High-Speed Reader and Punch

PIP can also be used with high-speed paper-tape devices. The format of the INPUT: and OUTPUT: responses
is the same. However, for the high-speed reader, the option is R and for the punch it is P.
Since the reader and punch are assignable devices, they are not always available (other users may have one or
both assigned). Therefore, whenever PIP is given a command which utilizes one of these devices, it checks to
make sure that the device is available. If it is, PIP automatically assigns it (thus, it is not necessary to assign
the device before running PIP). If the device is unavailable, PIP so informs the user. For example:
INPUT:
OUTPUT: ABCD
OPTION:R

PIP reads the paper tape in the high-speed reader and stores it in the system as ABeD.
INPUT:ABCD
OUTPUT:
OPTION:P

7-2

PIP punches out file ABCD on the high-speed punch.
I0JPUT:ABCD
OUTPUT:
OPTION:P
DEVICE NOT AVAILABLE

The punch is assigned to another user, or there is no punch on the TSS/8 system, or there is one but it is turned
off.

7.1.5

Using PIP to Transfer BIN Format Files

The examples above work for all ASCII fi Ie transfers (except BASIC programs, explained below.) They are also
valid for punching out BIN format files with either high- or low-speed devices. Loading BIN format tapes,
however, is a specia I case.
BI N format tapes must end with trai ler codes. The easiest way to ensure that they do is to cut off the tape near
the end of the trailer code. Failure to do this (or cutting it off very unevenly) does not prevent PIP from loading
tape into the disk file.

However, later attempts to load the file with LOADER will result in load errors.

NOTE
Sorne TSS/8 installations will not allow any BIN format tapes
to be loaded from the low-speed reader.

7.1.6

Moving Disk Files

PIP can be used to move the contents of one fi Ie into another. This is often useful in copying a fi Ie from another
user's library (providing the file is not protected) into your own library. To copy from disk file to disk file,
specify a file name for both input and output. Reply to OPTION: by striking the RETURN key. For example:

INPUT:FOCAL 2
OUTPUT:FOCALX
OPTION:

PIP gets FOCAL from account number 2's library and moves it into the file FOCALX.

7.1.7

Deleting Disk Files

One of the principal reasons for punching out files on paper tape is to free disk space. Once punched out, the
disk file is no longer needed. PIP offers a convenient means of deleting files, the Delete option:

7-3

INPUT:ABCD
OUTPUT:
OPTION:D

PIP deletes file ABCD, provided that the file is not protected against being changed.

7.1.8

Transferring BASIC-8 Files

BASIC-8 stores its programs in a unique file format. Therefore, it is not possible to load or punch BASIC-8
files in the usual way. To provide a convenient means of handling BASIC-8 programs, the B option is available
in PIP.
The B option is used for both reading and punching BASIC-8 programs. The responses to INPUT: and OUTPUT:
indicate the direction of the transfer; the high-speed reader or punch is always assumed for the B option. (To
read or punch tapes at low-speed, use BASIC-8 itself.)
PIP assumes that any BASIC-8 tapes it loads are clean and error-free. Only tapes actually created by BASIC
should be loaded with PIP. Tapes created off-line, and thus liable to contain errors, should be loaded lowspeed by BASIC-8 itself with the TAPE command.

7.1.9

Transferring SAVE Format Files

Another special TSS/8 file format is that of the SAVE files, those programs directly executed by TSS/8. (The
System library Programs are examples of SAVE format files.) PIP provides the S option, to allow these files
to be punched on paper tape. SAVE format tapes make sense only to TSS/8 PIP. They cannot be input to any
other System Program.
The responses to INPUT: and OUTPUT: indicate the direction of the transfer; the high-speed reader or punch is
always assumed for the S option.

NOTE
SAVE format tapes include a checksum. If PIP detects an incorrect
read, it prints LOAD ERROR, and terminates the load, repeating
the request for input.

7-4

7. 1. 10

Summary of PIP Options
Explanation

7.2

Transfer a file between the disk and the Teletype reader or punch. The response to
INPUT: and OUTPUT: indicates the direction of the transfer.

Read a tape from the high-speed reader and store it as a disk file.

Punch out the contents of a disk file on the high-speed punch.

Delete the file specified for input.

Transfer a BASIC-8 program file between the disk and the high-speed reader or punch.
The response to input and output indicates the direction of the transfer.

Transfer a SAVE format file between the disk and the high-speed reader or punch.
The response to INPUT: and OUTPUT: indicates the direction of the transfer.

COPY

Many TSS/8 installations include one or more DECtapes. For these installations, DEC tape provides a convenient
and inexpensive means of fi Ie storage. The COPY program is used to transfer files between disk and DECtape.

7.2.1

Using and Calling COpy

COPY is the intermediary between disk and DECtape. To write a disk file out to DECtape, COPY inputs the
file from the disk, then outputs it to the DECtape. To bring a DECtape file onto the disk, COPY inputs from
the DECtape, then outputs to the di sk.
Files kept on DECtape have file names just as they do on the disk. To avoid confusion, the user must tell COpy
where t~e fi Ie is to be found. If it is on DECtape, the DECtape designation and the number of the DECtape
unit must preface the file name. The DECtape number is always separated from the file name by a colon. Thus
D1 :FILEl means the file name ALEl on the DECtape which is currently mounted on DECtape unit number olle.
The number of available tape units varies among installations. The maximum is eight, (numbered 0 - 7). If
a file name is not prefaced by a DECtape number, then this file is assumed to be on the system disk.
Files stored on DECtape do not have protection codes in the sense that disk files do. They are, however, protected against unauthorized access. When a DECtape is not mounted, it is not available to any user. When it
is mounted, it is available only to the user who has assigned the DECtape unit on which it is mounted. Even
then it can not be altered unless the DECtape unit is set to WRITE ENABLE.
Users should be sure to assign a DECtape unit before mounting their tape, and dismount the tape before releasing
the device. Normally, the DECtape unit to be used should be assigned before calling COpy.

7-5

.ASSIG:J D 4
D 4 ASSIG:JED
.R COpy

To call COPY, type:

.R COpy

COpy responds by asking which option the user wishes to employ. The COpy options are discussed below.

7.2.2

Loading Files from OECtape

To load a file onto the disk from OECtape, use the COPY option. When COPY requests OPTION- respond with
COPY, or C, or strike the RETURN key (the COPY option is assumed). When COPY requests INPUT-type the
number of the OECtape unit on which the file can be found {OO, 01, 02, 03, 04, 05, D6, or 07}followedby
a colon and the name of the file on the OECtape. When COPY requests OUTPUT- type and enter the name to
be given to the output file on the disk. COPY then moves the OECtape file onto the disk. {When using COPY,
it is not mandatory to insert a space between the device designator and the device number.} For example:

OPTIO:J- COPY
INPUT - D4:PQR
OUTPUT - PQR

If for any reason, COPY cannot find the OECtape file specified for input (tl,e specified OECtape is unavailable
or nonexistent, or the file name does not exist on that OECtape), COpy prints a ? and repeats the request for
input. If the disk file specified for output already exists, COpy prints a ? and repeats the request for output.
COpy does not overwrite an existing file. For example:

OPTION - C
INPUT - D9:PQR
?INPUT - D4:PQRS
?INPUT - D4:PQR
OUTPUT - FILEl
?OUTPUT- PQR

7-6

7.2.3

Saving Disk Files on DECtape

Saving a disk file on DECtape is very similar to loading one. The option is still COPY. For input, respond with
the name of the file on the disk. For output, type the DECtape unit number, colon, and the name to be given
to this file. For example:
OPTIO)] - C
npUT - ABCD
OUTPUT - D4:ABCD

If COpy cannot find the file on the disk, or if it is protected, COpy prints a ? and repeats the request for in-

put. If COpy cannot set up the desired DECtape file (the specified DECtape does not exist or is unavailable,
or it is not WRITE ENABLED, or a file by that name already exists on the tape) COP'( types a ? and repeats the
request for output.

7.2.4

Listing Directories

COpy ca" be used to list the directory of a device. To list a directory, respond to OPTION-by typing LIST, or
just L. COpy then asks which device it is to list. To list a DECtape's directory, respond with the device name
(DO, .•. ,D7). Do not follow it by a colon. For example:
OPTIO)] - LI ST
DEVICE - D(l
1298. FREE BLOCKS
"JAt><E
XCOPY
XBASIC

FOO

SIZE
32
66
66

DATE
6-)]OV-69
6-)]OV-69
6-)]OV-69

The unit of DECtape storage is the block, which is 128 (decimal) words. Because the unit of disk storage, the segment, is generally 256 words, a file occupies twice as many blocks of DECtape storage as it did segments on the disk.
COpy can also be used to list the user's disk directory. Use the LIST option, but respond to DEVICE- by
simply striking the RETURN key. The directory listing is similar to the listing obtained by running the CAT
program.

7.2.5

Deleting Files

COpy can be used to delete files, either on the disk or on a selected DECtape. To delete a file, respond to
OPTION- by typing DELETE, or just D. Respond to INPUT - by typing the name of the file to be deleted.
7-7

If the file is on a DECtape, preface the file name with the DECtape unit number and a colon. For example:
OPTION - DELETE
I:-vPUT - D4:ABCD

If COpy cannot find the file to be deleted, or having found it, cannot delete it (it is a protected disk file or

a DECtape file on a unit which is not WRITE ENABLED), COPY prints a ? and repeats the request for INPUT-.

7.2.6

Deleting All Files on a Device

COpy can be used to delete all existing files on a device. To do so, respond to OPTION- by typing ZERO,
or just Z. When COpy requests INPUT- respond with the name of the device. To delete all files on the disk,
strike the RETURN key. The ZERO option should also be used to format a blank DECtape before attempting to
copy any files onto it. For example:

OPTION - ZERO
INPUT - D4

or
OPTION INPUT -

COpy cannot delete files from a DECtape unless it is WRITE ENABLED. It cannot delete disk files which are
write protected.

7.2.7

Summary of COpy Options
Option

Explanation

COpy

Transfer a file between disk and DECtape.

LIST

list a directory.

DElETE

Delete a file.

ZERO

Delete all files.

7-8

7.2.8

Example of COpy Usage

.ASSIG:'-J D 5
D 5 ASSIGNED
.R COPY
OPTIO:'-J - ZERO
DEVICE - D5
OPTI00J - LIST
DEVICE - D5

1462. FREE BLOCKS
0JAME

SIZE

DATE

OPTIO:'-J - LIST
DEVICE -

DISK FILES FOR USER 5440 ON 13-0CT-69.
:'-JAME
SOLVE

SIZE
1

PROT
12

DATE
13-0CT-69

TOTAL DISK SEGME:'-JTS:
OPTIO:'-J - COpy
I:-JPUT - SOLVE
OUTPUT - D5: SOLVE
OPTIO:'-J - DELETE
INPUT - SOLVE
OPTION - LIST
DEVICE - D5

1460. FREE BLOCKS
NAME
SOLVE

SIZE
2

DATE
13-0CT-69

7-9

OPTION - LIST
DEVICE DISK FILES FOR USER 5440 O:J 13-0CT-69.
:JAME

SIZE

PROT

DATE

TOTAL DISK SEGME:JTS: 0
COPY
INPUT- D5:S0LVE
OUTPUT- ABCD
OPTIO~-

OPTIO:J- LIST
DEVICEDISK FILES FOR USER 5440
:JAME
ABCD

SIZE

TOTAL DISK

PROT
12

13-0CT-69.

DATE
13-0CT-69

SEGME~TS:

OPTION- tBS
.RELEASE D 5

7-10

CHAPTER 8
ADVANCED MONITOR COMMANDS

8.1

INTRODUCTION

Chapter 2 described the fundamental Monitor commands, i.e., those needed to utilize existing TSS/8 System
Library Programs. The TSS/8 Monitor also provides powerful commands for users who wish to create their own
Library Programs.
To use the System Library Programs described in Chapters 3 through 7, it was not necessary to be fami! iar with
the actual machine that runs them, the PDP-8/I. To create new Library Programs for TSS/8, this is necessary
because they are written in the PDP-8 assembly language. The user codes his programs for a 4K PDP-8, subject
to the time-sharing conventions discussed in the following chapter.

The programs are created with TSS/8 EDIT,

then assembled by PAL-D a .... d loaded by LOADER. Only at this point are they able to be run by TSS/8. In the
course of this program development, the same program exists in many formats. The source program is a disk file
containing ASCII characters in an Editor format.
assembled program in BIN format.

PAL-D reads the file and translates it into a seco .... d file, the

Neither of these files is capable of being executed directly by TSS/8. The

BIN format tape must be loaded into core by LOADER before it can actually be executed.
At this point it is possible to save the program in a file format that is directly executable by TSS/8. Such a file,
referred to as a SAVE format file, contains an image of the user's core area after the program has been loaded
by LOADER. These SAVE format files differ from all the files which are created by System Library Programs and
cannot be executed directly by TSS/8. Thus, it is not possible to save a BASIC program, (for example FILE1,
while run"ing BASIC) then return to Monitor, type R FILE1, and get meaningful results. The program in FILE1
must be executed under control of the BASIC language processor. Only SAVE format files can be called into
execution directly by the R command. All TSS/8 System Library Programs are stored in SAVE format.

NOTE
In the following examples, Sn, Cn, and Dn are used to
stand for alphanumeric strings (such as file names), octa I numbers, and dec ima I numbers, respective Iy.

8-1

A number of Monitor command conventions are available to make the commands easier to use. First, more
than one command may be typed on a line. Individual commands are separated by a semi-colon (i). Second,
only enough characters of a command to uniquely specify it need be typed. Thus, DEPOSIT can be abbreviated
DE or DEP.
.LOAD FILEl; DEP

7000; ST 200
/

is exactly equivalent to:
.LOAD FILEI
.DEPOSIT 20 7000
.START 200

These conventions are avai lable for the elementary Monitor commands as well. They are, however, especially
convenient for the advanced commands.

