Saturday, January 5, 2019

Autumn 2018 report to the Computer Conservation Society

This was presented on November 15, 2018 to the Computer Conservation Society by Doron Swade.

The end is in sight creating the cross-referenced database for the set of some 20 Scribbling Books, the manuscript notebooks in which Babbage recorded his workings and thoughts on his engine designs. Tim Robinson, who has been compiling the database is up to the last year of Babbage’s life (1871) and is within striking distance of completion. The process has taken coming up for three years.

The motive for this undertaking was that before we could commit to building anything we needed to be sure that we had reviewed everything Babbage had to say on a particular topic. The situation is confounded by Babbage’s practice of returning to the same design issues time and time again over periods of decades as a consequence of which related material is unsystematically scattered through the archive of some 7,000 manuscript sheets.

While Tim Robinson’s emphasis so far has been data capture rather than interpretation there are several general preliminary findings that are already invaluable to the overall enterprise of constructing an Analytical Engine. One such is the confirmation that not only are the designs incomplete with respect to details of control and overall systems integration (this was anticipated) but that there are several critical features for which there are worked viable alternatives the final selection of which Babbage left open (method of multiplication, digit precision, method of carriage, for example). Also, that Babbage remained creatively active till the end with at least one instance of his most sophisticated design being modelled in the period immediately before his death in 1871.

The completion of the database will be a landmark in the developmental trajectory of this project. Next steps are, firstly, a scrape of a relatively small but potentially critical set of ‘mystery’ drawings that have not been catalogued or scanned. This is a manageable clean-up job undertaken for completeness and in the hope that some final gaps might be filled and some remaining blind references traced. Secondly, to model and build a mechanism (the advanced anticipating carriage mechanism) to assess logical and physical feasibility, and to use this to develop generic modelling and evaluation techniques to be extended to each of the core functions. 

Doron Swade