Motivations for reconstructions

The first historical construction to come to our attention was the project to build Babbage’s Difference Engine No. 2, then under way at the Science Museum in London.¹ Conversations with Tony Sale, the first CCS secretary, revealed that he planned to build a replica of Colossus, aided by his contacts in the code-breaking field. He had already replicated and demonstrated early cathode-ray tube (CRT) storage using modern electronics and a bench oscilloscope.² During these conversations, we discussed the possibility of replicating other early computers, in particular the Cambridge EDSAC and the first Manchester computer, the forerunner of the Manchester Mark 1. None of these machines survive in physical form, and replication would involve reconstructing them from surviving documentary and oral sources. Naturally, our interest was in early British computers, because we were more likely to know the relevant original pioneers.

Several factors motivated us to undertake the Manchester Baby project. One of the activities within the CCS and the Science Museum was recording and collecting taped oral history interviews with pioneers, and it was clear from this material that access to pioneers to answer questions about their early endeavors would be valuable in achieving an authentic replica. On the other hand, the actual building of a replica would require technical skills that were mainly possessed by the generation of engineers who happened to live through the relevant times. So there was a timeliness for such projects dependent on particular people, most no longer young, with appropriate knowledge and presumably, because they were likely retired, with time to spare.

Nostalgia also figured as a motivation. It seems to be a commonplace that every generation bemoans change. For engineers, the juggernaut of ever-changing technology presents a constant problem of learning new things and a reluctance to forget the old, in case the old may turn out to be useful. Of course, this is likely to be more noticeable among people who like to look to the past as a way to put the present into perspective. But it must be a powerful motivation, as witnessed by the large number of people who pursue an interest in other technologies such as steam trains and old aircraft. There is something quite exciting about reliving the experiences of people who brought about important innovations.

A further motivation was education and proselytizing. I am constantly dismayed that engineering achievements receive scant attention by the bulk of the population, which is led by the media and which relates to the degree of respect accorded to engineers. It is perhaps reasonable to ignore an innovation when it is new and future ramifications cannot be foreseen, but it is not reasonable to ignore an innovation when it has proved a major influence. The availability of a replica to look at and touch must be a valuable peg for all sorts of educational approaches to attempt to convey a balanced historical view of the past.

Discovery, and the hope of finding something new to say about the original system, was also a factor in our reasons to build a replica. There is curiosity about the details of an object that is not necessarily satisfied by study of its description in any surviving documentation.

Finally, there was the powerful motivator that building a replica is fun to do, and this gave the project team a focus, a social context, and a chance to stretch physical and mental skills.