8.2

CONTROL OF USER PROGRAMS

Once a PAL-D program has been loaded by LOADER, several Monitor commands are available for controlling
its execution.
Explanation

Command
START Cl

Start execution of a user program at location C 1. When a program is started,
keyboard input is no longer interpreted as commands to Monitor. Input characters are passed to the running program. START Cl clears the user's AC and
link.

START

Restart execution of a user program where it was interrupted (either by execution
of an HLT or by tBS typed at the keyboord). When the START command is given,
the program's state is restored.

DEPOSIT Cl C2 .•. Cn

Deposit the octal values C2 to Cn in the locations starting at C 1. DEPOSIT is
used to make small octal modifications to a user program. No more than 10
deci'Tlal locations can be modified by a single DEPOSIT instruction.

EXAMINE Cl

Print the octal contents of location C 1.

EXAMINE Cl Dl

Print the contents of Dl locations starting at C 1.

WHERE

Print the present status of the user program. The user's AC, PC, and LINK are
printed. If the TSS/8 processor includes the extended arithmetic element, two
additional registers, the SC and MQ are printed.

It is possible to give these uti lity commands whi Ie a user program is running. The CTRL/B character (tB) gets
the attention of the Monitor without stopping program execution. (tB followed by the S command stops the
program.) tB can be used together with the WHERE command to follow program execution. After executing
these commands, Monitor does not put the Teletype bock into Monitor mode.

8-2

•

8.3

DEFINING DISK FILES

TSS/8 Monitor allows the user to save core images of his program on the disk for future use. However, before
saving such a core image, the user must define a disk file in which to save it.
Disk files, like the user's core, are made up of 12-bit words. Unlike the user's core, which is always 4K in size,
a file can be any size. The unit of disk file storage is the segment; in most installations a segment is 256 (decimal) words but can be from 128 to 1024 words long. Files are at least one segment long when created and grow
by appending additional segments to the end of the file. In defining a file, the user first creates it, then extends it to whatever length he needs. To save a whole 4K image on a system with a segment size of 256 (decimal)
words, a 16 segment file is required. If only part of the contents of the user's core is to be saved, a correspondingly smaller file can be used.
A file can be created at any time. However, to modify or redefine it in any way, the file must be open. Up to
four files can be open for a user simultaneously. Opening a file connects it to an internal open file number (0,
1,2, or 3). Once a file is open, it is referenced by this internal file number rather than by its file name.

8.3.1

Creating a Disk File
CREATE S1

Define a one segment area of disk space and associate with
it the name given in the command line.

The fi Ie name can be one to six alphanumeric characters of which the first must be a letter. Creating a file
deletes any existing file of the same name, unless that file is write protected. When created, files are always
one segment in size. A new file is arbitrarily assigned a protection code of 12, meaning that other users may
access it but only the owner may change it. Until it has been written in, the contents of a newly defined file
are undefined.

8.3.2

Opening and Closing a File

To use a file, it must first be opened. A file can be opened on any of four internal file numbers: 0, 1, 2, or 3.
OPEN Cl S1

Associate the file S1 with the internal file number C1.

A user can have up to four files open at a time. If a file is open on an internal file number for which a file is
already open, that file is first closed. For example:

.CREATE
.OPE)J 1

AB
AB

AB is now an open file and can be referenced as file 1.

8-3

An open file can be closed at any time by means of the CL05E comrmnd.
Close the file presently open on internal file number C1.

CL05EC1

Once closed, a file cannot be accessed in any way until it ;s reopened. It is poss;ble to close more than one
file with a single command .
• CLOSE 0 1 2 3

8.3.3

Extending, Reducing, and Renaming a Disk File

When created, a file is one segment long. If a larger file is needed, the original file can be extended.
EXTEND C1 D1

Extend the file presently open on internal file C1 by D1
segments.

Extending a file adds one or more segments to the end of that file. The contents of the old part of the file are
not changed. Until written in, the contents of the newly added segments are unspecified.
An existing file may be reduced in size by means of the REDUCE command:
REDUCE C1 D1

Reduce the file presently open on internal file C1 by D1
segments.

Reducing a file deletes the number of segments indicated from the end of the file. The contents of remaining
segments of the fi Ie are unchanged. If a file is reduced to zero segments, or if D1 is greater than the number
of segments in the file, it is deleted entirely. An example of the creation and deletion of a 4K file:

.CREATE
.OPE:-J 3
.EXTEND
.REDUCE

FOURK
FOURK
3 15
3 16

Existing opened files can be renamed. Renaming a file does not change its contents in any way.
RENAME C1 51

8.3.4

The fi Ie open on internal file number C 1 is given the
new name 51.

Protection Codes

The user can protect his files against unauthorized access. He can also specify the extent of access certain
other users can have to his files. For example, a user's associates can be permitted to look at the data of
certain files but not permitted to alter that data.

8-4

When it is created, a file is assigned a protection code of 12. This protection code is defined below and can be
changed (see Appendix F), but on Iy by the owner of that fi Ie.
PROTECT C1 C2

The fi Ie open on interna I fj Ie number C 1 is given the
protection code C2.

The protection code is actually a 5-bit mask. Each bit specifies a unique level of protection. (See the
PROTECT lOT in Chapter 9 for the meaning of each bit.)
File protection masks (C2) are assigned as follows:
Read protect against users whose project number differs from owner's.
2

Write protect against users whose project number differs from owner's.

Read protect against users whose project number is same as owner's.

Write protect against users whose project number is same as owner's.

Write protect against owner • To change the program the owner must change
the protect code.

Protection codes are determined as the unique sum of any of the above codes.
Some of the more common protection codes are as follows:
• PROTECT 1 12

Allow other users to access the fi Ie but not change it.

· PROTECT 1 17

Allow only the file owner to read the file. He can also
change it.

• PROTECT 1 37

Allow on Iy the fi Ie owner to read the fi Ie • He cannot,
however, change it. (T 0 change it, he must first change
the protection.)

• PROTECT 10

Allow other users to access the fi Ie and change it.

Finally, the user can ask what file is open on a given internal fi Ie number by means of the F (Fi Ie information)
command.

F C1

Type out the following information about the file presently
open on internal file C1:
a.
b.
c.
d.

Account number of file owner.
Name of file.
Protection code.
Size of file in segments (decimal).

For example:
•F

0010 TYPE 0012

8-5

8.3.5

Error Conditions

There are a number of error conditions which prevent the execution of the file definition commands (as previously
described). One of the following error messages is typed by Monitor in the event that an error condition is
detected:
FILE NOT OPEN

An EXTEND, REDUCE, PROTECT, or RENAME command
has been issued for an internal file number for which no file
is open.

FILE IN USE

An EXTEND, REDUCE, PROTECT, or RENAME command has
been issued for a file which is in use elsewhere by another
user. Because changing a file which is being used (i.e., has
been opened) could disrupt another user's work, under these
conditions such a change is prohibited.
NOTE
Changing a file which the user himself has opened on another
internal file results in this error message.

8.4

DIRECTORY FULL

A CREATE command has been issued, but the user's directory
is full. He can delete any of his files to make room for the
new file.

PROTECTION
VIOLATION

An attempt has been made to change a file which is write
protected against the user.

FILE NOT FOUND

The user has attempted to OPEN a nonexistent file.

FAILED BY n
SEGMENTS

The user has attempted to extend a fi Ie, but the system has run
out of disk segments. The number of segments requested, but
not ava i lab Ie, is typed out.

SAVING AND RESTORING USER PROGRAMS

Ol1ce a file !'as been defined, the user can save all or any part of his user core in the file. Files and user core
are addressed in the same way, by 12-bit words. The user can transfer his file into any part of core.
The SAVE command requires one to five parameters. The name of the file to be written into must always be
given. If the file is not in the user's own library, the appropriate account number is entered before the file
name. (Writing into a file owned by another user is subject to file protection.) In either case, the parameters
are separated by spaces.
SAVE

Write the indicated section of core out into the indicated file.

If no parameters follow the file name, Monitor starts at location zero of the user's core and saves it in location

zero of the disk file. It continues to write core locations into the disk file until: (a) it has written out the
whole 4K or (b) it has filled the file. Either condition completes the SAVE.

8-6

The user can further define his SAVE command by indicating specific ports of core to be saved in specific parts
of the disk file. He does this by typing one to three parameters foUowing the file name. The first parameter
following the file name indicates a specific disk file address at which to begin writing. The second parameter
following the file name indicates a specific core address at which to terminate the transfer. If only the first
two parameters are typed, the transfer terminates when either the end of -:ore or the end of file is reached.
SAVE S1
SAVE C1 S1

Assuming that a disk file S1 exists, and that it is not write
protected, the contents of core is saved in 51. In the first
case, S1 is assumed to be in the library of the user giving the
command. In the second case, it is assumed to be in the
library of the user whose account number is C 1.

SAVE S1 C2 C3 C4

Locations C3 to C4 (inclusive) are saved in file S 1 starting at
disk file location C2. S1 is assumed to be in the user's own
library. If S1 is preceded by the parameter C 1, it is assumed
to be in the Iibrary of the user whose account number is C 1.

Once a core image has been saved in a disk fi Ie, it can be restored to core by means of the LOAO command.
It should be noted that the Monitor command LOAD is very different from the System library Program LOADER.
LOADER loads a BIN format file (created by PAl-O) into the user's core. LOAD loads a SAVE format file
(created by a previous SAVE command) into core.
The LOAD command requires from one to five parameters. The name of the file to be loaded must always be
given. If the file is in the user's ONn library, this file name is typed after the SAVE command itself. If it is in
another user's library, his account number is entered before the file name. {Reading another user's file is subject to fi Ie protection.} In either case, the parameters are separated by spaces.
LOAD

Read the indicated section of a disk file into the indicated
section of core.

LOAD S1
LOAD C1 S1

Assuming that a disk file S1 exists, and that it is not read protected,
the contents of the file S1 is loaded into core. In the first case S1
is assumed to be in the library of the user giving the command. In
the second case, it is assumed to be in the library of the user whose
account number is 01.

The user can further define his LOAD command by using the same optional parameters discussed in the section
on the SAVE command.
LOA 0 S 1 C2 C3 C4

Locations C3 to C4 {inclusive} are loaded from fi Ie S 1 starting at
file location C2.

Example:
.LOAD NEWF 5 10 17 Words 5 to 14 (inclusive) of the file named NEWF are loaded into
locations 10 to 17 of the user's core.

8-7

It is not necessary to open a file before using it in a LOAD or SAVE command. Both commands automatically
open the specified file on internal file number 3 before performing the transfer. After completion of the command, the file remains open on file number 3.
A special macro-command, RUN, exists to allow a program to be loaded and started all in one command.
RUN 51
RUN C1 51

Load file 51 into core from the disk and start execution at location O.
In the first example, file 51 is assumed to be in the user's own library.
In the second, it is assumed to be in the library of the user whose
account number is C 1.
RUN 51 is exactly equivalent to LOAD 51; START O. RUN C1 51 is
exactly equivalent to LOAD C1 51; START O.

The R command (see Chapter 2, Section 2.4) is a special case of the RUN command.

R 51

8.5

Load file 51 from the System library (account number 2) and start
at location O. R 51 is exactly equivalent to RUN 251.

UTILITY COMMANDS

TSS/8 Monitor provides a number of special purpose commands to aid in program development and use.
Explal1ation

Command
USER

Print the number of the job connected with this user and the console
number of the job.

USER C1

Pri nt the consol e numbers of job C 1•

SWITCH C1

Set the user's switch register to C1. Monitor maintains a switch
register for each user. When h is program executes an OSR (OR
tl,e switch register into the AC) this value is the one which is loaded.

BREAK

Type the current value of the user's delimiter mask.

BREAK Cl

Set the user's delimiter mask to C1. (The use of the delimiter mask
is discussed in the chapter on assembly language programming.)

DUPLEX

Place the user's Teletype in duplex mode. All characters typed at
the keyboard are automatically printed as tl,ey are entered.

UN DUPLEX

Take the user's Teletype out of duplex mode. Input characters are
received by the Monitor and by the user program without their being
printed at the console.

RESTART Cl

Set the user program restart address to C 1. If CTRL/C is typed at
the keyboard, Monitor forces a jump to location C1 in the user's program.

VERSION

Type out the version of TSS/8 Monitor being used.

8-8

CHAPTER 9
WRITING ASSEMBLY LANGUAGE PROGRAMS FOR TSS/8

9. 1 INTRODUCTION
In addition to the higher-level programming languages available in the TSS/8 library, the user can also code
and run programs written in the PDP-8 assembly language, PAL-D (Program Assembly Language). These programs
are prepared with EDIT, assembled with PAL-D, then loaded with LOADER. For those users unfamiliar with assembly language programming, the DEC Introduction to Programming is a useful guide.
A user can program TSS/8 iust as he would any other 4K PDP-8. (Assembly language programs must fit in 4K of
core.) All memory reference instructions (AND, TAD, ISZ, DCA, JMS, and JMP) function as on a stand-alone
PDP-8. All operate instructions (instruction code 7) also function as on a regular PDP-8 (Exception: microcoding HLT or OSR with any other operate instruction but CLA gives unpredictable results).
The major difference between TSS/8 programming and regular PDP-8 programming is in the lOT (Input/Output
Transfer) instructions. Some instructions which are valid on stand-alone PDP-8s, such as CDF, CIF, ION, IOF
are considered illegal instructions under time-sharing. There are a great many new lOTs within TSS/8 that are
not valid on a regular PDP-8. Finally, there are lOTs which operate on TSS/8 in the same manner as on standalone PDP-8s.
The way TSS/8 actually executes an lOT instruction is also different.

