From: choy@skorpio.usask.ca (I am a terminator.)
Subject: Re: What kind of computers are in the shuttle?
Organization: University of Saskatchewan, Saskatoon, Canada
Distribution: sci
Date: Sat, 14 Nov 1992 02:09:10 GMT

In article <BxKo4I.F9r.1@cs.cmu.edu>, roberts@cmr.ncsl.nist.gov (John Roberts) writes:
|> 
|> -From: choy@skorpio.usask.ca (I am a terminator.)
|> -Subject: What kind of computers are in the shuttle?
|> -Date: 11 Nov 92 17:53:36 GMT
|> -Organization: University of Saskatchewan, Saskatoon, Canada
|> 
|> -The computers used to control the shuttle use very complex programs
|> -that people don't want to rewrite for newer computers. Has any
|> -upgrades been done or are the computers still the same old beasts?
|> 
|> Most or all of the orbiters now have the new computers, which are much more
|> powerful (and have more memory) than the old computers. I believe they're
|> software-compatible. (I *don't* know whether any new functions were added,
|> or whether the software has been changed (other than lookup tables, etc.).
|> The Shuttle control software is claimed to be the most nearly error-free
|> complex code ever created - millions of dollars went into assuring that.)

|> >From: yee@trident.arc.nasa.gov (Peter E. Yee)
|> Subject: STS-49 Press Kit (Forwarded)
|> Date: Sat, 18 Apr 1992 19:56:05 GMT
|> 
|> 			   STS-49 PRESS KIT
|> 			        MAY 1992
|> 
|> ...
|> IMPROVED FEATURES OF SPACE SHUTTLE ENDEAVOUR
 
|> 	The advanced general purpose computers (GPCs) are now in the
|> process of being incorporated into the entire orbiter fleet and will be
|> installed and used on Endeavour for its first space flight.  The
|> updated computers have more than twice the memory and three times the
|> processing speed of their predecessors.  Officially designated the IBM
|> 10-101S, built by IBM, Inc., they are half the size, about half the
|> weight and require less electricity than the first-generation GPCs.
|> The central processor unit and input/output processor, previously
|> installed as two separate boxes, are now a single unit.
|> 
|> 	The new GPCs use the existing Shuttle software with only subtle
|> changes.  However, the increases in memory and processing speed allow
|> for future innovations in the Shuttle's data processing system.
|> Although there is no real difference in the way the crew will operate
|> with the new computers, the upgrade increases the reliability and
|> efficiency in commanding the Shuttle systems.  The predicted Rmean time
|> between failuresS (MTBF) for the advanced GPCs is 6,000 hours.  The
|> flight computers are already exceeding that prediction with an MTBF of
|> 18,500 hours.  The MTBF for the original GPCs is 5,200 hours.
|> 
|> New GPC Specifications
|> Dimensions: 		19.52S x 7.62S x 10.2S
|> [I wonder what an "S" is? From context, I'd guess "inches". - JR]
|> Weight: 		64 lbs.
|> Memory Capacity: 	262,000 words (32-bits each)
|> Processing Rate: 	1.2 million instructions per second
|> Power Requirements:  	550 watts

64 lbs? What's it made of? Lead?
1 Mb?
1.2 MIPs?
0.5 kW?

They want to put these in all the shuttles?
Why not give them 3lb 20Mb 25 MIPs 0.25W 0.5 Gb hard drive laptops? Doesn't
Compaq make laptops that can double for speed bumps? Just cross compile
everything. You can probably buy a hundred computers for each of these
heavyweights.

Henry Choy
choy@cs.usask.ca

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