Computer Centre Bulletin, Volume 2 Number 4, 8th April 1969

Volume 2, Number 4.

8th April, 1969.

UNIVERSITY

OF

QUEENSLAND

COMPUTER

CENTRE

COMPUTER

CENTRE

BULLETIN

Editor:

H.

L.

Smythe.

EDITORIAL

COMMENT

We

remind

our

readers

that

our

programmers

have

offered

to

discuss

any

difficult

or

unusual

problems

which

might

be

of

general

interest,

through

Our

new

"Letters

to

the

Editor"

section

of

the

Bulletin.

In

this

way,

with

your

interest

and

enthusiasm,

"Letters

to

the

Editor"

may

become a

regular

part

of

the

Bulletin.

If

you

have

any

item

of

general

computing

interest,

the

Bulletin

could

publish

both

letter

and

answer.

As

mentioned

last

month,

longer

articles

on

the

application

of

computing

to

various

fields

of

enterprise

and

research,

would

be

most

welcome.

This

could

include

individual

work on

computing

that

may

be

of

general

interest,

or

specialised

projects

carried

out

by

a

group

of

people.

If

readers

and

clients

of

the

Computer

Centre

were

to

become

interested

in

contributing

regularly

to

the

Bulletin,

it

will

surely

develop

as

a medium

for

the

interchange

of

information

and

ideas.

The

accent

of

this

month's

Bulletin

is

on

the

PDP

10 Computing

System.

Two

articles

are

included,

one

providing

helpful

information

on

the

use

of

the

computer

services,

and

the

other

describing

FORTRAN

memory

allocation

on

the

PDP

10.

The

section

on Programming

Advice

is

continued

with

an

advisory

flow

chart

designed

to

assist

the

less

experienced

programmer.

A

further

article

on

the

staff

is

provided,

and

new

Library

Accessions

are

listed.

STAFF

OF

THE

COMPUTER

CENTRE

INTRODUCING

TWO

LECTURERS

Jim

SokoZZ

holds

the

position

of

Lecturer

in

Computer

Electronics

within

the

Department

of

Computer

Science.

Jim

graduated

from

the

University

of

Queensland

in

1962

with

a

degree

in

Electrical

Engineering,

commencing

work

that

year

as

a Programmer

in

the

Computer

Centre.

In

1964,

he

was

appointed

to

the

position

of

Lecturer.

In

this

capacity,

Jim

is

responsible

for

the

lectures

on

Logic

Design

of

Computing

Devices,

a

major

subject

in

the

postgraduate

Diploma

in

Automatic

Computing.

He

also

instructs

second,

third

and

fourth

year

engineering

students

in

various

aspects

of

computing

systems.

42

Jim

is

also

responsible

for

the

maintenance

and

development

of

the

GE

225

and

the

PDP

10

computer

systems,

and

takes

care

of

all

matters

that

affect

computer

services.

In

1968,

he

attended

a

course

on

the

construction

and

maintenance

of

the

PDP

10

at

Maynard,

Massachusetts.

One

of

Jim's

main

interests

is

to

ensure

that

people,

who

have

a

limited

knowledge

of

computers.

are

able

to

use

the

system.

He

is

there~ore

interested

in

the

modification

of

both

hardware

and

software

to

make a

computer

system

usable

and

simple.

His

other

interests

are

concerned

with

compilers

and

digital

communication

systems.

John

Noad

is

a

Lecturer

in

Computing

within

the

Department

of

Computer

Science.

In

1960,

John

graduated

from

the

University

of

Queensland

with

a

Science

degree,

and,

for

the

following

three

years,

worked

as

a

Demonstrator

in

the

Department

of

Physics,

obtaining

Honours

in

Physics

in

1963.

He

joined

IBM

(Australia)

Ltd.

in

January

1964,

working

asa

Systems

Engineer

in

both

Sydney

and

Brisbane,

where

he

gained

considerable

experience

in

the

design

and

implementation

of

machine

systems,

and

in

the

development

of

programmed

applications.

In

January

1968,

he

joined

the

Computer

Centre

staff.

John's

prime

responsibility

is

the

postgraduate

Diploma

in

Information

Processing.

which

was

offered

for

the

first

time

in

1968.

John

lectures

in

the

subjects

-

Data

Processing

Equipment,

Computer

Programming,

and

Systems

Analysis

and

Design.

This

course

has

proved

to

be

so

popular

that

the

enrolment

for

1969

is

three

times

the

enrolment

of

the

preceding

year.