Non-lOT instructions (except HLT and

OSR) are executed by the TSS/8 hardware, while lOTs (and HLT and OSR) are not. As explained in Appendix C
lOTs are privileged instructions, executed by the TSS/8 Monitor rather than by hardware.
In general, TSS/8 provides the programming capabilities of a 4K PDP-8, and allows programs of considerably
greater complexity to be run within the constraints of each user's 4K of core. The TSS/8 Library Programs, all
of which were written in assembly language and make use of the TSS/8 lOT's dealt with below, are examples
of programs which can be run on TSS/8.

9-1

9.2

CONSOLE I/O

User programs handle console (Teletype) I/o in almost the same way as stand-alone POP-8 programs. The KRB
instruction is used to input a character, the TLS instruction to output a character. The KSF and TSF (followed by
JMP .-1) can be used but are not needed. TSS/8 Monitor handles all timing problems whether these skip lOTs
are present or not.
TSS/8 differs from the stand-alone POP-8 in that under TSS/8 the user program interacts with multi-character
input and output buffers (maintained by TSS/8 Monitor) rather than with single character registers.
the state of the system, these buffers may have one, many, or no characters in them.

Depending on

During normal program

execution, this fact is of no ccnsequence. User programs still send and receive characters one at a time. There
are times, however, when it is useful to clear out any and all characters in the buffers; a special lOT exists for
this purpose (SBC).
On a stand-alone system, characters are input as soon as they are typed, whether they are of immediate interest
or not. Usually, these characters are stored away by the program until a terminating (or delimiting) character is
found. At this time, the whole line of characters is processed. On a swapping, time-sharing system such as TSS/8,
this mode of operation is wasteful. It is far more efficient to allow input characters to accumulate in the Monitor
input buffer until a delimiter is found. There is an lOT to specify which characters are to be considered delimiters (KSB).
TSS/8 also allows programs to input and output strings of characters. The read string (KSR) and send string (SAS)
instructions provide a convenient and efficient means of doing lengthy transfers.
All keyboard input uses full-duplexed hardware, (there is no wired connection between the keyboard and printer,
i.e., characters are not printed on the console as typed). Input characters are echoed to the console under program control rather than by hardware. Because input charac ters are a lIowed to accumul ate in buffers before
being passed to the user program, it is important to have Monitor perform the echoing rather than user programs.
There is an lOT (OUP) to set up this automatic echoing as well as an lOT (UNO) to inhibit echoing for such
operations as reading tapes.
Read Keyboard Buffer (KRB)

Octal Code: 6036

Operation: Read the next input character into bits 4-11 of the AC.
Load Teleprinter Sequence (TLS)

Octal Code: 6046

Operation: The ASCII character in AC bits 4-11 is typed out on the user's console.
Skie on Kelboard FlaS (KSF)

Octal Code: 6031

Operation: The next instruction is skipped if there is a delimiter character in the user's input buffer.

9-2

Octal Code: 6040

Read Keyboard String (KSR)

Operation: Execution of this instruction initiates a transfer of one or more characters from the user's keyboard
to a designated core area. Before executing KSR, load the AC with the address of a two-word block, where:
Word 1:

negative of the number of characters to be transferred.

Word 2:

address of the core area into which characters are to be placed minus one.

The transfer is terminated when either:
a.

the indi cated number of characters have been input or

b. a del imiter is seen. At the end of the transfer, the word count and core address are updated
and the AC is cleared.
Octal Code: 6040

Send A String (SAS)

Operation: Before executing an SAS, load the AC with the address of a two-word block, where
Word 1:

contains the negative of the number of characters to be sent.

Word 2:

contains the add-ess -1 of the first word of the string.

The characters are stared one per word right justified starting at the add-ess specified by word 2. Upon execution
of SAS, the system takes only as many characters as will fit in the output buffer. It then makes the appropriate
adjustment to word 2 to indicate a new starting address and to word 1 to indicate the reduced character count;
it returns to the instruction following the SAS. If the character count is reduced to zero, the instruction following SAS is skipped. The instruction following the SAS should contain a JMP .-2 to continue the block transfer
of Teletype characters. The AC is cleared by SAS.
Octa I Code: 6400

Set Keyboard Break (KSB)

Operation: Rather than activate a user's program to receive each character as it is typed, TSSj8 accumulates
input characters until a certain character or characters is seen. To tell TSSj8 Monitor which characters to look
for (these characters are referred to as delimiters,) load the AC with a 12-bit mask before executing a KSB. For
each bit in the mask which is set, Monitor considers the corresponding character or characters to be delimiters.
Specifies

Bit

o
1
2

3
4
5
6

7
8
9
10
11

o = check rest of mask
1 = any character is break
301-332 (all letters)
260-271 (all numbers)
211
(Horizontal tab)
212-215 (line feed, vertical tab,
form feed, RETURN)
241-273 (!" I $ % & ' ( ) * + , - . j : ; )
240
(space)
274-300 « = > ? @)
333-337 ([ \J t +-)
377
(rubout)
(alt mode)
375
anything not in bits 1-10

9-3

Duplex (DUP)

Octal Code: 6402

Operation: DUP infonns Monitor that the user wishes each character typed at the console to be echoed on that
console's printer as it is received by Monitor. The DUP instruction does not affect the user's registers.
Octal Code: 6403

Unduplex (UNO)
-~-

Operation: UNO informs Monitor that the user wishes to suppress character echoing. This can be done for
reasons of privacy or because a program does its own character echoing. The user's registers are unaffected
by UNO.
Set Buffer Control (SBC)

Octal Code: 6401

Operation: SBC permits the user program to clear its Teletype input and/or output buffer. Before executing SBC
set bits 0 and 1 of the AC as indicated below:

9.3

Bit 0

Clear output buffer

Bit 1

Clear input buffer

FILES AND DISK I/o

All user programs can gain access to the Tss/8 disk storoge. The time-sharing Monitor maintains a pool of
available disk space which is allocated in units referred to as segments. (The size of a disk segment varies
among Tss/8 installations. Segments may be 128,256, 512, or 1024 words each). These segments are used
to make up user files on the disk. Monitor also maintains, for each user, a directory of all files which he has
defined.
The lOTs which allow the user to access the disk are of two types: those which define files on the disk and
those which transfer data between a defined file and the user's core.
NOTE
CREATE and OPEN require that a user set up a file name
in core. FINF and WHO return file names to core. Each
must be specified in TSS;8 internal code (excess 40 code)
as shown in Appendix A. Characters are packed two to
a word.
The first step in defining a file is to create it. Creating a file reserves a single segment cl disk storage and
associates it with a name. This file can then be extended to any length desired. Extending a file appends more
segments to it. Similarly, a file can be rewced by any number of segments. Reducing a file removes the last
segment or segments from the file. Reducing a file to zero segments deletes it entirely. Once created, a file
can be protected, thereby restricting access to it. When created, a file can be read by any user, but only the
creator can write in it. This protection can be reset if desired.
file.

9-4

Finally, it is possible to rename an existing

None of these actions affect the contents of the file -- they only reserve space on the disk. Until it has been
written in, the actual content of a file is unspecified. Extending a file does not alter the content of the file
as it previously existed. Once defined, files can be used to read and write data. ky number of words (1 to
4096) can be moved from any part of the user's core to any part of a file (subject to file protection). The user
program specifies a location in core and a word count. This indicates how many words are to be transferred
and from (or to) where in core they are to be moved. Also specified is a disk file address indicating what part
of the file is involved. This address is the address of a word in the file. Fi les are addressed in the same manner
as core: in 12-bit words. Unlike core, however, files can be longer than 4K. To address these files provision
is made fora 24-bit disk file address, containing the high-order and low-order file addresses.
File addresses are independent of any consideration of segments. The file address is meaningful only in defining
files. Files can be read and written across segment boundaries without restriction. (The user cannot read or
write beyond the last segment boundary.)
When it executes a fi Ie read or write lOT, the system updates the core add-ess and word count and places an
error code in the error word (see RFllE) if any error is detected. (The error word must be cleared before executing the lOT.) At the end of a successful transfer, the word count is set to zero and the core add-ess set to the
last word transferred. If the transfer cannot be completed for some reason, the word count and core address
indicate how much of the transfer was successful; the error word indicates the cause of the failure. All file
operations except CREATE (and OPEN) require that the file be open. Up to four files can be open at a time.
The process of opening a file associates it with one of four internal file numbers (0, 1, 2, or 3). All file lOTs
except CREAT and OPEN, are specified in terms of one of these internal file numbers, rather than a file name.
lOTs operate on the file which is indicated by that internal fik! number at the time. It is therefore possible to
write file handling programs which are independent of the actual file(s) they operate on.
File lOTs, that are successfully completed, return with the AC cleared. If an error was found which prohibited
execution of the lOT, one of the following error codes is returned:
4000

There was no file opened on the specified internal file number.

4400

Attempting to redefine a file which is open to another user.

5000

Attempting to create a file for a user whose directory is full .

6000

Fi Ie protection violation.

6400

Invalid file name.

7000

Attempting to open a nonexistent fi Ie.

7400

Disk is full.

Create a Fi Ie (CRF)

Octal Code: 6610

Operation: the user can request the system to create a new fi Ie of one segment. The user program provides the
new name for the file. load the AC with the beginning address of a 3-word block, where

9-5

Words 1 through 3:

contain the 6-character name.

If there is some reason why the request cannot be granted, the system will return a non-zero error code in the AC.
The protection code of a newly created file is 12.
Octal Code: 6611

Extend A File (EXT)

Operation: To extend the length of an existing file, that file must be currently open. Load the AC with the
beginning address of a 2-word block, where:
Word 1:

contains the internat file number of the file to be extended.

Word 2:

contains the number of segments the system should append to the fi Ie.

If for some reason the request to extend a file cannot be granted, the AC will contain 4000, 4400, 6000, or

the number of segments it failed to append.
Octal Code: 6612

Rewce A Fi Ie (RE D)

Operation: To rewce the length of an existing file, that file must be currently open. Load the AC with the
beginning address of a 2-word block, where:
Word 1:

contains the internal file number of the file to be reduced.

Word 2:

contains the number of segments to be removed.

This request is granted unless the file to be rewced is currently opened to another user or if the file is write
protected against the user.
Rename A File (REN)

Octal Code: 6600

Operation: REN is used to change the name of a file. Load the AC with the address of a 4-word block where:
Word 1:

contains the internal file number associated with the file whose name
is to be changed.

Words 2-4:

contains the new name. This name is in 6-bit characters packed two in
a word.

Protect A File (PROT)

Octal Code: 6604

Operation: The owner of a file can protect his file from unauthorized attempts to access it by using this instruction. Before executing PROT, load the AC with:
Bits 5 and 6

Internal file number of the reserved file to be protected.

Bit 7

Write protect against owner.

Bit 8

Write protect against users whose project number is same as owner's.

Bit 9

Read protect against users whose project number is same as owner's.

Bit 10

Write protect against users whose project number differs from owner's.

Bit 11

Read protect against users whose project number differs from owner's.

9-6

A file must be opened before it can be protected. PROT is legal only when performed by the file owner, i.e.,
the user who created the file. All attempts to access the file which violate any of the protection flags are considered illegal. (For further information on project numbers, see Appendix F.)
Open A File (OPEN)

Octal Code: 6601

Operation: OPEN is used to associate a file with an internal file number, which is necessary because all file
operations are in terms of the internal file numbers. Before executing the OPEN lOT, load the AC with the
beginning address of a 5-word block, where:
Word 1:

contains the internal file number.

Word 2:

contai ns the account number of the owner of the fi Ie. If 0, the
account number of the current user is specified.

Word 3-5:

contain the name of the file to be opened. This name is in 6-bit
characters packed two to a word.

If there was another file associated with the internal file number before the execution of the OPEN lOT, it is

closed automatically before the new file is associated with the internal file number.
Close A File (ClOS)

Octal Code: 6602

Operation: ClOS terminates the association between files and their internal file numbers. Before executing
ClOS, load the AC with a selection pattern for the interna' file numbers whose associated fi les are to be closed.
The file is closed if bit I is 1, where I = bit 0, 1,2, or 3.

Read Fi Ie (RFIlE) and Writit File (WFIlE)

Octal Codes: 6603 &
6605

Operation: Once the association of a file with an internal file number has been made, these lOTs allow the
actual file reference to be made. They are illegal on a file that has not been opened (associated with an interna I fi Ie number).
To read or write a file, load the AC with the address of a 6-word block, then execute the lOT. The format
for the 6-word block is:
Word 1:

contains the high-order file word address.

Word 2:

contains the internal file number.

Word 3:

contains the negative of the number of words for the operation. This
number is either the number of words to be read or the number of words
to be written.

Word 4:

contains a pointer to the beginning address -1 of a buffer located in the
user program. On a read operation this buffer receives the information
from the file: on a write operation this buffer holds the information that
is to be sent to the fi Ie.

Word 5:

contains the least significcnt 12 bit!: of the initial fi Ie word address to
begin the operation.

9-7

contains an error code:

Word 6:

if no error
if parity error
if file shorter than word count
if fi Ie not open
if protection violated

1
2
3
4

The read or write begins at the word specified by words 1 and 5. For example:
TAr; X

WFILE

• +1

0
1

-200
6477

200

means: write 200 (octal) wads starting at word 200 of the file that is associated with internal file number one
from a core area starting at location 6500.
After completion of the transfer, the word count (word 3) and core address (wad 4) are updated. If an error
was detected the appropriate error code is placed in word 6.
File Information (FINF)

Octal Code: 6613

Operation: FINF enables a user program to determine what file, if any, is associated with an internal file
number. Load the AC with the beginning address of a 7-word block, where:
Word 1:

contains the internal file number for which the user program wishes information.

Words 2
through 7

contain the information that the system returns after executing FI NF.

Word 2:

contains the account number of the owner or zero if no file is associated
with the internal fi Ie number, that is, the file is not open.

Words 3-5:

contains the name of the file in 6-bit code.

