Path: utzoo!news-server.csri.toronto.edu!rutgers!usc!sdd.hp.com!zaphod.mps.ohio-state.edu!samsung!umich!dgsi!gregc
From: gregc@cimage.com (Greg Cronau)
Newsgroups: sci.space.shuttle
Subject: Re: New Shuttle Computers
Message-ID: <1991Mar9.042500.27495@cimage.com>
Date: 9 Mar 91 04:25:00 GMT
References: <2352@ksr.com> <1991Mar4.202334.22118@casbah.acns.nwu.edu> <1991Mar5.013344.7971@umiami.ir.miami.edu>
Reply-To: gregc@dgsi.UUCP (Greg Cronau/10000)
Organization: Cimage Corp, Ann Arbor, MI
Lines: 25

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 
>> |> The new AP101S computers use static-RAM memory and Schottky logic
>> 
>> 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
>
>Static RAM memory, I believe, is non volatile memory.
>
>- Jonathan 

Argh. Non-volatile, when referring to computer memory, refers to storage
media that can maintain the stored data in the absence of power. Core planes,
rom, prom, eprom, eeprom, and bubble memory are non-volatile.
	Random-Access-Memory(RAM) comes in 2 flavors: dynamic and static. Dynamic
memory requires an occaisional memory refresh pulse to maintian the stored
data. If the refresh is lost, the data is lost. Static memory, OTOH, can 
maintain it's data without any kind of refresh mechanism. Both types require
the continual presence of electrical power, however small, to maintain data.

gregc@cimage.com