Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!uunet!world!ksr!jfw
From: jfw@ksr.com (John F. Woods)
Newsgroups: sci.space.shuttle
Subject: Re: New Shuttle Computers
Message-ID: <2447@ksr.com>
Date: 4 Mar 91 22:35:52 GMT
References: <2352@ksr.com> <1991Mar4.202334.22118@casbah.acns.nwu.edu>
Sender: news@ksr.com
Lines: 16

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.

The article specifically mentions leaving several flight routines in
"battery-backed SRAM", avoiding having to load them off of tape in-flight.
The article doesn't say whether all the SRAM is battery-backed or just some
choice piece, though.