Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!samsung!uunet!nuchat!steve
From: steve@nuchat.UUCP (Steve Nuchia)
Newsgroups: sci.space.shuttle
Subject: Re: New Computer, Erasable Optical Disk
Message-ID: <19155@nuchat.UUCP>
Date: 1 Feb 90 03:47:56 GMT
References: <15104@bfmny0.UU.NET> <4831@convex.convex.com>
Reply-To: steve@nuchat.UUCP (Steve Nuchia)
Organization: Houston Public Access
Lines: 23

In article <4831@convex.convex.com> dodson@convex.com (Dave Dodson) writes:
>probably will take well beyond 1992.  When you consider the tenet that
>you don't fix what isn't broken, it makes me wonder why they would even
>consider changing the shuttle flight computer system.

Two reasons come to mind:

	weight -- modern computers are lighter per MIP and every
		kilo you don't spend on computer you get to spend
		on people, payload, food, or fuel.

	memory -- a major limitation on shuttle operations right now
		is that the computers don't have enough memory to
		hold the software for all the mission profiles.  They
		have missed or nearly missed launch windows due to
		winds aloft not matching the profiles they had loaded
		in the onboard computers.  More memory would directly
		translate into better system availability.
-- 
Steve Nuchia	      South Coast Computing Services      (713) 964-2462
"If the conjecture `You would rather I had not disturbed you
 by sending you this.' is correct, you may add it to the list of
 uncomfortable truths."   - Edsgar Dijkstra