Computer History

Explore each of these articles, which focus on the early history of computers and give some insight into the early history of computers. They will introduce you to the powerful ideas that enabled computer architecture of today and that will influence computer architecture of tomorrow.

The Moore School Lectures

Some time between 1934 and 1950 the first modern computer was created. Pinning down exactly when that event occurred is not easy. It depends on how you define the term computer and what you think is more important: The concept, the design, the first successful test, or the first time the machine solved a real problem. In those early days it usually took years for a team to progress from concept through design to working machine. There were many such teams working mainly in the US and UK. These teams competed and cooperated sometimes they shared ideas and designs, and they sent representatives to visit each others laboratories. On one famous occasion in the summer of 1946 almost all the leaders in the field got together at the Moore School for an 8 week long series of lectures. In short the story of the emergence of the modern computer is a complex one that involves both direct and indirect contributions from many people.

In 1946 between July 8 and August 31, the Moore School of Electrical Engineering at the University of Pennsylvania held a special course entitled Theory and Techniques for Design of Electronic Digital Computers. The course was organized in response to interest generated by; the schools public announcement of the ENIAC, and the publication of the first draft of a report on the EDVAC by Jon von Neumann. Attendance was by invitation only and the "Students" were selected from the leading experts at the major institutions working on the development of computing devices in the US and UK. At the time of this event there were only three published designs for a stored program computer and it was expected that all those present were familiar with these documents:

  • The First Draft of a Report on the EDVAC, by Jon von Neumann (1945)
  • Proposed Electronic Calculator, by Alan Turing (1945)
  • Preliminary report on the proposal for an IAS machine, by A.W. Burks, H.H. Goldstine and John von Neumann (June 1946)

Within two years of these lectures, the first stored program computer was operational; within 3 years there were 5 operational machines; and within 5 years stored program machines were commercially available. The Moore School Lectures, as they became known, were responsible for focusing all the leading developers of computing devices on a single problem: how to design and build a stored program computer. It is interesting that despite being outnumbered and out-funded the British took, and held, the lead in this development effort between 1946 and 1953. In some areas such as business applications the British held the lead for much longer. How they were able to do this is not directly explained in any of the historical material available online, which tends to focus on individual development efforts and not on the larger picture.

 

Attendance at the Moore School Lectures

40 lectures were delivered 5 days a week over 8 weeks. Most days a formal morning lecture lasting up to 3 hours was followed by an unstructured afternoon seminar.

Hartree was very forward looking and was excited by the mathematical potential of the stored program computer. On the other hand, Aiken was absorbed in his own way of doing things and does not appear to have been aware of the significance of the new electronic machines. The excellent review by John H. Curtis gave a very clear picture of contemporary computer development in the United States. But for most of the Students the real value was gained from the informal afternoon seminars.

 

Analysis and Speculation

What follows is mostly speculation, I would be interested in evidence that supports or refutes these ideas.

I suspect the British were able to take the lead in computing in 1946 because the main challenge had become the rapid construction of a machine while solving the one remaining major technical problem – storing a program in memory. This problem was well understood in concept but the practical solution was more challenging than it appeared. As a result of their experience in the war the British were approximately 2 to 3 years in advance of the Americans in the crucial area of rapid prototyping and evolution of complex electronic devices. It was this ability that enabled them to take the lead from America.

During the War the British had developed RADAR further than any of the other combatants. This work occurred in secret at the Telecommunication Research Establishment TRE in Malvern. Meanwhile at Bletchley Park, they had secretly built and operated 10 Colossus Mk II code breaking machines. These machines were complex special purpose computing devices, they matched ENIAC in complexity and capability if not in size and generality. At the end of the war Britain had the largest concentration of electronic computing devices in the World and a significant number of engineers with practical skills in rapidly building complex electronics. The British centers of electrical engineering excellence which included; Bletchley Park, the Telecommunications Research Establishment (TRE) at Malvern, and The General Post Office Research Station at Dollis Hill, had all been driven by desperation to work with great speed and had each developed similar evolutionary prototyping approaches. The Colossus Mk I, and Mk II were constructed by Tommy Flowers in a matter of months at Dollis Hill, and the development of RADAR at the TRE had been similarly rapid. Americas leading center of excellence in the field of electronic computing – The Moore School – had become used to working at a slow pace. The ENIAC had taken 5 years to construct and was not completed until after the war ended.

In 1946 the Moore School's leading experts left the school and went to other institutions. John von Neumann went with Herman Goldstine to the Institute for Advanced Study in Princeton and Mauchly and Eckert also left to setup their own company which was later purchased by Remington Rand. Both these groups lost valuable time in these reorganizations, however this was not the cause of the lead in computing passing to the UK. Similar reorganizations had happened already in the UK and other countries, as military programs were wound down and research expertise returned to civilian institutions.

By 1946 the conceptual architecture for a stored program computer was well understood by those interested in the field of electronic computing. Both John von Neumann and Alan Turing had developed and published designs. While these designs were revolutionary they were not particularly complex conceptually. As has been pointed out elsewhere a competent electrical engineer can grasp the main features of von Neumanns' design in a day. Maurice Wilkes was famously given only one night to read the First Draft and decided there and then that this was the correct approach and that he would develop a machine along these lines – the EDSAC, generally accepted as the second operational stored program computer and the first machine to actually perform useful work. By the time the Moore School lectures had finished there were many people who understood exactly what needed to be done.