INTRODUCING

A

NEW

MEMBER

OF

STAFF

A new

addition

to

the

staff

is

John Hendry

who

graduated

with

First

Class

Honours

in

Chemical

Engineering

in

1968.

John

is

presently

employed

as

a

half-time

Demonstrator,

and

is

enrolled

full-time

in

the

postgraduate

Diploma

in

Automatic

Computing.

He

intends

to

specialize

in

the

application

of

digital

computers

.to

chemical

engineer:ing.

John

hopes

to

go

overseas

in

September

to

study

for

his

Doctorate

in

either

Canada

or

the

United

States.

We

wish

him

every

success

in

his

career.

43

RECORD

STUDENT

ENROLMENT

The

increasing

demand

for

computer-oriented

courses

is

apparent

from

the

1969

enrolments

in

the

Postgraduate

Diplomas

in

Automatic

Computing

and

Information

Processing,

as

there

is

a

very

significant

increase

over

the

1968

figures.

In

the

Diploma

in

Automatic

Computin~there

is,

at

the

time

of

publication,a

total

of

thirty-two

students

enrolled

(five

full-time

and

the

remainder,part-time).

This

compares

strikingly

with

the

1968

total

of

seventeen.

The

Diploma

in

Information

Processing

is

now

being

offered

for

the

second

year,

and

has

an

enrolment

of

thirty

students.

(Sixteen

full-time,

fourteen

part-time).

This

is

a

three-fold

increase

over

the

1968

total

of

nine.

It

is

hoped

that,

with

the

creation

of

the

Department

of

Computer

Science

and

the

arrival

of

Professor

Rose.

an

undergraduate

computer

science

degree

will

be

introduced

in

the

near

future.

This

should

further

cater

for

the

growing

demand

for

courses

in

this

fie~d.

RECENT

PUBLICATIONS

The

following

publication

is

available

at

the

Computer

Centre:

TECHNICAL

MEMORANDUM

No.4:

Character

Codes

for

the

PDP

10

Computer

System.

R.E.

Kelly,

E.J.

Sokoll.

The

establishment

of

a

standard

character

set

and

is

essential

for

the

interchange

of

information

between

computer

systems

and

for

representing

information

within

a

particular

system.

The

International

Standards

Organization

has

recommended a

standard

code

for

information

interchange

which

has

been

substantially

adopted

for

the

PDP

10

computer

system.

This

memorandum

defines

the

character

set

adopted

for

the

PDP

10,

and

details

those

codes

used

to

represent

characters

on

.the

various

recording

and

storage

media.

44

PROGRAMMING

ADVICE

A

GUIDE

TO

PROGRAMMING

Find out

what

is

required.

Draw system

chart

Is

this

what

is

really

required?

No

Revise

system

~""-I

chart

Ves

Draw

necessary

......

___

...... _

detail

charts.

Dry run

with

test

data

gives

correct

results

?

No

Revise

detail

chart

No

still

satisfied

--

__

-f

with

system?

Ves

Satisfied

with

No

detail

method?

~---

...

Time spent thinking about the

probLem

and

specifying the

problem

in

detail greatly reduces

the debugging time and ensures

the desired results.

I A

weLL

documented program

can

be

aLtered or extended

by

any competent programmer.

I

Test data must

be

simple yet

test

aLL

options.

Wr i

te

program

and

get

punched.

Compile without

errors

?

No

Eliminate

~---Ipunching

and

coding errors.

Ves

Program

follow

Ves

deta

i l

charts

?

No

Alter

coding

Program

works

I

A

working

program is not

necessari

ly

a

good

program.

A

computer

does

exactly

what

you

tell

it

not

what

you

want

it

to

do

(unless these

happen

to

coincide-

!!

)

Leave

Immediately

And

never

Return

46

PDP

10

COMPUTER

SERVICES

THE

COMPUTER

CENTRE

The

University

of

Queensland

Computer

Centre

now

operates

within

the

newly-created

Department

of

Computer

Science,

offering

computer

services

to

all

University

Departments

and

a number

of

non-University

organizations.

The Head

of

the

Department

of

Computer

Science

(Professor

G.A.

Rose)

is

administratively

responsible

for

the

operation

of

the

Computer

Centre.

whilst

policy

matters

affecting

computer

service

and

major

capital

expenditure

are

determined

by

the

Computer

Centre

Executive

Committee.

