Computer in 1900, was RE: Oldest operational computer was Re: cctalk Digest, Vol 54, Issue

Hi, As the OP who started this discussion I appreciate all the comments. The original spec was not to invent new components, but to use things you could actually get in 1900. Just because I know how to make an IC now doesn't mean I could have made one in 1900. While I could have obtained Silicon, it's unlikely it would have been usable purity, and the imaging, etching and depositation would be simply impossible. The "was it available" we have looked hardest at is the transistor, and could have we made a point contact transistor then, even a FET (made before the transistor but didn't recognise it). While we might be able to do this, we're trying to limit our search to things we could get, rather than make, or materials we could get rather than make ie iron cores, as opposed to point contact transistors. ( We are, however keeping an eye on the 256 2n2222 project). Some of the components we have looked at are: Fluidics/pneumatics: possible, but way less fun, and we suspect manufacturing tolerances of the time would have made this really hard. Valves: Not really -- more like 1905/6 depending on what source. If it had to have gain then not. Cathode rays from John Joseph Thomson in 1897. Thermionic diodes: Yes -- from 1873. Solid State Diodes: Yes -- from 1874. Relays: Possible, but even in 1945 was very hard. Available by 1901 at the latest. Magnetic Logic: Certainly available, more later. Core Memory: No ferrite. :-( Probably not until 1947. Mechanical: Certainly, but we're electronics people, and that would be too little fun. Optical: Photo electric "cells" (not intentional) using selenium were around in 1873. Delay Lines: Possibly, piezo ceramic drive uncertain, but close. Magnetic drive -- yes. Both wire and mercury practical. Unfortunately the big book of everything we've looked at is at work, and I'm not right now. Our current research is based around magnetic logic, and there have been commercial magnetic computers made albeit much later. I'm not talking about the exotic cores with 19 windings on them, but basic 1/2/3 winding cores exploiting saturation and simple magnetic properties. It's early days yet, but we have found you need 4 things to make this work (1) simple cores, (2) diodes, (3) AC excitation and (4) some gain every now and again. 3 might be harder than it looks, but we think 20kHz should be enough for iron cores, scale probably 1-2kW. Right now I'm working on the "some gain" area using magnetic amplifiers in cores pushed near to saturation. Without some gain magnetic logic runs out of steam. We do have the schematics of the Univac magnetic logic computer using "Ferractors", but this gets deep into the "we made the material" area with a magnetic material with a square BH curve, and many, many transistors. Construction is likely to be bit serial, and the target is 500k - 1000k bits per second through the loop, maybe an instruction rate of 10% of that. I will say some of the replies on this group are realistic -- when I mentioned this at work one colleague (Windows Programmer) asked if it would run a web server. Sigh. -- Regards, Gavin Melville gavin.melville at acclipse.co.nz