Notes from Virtual Meeting 27th June 2020


Eddie Shore (California), Nigel Fraser Ker (England), Martin Macrae (England), John Struthers (Scotland), Wlodek Mier-Jedrzejowicz (England), Nigel Rumble (England), Bruce Horrocks (England), Bob Prosperi (New York), Sylvain Cote (Quebec, Canada), Johnny Bjørn Rasmussen (Denmark), Bob Penick (South Carolina), Ed Spittles (England) and Mark Power (England).


1) For those writing articles for Datafile please use this template if possible. Bruce will also access Pages documents and will reformat them appropriately, though formulae may get corrupted and are not easy to spot, so please also send a PDF to show the required output.


2) Slide rules: Wlodek has a problem with a bent slide rule. Various solutions were suggested with hot air and hot water being suggested. Possible use of light machine oil as a lubricant. 

K + E Slide Rule Manual Log Log Duplex DeciTrig No. N4081 (Keuffel & Esser Co.) - New York, 1947 (Lyman M. Kells, Willis F. Kern, and James R. Bland)

For those who want to use an online slide rule:

A quick tour around the web pulled up these interesting sites:

3) Brief discussion of a HP9100A potentially looking for a new home, maybe in a technology museum, and also that John saw the clay model of the case for this while working at HP.

4) Loss of HP archive material in a fire: search for "Loss of Hewlett-Packard Archive a Wake-Up Call for Computer Historians" and "Hewlett-Packard history lost to Santa Rosa fires"

5) Membership badge computers, bare-board computers, re-inventions of classic computers and restoration of LEDs were then discussed:

Chris Chung's MSP430-based bare-board calculators that run Eric's Nonpareil emulators of HP calculators

A Z80-based calculator build, again using nonpareil:

LED Module repair kit:

Bubble displays

6) We also got onto video switching, older apple computers, older Sigma Foveon digital cameras and the resolution of various forms of video conferencing:

7) CD cover disks. The Internet Archive has a massive collection of CD cover disks: and anyone can upload.

Next meeting via Webex on 11th July, 1500-1700 BST (UTC+1). If you have a specific topic that you want to present or discuss, or have a problem that you need assistance with, please let us know beforehand so that suitable discussion time is given.




  • Thanks Mark! I believe Eddie Shore mentioned a Casio model which was comparable to the nearly-incomparable HP-16C "Computer Scientist" - but I didn't catch the model number. I got the feeling it was a near-contemporary model but I suppose it might be a more recent one.

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