discrete transistor computer

On 16/11/2012 08:13, ben wrote: There was a dire shortage of the very rare round tuits during that period of my life, plus no access to a decent scanner. I actually wrote my first program when I was 17 or 18 years old ( so 1971/2) on a germanium transistor computer that had been built by my school derived Teacher Hector Parr (http://www.hectorparr.freeuk.com/) who learnt to program so he could calculate tables of Organ Pipe lengths to assist in re-building the School pipe organ. I can't remember how many memories it had, or the word length, but I do remember that it was composed of flip-flops constructed from surplus "red spot" transistors. Each as bit was constructed on a small paxolin panel with a screw-in flash lamp bulb to show if it contained a "1" or a "zero". The whole assemble was mounted on the wall on a panel about 6 or 8 feet square, with a small console attached by a cable. It was a serial design so each "bit" was loaded separately by pressing a couple of door bell pushes labelled "0" and "1". The first thing you did before using it was to load it full of "1"s so you could check no bulbs had worked loose or blown. I do remember it would play NIM if you used the final HALT instruction as a "0" data byte. We didn't write much code on it, once we had written a successful program we were allowed to code Fortran II on an IBM1620 at a nearby college. We posted (or mailed for the US readers) our coding forms off on a Wednesday and with a bit of luck got the answers back on Friday, so sometimes you got two runs a week. I wasn't very careful and needed the two runs to get things working... -- Dave Wade G4UGM Illegitimi Non Carborundum P.S. Al, if you want to take a coipy of the scan, or of any of the other stuff on that site please feel free.