Word 6:

contains:
Bit-1

Means

write protected against owner

write protected against users whose project
number is same as owner's

read protected ogainst users whose project
number is same as owner's

write protected against users whose project
number differs from owner's

9-8

Word 6 (Cont)

Word 7:

9.4

Means

Bit-1

read protected against users whose project number
differs from owner's

contains the number of segments which compose the file.

ASSIGNABLE DEVICES

Users can access both their own Teletypes and the disk; with the remaining system devices (referred to as the
assignable devices) this is not true. One function of the TSS/8 Monitor is to ensure that device usage never
confl i cts. On Iy one user at a time can access the high-speed, paper-tape reader or punch, or anyone of the
DECtapes.
To ensure that only one user can access a device, TSS/8 requires that the device be assigned before it is used.
After a device is assigned, it is not available unti I it is released by its owner.
Once assigned, the device is programmed exactly as on a stand-alone PDP-8.

The RRB instruction is used to

read a character from the high-speed reader; the PLS instruction is used to punch one on the high-speed punch.
The skip lOTs (RFS and PSF) can be used (followed by JMP . -1) but are not necessary. For block transfers,
there are two string transfer commands: RRS and PST.
The DECtape instructions have been simplified. A single instruction, DTXA, initiates the transfer of a block of
data. The DTRB instruction is then used to determine if the transfer was successful. The skip instruction, DTSF,
can be used (followed by JMP . -1) but is not necessary.
Executing any of the assignable device lOTs without first assigning the device gives the following results: (a) If
the device is assigned to another user, the instruction is considered illegal; program execution is now terminated
and an error message typed out; (b) If the device is available it is automatically assigned before execution of
the lOT. The device then belongs to this user until he releases it.
Because these devices are shared by all users, Monitor must ensure that they are operable at all times. In particular, Monitor must ensure that a user is not waiting (futilely) for a device which is not avai lable. This
situation can arise when trying to use the punch when it is turned off, or when the reader has read off the end
of a tape. All these conditions, referred to as "hung devices" are considered to be system errors. If the program
doing the transfer has been enabled for system errors, (by executing an SEA) control transfers to the error routine
indicated which must clear the error flag in the status word before continuing (see Section 9.4). If the user
program has not been enabled for system errors, a hung device causes the program to be terminated and an error
message is typed out.

9-9

Assign Device (ASD)

Octal Code: 6440

Operation: If the device specified by the contents of the AC is available, it is assigned to the user program
and the AC is cleared. Otherwise, the number of the job owning the device is placed in the AC. If the device does not exist, 7777 is returned in the AC.
4000

Paper-tape reader

4001

Paper-tape punch

4005 + N

DECtape unit N

The assignment is in effect until a corresponding REL instruction or LOGOUT.
Release Device (REL)

Octal Codes: 6442

Operation: The device specified by the contents of the AC is released (praviding it was owned by the user
executing the REL). The AC is cleared. Releasing a device makes it available to other users.
Skip on Reader Flag (RSF)

Octal Code: 6011

Event Time: 1
Operation: The reader flag is sensed, and if it contains a binary 1, the contents of the PC are incremented by
one so that the next sequential instruction is skipped. The reader flag is bit 8 of status register 1, and has a
value of 1 if the reader buffer is not empty.
Octal Codes: 6012 &

Read Reader Buffer (RRB)

6016

Event Time: 2
Operation: The contents of the reader buffer are transferred into bits 4 through 11 of the AC and the reader flag
is cleared if the reader buffer is empty. This instruction does not clear the AC. If the reader buffer is empty,
the user program is dismissed until the reader flag is 1 or an end-of-tape condition is detected.
Reader Fetch Character (RFC)

Octal Code: 60 14

Event Time: 3
Operation: The reader flag and the Monitor reader buffer are both cleared, the readeris started to fill the
Monitor reader buffer and the reader flag is set after the buffer is full or the end of tape is detected.
Read Reader String (RRS)

Octal Code: 6010

Operation: This instruction initiates a transfer from the high-speed reader to a selected area in the user's core.
Before executing RRS, load the AC with the address of a 2-word block, where:
Word J:

minus the number of characters to be transferred.

Word 2:

the address of the user core area minus one.

The transfer is terminated by either of two conditions: (a) the word count is zero indicating that the required
number of characters have been read or (b) the reader has read off the end of the tape (a system error condition).

9-10

In either case, the word count and core address are updated. RRS clears the AC.
Octal Code: 6026

load Punch Buffer Sequence (PlS)

Operation: The ASCII character is in AC bits 4 through 11 and is transmitted to the high-speed punch. PlS
does not clear the accumulator.
Octal Code: 6021

Skip on Punch Flag (PSF)
Event Time: 1

Operation: The punch flag is sensed, and if it contains a binary 1, the contents of the PC is incremented by one so
that the next sequential instruction is skipped. The punch flag is bit 9 of status register 1, and has a value of 1
if the punch buffer is not full. If the punch flag is 0, the program is dismissed until the punch flag is 1.
Octal Code: 6020

Punch String (PST)

Operation: PST allows a user program to punch a string of characters. Before executing PST, load the AC with
the beginning address of a 2-word block, where:
Word 1:

contains the negative of the number of characters to be punched.

Word 2:

contains the beginning address -1 of the string to be punched; the
characters should be right justified one per word.

After execution of PST, the system takes only as many characters as fit in the punch buffer; it then makes the
appropriate adjustment to word 2 to indicate a new starting address and to word 1 to indicate the reduced character count. It returns to the instruction following the PST which should be a JMP . -2 to continue the transfer.
If the character count is rewced to zero, the instruction following PST is skipped. The AC is cleared by PST.

load Status Register A (DTXA)

Octal Code: 6764

Operation: DTXA allows a user program to read and write records (129-word blocks) on DECtape. load the AC
with the beginning address of a 3-word block, where:
Word 1:

contains:
Bit 1

Means

0-2

contains the transport unit select number,

3-5

6-8 = 2

for read elata function,

for write data function,

9-11

Word 2:

contains the DECtape block number.

Word 3:

contains the beginning core address -1 of record buffer.

After DTXA is given, the DECtape request is placed in the DECtape request queue. After the completion of
any DECtape request, the DECtape flag in status register 2 is turned on. DTXA elaes not update word 3. The AC
is cleared by DTXA.

9-11

Octal Code: 6771

Skip on Flags (DTSF)

Operation: The content of both the error flag and the DECtape flag is sampled, and if either flag contains a
binary 1, the content of the PC is incremented by one to skip the next sequential instruction. If both flags are
zero, the user program is dismissed until the skip is satisfied.
Octal Code: 6772

Read Status Register B (DTRB)

Operation: The content of DECtape status register B is loaded into the AC by an OR transfer. The AC bit assignments are:

error flag
mark track error
end of tape
select error
parity error
timing error
unused
DECtape flag

1
2

3
4
5

6-10

9.5

PROGRAM CONTROL

There are a number of ways that the status of a running proqram can be changed. The program can be terminated
in one of three ways: by execution of a HLT, by the user typing tBS to force a program halt, or by a program
error which forces Monitor to terminate the pragram after typing out an error message.
It is also possible for the status of a running pragram to change without it being terminated. First, the user
program can request that it handle its own program error conditions. In this case, Monitor does not terminate
a job on an error; instead, it transfers control to a user error handler. This error handler then determines what
the error was, by a CKS instruction and takes appropriate action. Monitor also provides the pragram with an
interrupt key, tC.t

If the user types a tC, Monitor unconditionally transfers control to a restart address. Thus,

the user program can handle its own restarts.
Halt (HLT)

Octal Code: 7402

Operation: This instruction is used to stop the user program and return control to Monitor. Executing HLT is
equivalent to typing tBS followed by RETURN.

t tC is a control character obtained by depressing the CTRL key at the same time as depressing the C key. tBS
is obtained by depressing control key and B together followed by S.

9-12

Set Restart Address (SRA)

Octal Code: 6417

Operation: This instruction allows the user to specify an address to which control is transferred when an fC is
typed on the user's console. Load the AC with the restart address and execute SRA. If fC is detected, the
program's input and output buffers are cleared, the AC and Link are cleared and control goes to the restart
address.
Set Error Address (SEA)

Octal Code: 6431

Operation: This instruction allows the user to specify an address to which control is transferred in the event of
a system error. Load the AC with an address before executing SEA. If a system error is detected, Monitor
simulates a JMS to the error address. The program counter is stored in the error address and control transferred
to the error address + 1. AC, Link, and input/output buffers are not affected. The error code of the system error
is in STRO bits 9-11. Bit 10 of STR1 is set. The error routine must read these bits (by a CKS) to determine the
cause of the error, then clear them by means of a CLS.
The only error code that occurs in the course of normal system usage is we to a hung device. This error occurs
when the user attempts to use a punch not already turned on, access a DECtape not yet selected, or allows the
paper-tape reader to run off the end of a tape. The error routine must release the device to clear the error condition. The illegal lOT error probably means that an assignable device lOT was executed without the device first
being being assigned. Swap and file errors occur if a hardware error is detected while Monitor is swapping user programs or while reading or writing file directories. These are system malfunctions from which there is no recovery.

9.6

PROGRAM AND SYSTEM STATUS

Because TSS/8 programs run under control of a time-sharing Monitor, it is important for them to determine their
status within the system and the status of the system as a whole.

Several lOTs, listed below, have been de-

fined for this purpose.

Check Status (CKS)

Octal Code: 6200

TSS/8 Monitor maintains for each user a complete set of status information, his program's running status and the
state of his input/output devices. This status information, stored in three words, can be accessed by a running
program with the CKS instruction. Before executing a CKS, load the accumulator (AC) with the address of a
three-word block. Executing CKS stores the three status words (STRO, STRl, and STR2) in the three-word block
and clears the AC. Information about the status of individual devices can also be checked by the skip lOTs.

9-13

The formats of these registers are:
STRO Bits

o
1

User program is in the run state
Program handles its own errors
Unused
System use on Iy
System use only
System use on Iy
Unused
System detected error condition
1 Illegal lOT
2
Swap read error
Swap write error
3
5
Disk file error
6
Hung device

Run Bit
Error Enable

2-4
5
6

7
8
9-11

JSIOT
JSIOTC
JSEXON
Error Code

STRI Bits

Teleprinter
Reader
Punch
Error

Wait

Time is up
Internal file 0 is not busy
Internal file I is not busy
Internal fi Ie 2 is not busy
Internal fi Ie 3 is not busy
There is a delimiter in the input buffer
Unused
Output buffer is not full
Character in reader buffer
Punch buffer is not full
System error detected, code in bits 7
through 11 of STRO
Job is not waiting

DECtape
Error
DECtape

Unused
DECtape transfer requested
DECtape error
DECtape flag

1
2

3
4
5
6

7
8
9

Timer
File 0
File 1
File 2
File 3
Delimiter

STR2 Bits

0-8
9
10

Each user has available to him a 12-bit switch register just as he does on a stand-alone PDP-8. This switch
register can be manipulated by means of the Monitor command SWITCH or under program control.
OR With Switch Register (OSR)

Octal Code: 7404

Operation: The content of the user's switch register is inclusively ORed into the AC.
Set Switch Register (SSW)

Octal Code: 6430

Operation: The content of the AC is stored in the user's switch register. The AC is cleared.
Assembly language programs run under control of TSS/8 Monitor. The following lOTs are defined to allow a
program to determine the status of the system as a whole.

9-14

Segment Size (SIZE)

Octal Code: 6614

Operation: The segment is the basic unit of on-line file storage. Different TSS"..a systems have differing segment
sizes. SIZE allows a program to determine the segment size. The segment size is returned in the AC.
Segment Count (SEGS)

Octal Code: 6406

Operation: The number of available disk segments is returned in the AC.
Account (ACT)

Octal Code: 6617

Operation: The account number (of the job number given) is returned in the AC. If AC is 0, the account
number for the current job is returned. If the requested job does not exist, zero is returned.
Octal Code: 6616

Who (WHO)

Operation: The account number and password of the current job are returned to the 3-word block whose address
is in the AC and the AC is cleared.
User (USE)

Octal Code: 6421

Operation: Return in the AC the number of the current job.
Console (CON)

Octal Code: 6422

Operation: Return in the AC the console unit number assigned to the job whose number is in the AC, if that
console number does not exist, -1 is returned.
User Run Time (URT)

Octal Code: 6411

Operation: load the AC with the address of a 3-word block, where word 1 contains the number of the job
for which the run time is sought. The run time is returned in the last two locations of the block. If job 0 is
specified, the run time of the current job is returned. The AC is cleared.
Time-oF-Day (TOO)

Octal Code: 6412

Operation: Returns the value of the System Clock in military time (using a 24-hour cycle) in the two locations
starting at the location of the address in the AC. The AC is cleared.
Return Clock Rate (RCR)

Octal Code: 6413

Operation: The number of clock ticks per second is returned in the AC.
Octal Code: 6414

Date (DATE)
Operation: Returns the date in the AC. The format of this 12-bit number is:
DATE=«YEAR-1964)*12+(MO~TH-l

))*31+DAY-l

9-15

Octal Code: 6420

Skip on T5S/8 (TSS)

Operation: This instruction is used by programs which run under both TS5j8 and a standard PDP-8/I. Under
TSS/8, the instruction following T55 is skipped and the Monitor version number is returned in the AC. On a
standard PDP-8/I, the lOT has the effect of a NOP instructi on.
Octal Code: 6415

Quantum Synchronization (SYN)

Operation: Upon execution of this instruction, the system dismisses the user program and sets it in the run state
so that it will be run again in turn. Ordinarily, this instruction is used to ensure a full time quantum to perform
some critical operation.
Octal Code: 6416

Set Time (STM)

Operation: The system provides a clock time for each user program. By means of this lOT, the time can be set
to "fire" after a specified number of clock ticks have elapsed.
Load the AC with the time (in seconds) to prime the timer. Upon execution of the STM instruction, the system
sets the time to "fire" in the specified number of seconds and turns the time bit (bit 0) in status register 1 to 0,
clears the AC, and dismisses the job. After the specified time has elapsed, the system turns bit 0 back to 1,
and the job is restarted.

