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From: david@linc.cis.upenn.edu (David Feldman)
Newsgroups: comp.arch
Subject: Re: delay lines for memory
Summary: I have examined one
Message-ID: <9175@netnews.upenn.edu>
Date: 26 Mar 89 19:38:13 GMT
References: <21976@lll-winken.LLNL.GOV> <94250@sun.Eng.Sun.COM>
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Reply-To: david@linc.cis.upenn.edu.UUCP (David Feldman)
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Organization: University of Pennsylvania
Lines: 33

> From: rfm@sun.com (Rich McAllister)
> Here's a shortend quote from _IBM's_Early_Computers_, by Bashe, Johnson,
> Palmer, and Pugh, MIT Press, 1986, p110.  Highly recommended, especially for
> people who think IBM never invents anything.
>
>    The idea of using a mercury tank acoustic delay line for
>    storage in computers had originated about [1944] at the
>    University of Pennsylvania, where [Eckert and Mauchly
>    were working on the EDVAC.]  Eckert had invented the

We had a mercury delay system laying around the Digital Systems Lab
here at the Moore School at Penn.  According to Eckert, who came to Penn
for publicity, there were piezo quartz elements at both ends of the delay
lines.  This unit had five or six tubes (now emptied of mercury) arranged
cylindrically.  It also had some sort of interfaces in the middle of the
delay tubes with vacuum tube amplifiers attached.  Eckert told me that
(if his memory was correct, he said) this unit was designed to test variable
delay delay lines.

We had some more old stuff laying around too.  There was a drum memory with
256 read heads.  Pieces of the ENIAC that weigh nearly 1000 pounds each.
Bits of the old differential analyzer.  An original PDP 8 made of discrete
transisters and diodes, with a polar vector scope used (among other things)
to play the original "Space Wars".

All of this stuff has been thrown out now.  I consider myself lucky to have
seen it.

_   /|					Dave Feldman
\'o.O'					david@dsl.cis.upenn.edu
=(___)=		Ok, cough!
   U					DSL - land of wonder and enchantment
ACK! PHHT!