Hi I've both used and worked on core memory machines. They ones I have seen all used solid state devices in the core memory sections of the machine. I've never heard of a pure tube machine with more than "register sized" core.
Bob On Jun 23, 2013, at 1:47 PM, Chris Albertson <albertson.ch...@gmail.com> wrote: > Magnetic cores were not invented until the 1950's and realy cam into use as > tubes were beibg replaced by SS. But there isnot reason yu can't build a > tube computer with core memory. I have actually seen and used a computer > that had one megabyte of core memory. The stuff was still in use in the > late 1970s 1MB was a lot of RAM in 1975. > > You can have very good reliability with tube circuits. It was just that > few people wanted to pay for it. Down time was cheaper. It is not hard to > add redundancy to a circuit but it does have a huge cost multiplier effect. > 4x or 5x the price. One simple way is to use 3 or 4 tubes with their > output tied to a resistive adder. If one tube fails the result (because it > is binary) is still the same. With computers no one would pay for fault > tolerant design until it was reasonably affordable. Even today we mainly > just put up with failure except for airplane controllers, huge web sites > like Amazon and the like. > > > On Sun, Jun 23, 2013 at 9:53 AM, Brian Alsop <als...@nc.rr.com> wrote: > >> On 6/23/2013 14:40, Bob Camp wrote: >> >>> Hi >>> >>> AC137 doesn't ring any bells. True tube core (no solid state at all) >>> isn't something that was dimensioned in K words. A couple hundred words was >>> pretty big stuff. "Quite a bit" of core done that way is a lot of tubes. As >>> the number of tubes goes up, the time to failure comes down….. hours … >>> minutes … who knows. >>> >>> Bob >>> >>> >> Yeah, it gets to be like the cross country aircraft races in the 20's. The >> mechanic had to fly with the pilot. (The MTBF of many of the engines used >> was measured in hours.) If necessary he had to climb out on the cowling >> while in flight to change plugs and fix whatever possible without landing. >> What would OSHA say about that? >> >> Needless to say future generations will probably find lots of aircraft >> spark plug artifacts in their digs. >> >> Brian/K3KO >> >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2012.0.2242 / Virus Database: 3199/5932 - Release Date: 06/22/13 >> >> >> ______________________________**_________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/** >> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >> and follow the instructions there. >> > > > > -- > > Chris Albertson > Redondo Beach, California > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.