9.7

PDP-8 COMPATIBILITY

Programming TS5/8 in assembly language is very similar to programming a stand-alone PDP-8. All instructions
except the lOTs operate identically in either case. As discussed in the earlier sections of this chapter, programming such devices as the Teletype and high-speed reader/punch for TS5/8 is somewhat simpler. T55/8 runs
programs which include timing loops. It also properly executes the lOTs not mentioned in this manual, e.g.,
TCF, PCF, RRB, RFC, etc. Thus, programs written for stand-alone PDP-8s with Teletype and high-speed reader
or punch will run on TSSj8, although generally not as efficiently as programs which are written specifically
for TSS/8.
The same is not true for disk and DECtape operations because T55/8 uses a simplified programming structure for
these devices. The actual differences in coding are very small. It is a simple task to adapt previously written
code for T5S/8 disk and DECtape.
There are a few standard changes which users generally make in adapting PDP-8 code to TS5j8. The T55j8
Monitor does the echoing rather than the user program. The TLS which does the echo can be deleted and a DUP
instruction added somewhere near the start of the program. Also, for efficiency, the T5Sj8 delimiter capability
can be used. A K5B in the program determines what the delimiters are.

9-16

Many PDP-8 programs execute a reader and punch lOT early in the program, to initialize the device, whether
they are actually to be used or not. If the devices are free, they can be assigned and thus made unavailable
to other users. If they are unavailable, the program terminates on an illegal lOT. Thus, it is important not to
execute these lOTs randomly. If disk or DECtape is involved the actual transfer code must be altered to conform to TSS/8. {The fact that core page 37, locations 7600 through 7777, is avai lable to TSS/8 programs is
useful in making these changes.

New code can be placed in the area normally reserved for the Binary loader.}

The most difficult code to convert is that code which operates under interrupt. To be run under TSS/8, these
programs must be recoded so as not to use the interrupt.
lOTs for nonexistent devices are ignored as are CDFs and CIFs to field zero. {Other CDFs and CIFs are illegar.}
It must be remembered, that many lOTs have been redefined for use as special TSS/8 instructions. In all other
situations, TSS/8 remains compatible with stand-alone systems whenever possible.

9-17

APPENDIX A
TSS/8 CHARACTER SET

TSS/8 accepts 8-bit ASCII characters only. ASCII is an abbreviation for USA Standard Code for Information
Interchange. The acceptable characters and their 6- and 8-bit octal equivalents are I isted below.

Character
Space
!

$
%
&

(
)

*
+

0
1
2
3
4
5
6
7
8
9

<
>
?

6-Bitt
Octal

8-Bit
Octal

00
01
02
03
04
05
06
07
10
11
12
13
14
15
16
17
20
21
22
23
24
25
26
27
30
31
32
33
34
35
36
37

240
241
242
243
244
245
246
247
250
251
252
253
254
255
256
257
260
261
262
263
264
265
266
267
270
271
272
273
274
275
276
277

Character
@

A
B
C
D

E
F
G
H
I

J
K

L
M
N

P
Q
R
S
T
U
V

W
X
Y
Z
[

]

tUsed to store passwords and filenames only.

A-1

6-Bitt
Octal

8-Bit
Octal

40
41
42
43
44
45
46
47
50
51
52
53
54
55
56
57
60
61
62
63
64
65
66
67
70
71
72
73
74
75
76
77

300
301
302
303
304
305
306
307
310
311
312
313
314
315
316
317
320
321
322
323
324
325
326
327
330
331
332
333
334
335
336
337

APPENDIX B
SUMMARY OF MONITOR COMMANDS

B.1

MONITOR COMMANDS

A Monitor command is a string of characters terminated by a semicolon (;), a colon (:), or a carriage return
(RETURN key). Parameters of commands can be octal numbers, decimal numbers, character strings, or single
letters. In the following summary, parameters are coded as follows:

B. 1. 1

B.l.2

C1, C2,

represent octal numbers

01, 02,

represent decimal numbers

S 1, S2,

represent character strings

11, L2,

represent single letters

Logging In and Out
LOGIN C1 Sl;

Request to login;
Cl = user's account number
S1 = user's password

LOGOUT;

Request to logout; processing
and console time is typed out

TIME Cl;

Request typeout of processing time;
Cl = job number
Without Cl, current job is assumed;
before logging in and without Cl,
time-of-day is typed out;
If C 1 = job 0, time-of-day is typed
out.

Device Allocation
ASSIGN 11;

Access device;
L1 = R for paper tape reader
P for paper tape punch
o for any DECtape unit

ASSIGN 0 Cl;

Access DECtape unit;
0= DECtape
Cl = device number

B-1

RELEASE Ll;
RELEASE 0 Cl;

8.1.3

Release device;
L1 = R, P (see ASSIGN ll;)
o = OECtape unit
Cl = console or OECtape number

File Handling
OPEN Cl Sl C2;

Establish association between
internal file number and file;
Cl = internal file number
Sl = file name
C2 = account number

CLOSE Sl;

Close files;
Sl = list of internal file numbers

CREATE Sl;

Create new fil e;
Sl = name of new file

RENAME Cl Sl;

Rename a file;
Cl = internal file number
Sl = new name of file

REDUCE Cl 01;

Reduce length oHile;
Cl = internal file number
01 = number of segments to be removed from end of fiI e

EXTEND Cl 01;

Extend length of file;
Cl = internal file number
01 = number of segments to be added
to end of file

PROTECT Cl C2;

Protect a file;
Cl = internal file number
C2 = new file protection mask
1 read protect against users
with different project number
2 write protect against users
with different project number
4 read protect against users
with same project number
10 write protect against users
with same project number
20 write protect against owner
or the sum of any cormination

F Cl;

Print out association between internal file
numbers and files
C 1 = i nterna I fil e number

8-2

B.l.4

Control of User Programs
START Cl;

Execute user program;
Cl = starting location

START;

Restart user program;

RESTART Cl;

Set program restart address

DEPOSIT Cl C2
••• Cn;

Store in core memory;
C 1 = location
C2 = contents to be stored

Cn = location Cl +n-l
n < 10 decimal
EXAMINE Cl 01;

B.l.5

List specified contents;
Cl = first location
01 = number of location to be
listed 01 ~ 10 decimal

Utility Commands
SAVE Sl;
SAVE Cl Sl C2;
SAVE Cl Sl C2 C3;
SAVE Cl S 1 C2 C3 C4;

Save core image;
C 1 = owner's account number
Sl = name of file
C2 = file address of first word to
be saved; if not specified,
entire 4K is saved
C3 = core address of first word to
be saved; if not speci fi ed ,
entire core is saved
C4 = core address of last word to
be saved; if not speci fi ed ,
entire core is saved

LOAD Cl Sl;
LOAD Cl S1 C2;
LOAD Cl Sl C2 C3;
LOAD Cl S 1 C2 C3 C4;

Load core image;
C1 = owner's account number
Sl = name of file
C2 = file address of first word to
be loaded; if nof specified,
entire 4K is loaded
C3 = core address of first word to
be loaded, if not speci fi ed,
entire core is loaded
C4 = core address of last word to
be loaded; if not specified,
entire core is loaded

R S1;

Run System file;
S1 = name of file

B-3

B.l.6

Utility Commands (Cont)
RUN Sl;

Run user file;
Sl = name of file

RUN Cl Sl;

Run user fit e;
C 1 = owner's account number
Sl = name of file

S·,

Stop execution

WHERE;

Type out contents of location counter,
accumulator, link, and switch register

USER;

Type out number of the job and devices
owned

USER Cl;

Type out device numbers;
Cl = user's account number

SWITCH Cl;

Set switch register;
Cl = word to be set

BREAK Cl;

Set keyboard break mask;
Cl = new mask

DUPLEX;

Echo typed characters on pri nter

UNDUPLEX;

Ignore previous DUPLEX command

TALK Cl Sl;

Send a message to canso I e C 1;
Cl = destination console
Sl = message

8-4

APPENDIX C
SUMMARY OF lOT INSTRUCTIONS

C.l

C.2

PROGRAM CO NTROL
Number

Instruction

Function

6200
6402
6403
6405
6411
6412
6413
6414
6415
6416
6417
6420
6421
6422
6430
6431
6440
6442
7402
7404

CKS
DUP
UNO
CLS
URT
TOO
RCR
DATE
SYN
STM
SRA
TSS
USE
CON
SSW
SEA
ASD
REL
HLT
OSR

Check Status
Duplex Console
Unduplex Console
Clear Status
User Run Time
Time of Day
Return Clock Rate
Date
Quartum Synchronization
Set Timer
Set Restart Address
Skip on TSS/8
User
Console
Set Switch Register
Set Error Address
Assign Device
Release Device
Halt
OR With Switch Register

Number

Instruction

Function

6600

REN
OPEN
CLOS
RALE
PROT
WFILE
CRF
EXT
RED
FINF
SIZE
SEGS
ACT
WHO

FILE CONTROL

6601
6602
6603
6604
6605
6610
6611
6612
6613
6614
6406
6617
6616

Rename File
Open File
Close File
Read File
Protect Fi Ie
Write File
Create File
Extend File
Reduce File
File Information
Segment Size
Segment Count
Account Number
Who
C-l

C.3

C.4

INPUT BUFFER CONTROL
Number

Instruction

Function

6030
6031
6032
6034
6036
6400
6401

KSR
KSF
KCC
KRS
KRB
KSB
SBC

Read Keyboard String
Skip On Keyboard Rag
Clear Keyboard Flag
Read Keyboard Buffer Static
Read Keyboard Buffer Dynamic
Set Keyboard Break
Set Buffer Control Flags

OUTPUT BUFFER CONTROL
Number

Instruction

6040
6041
6042
6044

SAS

6046

C.5

C.6

C.7

TSF
TeF
TPC
TlS

Function
Send A String
Skip On Teleprinter Rag
Clear Teleprinter Rag
load Teleprinter and Print
load Teleprinter Sequence

HIGH-SPEED PAPER-TAPE READER AND CONTROL (TYPE PC02)
Number

Instruction

6010
6011
6012
6014

RRS
RSF
RRB
RFC

Function
Read Reader String
Skip On Reader Flag
Read Reader Buffer
Reader Fetch Character

HIGH-SPEED PAPER-TAPE PUNCH AND CONTROL (TYPE PC03)
Number

Instruction

Function

6020
6021
6022
6024
6026

PST

Punch String
Skip On Punch Flag
Clear Punch Flag
load Punch Buffer and Punch Character
load Punch Buffer Sequence

PSF
PCF
PPC
PlS

DECTAPE CONTROL (TYPE TeOl)
Number

Instruction

6764
6771
6772

DTXA
DTSF
DTRB

Function
load Status Register A
Skip On Rags
Read Status Register B

C-2

APPENDIX D
OFF-LINE TAPE PREPARATION AND EDITING

D.l

INTRODUCTION

To run a program 01" the computer, instructions and data must be fed into the computer from the input device.
The program and data are usually typed into the computer on-line or prepared with the aid of the Symbolic
Editor. It is sometimes convenient to prepare the program and data off-line, that is, to punch the program and
data onto paper tape using a separate machine, one not actually connected to the computer.
The Model 33 ASR Teletype can be used off-line to prepare source program tapes, to duplicate tapes, and to
edit tapes previously punched in the ASCII format. (Tapes punched from the Teletype keyboard are in ASCII
format .)
When the Teletype power control switch is turned to LOCAL, the unit becomes an off-line tape preparation
facility.

Procedures for using the Teletype off-line are listed below. The Teletype controls are described in

Section 1.4.

D.2

DUPLICATING TAPES

The following is a description of the procedure used in duplicating tapes.
Procedure
Tum TIY to LOCAL.

Set LSR to FREE.

Put original tape into LSR.

Depress LSP ON.

Depress HERE IS key to generate leader tape.

Set LSR to START. (New tape is punched and data is typed on printer.)

After the original tape is read in, depress HERE IS key to generate trailer
tape.

Remove tapes from LSR and LSP.

D-1

0.2.1

Preparing New Program Tapes

When preparing a program tape off-I ine, the user should observe the salT'e conventions of his programming
language as when preparing a program on-line using Editor. The following are the manual operating procedures
for off-I ine tape preparation.
Procedure

Step
Turn TTY to LOCAL.

Depress LSP ON.

Depress HERE IS key to generate leader tape.

Type the source program, observing the conventions of the programming language being
used.

NOTE
The RETURN and LINE FEED keys must be depressed at
the end of each line.
Depressing the CRTVTAB keys perforates the tab character onto the tape, and the typewheel moves only one
position to the right. When the computer reads the
punched tab character on output, the typewheel tabs
(a tab is usually equal to 10 spaces) to the next tabs top •

0.2.2

After the source program is punched, depress HERE IS to generate trailer tape.

Remove the source program tape from LSP.

Correcting Typing Errors

Typing errors can be corrected using the B. SP. button on the tape control and the RUBOUT key on the console
keyboard. The B. SP. button backspaces the tape one column for each depression of the button, and the
RUBOUT key perforates all eight channels of the tape (this perforation is ignored by the computer).

0.2.3

Editing

Punched tapes can be edited off-I ine. However, the user must be able to read the perforati ons on the tape,
otherwise, off-line editing is virtually impossible. The following is a description of the process used to edit
a paper tape off-line.

0-2

Step

ProcecLre
Tum TTY to LOCAL.

SET LSR to FREE.

Put tape to be edited into LSR.

Depress LSP ON.

Depress HERE IS to generate leader tape.

Set LSR to START.

Observe the printer as the program is being typed, and

Set LSR to STOP a few characters ahead of the text to be edited.

Advance the tape one character at a time by toggling the LSR control from START to STOP.

