Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ames!sun-barr!apple!voder!pyramid!prls!philabs!ttidca!hollombe
From: hollombe@ttidca.TTI.COM (The Polymath)
Newsgroups: comp.misc
Subject: Re: USSR Microcomputers: How far behind US?
Message-ID: <4405@ttidca.TTI.COM>
Date: 10 May 89 19:13:31 GMT
References: <1805@orion.cf.uci.edu> <8013@phoenix.Princeton.EDU> <528@laic.UUCP> <1905@etive.ed.ac.uk> <4366@ttidca.TTI.COM> <1203@isieng.UUCP>
Reply-To: hollombe@ttidcb.tti.com (The Polymath)
Organization: The Cat Factory
Lines: 33

In article <1203@isieng.UUCP> roy@isieng.UUCP (Roy Wells) writes:
}Also remember that our shuttle has really antique computers onboard.  
}If memory serves (small pun here) the Shuttle's main computer has 
}all of 64KB DRAM.  The reason?  The Shuttle was designed in the 
}1970s, using the technology of that time.  

Actually, there's no DRAM in the AP-101 at all.  Their memory is
non-volatile -- a source of much puzzlement to rookies (i.e.:  Me) and
much amusement to the old hands in the Rockwell Avionics Development Lab.

}Putting an AT aboard the Shuttle would measureably increase it's 
}computing power.

Not hardly.  The AP-101 may be an old design, but it's basically a compact
mainframe.  I'm not aware of any production single-chip CPU that could
begin to cope with it's throughput.  I don't recall the exact figures, but
the amount of data pouring into them, in a constant stream, is awesome.

Anyone who's ever run a flight simulator program on an AT would fall down
laughing at the idea of trying to fly the Shuttle with one.

}What boggles the brain is that we won't retrofit the thing with 
}something more modern.

If it ain't broke, don't fix it.  The existing systems cost $Sagans to
develop, debug and implement.  Replacing them would require a similar
effort at even higher cost.

-- 
The Polymath (aka: Jerry Hollombe, hollombe@ttidca.tti.com)  Illegitimati Nil
Citicorp(+)TTI                                                 Carborundum
3100 Ocean Park Blvd.   (213) 452-9191, x2483
Santa Monica, CA  90405 {csun|philabs|psivax}!ttidca!hollombe