Technical Details of the Elliott 152 and 153
Appendix 1 Technical Details of the Elliott 152 and 153 Introduction The Elliott 152 computer was part of the Admiralty’s MRS5 (medium range system 5) naval gunnery project, described in Chap. 2. The Elliott 153 computer, also known as the D/F (direction-finding) computer, was built for GCHQ and the Admiralty as described in Chap. 3. The information in this appendix is intended to supplement the overall descriptions of the machines as given in Chaps. 2 and 3. A1.1 The Elliott 152 Work on the MRS5 contract at Borehamwood began in October 1946 and was essen- tially finished in 1950. Novel target-tracking radar was at the heart of the project, the radar being synchronized to the computer’s clock. In his enthusiasm for perfecting the radar technology, John Coales seems to have spent little time on what we would now call an overall systems design. When Harry Carpenter joined the staff of the Computing Division at Borehamwood on 1 January 1949, he recalls that nobody had yet defined the way in which the control program, running on the 152 computer, would interface with guns and radar. Furthermore, nobody yet appeared to be working on the computational algorithms necessary for three-dimensional trajectory predic- tion. As for the guns that the MRS5 system was intended to control, not even the basic ballistics parameters seemed to be known with any accuracy at Borehamwood [1, 2]. A1.1.1 Communication and Data-Rate The physical separation, between radar in the Borehamwood car park and digital computer in the laboratory, necessitated an interconnecting cable of about 150 m in length.
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