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From: arnold@ucsfcgl.UUCP (Ken Arnold%CGL)
Newsgroups: net.space
Subject: Re: Shuttle Computers and STS power consumption
Message-ID: <547@ucsfcgl.UUCP>
Date: Thu, 20-Jun-85 22:57:33 EDT
Article-I.D.: ucsfcgl.547
Posted: Thu Jun 20 22:57:33 1985
Date-Received: Sun, 23-Jun-85 06:53:30 EDT
References: <2322@mordor.UUCP>
Reply-To: arnold@ucsfcgl.UUCP (PUT YOUR NAME HERE)
Organization: UCSF Computer Graphics Lab
Lines: 32

In article <2322@mordor.UUCP> @S1-A.ARPA,@MIT-MC.ARPA:jim@TYCHO.ARPA writes:
>A recent posting about shuttle cooling reminded me of an article I ran
>across in an old (1980) IBM document.  The article described the
>onboard computers as System/4Pi model AP-101 processors.  The AP-101
>appears to be a 3 KIP machine with an intensely ugly architecture.
>Main memory was described as 104KW (36 bit) of core (really core!)
>with 400 ns access time. ...  Did they actually use this refugee from
>the Smithsonian on the Shuttle and if so are there any reasonable
>plans afoot to upgrade?

One of the main problems with space ship design is that, by the time
the design sits on the launching pad, its technology is quite out of
date.  This is true of all technology, but since computer technology
evolves considerably faster than other kinds, it is much more critical
(as the above description shows).

The California Space Resources institute (attached to the University of
California at San Diego) is currently coordinating a study which
includes this problem, relating the design of the space station.  As I
understand it, the problem is to define computer (and where possible
other techonological) needs by interface, and maximum physical
attributes (which, as things get smaller and generate less heat,
becomes not much of a problem); basically a form of modular technology
design.  That's what seemed most promising last time I was informed,
but it has been several months.

As an aside, in case you've been wondering where your defense dollars
are going, the same problem exists in front line equipment, which takes
just as long to get to the front.  Of course, the degree to which
computers are out of date varies among different pieces of equipment.

		Ken Arnold