Minor Edit: Advance tape past the character(s} to be edited and use the B. SP. and RUBOUT keys to erase
any incorrect characters, then type and punch corrected text.
Major Edit: Following Step 9:
a.

Set LSR to STOP one character ahead of the text to be edited;

Type new text;

Set LSR to FREE;

Advance tape past edited area (reading the perforated tape);

Set LSR to START.

Repeat from step 6 until editing is completed.

Set LSR to START.

After new source program tape is punched, depress HERE IS to generate trailer tape.

Remove old tape from LSR and discard. t

Remove new tape from LSP and save.

0.2.4 listing of a Punched Paper Tape
The printer can also be used to obtain a listing of a punched paper tape; this can be done with a minimum of

tIt is good programming practice to list the new tape before discarding the old, ensuring that the new tape is
correct .

0-3

effort and no use of computer time. To do this, tum the LINE-OFF-LOCAL knob to LOCAL, depress the OFF
button, correctly position the paper tape, and fl ick the switch to START. This procedure causes the tape to be
printed at the consol e, independent of the computer.

0.3

PAPER TAPE FORMATS
r~--~A'--3-2---"'\

Data are recorded (punched) on paper tape by groups of holes arranged in a definite

8 7 6 5 4

format along the length of the tape. The tape is divided into channels which run
the length of the tape, and into columns which extend across the width of the tape
as shown in the adjacent diagram. The paper-tape readers and punches used with

•

••

COLUMN

•
•

the POp-a/I computers accept 8-channel paper tape. The various formats are
briefly explained and identified below.

1
L
0.3.1

Leader/Trailer Format

Leader/trailer tape is used to introduce and conclude the object program when punched on

•
•

paper tape. Leader/trailer tape can be recognized by a consistent channel a punch only as

•
•

shown in the adjacent diogram.

1
0.3.2

sPROCKET
HOLE

RIM Format

Paper tape punched in RIM format can be identified by the absence of a channel
a punch, and by a channel 7 punch in every fourth column. The channel 7 punch
indicates the start of a line of coding, and that (the first) column and the second

•
•
•
•
•
•
•
•

CHANNEL 7

• ••••••• 6177
••
•
• • • • 32'2
•• •
• ••••••• 52
• •• •• • 13
• • • •• "
• ••••••• 53
• • • • • '3
• • •• '0
••
• ••••••• 00
• • • • • • • 07
17

column contain the location and the third and fourth columns contain the contents of the location.

LOCATION
CONTE"TS
LOCATION
CONTENTS
LOCATION

CONTE"TS
LOCATION

•••• 07
• •••

0-4

CO"TE"TS

LOCATION

0.3.3

., • • •
324
3'0
•• ••
• • • • • 311
32!0

••
•• • •
• • • • 240
••
•• ••

USASCII Format

.• -•

USASQI (USA Standard Code for Information Interchange) format uses all eight
channels to represent a single choracter (letter, number, or symbol) as shown in

D.3.4

31\

240
30'

•
••
• • 323
• • • • • • 303
• • • • • 311
• 240
••
• •
• • • 30'
••
317
• • • •••• 322
•• •
•
•
• • • ••
•
• 30'
•• •

the adjacent diagram.

31 ,

0
R

315

II
A

324

Binary Format

•

Binary format can be recagnized by the absence of a channel 8 punch, an
occasional channel 7 punch, and frequent sections of blank tape. The

• •••• 32,7
• •• • 50
• ••
00

channel 7 punch denotes an origin of a program or subprogram or a chonge

•

in origin, and subsequent columns contain the instructions (two columns per
instruction) or data of succeeding locations.

00
00
00
02

• • •••
• • • • • • • 0'
•
• • • • • • 00
•••• •••
••
• 0'
• • • • • • • 45
• •• •
56
77
76
77

60
77
77

D-5

ORIGIN
INSTRUCTION

INS TRue T ION
INSTRUCTION
INSTRUCTION
INSTRUCTION
tNSTRlJCTION
INSTRUCTION

INSTRUCTION
INSTRUCTtON

APPENDIX E
SYSTEM CONFIGURATION AND OPTIONAL HARDWARE

E. 1

INTRODUCTION

Depending on the hardware configuration of a particular TSS/8, there can be as many as 24 users working on
the system simultaneously. The minimum hardware configuration is designed to service from four to eight users;
it requires a 12K core memory (three fields). The first 8K (fields 0 and 1) are shared by the various Monitor
subprograms. The other 4K (field 2) and any additional fields are shared by users of the system.
Each user has the following resources: 4K core memory for execution of programs and a corresponding 4K disk
track for temporary storage of his core image when it is swapped out by the Monitor. The disk is divided as
follows:
a. Monitor Area -- The first 20K of the disk is occupied by Monitor subprograms. These subprograms
are swapped into core memory as needed.
b. User Swapping hea -- This area consists of a 4K track for each user in the system. When a user
is temporarily swapped out of core, his program is stored on his 4K disk track.
c. File Storoge Area -- The remaining disk area is used for storing System library Programs and user
files.
The system can have a maximum of 32K of core memory. Additional fields of core permit overlapping the run
time of one user program with the swapping time of another, thus increasing operating speed.
A high-speed, paper-tape reader and punch unit is pictured in Figure E-1 and descriptions of the reader and
punch units follow.

E. 2

READER UNIT

The high-speed, paper-tape reader is used to photoelectrically input data into core memory from eight-channel
fan-folded (non-oiled) punched paper tape at 300 characters per second. Power is applied to the reader when
the computer POWER switch is turned on. The high-speed reader is under program control. However, tape can
be advanced past the photoelectric sensors without causing input by pressing the FEED button (the white rectangular button shown in Figure E-l).

E-l

•...-..I~
Ii,
Figure E-l

E.3

High-Speed, Paper-Tape Reader and Punch Units

LOADING THE READER UNIT

The following is a description of the steps necessary to read a paper tape with the high-speed reader.
Step

Procedure
Raise tape retainer cover {located beneath the tape feed button}.

Put tape into right-hand bin with channel one (see Section D.2) of the tape toward the
rear of the bin.

Place several folds of leader tape through the reader and into the left-hand bin.

Place the tape over the reader head with feed holes engaged in the teeth of the sprocket
wheel.

Close the tape retainer cover.

Depress the tape feed button (white rectangular button shown in Figure E-1) unti I leader
tape is over the reader head.

CAUTION
Do not use oiled paper tape in the high-speed reader because oil collects dust and dirt which can cause reader
errors.

E-2

PUNCH UNIT

The high-speed, paper-tape punch is used to record computer output on eight-channel fan-fold tape at
50 characters per second. All characters are punched under program control from the computer. Blank tape
(feed holes only, no data) may be produced by pressing the FEED button (see Figure E-l). Power is appl ied
to the punch when the POWER button on the punch unit is depressed (the punch motor can be heard). The two
labeled buttons on the punch unit are described below.

E.5

POWER

This button is depressed to turn the punch ON and OFF.

FEED

While this button is depressed, the punch produces feed-hole-only punched tape
for leader/trailer purposes.

DECTAPE CONTROL AND TRANSPORT UNITS

DECtape is a fast, convenient, input/output and data storage facility. The standard DECtape Transport unit is
shown in Figure E-2.

Figure E-2

DECtape Transport Unit

E-3

E.6

CONTROL UNIT

The DECtape control unit (located internally) interprets and controls the transfer of data between the computer
and the transport unit. The DECtape control unit is located inside the rack containing the DECtape transport
and can control up to eight separate DECtape transports.

E.?

TRANSPORT UNIT

The DECtape transport unit is a bidirectional magnetic tape transport utilizing a lO-track recording head to read
and write five duplexed channels . Tape movement can be controlled by commands from the computer program
or by the manual operation of switches located on the front panel of the transport; however, manual operation
does not transfer data to the computer.

NOTE
Only certified DECtapes (pre-recorded with timing and marking
tracks) should be used. Otherwise, the blank tape must be certified using the DECTOG Program (DEC-08-EUFA-D).

E.? 1

Transport Controls

The following is a description of the settings on the OECtape transport and their functions.

Settings

•

Function
When depressed (must be in LOCAL mode), tape feeds onto
right spool.

REMOTE

Transport is energized and under program control.

OFF

Transport is de-energized.

LOCAL

Transport is energized and under user control from external
transport switches.

Unit Selector

Identifies the transport to the control unit.

WRITE
ENABLED

DECtape is available for search, and write activities.

WRITE LOCK

DECtape is available for search and read activities only.

•

When depressed (must be in LOCAL mode), tape feeds
onto left spool.

E-4

NOTE
The REMOTE and WRITE ENABLED lamps light to indicate the
status of the transport.

E. 7. 2

Operat ing Procedure

The following is a description of how to mount a DECtape on a transport unit.
Step

Procedure
Set switch to OFF.

Place DECtape on left spindle with DECtape label out.

Wind four turns of tape on right spool.

Set switch to LOCAL.

Wind a few turns on right spindle with'" switch to make sure
tape is properly mounted.

Dial correct unit number on unit selector (number 8 is equivalent
to 0).

Set switch to REMOTE. Select either WRITE ENABLE or WRITE
LOCK setting.

E-5

APPENDIX F
STORAGE ALLOCA TIO N

F.l

STORAGE MAP

The system's storage allocation is illustrated below.
CORE MEMORY
~

RESIDENT
MONITOR

PHANTOMS
INIT
l'':ol:.k
PR·)·:.r'AM

USER
PROGRAM

USER
PROGRAM )

USER
PROGRAM

01 SK STORAGE
)

FIP
4K

INIT

TS8
(RES 01

TS811
(RES 11

JOB #1

JOB #2

JOB #N

FILES

o
k:J

1o..I1t - - - - - - - - - - MONITOR ---------,,_*1.._ - - SWAPPING AREA - - -...j....t - - - FILE AREA---I
08-0466

Figure F-l

F.2

TSS/8 Storage Map

ALE DIRECTORIES

There are two directories on the disk: the Moster file Dir.ectory (MFD) referenced mainly by the system, and
the User Fi Ie Directory (UFD), referenced by the TSS/8 user. One of the functions of the MFD is to service
the UFO. A UFD is a particular user's file directory containing the names of programs he has created on the
disk.
The UFO is a file like any other file except that its filename is the project-programmer number and password.
(See Section F.3 for an explanation.) When a user is logged in under a specific number and references the disk,
he is actually referencing his own file area on the disl<: through the UFD which has his project-programmer number as its name. He can specifically code his routine to reference UFOs of other users or the MFD; whether he
is successful or not depends on the type of protection that has been specified for the area he is trying to reference.

F-l

MASTER FILE OIRECTORY
WO RD 1

p~ISS

(I CHAR)
(I CHAR)

USER FILE

I PROG NO

PROJECT NO

WO RO

(I CHAR)
(I CHAR.)

PRe.TE. TED
RIT:::,_
TIME

CONSOLE

(ICHAR)

(I CHAR)

NAME

(I CHAR)

WO RD

(I CHAR.)

IPROTECTED SITS

UNUSEO

SEGMENT COUNT

TIME

CPU
WO RD S

FI LE

LINK TO NEXT ENRTY

LINK TO NEXT ENTRY
UNUSEO

OIRECTORY

(I CHAR)

OATE OF CREATION

POINTER TO RETRIEVAL

POINTER

LINK TO NEXT

TO RETRIEVAL

RETRIEVAL BLOCK

SEGIoIE"IT

SEGMENT

.. I

SEGMENT

.. 2

SEGMENT

*4
SEGMENT *5

SEGME NT

SEGMENT

.. 5

SEGMENT

SEGMENT .. 7

SEGMENT

.. 7

SEGMENT

080352

Figure F-2

F.3

File Directories

PROJECT-PROGRAMMER NUMBERS

System account numbers are a combination of project number and programmer number. The account number
(always written in octal) has a binary equivalent. When expressed as a 12-bit binary number, the project
number is formed by the leftmost 7 bits and the programmer number is the rightmost 5 bits. For example, the
account number 623 (octal) equals 000 110010 011 (binary). The left 7 bits (leading zeros included if any)
are 0001100 (binary) and equal 14 {octal} which is the project number. The programmer number is 10011 (binary)
or 23 (octal). Therefore a user with "account number" 623 has:

project number 14
programmer number 23

F-2

APPENDIX G
GLOSSARY OF ABBREVIATIONS AND TERMS

G.1

COMMONLY USED ABBREVIATIONS

The abbreviations listed below are used throughout the guide.
Abb.

Meaning

AC
ADDR
B. SP.
BIN
CLC

Accumulator
Address
Back Space
Binary
Current Location
Counter
Continue
Carriage Return
Carriage RetumLine Feed
Control/Form (which represents holding down the
CTRL key while depressing
the Form key).
Digital Equipment
Corporation
Deposit
Data Field
Extended Arithmeti c
Element
Examine

CONT
CR
CR/LF
CTRL/FORM

DEC
DEP
DF
EAE
EXAM

G.2

Abb.
HSP
HSR
IF
INST
KBRD
L
LF
LOAD ADD
LOC
LSP
LSR

MA
MB
MQ
MRI

PC
PROG
REL
RIM
SING INST
SING STEP
SR
TTY

Meaning
High-Speed punch
High-Speed Reader
Instruction Field
Instruction
Keyboard
Link
Line Feed
Load Address
Location
Low-Speed Punch
Low- Speed Reader
Memory Address
Memory Buffer
Multiplier Quotient
Memory Reference Instruction
Program Counter
Program
Release
Read- In Mode
Single Instruction
Single Step
Switch Register
Teletype

GLOSSARY OF TERMS

The following list of computer/programming terms is by no means complete. However, it does include many of
the terms used in data processing.
Absolute
Address

(1) An address that is permanently assigned by the mochine designer to a storage location.
(2) A pattern of characters that identifies a unique storage location without further
modi fi cation.

G-1

Accumulator

A register in which the result of an operation is formed; Abbreviation AC

Acronym

A word formed from the first letter or letters cJ the successive words of a multiple
word term.

