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From: mike@UC780.UMD.EDU (Mike Santangelo)
Newsgroups: sci.space.shuttle
Subject: Re: New Shuttle Computers
Message-ID: <1991Mar6.171301.4345@ni.umd.edu>
Date: 6 Mar 91 17:13:01 GMT
References: <2352@ksr.com> <1991Mar4.202334.22118@casbah.acns.nwu.edu>,<1991Mar5.013344.7971@umiami.ir.miami.edu>
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In article <1991Mar5.013344.7971@umiami.ir.miami.edu>, jdeitch@umiami.ir.miami.edu (Jonathan Deitch) writes:
>phil@eecs.nwu.edu (William LeFebvre) writes:
>> In article <2352@ksr.com>, jfw@ksr.com (John F. Woods) writes:
>> |> The Electronic Engineering Times for 25 February 1991 has an article about
>> |> the new shuttle computers which are scheduled to fly on Discovery "next week."
>> |> The new AP101S computers use static-RAM memory and Schottky logic, replacing
>> |> the old core-memory AP101B computers.
>> 
>> Does the article say if the RAM is battery-backed or otherwise anything
>> in place to make the memory non-volatile?  One standard procedure is
>> "freeze-drying" a GPC (general purpose computer), which relies on the
>> memory being non-volatile.  I'm curious if they are going to scrap that
>> procedure or not.  Freeze-drying consists of loading the re-entry software
>> into a GPC and turning the GPC off.  That way if the tape drives that
>> contain the software both break, at least they have one computer to
>> get them home again.
>> 
>> Thanks for the summary!  My wife will be most interested in it.
>> 
>> 		William LeFebvre
>> 		Computing Facilities Manager and Analyst
>> 		Department of Electrical Engineering and Computer Science
>> 		Northwestern University
>> 		<phil@eecs.nwu.edu>
>
>Static RAM memory, I believe, is non volatile memory.
>
>- Jonathan 
>-------------------------------------------------------------------
>Internet : jdeitch@umiami.miami.edu       "Good musicians execute
>                                           their music but bad ones
>Voice : (305) - 284 - 6482                 murder it !!! "

Nope, sorry, STATIC RAM is quite volatile.  It just doesn't need to
be refreshed every so many milliseconds like Dynamic RAM.  If you
remove power to it though, data goes away.

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