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54872 Notes on a Visit to Cambridge, Jul 1953
Report by John Pinkerton on his visit to Cambridge of 23rd July 1953, ostensibly for a 'colloquium given by Mr D Willis on the tape recording equipment now being tried out with EDSAC'.
Research comments: Mr Willis is likely to be Donald Willis, a Research Assistant at the Mathematical Lab from 1948-50 and 1952-55 who worked on mag tape development. Other people referred to are computer pioneer Christopher Strachey (of the N.R.D.C. (National Research Development Corporation) who is noted to be at the Mathematical lab using a temporarily installed Elliott computer.
The document refers to using mag tape to extend storage capacity rather than as input/output. Information is stored in "blocks of 100 words, a word being a long number." Pinkerton reports that the tape used on EDSAC is the same as on LEO I (i.e. R.G.D. paper tape) which runs at a speed of 100" per second. In the process described, the shifting register is used to "effect change between the slower tape speed and the higher calculator speed". Also described are the "tape drive arrangements".
The document suggests that tape made by Thermionic Products was "extremely bad because oxide could easily be scraped off" and that made by Ferro-Voice was also substandard. Paper is preferred to plastic tape due to reduced stretching and potential breaks. Ferranti use Gavaert tape.
Section 3 refers to Elliot (sic, Elliott) computers, in connection with Christopher Strachey. Strachey is noted to have "invented a simple method of doubling the speed of multiplication" on the Elliott and gives a brief explanation of how. The report then concludes that it wouldn't be easy to transfer this modification to LEO and explains why.
Section 4 reports on mechanical tape comparators.
it is interesting to note how much of an inter-relationship there seems to be between all the various early computer developers. (LM)Date : 23rd July 1953
Creator : John Pinkerton
Physical Description : 1 item (5 pages), paper; typescript
Archive References : CMLEO/DC/DR/EDS/19530727 , DTC/8/16/17-21
This exhibit has a reference ID of CH54872. Please quote this reference ID in any communication with the Centre for Computing History.