milan.budimirovic at sympatico.ca
Tue Jan 6 21:31:38 EST 2004
On Tue, 2004-01-06 at 08:10, Matthew Wilcox wrote:
> Um, kind of ... what I heard was 5 computers, 4 running the same
> combination and one completely independent. But you have to bear in
> mind that these computers have the processing power of a small peanut.
> They don't run general purpose operating systems. They're space-hardened
> and safety-critical.
> landers and unmanned vehicles are merely mission-critical. i suspect
> other engineering decisions (such as cost) prevent there from being 5
> independent systems. i would expect them to run only one OS.
> the "independent systems buys you more reliability" thinking is slightly
> a myth anyway. i've read about studies that give the same problem to
> 20 different students and 19 of them coming back with the same bug in
> their program. nothing substitutes for good testing, remember Ariane 5?
> I have some amateur satellite contacts, would there be interest in
> getting someone up here to talk about use of Linux in the amsat community?
Also, the unmanned probes of the past decade have all been decidedly
low-budget affairs by NASA standards. Nowadays they just don't have the
resources to have the same code rewritten 5 times over.
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