THE

PDP

10

COMPUTER

SYSTEM

,

The

PDP

10*

is

a

dual-processor.

multiprogrammed.

timesharing

computer

system,

which

will

augment

and

extend

the

computer

services

currently

offered

on

the

GE

225

computer.

The

introduction

of

the

PDP

10

will

result

in

greatly

reduced

turnaround

on

jobs.

and

a

reduction

in

the

costs

of

processing

work.

Initially,

batch

processing,

only,

will

be

available,

but

the

service

will

gradually

be

extended

to

include

interactive

timesharing

from

remote

terminals.

sixteen

of

which

will

be

installed

during

1969.

AVAILABILITY

All

University

users

wishing

to

use

the

facilities

at

the

Computer

Centre,must

first

obtain

the

authorization

of

the

head

of

their

department.

(Non-University

organizations

may

also

elect

to

follow

a

similar

procedure).

In

the

case

of

the

PDP

10,

this

authorization

is

in

the

form

of

an

Order

for

computer

Services,

obtainable

in

pad

form from

the

University

Store.

Each

order

must

be

completed

in

triplicate

and

two

copies

forwarded

to

the

Computer

Centre

before

any

work

is

undertaken.

One

copy

will

be

retained

by

the

Computer

Centre~and

the

second

copy

will

be

forwarded

to

the

University

Accounts

Section.

The

third

copy

should

be

retained

by

the

department

concerned

for

their

own

records.

* A

fuller

description

of

the

PDP

10

is

contained

in

TechnicaZ

Memorandum

No.

1 -

The

University

of

QueensZand Timesharing System,

copies

of

which

may

be

obtained

from

the

Computer

Centre.

Information

which

must

be

supplied

on

each

order

includes

a

project

number,

the

department

name,

the

name

of

the

person

responsible

for

the

project,

a

limit

of

expenditure,

and

the

account

to

which

the

expenditure

should

be

charged.

The

order

must,

of

course,

be

signed

by

the

head

of

the

department

or

by

some

other

person

authorized

to

sign

orders.

Unlike

the

system

of

accounting

for

the

GE

225,

each

project

on

the

PDP

10

will

be

uniquely

identified

by

a

single

number.

This

Project

Number

will

be

assigned

by

the

Computer

Centre

to

all

new

project~

and

must

be

quoted

whenever

computer

services

are

required.

This

project

number

will

remain

current

until

terminated

by

thedepartmen~

or

until

the

project

becomes

inactive.

A

brief

description

of

the

work

to

be

carried

out

is

required

for

all

new

projects;

subsequent

orders

on

existing

projects

need

only

quote

the

proj

ect

number.

It

should

be

noted

that

the

limit

of

expenditure

quoted

on

the

order

will

be

interpreted

as

an

absolute

limi~

an~under

no

circumstances,

will

the

expenditure

be

permitted

to

exceed

that

amount.

Subsequent

orders

may

authorize

further

expenditure

against

an

existing

projec~

and

the

cost

may

be

charged

to

any

valid

account.

However,

the

limit

of

expenditure

on

will

be

exhausted

before

any

subsequent

orders

take

effect.

USING

COMPUTER

SERVICES

Unless

a

computer

program

already

exists

for

a

given

job,

users

will

be

required

to

write

their

own

programs.

The Computer

Centre

does

not

provide

a programming

service.

Initially,

FORTRAN

IV

will

be

the

only

programming

language

available

on

the

PDP

10,

but

other

languages

such

as

MACRO,

AID, BASIC,

COBOL,

and

LISP,

will

be

gradually

introduced.

From

time

to

time,

the

Computer

Centre

will

be

conducting

classes

in

these

languages,

and

these

will

be

notified

as

they

are

scheduled.

Work

for

batch

processing

on

the

PDP

10

should

be

submitted

to

the

Administrative

Officer

(Mr.

J.

Jauncey)

or

deposited

in

the

input.

tray

in

the

clients'

room.

Completed

jobs

will

be

stacked

under

.pr.oject

number,

in

the

output

racks,

which

are

also

located

in

the.

clients'

room.

48

Key

punching

and

verifying

services

are

also

availabl~

and

should

be

submitted

on

standard

coding

sheets

to

the

Administrative

Officer.

Two

keypunches

are

available

in

the

clients'

room,

but

the

use

of

these

machines

is

limited

to

five

minutes

at

a

time.

Further

details

concerning

the

use

of

computer

services

may

be

obtained

from

Mr.

Jauncey

(Ext.

8471).

