Hello all! I?m a long time ?list lurker? but felt it was perhaps time to contribute. I?ve just spent the morning being shown a working replica of the Manchester Small-Scale Experimantal Machine (SSEM), also commonly referred to as the ?Manchester Baby?. It?s located in the ?1830 Warehouse? at the Manchester Museum of Science and Industry. One of the curators is (by lucky chance) my Uncle Michael and he?s personally written a number of programs for this old beast. The replica is fantastic, with incredible attention to period detail. For example, the switchgear is proper 1940?s vintage (salvaged from RAF aircraft) and the frames upon which the replica is built are from former GPO telecoms exchanges. Apparently the donor of said frames was using them to prevent his garden subsiding into a nearby river! The computer itself, for anyone unaware of it is regarded as the world?s first stored program computer. It ran its first program on June 21st 1948, jointly designed by Frederic C. Williams and Tom Kilburn at the University of Manchester, UK. The stored memory is in the form of a ?Williams Tube? - a cathode ray tube capable of storing 32 X 32bit words. It?s an extremely limited bit of kit (as one might imagine!) with an instruction set of only 7, and no adder (addition achieved by negating numbers during their move to the accumulator). It?s a great exhibit if anyone?s in this part of the world on a Tuesday with nothing to do. No charge for entry into the museum. Here are some informative links, including a beautifully crafted ?Manchester Baby Emulator? (in Java). http://en.wikipedia.org/wiki/Manchester_Baby http://www.computer50.org/ http://www.davidsharp.com/baby/index.html Regards, Austin. P.S. The guys at the museum have hooked it up to a PC, so that programs written on the emulator can be loaded into the baby to be run. Does this qualify it as the world?s most ancient add-on / peripheral / co-processor? ;-)