Oldest operational computer was Re: cctalk Digest, Vol 54, Issue

Hi, Not completely on topic, but my boss wishes to build a computer using modern knowledge, but only materials, IO etc that existed as at 1st Jan 1900. The basic premise is that had a need existed, and they knew how to make one, could have it been done. That initially seemed hard, and certainly isn't easy, in that I'm the one doing the "building" :-) however we have fairly quickly identified that magnetic logic is the only likely candidate. Currently I'm playing with saturable reactors to try and get enough gain to make more than simple logic viable. We keep on hitting little curve balls ie. the highest frequency sinusoidal AC we can find stuff on as at 1900 was 20kHz. Modern core materials and 20 kHz don't totally work together... This is to be a real computer, stored program, RAM, ALU etc. Ian has already built 2 of those by hand, one with TTL and one with 4000A CMOS, so has some idea of how to do it (personally I'd just get a micro), but he has the determination and the resources complete this. I'll keep the list posted if there is any interest. Regards, Gavin Melville gavin.melville at acclipse.co.nz