CHARGES

FOR

PDP

10

COMPUTER

SERVICES

Because

the

PDP

10

is

a

time

shared

computer

system

and

is

able

to

run

several

programs

concurrently.

charges

are

calculated

on

the

basis

of

facilities

used

by

a

particular

program.

There

are

four

groups

of

charges:

I.

Processor

Time

and

Memory

Space.

A

charge

is

made

for

the

processor

time

used

by

each

program

plus

a

charge

for

the

core

memory

~equired

while

the

program

is

in

execution.

This

latter

charge

is

calculated

from

the

product

of

processor

time

and

memory

space

used.

Memory

space

is

allocated

in

the

PDP

10

in

integral

blocks

of

1024

words

(=

lK

words).

The space

occupied

by

anyone

program

is

currently

limited

to

24K

words.

However,

it

should

be

noted

that

program~which

occupy

a

large

amount

of

memory

space,will

cost

more

to

run

and,

because

of

the

manner

in

which

the

PDP

10

schedules

programs

for

execution,

may

take

a

longer

time

to

be

completed.

2.

Information

Throughput.

A

charge

is

made

for

the

quantity

of

information

processed

by

a

program

on

each

input

and

output

file.

The

charge

is

on

the

basis

of

the

number

of

K

words

(where

K =

1024)

or

part

thereof.

There

are

various

rates

applying

to

the

items

of

peripheral

equipment

attached

to

the

PDP

10.

These

rates

are

based

on

the

capital

costs,

the

operating

costs,

and

the

utilization

of

the

peripheral

devices.

A

charge

will

also

be

made

for

the

transfer

of

information

to

and

from

the

file

storage

system.

3.

Storage

of

Files.

Both

programs

and

data

files

may

be

stored

for

future

reference.

A

charge

is

made on

the

basis

of

the

size

of

each

file

(in

K

words)

and

the

time

for

which

the

information

is

stored

(in

days).

4. l;)evice Set,up and

~onsumable

Items

.Whe.r~

any

special

action

is

required

in

setting

up a

peripheral

device,

e.g.

to

allow

special

paper

to

be

used,

a

device

setup

charge

will

be

made. A

fee

will

also

be

charged

for

access

to

a:

f:i,.le

which

has

been

preserved

on

behalf

of

a

user.

Access

to

system

files

will

be

allowed

free

of

charge.

Where

the

use

of

consumable

items,

such

as

printer

paper

or

plotter

paper,

is

excessive,

these

items

will

be

charge

for.

All

charged

will

be

calculated

as

a

run

is

processed.

Upon

completion

of

a

job,

the

charge

so

far

accumulated

for

each

item

will

be

rounded

to

the

nearest

cent,and

the

total

of

all

charges

for

that

job

debited

against

the

authorized

expenditure

for

that

project.

A

schedule

of

charges

on

the

PDP

10

for

University

Departments

or

for

Non-University

Organizations

is

available

from

the

Computer

Centre.

INVOICES

AND

STATEMENTS

Each month, a

Statement

of

Account

will

be

forwarded

to

each

University

Department.

For

each

project,

this

will

contain

details

of

the

total

expenditure

this

month,

the

total

expenditure

authorized

60

far

this

year,

the

total

expenditure·so

far

incurred,

and

the

balance

still

authorized.

These

totals

will

be

summarized

for

each

departmental

account,

and

for

the

department

as

a

whole.

The

Accounts

Section

will

use

this

information

to

automatically

debit

the

appropriate

departmental

accounts.

Non-University

Organizations

will

be

:i,.nvoiced on a

monthly

basis.

The

expenditure

against

each

project

will

be

itemized

against

the

apprqpriate

order.

LIB~ARY.

ACCESSIONS

This

section

details

the

books

and

periodicals

relating

to

the

computer

field,

that

have

been

acquired

by

Libraries

of

the

University

of

Queensland

in.November

and

December,

1968.

November

Accessions

Stewart,

David

J.

edt

Automation Theory and Learning Systems. 1967.

(001.53

STE, Main

Lib.)

Machine

Intelligence.

No.1;

1967(001.535

MAC,

Engin.

Lib~)

50

Practical

Problems

of

Library

Automation. 1967. (Q029.7

PRA,

Main

Lib.)

Interdisciplinary

Clinic

on

Instrumentation

Requirements

for

Traffic

Control

Systems.

New

York, 1963.

Traffic

Control

1965.

(388.31INT,

Engin.

