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Further reading □ Overview1962: Introducing ACL1964: Orbit article1966: ACL operation and research1967: atlas newsletter1968: atlas newsletter1969: atlas newsletter1969: ACL users' handbook1972: atlas newsletter1973: ACL brochure1973: ACL notes for new entrants1973: Atlas closing ceremony1974: ACL Handbook (ICL and IBM) □ Symposia and publications □ 1967: Abstract Algebra1969: Number Theory1970: Radiative Transfer1973: Computer Chess (Ed. Bell)1974: Finite Elements1974: Quantum Chemistry
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ACLLiteratureACL Publications :: Literature: ACL Publications
ACLLiteratureACL Publications :: Literature: ACL Publications
ACL ACD C&A INF CCD CISD Archives
Further reading

Overview
1962: Introducing ACL
1964: Orbit article
1966: ACL operation and research
1967: atlas newsletter
1968: atlas newsletter
1969: atlas newsletter
1969: ACL users' handbook
1972: atlas newsletter
1973: ACL brochure
1973: ACL notes for new entrants
1973: Atlas closing ceremony
1974: ACL Handbook (ICL and IBM)
Symposia and publications
1967: Abstract Algebra
1969: Number Theory
1970: Radiative Transfer
1973: Computer Chess (Ed. Bell)
1974: Finite Elements
1974: Quantum Chemistry

Closing Ceremony of the Ferranti-ICL Atlas-1

30 March 1973

Atlas Computer Laboratory

Atlas Closure: 1973

Atlas Closure: 1973
Full image ⇗
© UKRI Science and Technology Facilities Council

An invitation to the
Atlas Computer Laboratory
of the
Science Research Council
at Chilton, Didcot, Berkshire
for the

CLOSING CEREMONY

of the

FERRANTI - ICL

ATLAS - 1

- the Laboratory's original computer

by
Sir Brian Flowers, FRS
Chairman of the Science Research Council
on
Friday, 30th March 1973

PROGRAMME

11.00 THE LABORATORY IS OPEN TO GUESTS
12.00 THE DIRECTOR - DR J HOWLETT, CBE WILL BE AVAILABLE TO TALK TO THE PRESS REPRESENTATIVES IN THE CONFERENCE ROOM
13.00 BUFFET LUNCH
14.30

CLOSING DOWN CEREMONY

Mr Basil de Ferranti will speak about the Atlas project

Professor David Howarth (who led the team who wrote the Supervisor) will run the last program

Sir Brian Flowers will switch off the machine

15.30 TEA WILL BE SERVED

THE ATLAS COMPUTER

Atlas, designed in the University of Manchester in 1958 to 1961 by the distinguished team led by Dr Tom Kilburn - now Professor Tom Kilburn, FRS - and manufactured initially by Ferranti Limited, whose Computer Department later formed an important part of ICL, was a great and classic machine.

It was remarkably advanced for its day, pioneering many features , which have had a profound effect on computer design and use. Probably the most important were first the paged store, which made possible among other things the concept now called virtual memory; and second the Supervisor, which was the first instance of a comprehensive and largely automatic operating system. The Chilton machine, which was the third of the 6 which were made, has had 8½ years in service and has enabled many research workers, in all the British universities, to tackle projects which otherwise would have been beyond them. Here are some facts about our machine and the work it has done in its busy life.

CONFIGURATION OF THE ATLAS COMPUTER

(the Atlas word is 48 bits, organised in 8 6-bit characters)

Central Processor
with 128 index registers (B-lines)
Main Store
48K ferrite cores 2µa cycle time
96K magnetic drums, transfer time 2ms for 512 words, average access time 7.8 ms
Magnetic Disc
Data Products Model 5045, capacity 16 million words, transfer time 6.5ms for 512 words, average access time 80ms
Magnetic Tape
16 Ampex TM.2 decks (1 inch tape)
2 IBM 729 Mark IV deck (½in tape)
Console
Engineers' console with input and output peripherals
Direct access typewriter for operators' messages and enquiries
Input
Card readers: 2 ICT - 600 cards/minute
Paper tape readers:
  • 1 Ferranti - 300 characters/sec
  • 1 Elliott - 1000 characters/sec
Output
Printers: 2 Anelex - 1000 lines/minute, 120 characters/line
Card punch: 2 ICT - 100 card/minute
Paper tape punch: 3 Teletypes 100 characters/sec

NB The paper tape equipment will handle 5, 7 or 8 track tape

THE HISTORY OF THE ACL "ATLAS"

JUNE 1964 Installation and commissioning started
OCTOBER 1964 Start of "at risk" service
MAY 1965 HANDOVER and acceptance period began
FEBRUARY 1966 Full 3-shift operation
MAY 1966 FINAL ACCEPTANCE
FEBRUARY 1968 DATA PRODUCTS DISC AND SIGMA 2 ADDED TO THE SYSTEM
MAY 1969 Multi access system in full operation
30 MARCH 1973 End of computer service

THE "WORK DONE" (MAY 1965 TO MARCH 1973)

HOURS OF WORK AND VALUE
Scheduled hours 44,500
Available hours 43,000
% AVAILABILITY 97
NUMBER OF JOBS HANDLED 836,000
VALUE OF WORK DONE £10.8M
NUMBER OF UNIVERSITY PROJECTS SUPPORTED 2,300

PERIPHERAL ACTIVITIES

Input cards 300M cards
Input paper tape 4000M characters
Output lineprinter 800M lines
Output cards 17M cards
Magnetic tape transfers 500M blocks
Drum transfers 300M blocks
USE OF CPU - Proportion User programs 0.82
USE OF CPU - Proportion Supervisor 0.12
USE OF CPU - Proportion Idling 0.06

THE USERS' PROFILE

Number of University Projects supported 2,300
% of time (1972) to University use 89%
% of time (1972) to Government Departments 2%
% of time (1972) used by FORTRAN 71%
% of time (1972) used by ALGOL 12%
% of time used for compilation of programs 7-10%
Average job length 1966-1967 121 seconds
Average job length 1968-1970 142 seconds
Average job length 1970-1973 198 seconds
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