Two basic types of stored memory were under investigation, Serial Access Memory (SAM) and Random Access Memory (RAM). SAM could only be read in the order it was written while RAM was much faster as it could be read in any order. SAM devices in the form of mercury acoustic delay lines were already available as a result of RADAR development which need memory devices to improve image quality. RAM devices such as the Selectron were still under development but at the time of the Moore school lectures they were expected to be ready within a year.

In the UK all three centers of computer development hired people from either TRE Malvern, Bletchley Park or both to fill Senior positions. These men combined their expertise and rapidly developed plans for building stored program computers.

At Manchester University Max Neumann, who had directed efforts to break the Lorenz Cypher at Bletchley Park, became Fielden Professor of Pure Mathematics. He recruited, I.J. Good and D. Rees both from Bletchley. Meanwhile the Electrical Engineering Department recruited Freddie Williams from the TRE Malvern. Williams brought Tom Kilburn and later Geoff Tootill also from TRE to continue the development of a memory device based on the Cathode Ray Tubes CRT. Once at Manchester Williams and Kilburn rapidly perfected a working RAM based on the cathode ray tube. The Williams-Kilburn tube was working by March 1947 just over a year later The Baby, the first stored program computer was operational. The speed of this development must be compared with the ill-fated development of the Selectron which was running into difficulty in the US and was still not operational in the middle of 1948 when The Baby became operational. It was not used in a computer until the Johniac in 1953.

There is some dispute over who actually led the effort to build the Baby at Manchester the mathematics department or the Electrical Engineering departments. But what is clear is that men from TRE Malvern were able to solve the technical problems that were slowing efforts elsewhere and by employing a rapid evolutionary prototyping approach the Manchester University team was able to beat all the other teams in the UK and US to build a working stored program computer. The Baby ran its first successful program on June 21, 1948.

At Cambridge University, Maurice Wilkes who had also been involved in Radar Development at TRE Malvern took a different approach. He chose to build a machine of modest capabilities from stock parts, or as near to stock as he could get – he chose mercury delay lines for the memory. The machine was called EDSACit was the second operational stored program computer after the Baby in Manchester and ran its first successful program on May 6, 1949. Wilkes was funded in part by the J. Lyons Company a forward thinking British teashop chain similar to today's Starbucks. Lyons decided to build a computer of their own based on the EDSAC designed. Lyons hired John Pinkerton also of TRE who seconded two of his staff to Wilkes to help build EDSAC. In 1951, Lyons built their machine and called it LEO. It was the first business computer every used and was rapidly commercialized. IBMs first computer the Defense Calculator was not available until March 1953.

At the National Physics Laboratory (NPL) Alan Turing of Bletchley Park was leading efforts to build a computer of his own design called the Pilot ACE. Both Max Neumann and Alan Turing tried to recruit Tommy Flowers to help with development in 1946. Both failed, sadly he stayed at the Post Office. Alan Turing continued to use the Post Office research center at Dollis Hill to build mercury delay lines but Flowers and W. M. Combs another Bletchley man were being pulled onto other "more important" work and progress was delayed. Eventually Turing was persuaded to go to Manchester by Max Neumann. The Pilot ACE was constructed without him and was operational in 1951.

Meanwhile in America the situation was not improving. The Eckert Mauchly Computer Corporation built the BINAC for the Northrup Aircraft Corporation for a classified airborne application. It was tested and ran successfully for 44 hours in April 1949. It was then dismantled and delivered to Northrop in California were it was never successfully rebuilt. The IAS team led by von Neumann at Princeton was struggling with the Selectron and switched to the Williams-Kilburn tube soon after the Manchester team announced the Baby.

In Australia yet another alumni of TRE Malvern was having more luck. Trevor Pearcey had moved from the UK to Australia in 1945 where he decided to design and build a computer. In 1948 he visited England and confirmed the soundness of his design. By November 1949 the CSIR Mk I was operational.

With 50+ year hindsight and knowledge of the secret British activities at TRE Malvern and Bletchley Park the Moore school lectures can be seen in a different light – one that raises many questions. To what extent did the hosts at the Moore School know about their British guests experience and skills? Had they known the truth would they have been so open with their information?. What would have happened if the British had been able to share their knowledge? One fact seems undeniable, only four stored program computers were operational before 1950 and three of these were built by people who had worked at TRE Malvern during the Second World War. The one exception, the BINAC, worked for 40 hours and was then dismantled never to work again. At the beginning of 1950 there were three working stored program computers in the world and none of them were in America. The expertise developed at Telecommunications Research Establishment (TRE) Malvern placed its engineers 2 to 3 years ahead of anyone else. How the British lost this lead is much less clear. The post war Austerity measures contributed and the failure of the UK government to make adequate investments may have been a factor. There was no direct equivalent to the US ARPA and the agencies that did exist were not well funded. Industry and universities failed to partner well in the way J. Lyons and Cambridge University had done. Whatever the case between 1950 and 1960 the British lost a 2 to 3 year lead in computing to America. But it may be fairer to say that the Americans took the lead back from the British.

Finally consider the case of David Rees of Manchester University. He must have had a uniquely interesting and frustrating experience at the Moore school in 1946. He had been sent by Max Neumann from Manchester University to the lectures as a "student" and yet he was the only person present who had first hand knowledge of Bletchley Park – the largest computing facility in the world, but, in the interests of British national security he was not allowed to talk about it.