Lib.)

Clyde,

Dean

J.

MUltivariate

Statistical

Programs. 1966. (Q519.92

,CLY,

Engin.

Lib.)

Coleman,Monte

W.

BRLESC

Plotting

Subroutines.

1967. (Q519.92

COL,

Engin.

Lib.)

European Atomic

Ener.gy

Community.

Scientific

Data

Processing

Centre.

1965.

(Q519.92

EUR,

Engin.

Lib.)

Hockney, Roger

W.

Minimum

Multiplication

Fourier

Analysis.

1965. (Q517.355

HOC,

Engin.

Lib.)

Knuth, Donald E.

The

Ar.t,

of

Computer Programming.

[c

1968]

(519.92

KNU,

Engin.

Lib.)

Mueller,

Dennis

J.

Fortran

Subroutines

for

Householder's Method

in

the

Complex

Case

and Eigen Systems

of

Hermitian

Matrices.

1966. (Q519.92

MllE,

Engin.

Lib.)

Seminar on

Linear

Programming

in.Practice.

University

of

New

South Wales, 1960.

Proceedings

1960. (Q519.92SEM,Maths.

Lib.)

ZUkhovitskii,

Semen

I.

Linear

and Convex Programming. 1966.

(519.92

ZUK,

Engin.

Lib.)

Computer

Digest.

V.

3;

1968

[and

onwards]

(510.78

COM,

Engin.

Lib.)

Journal

of

Computer and System

Sciences.

V.

2;

1968

[and

onwards]

(510.78

JOU,

Engin.

Lib.)

Moseley,

Maboth.

Irascible

Genius: a

Life

of

Charles Babbage. 1964. (608.742

BAB,

3

MOS,

Main

Lib.)

Holmes, James F. Data Transmission and Data Processing

Dictionary.

1965. (621.3803

HaL,

Engin.

Lib.)

Baker,

C.L.

JOSS:

Console Design. 1967 (Q651.89

BAK,

Engin.

Lib.)

Bryan,

G.E.

JOSS:

Accounting and Performance Measurement. 1967 (Q651.89

BRY,

Engin.

Lib.)

Coffman, Edward

G.

Stochastic

Models

of

Multiple

and Time-Shared Computer

Operations. 1966. (Q651.84

COF,

Engin.

Lib.)

Evarts,

Harry

F.Introduction

to

PERT.

1964.

(658.5

EVA,

Main

Lib.)

Gonzale'z,

R.

Associative

Techniques

for

Control Functions

in

a

Multi-Processor

Simulation

Investigation.

1967. (Q651.89

GON,

Engin.

Lib.)

Greenwald,

I.D.

JOSS:

Disc

File

System. 1967. (Q651.89

GRE,

Engin.

Lib.)

Insti

tution

of

Cost and

Works

Accountants.

Management

Information

Systems and

the

Computer. 1967 -(658.505 INS, Main

Lib.)

51

Kintner,

Paul

M.

Electronic

Digital

Techniques.

1968.

(651.8

KIN,

·Engin.

Lib.)

McCrimmon, Kenneth

R.

An

Analytical

Study

of

the

PERT

Assumptions. 1962.

(Q658.5

MACe,

Main

Lib.)

Massachusetts

Institute

of

Technology..

Project

MAC.;

Progress Report

III.

1966.

(Q651.8

MAS;

Engin

..

Lib.)

Rohrbac

her,

Donald L. Advanced Computer Organization Study.

(Q651.

89

ROH,

Engin

•.

Lib.)

1966.

Totschek,

Robert

A.

Time-Sharing

Grench,

R.E.;

comll.

An

Empirical

Investigation

into

the

Behaviour

of

the

SDC

System.

1965.·

(Q651.84

TOT,

Engin.

Lib.)

Collected

Algorithms.

1960-1963.

1965 (Q510.78

GRE,

Engin.

Lib.)

December

Accessions

Computers and

the

Lawyer.

1968.

(Q510.7834

COM,

Law

Lib.)

Morris,

Stan1eyM.Salem

-A Programming System

for

the

Simulation

of

Systems

Described by

Partial

Differential

Equations.

1968.

(519.92

MOR,

Engin.

Lib.)

The

Computer

Bulletin.

V.

12,

No.4;

1968,

and

onwards.

(510.78

COM,

Engin.

Lib.)

Symposium

on

the

Prospects

for

Simulation

and

Simulators

of

Dynamic

Systems~

Baltimore,

1966.

