Hi Switching diodes came along much earlier than transistors. A lot of "tube" logic was actually diode / resistor / tube logic. To fit my (likely bent) definition of "pure tube" you would have to *not* use solid state switching diodes.
Bob On Jun 23, 2013, at 6:06 PM, Kenton A. Hoover <[email protected]> wrote: > Weren't the original TRANSIT computer (AN/UYK-1) proofed out in vacuum tubes > before they were able to build it with transistors? > > -- > Kenton A. Hoover > [email protected] > +1.415.830.5843 > > > On Sunday 23 June 2013 at 14:50, Paul Berger wrote: > >> Hi: >> >> The SAGE computers, which I had the pleasure of seeing the last two >> operating, had an all vacuum tube array of core that consisted of 33 >> planes of 64 x64 cores for about 16K worth of memory. These where all >> vacuum tube computers. IBM offered a 4K all vacuum tube core storage >> unit for the 701 and 702, the same unit was built into the 704 and the >> 705 had a larger core storage with 35 planes of 50 x 80 cores. The >> Remington Rand Corp. and the RAND Corp. also shipped computers that used >> core for main storage in the mid 50s which likely used vacuum tube >> drivers. At that time there where apparently no transistors available >> that could supply the drive current required for core memory. >> >> On 6/23/13 5:29 PM, Bob Camp wrote: >>> 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 <[email protected] >>> (mailto:[email protected])> 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 <[email protected] >>>> (mailto:[email protected])> 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 (http://www.avg.com) >>>>> Version: 2012.0.2242 / Virus Database: 3199/5932 - Release Date: 06/22/13 >>>>> >>>>> >>>>> ______________________________**_________________ >>>>> time-nuts mailing list -- [email protected] (mailto:[email protected]) >>>>> 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 -- [email protected] (mailto:[email protected]) >>>> To unsubscribe, go to >>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] (mailto:[email protected]) >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] (mailto:[email protected]) >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