Accuracy

The degree of freedom from error, i.e., the degree of conformity to truth or to a rule.

Address

A label, name, or number which designates a register or a location where information
is stored. That part of an instruction which specifies the location of an operand.

Address
Register

A register in which an address is stored.

Algorithm

A prescribed set of well-defined rules or processes for the solution of a problem in a
finite number of steps.

Alphabet

An ordered set of unique representations called characters, e.g., the 26 letters of
the Roman alphabet.

Alphanumeric

Pertaining to a character set that contains both letters and numerals, and usually
other characters.

Arithmetic Unit

The component of a computer where arithmetic and logical operations are performed.

ASCII

An abbreviation for USA Standard Code for Information Interchange.

Assemble

To translate from a symbolic (source) program to a machine language (object) program
by substituting binary operation codes for symbolic operation codes and absolute or
relocatable addresses for symbolic addresses.

Assembler

A program that assembles.

Auto-Indexing

When an absolute location 0010 through 0017 is addressed indirectly, the content of
that location is incremented by one, rewritten in that same location, and then read
as the effective address of the next instruction.

Auxiliary
Operation

An operation performed by equipment not under direct control of the computer. Offline operation.

Auxiliary
Storage

Storage that supplements the primary storage.

Binary

(1) Pertaining to a characteristic or property involving a selection, choice, or condition in which there are two possibilities. (2) Pertaining to the numeration system
with a radix of two.

Binary Digit

One of the symbols 1 or O. A digit in the binary scale of notation; called a bit.

Bit

A binary digit.

Blank Character

A character used to produce a space on an output device.

Block

A set of things, such as words, characters, or digits, handled as a unit.

G-2

Bootstrap

A technique or device designed to bring itself into a desired state by means of its
own action, e.g., a routine whose first few instructions are sufficient to bring the
rest of itself into the computer from an input device.

Branch

A point in a routine where one of two or more choices is made under control of the
routine, i.e., a conditional transfer (jump).

Buffer Storoge

A part of core memory where information is stored temporari Iy during transfer; it may
attempt to match the speeds of internal computation and the I/o device, thus permitting simultaneous computation and input/output.

Byte

A group of binary digits usually operated upon as a unit, e.g. , 8-bit or b-bit byte.

Call

To transfer control to a specified routine.

Colling
Sequence

A specified set of instructions and data necessary to set up and call a given routine.

Carriage Return

The Teletype operation that causes the next character to be printed at the left margin.

Central Processing Unit

The unit of a computing system that includes the circuits controlling the interpretation
and execution of instruction; the computer proper, excluding I/o and other peripheral
devices.

Character

A single letter, numeral, or space mark used to represent information.

Clear

To erase the contents of a storage location by replacing the contents with blanks or
zeros.

Closed
Subroutine

A subroutine not stored in the main part of a program. Such a subroutine is entered
by a jump operation and provision is made to return control to the main routine at
the end of the surbroutine.

Coding

To write instructions for a computer using symbols meaningful to t"e cOlTlputer.

Command

A control signal, usually written as a character or group ci characters, to direct
action by a system program.

Compile

To produce a machine language routine from a routine written in source language by
selecting appropriate subroutines from a subroutine library, as directed by the instructions or other symbols of the original routine, supplying the linkage which combines
the subroutines into a workable routine and translating the subroutines and linkage
into machine language.

Compiler

A program that compiles.

Complement

To form the negative of a binary word by replacing all 0 bits with 1 bits and vice versa.

Computer

A device capable of accepting information, processing it, and providing the results
in a usable form.

Computer
Program

A plan or routine for solving a problem on a computer.

G-3

Computer Word

A sequence of 12 bits treated as a unit and capable of being stored in one computer
location.

Console

Usually the external front side of a device where controls and indicators are available
fa- manual operation of the device.

Control
Character

A character whose occurrence in a particular context initiates, modifies, or stops a
control operation, e.g., a character to control carriage return.

Control Panel

The part of a device console that contains manual controls.

Convert

To change the representation of data from one form to another.

Copy

To reproduce data, leaving the original data unchanged.

Core Memory

The main storage device in the PDP-8 in which binary data is represented by the
direction of magnetization in each unit of an array of magnetic material.

Cycle

To repeat a set of operations until a stated condition is met.

Cycle Time

An interval of time in which one set of events is completed.

Data

A general term used to denote any or all facts, numbers, letters, and symbols. It connotes basic elements of information which can be processed or produced by a computer.

Data Break

A faci lity which permits I/o transfers to occur simultaneously with program executior'l
on a cycle-stealing basis.

Debug

To detect, locate, and correct mistakes in a program.

Decision

A determination of future action.

Delay

The amount of time by which an event is retarded.

Delimiter

A character that separates and organizes items of data.

Diagnostic

Pertaining to the detection and isolation of a malfunction or mistake.

Digit

A character used to represent one of the non-negative integers smaller than the
radix, e.g., in binary notation, either 0 or 1.

Digital
Computer

A device that operates on discrete data, performing sequences of arithmetic and
logicClI operations on this data.

Direct Address

An address that specifies the location of an operand.

Display

A visual presentation of data.

Document

A medium on which information is recorded for human or machine use.

Double
Precision

Pertain ing to the use of two computer words to represent a number.

Downtime

The time interval during which a device is inoperative.

G-4

Dummy

An artificial address, instruction, or record ci information inserted solely to fulfill
prescribed conditions.

Dump

To copy the contents of all or part of core memory, usually onto an external storage
medium.

Dynamic Dump

A dump that is performed during the execution of a program.

Edit

To rearrange information for machine input or output.

Effective
Address

The address actually used in a particular execution of a computer instruction.

End-Around
Carry

The action of adding the most significant bit of a binary number to the least significant
bit.

Execute

To carry out an instruction or run a progran on the computer.

Executive
Routine

A routine that controls or monitors the execution of other routines.

External
Storage

A facility or device, not an integral part of the computer, on which data usable by
the computer is stored, such as paper tape, DECtape, or DECdisk.

File

A collection of related records treated as a unit, generally data or a program.

Fixed Point

In a numeration system the position of the radix point is fixed with respect to one end
of the numerals, according to some convention.

Flip-Flop

A basic computer circuit or device capable of assuming either one of two stable
states at a given time.

Floating Point

A numeration system in which the position of the radix point is indicated by one part
(the exponent part), the other part represents the significant digits (the fractional partt.

Flowchart

A graphical representation of the sequence of instructions required to carry out a data
processing operation.

Format

The arrangement of data.

Function

A specific purpose of an entity or its characteristic action.

Hardware

Physical equipment, e.g., mechanical, electrical, or electronic devices.

Head

A device that reads, records, or erases data on a storage device.

Heuristic

Pertaining to exploratory methods of problem solving.

I/O

Input or output or both.

Identifier

A symbol whose purpose is to identify, indicate, or name a body of data.

Indirect
Address

An address in a computer instruction which indicates a location where the address of
the referenced operand is to be found.

G-5

Initialize

To set counters, switches, and addresses to zero or other starting values at the
beginning of, or at prescribed points in, a computer routine.

Input

The transferring of data from auxiliary or external storage into the internal storage
of the computer.

Instruction

A set of bits (in an object program) or characters (in a source program) which as a
unit cause the computer to perform an operation.

Internal
Storage

The storage facilities forming an integral physical part of the computer and directly
controlled by the computer. Also called main memory and core memory.

Interrupt

To stop a process in such a way that it can be resumed.

Jump

A departure from the normal sequence of executing instructions in a computer.

label

An identifier.

language

A set of representations, conventions, and rules used to convey information.

leader

The bl ank section of tape at the beginning of the tape.

least Significant The rightmost digit of a binary number.
Digit
library

An organized collection of standard and proven routines and subroutines which can
be incorporated in larger routines.

library
Routine

A proven routine that is maintained in a program library.

load

To place data into internal storage.

location

A place in storage or memory where a unit of data or an instruction may be stored.

loop

A sequence of instructions that is executed repeatedly until a terminal condition
prevails.

Machine
Instruction

An instruction written in machine language.

Machine
language

A language designed for interpretation and use by the machine without translation.

Macro
Instruction

An instruction in a source language that is equivalent to a specified sequence of
machine instructions.

Manua I Input

The entry of data by hand into a device at the time of processing.

Manual
Operation

The processing of data in a system by direct manual techniques.

Memory

(1) The erasable storage in the computer. (2) Pertaining to a device in which
data can be stored and from which it can be retrieved.

G-6

No Op

An instruction that specifically instructs the computer to do nothing, except to
proceed to the next instruction in sequence.

o,ject Program

The machine language program which is the output after translation from the source
language. The binary program wh ich runs on the computer.

Octal

(1) Pertaining to a characteristic or property involving a selection, choice, or condition in which there are eight possibilities. (2) Pertaining to the numeration system
with a radix of eight.

Off Line

Pertaining to equipment or devices not under direct control of the computer.

On Line

Pertaining to equipment or devices under direct control of the computer; also to programs operating directly and immediately to user commands, e.g., FOCAL and DDT.

Open
Subroutine

A subroutine that must be relocated and inserted into a routine at each place it is
used.

Operand

That which is effected, manipulated, or operated upon.

Origin

The absolute address of the beginning of a program.

Output

Information transferred from the internal storage of a computer to output devices or
extema I storage.

Overflow

The generation of a quantity beyond the capacity of a register.

Poge

In the PDP-8/I, a unit of 200 (octal) locations which may be addressed directly.

Patch

To modify a routine in a rough or expedient way.

Predefined
Process

A named process consisting of one or more operations or program steps that are
specified elsewhere in a routine.

Procedure

The course of action taken for the solution of a problem.

Processor

A computer program that includes the compiling, assembling, translating, and
related functions for a specific programming language.

Program

The complete sequence of instructions and routines necessary to solve a problem.

Program
Library

A collection of available computer programs and routines.

Programming
Languoge

A language used to prepare computer programs.

Protected
Location

A storage location reserved for special purposes in which data cannot be stored without undergoing a screening procedure to establish suitability for storage therein.

Punched
Paper Tape

A paper tape on wh ich a pattern of holes is used to represent data.

Pushdown
List

A list that is constructed and maintained so that the next item to be retrieved is the

most recently stored item in the list, i.e., last in, first out.

G-7

Radix

The quantity of characters for use in each of the digital positions of a numbering system.

Read

To transfer information from an input device to internal storage; also refers to the internal acquisition of data from memory.

Real Time

Pertaining to computation performed while the related physical process is taking place
so that results of the computation can be used in guiding the physical process.

Record

A collection of related items of data, treated as a unit.

A device capable of storing a specified amount of data, such as one word.

Reset

To restore a storage device to a prescribed state.

Restart

To re-establish the execution of a program.

Routine

A set of instructions arranged in proper sequence to cause the computer to perform
a desired task.

Run

A single, continuous performance of a program.

Scan

To exam i ne sequentia II y part by part.

To examine a set of items for those that have a desired property.

Set

To place a storage device into a specified state.

Single Step

Operation of the computer in which each instruction is performed in response to a
sing Ie ma nua I operati on •

Skip

To ignore one or more instructions in a sequence of instructions.

Software

The collection of programs and routines associated with the computer.

Source
language

A symbolic language that is an input to a given translation process.

Source Program

A program written in a symbolic (source) language.

Statement

A meaningful expression or generalized instruction in a source language.

Step

One operation in a routine.

Storage
Allocation

The assignment of blocks of data to specified blocks of storage.

Storage
Capacity

The amount of data that can be contained in a storage device.

Storage
Device

A device into which data can be entered, in which it can be held, and from which it
can be retri eved.

Store

To enter data into a storage device.

G-8

String

A connected sequence of entities such as characters in a command string.

Subroutine

A routine that can be part of another routine.

Switch

A device or programming technique for making selections.

Symbol ic Address An address expressed in symbols convenient to the programmer. A label.
Symbolic
Coding

Writing instructions using symbolic notation instead of actual machine instruction
notation.

System

An assembly of software and hardware united to form an organized whole.

Tape Drive

A device that moves tape past a head.

Temporary
Storage

Storoge locations reserved for intermediate results.

Terminal

A point in a system at which data can either enter or leave.

Time Sharing

The interleaving of the time of a device.

Toggle

Pertaining to the operation of a flip-flop or switch.

Translate

To convert from one languoge to another.

Underflow

The condition that arises when a computation yields a result whose magnitude is
smaller than the system is capable of representing.

Variable

A quantity that can assume any of a given set of values.

Word

A 12-bit unit of data in the PDP-8/I which may be stored in one addressable location.

Word Length

The number of bits in a word.

Write

To transfer information from internal storage to an output device or to auxiliary
storage.