Prospects

for

Simulation

and

Simulators

of

Dynamic

Systems.

1967.

(610.7

SYM,

Engin.

Lib.)

Saxon,

James

A.

Basic

Principles

of

Data Processing.

1967.

(651.8

SAX,

Engin.

Lib.)

FORTRAN

MEMORY

..

ALLOCATION

.ON

THE

PDP

10.

A

question

frequently

p.ut

to

the

Computer

Centre

staff

is:

how

large

a

FORTRAN

program

will

I

be

able

to

run

on

the

PDP

107

There

is

no

brief

answer

to

this

question,

and,

in

particular,

it

is

not

possible

to

base

an

estimate

of

the

amount

of

core

needed

on

the

PDP

10 upon a knowledge

of

the

amount

of

core

used

by

the

same

program

when

run

on

the

GE

225.

This

article

contrasts

the

methods

of

organizing

the

memory

in

the

PDP

10 and

GE

225

FORTRAN

IV

systems.

An

appreciation

of

the

different

philosophies

involved

52

FIGURE.

I.

Memory allocation

in

the

GE

-225

during a

FORTRA~IV:

run.

'53

USER

*1

FIGURE.2. Typical Memory

allocation in the PDP-IQ

Two

FORTRAN

users

are shown in core

together.

will

enable

the

FORTRAN

programmer

accustpmed

to

the

GE

225

to

design

programs

which

make

optimal

use

of

core

space

on

the

PDP

10.

Let

us

begin

by

reviewing

the

situation

for

the

GE

225.

Here,

only

one

program

can

be

stored

in

the

memory

at

a

time,

so

that

more

than

half

the

memory

can

be

le~t

unused

~or

quite

long

periods.

The

first3K

(where

K = 2

10

=

1024)

memory

locations

are

occupied

by

the

GE

225

FORTRAN

IV

Operating

System

(region

A

in

Figure

1).

T

he

locations

are

available

for

the

user's

FORTRAN

program

(which

is

shaded

as

region

B

in

Figure

1),

and

the

remainder

(region

C)

m~

be

used

for

the

storage

of

data

in

COMMON

storage.

Object

program

instructions

and

simple

variables

canpot

be

stored

in

the

upper

half

of

the

memory.

The

FORTRAN

IV

Operating

System

for

the

GE

225

is

of

fixed

size

and

.consists

of

a

large

number

of

implicitly-called

subroutines

for

performing'

input/output,

conversion

of

numbers,

etc.

It

contains

subroutines

to

handle

F,

E,

I,

0

type

format

specifications

(among

others),

even

though

few

programs

use

all

of

these.

Reference

in

a

program

to

a

mathematical

function

such

as

COS

or

SQRT,

however,

automatically

causes

the

appropriate

subroutine

to

be

plac.ed

in

region

B,

thereby

expanding

that

region.

The

only

mathematical

subroutines

loaded

into

core

are

those

actually

used.

(A

few

implicitly-

called

input/output

routines

are

also

handled

in

this

w~).

With

these

aspects

of

the

GE

225

system

in

mind,

let

us

consider

the

PDP

10

.

Figure

2

provides

atypical

"snapshot"

of

core

at

a

time

when two

FORTRAN

programs

are

in

core

together,

a

situation

which

cannot

exist

on

the

GE

225.

The

first

16K memory

locations

are

reserved

for

the

PDP

10

Operating

System,

which

is

permanently

resident

in

core.

It

is

common

to

all

programs

being

executed,

and

performs

functions

such

as

input/output,

time

accounting

and

scheduling.

At

any

given

instant,

the

remaining

core

may

be

occupied

by

a

single

program

or

by

several

small

programs*.

As

shown

in

Figure

2,

each

FORTRAN

program

is

loaded

with

its

own

tailormade

version

of

FORSE

which

acts

as

an

interface

to

the

Operating

System.

*

While

this

would

imply

that

a

single

program

could

occupy

the

remaining

32K

of

core,

in

fact

the

operating

system

limits

all

programs

to

a

maximum

size

of

24K.

This

is

done

to

permit

reasonable

efficiency

in

the

scheduling

of

jobs

for

execution.

and

also

to

ensure

a

satisfactory

response

time

for

all

jobs.

54

FORSE

is

similar

to

the

FORTRAN

operating

system

on

the

GE

225,

in

that

it

contains

routines

falling

into

two

main

Computer Centre Bulletin, Volume 2 Number 4, 8th April 1969

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