Path: utzoo!attcan!uunet!cs.utexas.edu!ut-emx!nather
From: nather@ut-emx.UUCP (Ed Nather)
Newsgroups: comp.arch
Subject: Re: Mercury delay lines
Message-ID: <31281@ut-emx.UUCP>
Date: 9 Jun 90 16:21:51 GMT
References: <3040@softway.oz> <1990Jun7.154830.3294@esegue.segue.boston.ma.us>
Organization: The University of Texas at Austin, Austin, Texas
Lines: 23

In article <1990Jun7.154830.3294@esegue.segue.boston.ma.us>, johnl@esegue.segue.boston.ma.us (John R. Levine) writes:
> In article <3040@softway.oz> adjg@softway.oz (Andrew Gollan) writes:
> >I have always liked the idea of mercury delay lines, ...
> 
> >Can anyone tell me what machines had these memories?
> 
> They were popular in the 1950s.  Some of the early British machines used them.
> The only commercial delay line machine I know of is the Packard Bell 250,
> 
That machine used magnetostrictive delay lines, not mercury, which is why it
was so small.  The only machine I ever saw that used mercury delay lines for
its memory was the original Univac; they were huge tanks suspended from the
ceiling of the chassis (you walked into the chassis through a door).  The
tanks had vacuum tubes festooned all over them.  I asked the tech how they
ever kept it all running, and he repleid it wasn't very hard: if it failed,
just walked in and looked for the tubes whose filaments were out (which you
could see through the glass bulbs).  Apparently the flipflops were so well
designed, with such wide margins, they never failed unless the filament
died and electrons quit flowing through the tubes.

-- 
Ed Nather
Astronomy Dept, U of Texas @ Austin