Third part of a file of photocopies of correspondence between Ernest Lenaerts and his managers at Lyons - John Simmons, W.J. Edwards and T.R. Thompson, during Lenaerts' secondment to the Cambridge University Mathematical Laboratory, working as part of the EDSAC team under Maurice Wilkes. 

Many of Lenaerts' original letters were written enclosing reports on the progress of the EDSAC team, but photocopies of the reports themselves were not included in this file of photocopies.  Presumably the original reports are included in the archive copy held at Manchester, ref. GB 133 EHL/2 EDSAC.

Comprises:
- 66. Photocopy of a letter from Ernest Lenaerts to John Simmons, 7th Apr 1948;
- 67-68. To Ernest Lenaerts from John Simmons,  9th Apr 1948;
- 69-70. Ernest Lenaerts to John Simmons, 12th Apr 1948
- 71. To Ernest Lenaerts from John Simmons,  21st Apr 1948;
- 72-73. Ernest Lenaerts to John Simmons, 4th May 1948;
- 74-77. Ernest Lenaerts to W.J. Edwards (Electrical Dept, Lyons), 10th May 1948;
- 78. To Ernest Lenaerts from John Simmons,  11th May 1948;
- 79. To Ernest Lenaerts from R. Drazney (Engineering Dept, Lyons),  12th May 1948;
- 80. Ernest Lenaerts to John Simmons, 13th May 1948;
- 81. To Ernest Lenaerts from John Simmons,  18th May 1948;
- 82-83. To Ernest Lenaerts from W.J. Edwards (Engineers' Dept, Lyons), 19th May 1948;
- 84-87. Ernest Lenaerts to W.J. Edwards (Engineers'l Dept, Lyons), 21st May 1948;
- 88-89. Ernest Lenaerts to John Simmons, 27th May 1948;
- 90-91. Ernest Lenaerts to W.J. Edwards (Engineers' Dept, Lyons), 31st May 1948.

Page numbers in red were added by Peter Bird.

Research Comments: In the first in this series of letters, Lenaerts refers to the multi-channelled input and output that will be required by the Lyons computer if it is to function in a commercial setting. He states that the Cambridge machine has no need for it. A Mr. Amos of Creeds is mentioned several times. In his reply, Simmons tells Lenaerts that he is "doing a grand piece of work".

The letter from Lenaerts to Mr. Edwards dated 10/05/1948 reports that several previously discrete parts of EDSAC are now being connected together and he states that he "can say now that the best part of the machine exists, and there are immediate prospects of being able to put a number into a certain part of the memory and being able to locate it again at will".

Lenaerts reports on 10/05/1948 that Derek Hemy is currently in Cambridge "studying the art of programming". On 13/05/1948 he refers to "an Australian, Dr. Myers, who is at Cambridge just now studying EDSAC".

Edwards' reply to Lenaerts on 19th May 1948 is prescient. He states: "I always had the idea that our problem was such that the programming would cause more difficulty than the actual machine, and that it is most likely that the machine may have to be considerably modified to suit our problem.", which he clarifies by pointing out the differing nature of the Cambridge and Lyons machines, i.e. that Lyons require a "machine which will cope with large volumes of relatively simple calculations" in a way that EDSAC does not. He points out that "It is this large volume of work and its input which strikes me as being the difficult problem.". (LM)

Provenance :
The photocopies were originally requested by Peter Bird, as part of his research for LEO - The First Business Computer, and later donated to the NAHC, then transferred to CCH at the request of the LEO Computers Society for inclusion in their archive.