Path: utzoo!attcan!uunet!husc6!bloom-beacon!mit-eddie!rutgers!bellcore!faline!thumper!karn
From: karn@thumper.bellcore.com (Phil R. Karn)
Newsgroups: sci.space.shuttle
Subject: Re: Shuttle computer reprogramming
Summary: no, it's not msdos
Message-ID: <1347@thumper.bellcore.com>
Date: 10 Oct 88 13:15:38 GMT
References: <6689@nsc.nsc.com> <6980@ihlpl.ATT.COM> <1938@kalliope.rice.edu> <1988Oct8.233609.11835@utzoo.uucp>
Organization: Bell Communications Research, Inc
Lines: 32

No, it's not MS-DOS. That should be obvious from the term
"multi-tasking".  The OS is called "qCF" and is by a company called
Quadron Services, Inc.  The principals of this company just happen to be
several very active amateur packet radio enthusiasts.

When I said that it ran .exe files, I meant that they had the same load
image format as a MS-DOS .exe file. However, standard MS-DOS executables
will NOT run under this system; they must be linked with a library
provided with qCF. The use of .exe format is simply to facilitate the
use of standard PC development tools.

To quote the major author of qCF (Harold Price, NK6K), "I expect the
Microsat CPU to crash occasionally". By that, he meant that he expected
a lively, ongoing series of software experiments on at least one
spacecraft, and that inevitably one of these would cause a crash (there
is no hardware memory protection in the V40).  In other words, the low
cost of the mission and its non-life-and-death nature (no humans on
board, remember?) make it feasible to carry out interesting and useful
experiments that would otherwise be too risky. Trading off continuous
availability in favor of development progress makes sense here. If a
spacecraft computer crashes, you just boot it again on the next pass;
it will keep itself safe until then.

By the way, the Microsat project has already attracted an enormous amount
of interest from outside the amateur satellite program, since many people
have begun to see the advantages of a simple, small and inherently
cheap satellite. Weber State College (Utah) has a Microsat of their own
that will fly with us, and it will carry a CCD camera experiment in the
otherwise unused module. (Weber State was the group that launched NUSAT
on the Shuttle some years back).

Phil