This document discusses the history of analog computing and its role in engineering applications such as modeling aircraft flutter. It notes that analog computers were used to represent physical systems because digital computers were not fast enough for complex problems in the early postwar period. While the superiority of digital was understood, analog persisted due to issues with training, engineering trust in programs, and the ability of analog to enable interactive exploration of tentative or experimental problems. The document also outlines the researcher's work on the history of analog computing at BP and in higher education, as well as applications in aeronautics where both analog and digital were used.

1. The computer as a modelling machine
a history of analog computing
Charles Care
http://www.warwick.ac.uk/go/ccare
26th June 2006

2. History of computing
• Story of the progression of
technology
• Popular to trace the history
back to
– calculating machines (e.g.
abacus, sliderule)
– data processing
technologies (e.g. punched
cards)
– early office machinery (e.g.
typewriters)
– early communications
technology (e.g. telegraphs)

3. Computers and Engineers
• Use computers to represent physical systems
and natural phenomena
• … problem solving mediated by
– …differential equations
– …other notations
• …computers solve the problem by
– …numerical methods
– …more direct techniques
• Supported by engineering knowledge,
experience and trust.

4. An alternative history
A recent conference... attempted to map out the history
of software, considering it as science, engineering,
labour process, reliable artefact and industry...
The focus lay on software and its production as general
phenomena. What the conference missed was
software as model, software as experience, software
as medium of thought and action, software as
environment within which people work and live.
It did not consider the question of how we have put the
world into computers.
(Mahoney, 2005)

5. From experimental to computational
• Progression from one-off modelling to the
development of a laboratory science of
aeronautics.
– Full size
– one-off model
– model in wind tunnel
– electrolytic tank (special purpose analog)
– general purpose analog
– general purpose digital.

6. Aircraft Flutter – a complex problem
…flutter calculations required on a modern
aircraft are usually beyond the scope of a
desk calculating machine, and high speed
computational aids have become a necessary
adjunct to flutter prediction. (Templeton,
1955)
• Royal Aircraft Establishment developed
‘flutter simulators’ (analog computers)

7. Aircraft Flutter – a complex problem

8. Aircraft Flutter – a complex problem

9. Aeronautics and analog/digital
• ARC computation panel
– Wilkes: “No desire to discourage anybody from
doing work which may get results, but in the near
future when there were more digital machines …
analogue machine building just would not be able
to keep up with them.”
– “Diprose viewed with alarm the implied tendency
to build up large programmes and so have the
arithmetical processes divorced from the physical
problem.”
(Meeting 3 pp 2 – 3, 1953)

10. Why did analog persist?
• Superiority of digital was understood
• But digital was not fast enough
• Issues relating to training engineers in
programming
• Engineering trust – how reliable is a program
• Closed shop computing vs open shop
interaction
• Users rather than inventors.

11. My research
• The history of an analog computer installed at
British Petroleum (BP)
• The role of analog computers in higher
education (HE), and the agency of higher
education in the development of analog
• Analog/digital applications and use in
aeronautics
• The relationship between analog computing
and ‘soft’ computing.

12. Analog computing at BP
EMIAC computer installed at
BP, Sunbury (1962)

13. Analog Computer in HE

14. Modelling machines
• Engineering knowledge and modelling
• Campbell-Kelly and Aspray (2004)
– Focus: Office machines, communication, and data
processing
– Theme: computer as information machine
• My work
– Focus: Modelling, engineering design, simulation,
and analog computers
– Theme: computer as modelling machine

15. Aeronautics and analog/digital
• Perceptions of superiority
– “…when the automatic digital machine became
established…[many suggested] that analogue was
obsolete. This view is no less widely held.”
(Diprose, 1955)
• Trial and error process
– “The analogue machine… is more convenient
where the problem is itself tentative and
experimental… where the choice of later
calculations may depend on the results of earlier
ones.” (Hollingdale and Diprose, 1953)

16. Post WWII analog computing
• Problems with this
history
– View past with the
eyes of the present
– Focus on successes
rather than failure
– Small (2001)
– c.f. Hamilton (1997)

17. Role of Users
• Cybernetic story
– Role of feedback
– Humans and
Machines working
together.
– Mindell (2002)
• Connections with
Empirical Modelling
– Human Computing

18. References
• Anon. Minutes of the Computation Panel of the ARC. TNA DSIR
22/206. 1952-3.
• K. V. Diprose. Analogue computing in aeronautics. Copy of of a lecture
given to the Royal Aeronautical Society. TNA DSIR 23/23384, 1955.
• Martin Campbell-Kelly and William Aspray. Computer: A History of the
Information Machine. 2nd. ed., Westview Press, Colarado, 2004.
• Ross Hamilton. Continuous path : the evolution of process control
technologies in post-war Britain. PhD thesis, University of Warwick,
1997.
• S. H. Hollingdale and K. V. Diprose. The role of analogue computing in
the aircraft industry. TNA DSIR 23/21372, 1953.
• David A. Mindell. Between Human and Machine: Feedback, Control,
and Computing Before Cybernetics. The John Hopkins University
Press, Baltimore, 2002..
• James S. Small. The Analogue Alternative: The Electronic Analogue
Computer in Britain and the USA, 1930-1975. Routledge, London, 2001