Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!wugate!uunet!portal!cup.portal.com!mmm From: mmm@cup.portal.com (Mark Robert Thorson) Newsgroups: comp.arch Subject: Re: ENIAC Query Message-ID: <24063@cup.portal.com> Date: 14 Nov 89 21:45:51 GMT References: <38193@lll-winken.LLNL.GOV> <405@gvlv2.GVL.Unisys.COM> Distribution: usa Organization: The Portal System (TM) Lines: 28 kleonard@gvlv2.GVL.Unisys.COM (Ken Leonard) says: > well, for sure, neither if these is what one would call "low power consumption" > but then... > * 350 807 (Enlarged 6L6) > I dimly recall ham transmitters that used a couple of these > as final amplifier--at a plate power level of a couple hundred watts. > Do I remember correctly, or do I have an advanced case of cranial decrepitude? > What was ENIAC doing to need _that_much_ power in one stage of logic? > Or did the builders include these just so they would have a place to fry > their eggs in the morning? I believe that to increase reliability, ENIAC ran their tubes well below their rated power. Whether or not that's true, a high-power device might have been used for transmitting a clock signal, or other signals global to many circuits, such as the program trunk lines, of which there were more than 100 in ENIAC. (A program trunk line is roughly equivalent to a control line from the instruction word.) The figures I have for ENIAC are: over 18,800 tubes, ten different types of tubes, about 60 different kinds of resistors, and about 30 kinds of capacitors. Speed was 5000 additions or subtractions per second, 360-500 multiplies per second, 50 divisions. Power was 150 kilowatts. "... for a typical week of actual work, ENIAC has already proved to be equal to 500 human computers working 40 hours with desk calculating machines, and it appears that soon two or three times as much work may be obtained from ENIAC."