G-9

INDEX

Command Summary, B-1, C-1
Abbreviations, G-1
Access to Another User's Library, 3-2
Advanced Monitor Commands, 3-1
ALREADY LOGGED IN?, 2-10
ASOI Character Set, A-1
ASCII Format, D-5
Assembly Language Programs, 9-1
ASSIGN, 2-7

Communication with Other Users, 2-5
Compatibility with PDP-8, 9-16
Console, 1-3
Console lOT's, 9-3
Duplex (DUP), 9-4
Read Keyboard String (KSR), 9-3
Send a String (SAS), 9-3
Set Buffer Control (SBC), 9-4
Set Keyboard Break (KSB), 9-3
Unduplex (UND), 9-4

Assignable Devices, 9-9

Control of System Library Programs, 3-3

Assigning Devices, 2-7

Control of User Programs, 8-2

Available Device Units, 2-7

COPY, 7-5

BASIC-8, 3-5
Command Summary, 3-7
Editing Phase, 3-5
Error Messages, 3-10
Example Program, 3-6
Functions, 3-8
Implementation Notes, 3-12
Binary Format, D-5
BREAK, 8-8
BUSY, 2-5, 2-10

Calling, 7-6
Deleting Files, 7-7, 7-8
Example of Usage, 7-9
Listing Directories, 7-7
Loading Files from DECtape, 7-6
Saving Disk Files on DECtape, 7-7
Summary of Options, 7-8
CREATE, 8-3
Creating a Disk File, 8-2
Creation of System Library Programs, 8-1
CTRL/B, 2-1, 3-3, 8-2
CTRL/BS, 2-2, 3-4
CTRL/C, 3-3

Calling Monitor, 2-1
Calling System Library Programs, 2-4
CAT, 6-7
Calling, 6-7
Example Usage, 6-7
CATALOG, see CAT

Debugging Program, 6-5
DECtape, E-3
Control and Transport Units, E-3
Transport Controls, E-4
Transport Operating Procedures, E-5
Usage, 7-5

Characters on Keyboard, 1-4

Defining Disk Fi les, 8-3

Character Set for TSS/8, A-1

Deleting Files, 7-7, 7-8

CLOSE, 8-4

Delimiters, 9-16

Closing a File, 8-4

DEPOSIT, 8-2

INDEX (Cont)

Devices, 2-6
Assignment, 2-8
Designators, 2-7
Handling, 2-6
Unit Numbers, 2-7
Device lOT's, 9-9
Assign Device (ASD), 9-10
load Punch Buffer Sequence (PlS), 9-11
load Status Register A (DTXA), 9-11
Punch Stri ng (PST), 9-11
Reader Fetch Character (RFC), 9-10
Read Reader Buffer (RRB), 9-10
Read Reader String (RRS), 9-10
Read Status Register B (DTRB), 9-12
Release Device (REl), 9-10
Skip on Flags (DTSF), 9-10
Skip on Punch Flag (PSF), 9-11
Skip on Reader Flag (RSF), 9-10
DUPLEX, 8-8
Duplicating Paper Tapes, D-1

Echoing, 9-16
EDIT, 6-1
Calling, 6-1
Command Summary, 6-3
Summary of Operations, 6-2
Elementary Monitor Commands, 2-1
Error Handler, 9-12
Error Messages, Monitor, 2-9
EXAMIN E, 8-2
EXTEND, 8-4

F, 8-5
Files, 3-1
Closing, 8-4
Defining Disk, 8-3
Error conditions, 8-6
Internal numbers, 8-3
Opening,
Protecting, 3-3, 9-6

File and Disk I/O (PAL-D), 9-4
Close File (ClOS), 9-7
Create File (CRF), 9-5
Extend File (EXT), 9-6
File Information (FINF), 9-8
Open File (OPEN), 9-7
Protect File (PROT), 9-6
Read File (RRlE), 9-7
Reduce File (RED), 9-6
Rename File (REN), 9-6
Write Fi Ie (WFllE), 9-7
File Deletion Error Conditions, 8-6
Fi Ie Directories, F-1
File Information Command, 8-5
File Protection Masks, 8-5
Fi Ie Protect, 3-3
FOCAL, 3-13
Calling, 3-13
Command Summary, 3-13
Control Characters, 3-16
Error Messages, 3-17
Example Program, 3-17
Math Functions, 3-16
MODIFY, 3-15
Output Format, 3- 15
Reading FOCAL Paper Tapes, 3-17
Formats, Paper Tape, D-4
FORTRAN-D, 4-1
Calling, 4-1
Compiler Diagnostics, 4-6
Device Codes, 4-2
Disk Files, 4-3
Editing, 4-2
Example Programs, 4-4
FORT, 4-1
FOSl, 4-1
I/O, 4-2
Operating System Diagnosti cs, 4-8
Statement Summary, 4-5
Freeing Devices, 2-8
FUll, 2-10

Glossary, G-1

INDEX (Cont)

High Speed Reader, E-1

Manual, How to Use, 1-5

High Speed Punch, E-3

Master File Directory, F-1

How to Use This Manual, 1-5

Monitor, 1-1

ILLEGAL REQUEST, 2-10
lOT's, see
Console
Device
File and Disk
Program and System Status
Program Control

Calling, 2-1
Commands, 2-1, 8-2
Command Abbreviations, 8-2
Echoing on Keyboard, 9-16
Elementary Commands, 2-1
Error Messages, 2-9, 8-6
Return to, 3-4
Mounting a DECtape, E-5
Multiple Device Assignments, 2-8
Multiple Device Units, 2-7

Initialize Reader/Punch, 9-17

Internal File Numbers, 8-3
Interrupt Processing, 9-17

Octal Debugging Technique, see ODT
ODT,6-5

Keyboard, 1-4

Calling, 6-5
Command Summary, 6-6
Programming Notes, 6-6
Off-Line Tape Preparation and Editing, 0-1

Leader/frailer Format, 0-4
LINE-OFF-LOCAL Knob, 1-3
Listing a Paper Tape, 0-3

OPEN, 8-3
Opening a File, 8-3
Optional Hardware, E-1

Listing Directories, 7-7
LOAD, 8-7
LOADER, 6-4
Calling, 6-4
Usage, 6-4
With ODT, 6-5
Loading Files from DECtape, 7-6
Loading High Speed Reader, E-2
LOGIN PLEASE?, 2-10
LOGIN Procedure, 2-2
Logout Procedure, 2-4
Low Speed Pr inter, 1-3

PAL-D, 5-1
Buffers, 9-2
Calling, 5-1
Console I/O, 9-2
Control of Programs, 8-2
Error Diagnostics, 5-6
Example Program, 5-2
File and Disk I/O, 9-4
Fu II-Dup lex Hardware, 9-2
Strings, 9-2
Symbol List, 5-3
TSS/8 PAL-D, 5-1 9-1
Writing a Program, 5-2, 9-1
Paper Tape Control, 7-1

INDEX (Cont)

Paper Tape Formats, 0-4
Paper Tape Preparation, 0-1
Paper Tape Reader/punch, 1-4
PDP-8 Compatibility, 9-16
PIP, 7-1
BIN Format Files, 7-3
Call ing, 7-1
Deleting Disk Files, 7-3
Loading Paper Tape onto Disk, 7-1
Moving Disk Files, 7-3
Punching out a Disk File, 7-2
Summary of Options, 7-5
Transferring BASIC Files, 7-4
Transferring SAVE Format Files, 7-4
With High Speed Reader/punch, 7-2
Power Control Knob, 1-3
Processing Interrupts, 9-17
Program and System Status lOT's, 9-13
Account (ACT), 9-15
Check Status (CK S), 9-13
Console Number (CON), 9-15
Current JOB (WHO), 9-15
Current Job Number (USE), 9-15
Date (DATE), 9-15
OR with Switch Register (OSR), 9-14
Quantum Synchronization (SYN), 9-16
Return Clock Rate (RCR), 9-15
Segment Count (SEGS), 9-15
Segment Size (SIZE), 9-15
Set Switch Register (SSR), 9-14
Set Time (STM), 9-16
Skip on TSS/8 (TSS), 9-16
Time of Day (TOO), 9-15
User Run Time (URT), 9-15
Program Control lOT's, 9-12
Halt (HL T), 9-12
Set Error Address (SEA), 9- 13
Set Restart Address (SRA), 9-13

Reader/punch Initialization, 9-17
REDUCE, 8-4
RELEASE, 2-8
RENAME, 8-4
Resources, 2-6
RESTART, 8-8
Return to Monitor Level, 3-4
RIM Format, 0-4
RUN, 8-8

SAVE, 8-6
SAVE Format Files, 8-6
Saving Disk Files on DECtape, 7-7
START, 8-2
Status Words, 9-13
Storage Allocation, F-l
Storage Mop, F-l
Summary of Monitor Commands, B-1
Logging In and Out, B-1
Device Allocation, B-1
File Handling, B-2
Control of User Programs, B-3
Uti I i ty Commands, B-3
Summary of TSS/8 lOT's, C-l
DECtape Control (TC01), C-2
File Control, C-l
High Speed Reader and Control (PC02), C-2
Input Buffer Control, C-2
Output Buffer Control, C-2
Program Control, C-l

Project-Programmer Number, F-2

SWITCH, 8-8

PROTECT, 8-5

Switch Register, 9-14

Protection Codes, 8-4

Symbolic Editor, 6-1

Protection of Files, 3-3

SYSTAT, 2-6, 6-8
Calling, 6-8
Description of Output, 6-8
Example, 6-8

INDEX (Cont)

System Configurations, E-1

Use of th is Manua I, 1-5

System Library Programs, 3-1

USER, 8-8

BASIC-8, 3-5
Calling, 2-4
CATALOG, 6-7
Controlling, 3-3
COPY, 7-5
Creation of, 8-1
EDIT, 6-1
FOCAL, 3-13
FORTRAN-D, 4-1
LOADER, C-4
ODT, 6-5
PAL-D, 5-1
PIP, 7-1

User File Directory, F-1
User Program Status, 9-13
User Program, Control of, 8-2
User Switch Register, 9-14
Users, Communication with Other, 2-5
Utility Commands in Monitor, 8-8

VERSION, 8-8

System Resources, 2-6
System Status Reports, 2-6
WHERE, 8-2
Writing Assembly language Programs, 9-1
TALK, 2-5
Tape, How to Insert in Reader, 1-5
Tape Editing, 0-1
Tape Preparation, 0-1
Te lepri nter, 1-3
Teletype, 1-2
Keyboard, 1-4
TIME, 2-6
Time-Sharing, 1-1
Transport Controls, E-4
TSS/8 Character Set, A-1
TSS/8 Monitor, 1-1
TSS/8 versus Paper Tape Versions of PAL-O, 9-1
TYPE tBS ARST, 2-10

UASOI Format, 0-5
Unit Number, 2-7
UNAUTHORIZED ACCOUNT, 2-10
UNDUPLEX, 8-8

HOW TO OBTAIN SOFTWARE INFORMATION
Announcements of new and revised software, as well as programming notes, software problems, and documentation
corrections are published by Software Information Service in the following newsletters:
Digital Software News for the PDP-8 Family
Digital Software News for the PDP-9/l5 Family
These newsletters contain mformation to update the cumulative
Software Performance Summary for the PDP-8 Family
Software Performance Summary for the PDP-9/l5 Family
The appropriate edition of the Software Performance Summary IS included in each basic software kit for new customers.
Additional copies may be requested without charge.
Any questions or problems on the articles contained in these publications or concerning the use of Digital's software should
be reported to the Software Specialist or Sales Engineer at the nearest Digital office.
New and revised software and manuals, current issues of the Software Perfornlance Summary, and cumulative Software
Manual Updates are available from the Program Library. To place an order, please contact your local Digital office or
write to:
Program Library
Digital Equipment Corporation
146 Main Street, Bldg. 3-5
Maynard, Massachusetts 01754
When ordering, include the code number and a brief description of the program or manual requested.
Digital Equipment Computer Users Society (DECUS) maintains a user library and publishes a catalog of available programs
as well as the DECUSCOPE magazine for its members and non-members who request it. For further information, please
write to:
DEC US
Digital Equipment Corporation
146 Main Street
Maynard, Massachusetts 01754
Please complete the return postcard below if you would like to receive Digital's newsletters
Send c:::J Digital Software News for the PDP-8 Family, or
c:::J Digital Software News for the PDP-9/l5 Family
Name _______________________________________________
To
Company Name _______________________________________
Address ______________________________________________

(zip code)
My compu ter is a

0 PDP-8I

o PDP-8L
o PDP-8S

o PDP-12
o PDP-9
o
LINC-8
5
o Other _ _ _ _o_PDP-I
_ _ _ _ _ _ _ __

- - - - - - - - -

- - -

- - - - - - - - -

- - - -

Fold Here - - - - - - - - - - - - - - - - - - - -

- - Do Not Tear - Fold Here and Staple -

- - - - -

- - -

FIRST CLASS
PERMIT NO. 33
MAYNARD. MASS.
BUSINESS REPLY MAIL
NO POSTAGE STAMP NECESSARY IF MAILED IN THE UNITED STATES

Postage WIll be paId by:

mllmllllma
Digital Equipment Corporation
Software Information Services
146 Main Street, Bldg. 3-5
U",vn .. r.l U"'"" .....hll~tt" n17.c::.d.

READER'S COMMENTS

TSS/8 TIME-SHARI NG
SYSTEM USER'S GUIDE
DEC-T8-MRFB-D

Digital Equipment Corporation maintains a continuous effort to improve the quality and usefulness of its
publications. To do this effectively we need user feedback - your critical evaluation of this manual.
Please comment on this manual's completeness, accuracy, organization, usability, and readability.

Did you find errors in this manual? \'".s;

How (an this manual be Improved? _____________________________

DI:(' also strives to keep Its customers mformed of current DEC software and publtcattons. Thus, the followmg period·
u:ally dl~tflbuted publtcattons are available upon request. Please check the appropnate boxes for a current issue of the
publtl:Jtlon(s) destred.

o Sollware Manual Update, a quarterly collectIOn of reVIsions to current software manuals.
o User's Bookshelf, a blbltography of current software manuals
o ProgrJm LIbrary Pnce LIst, a Itst of currently avaIlable software programs and manuals.

Name _______________

Organization

Street _______________

Department ___________________

City _ _ _ _ _ _ _ _ _ _ _ State _ _ _ _ _ _ _ _ _ _ _ _ _ _ Zip or Country _ _ _ __

- - - - - - - - -

- - -

- - - -

Fold Here - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - Do Not Tear-Fold Here and Staple -

-- -

- -

- --

FIRST CLASS
PERMIT NO. 33
MAYNARD. MASS
BUSINESS REPLY MAIL
NO POSTAGE STAMP NECESSARY IF MAILED IN THE UNITED STATFS

Postage will be paId by

mamaoma
Digital Equipment Corporation
Software Information Services
146 Main Street, Bldg. 3-5
u ..,,_ ....AI

Uft~ ...

ft._.,. ••

ro_ .... ro

n1'7t:.A

----"