Post #137,975
1/26/04 5:50:56 PM
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And?
Every one needs its own targeted control module. The underlying structure should be built exactly for the purpose of controlling those things. There should not be one single wasted line of code, or one bit of wasted memory.
Now, are you telling me that the VxWorks based solution is that tight?
Also - look at the results. Apollo - perfect. Shuttle computers - perfect. Vikings - perfect. Mariners to Mercury, Venus, and Mars - perfect. Voyagers and Pioneers to the outer planets - perfect. Only in recent years are things getting fucked up by bad software. What more proof do you need, a core dump from Spirit? This entire problem with the rover was caused by shitty software and/or shitty software related maintenance.
-drl
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Post #137,981
1/26/04 5:54:03 PM
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And you know this how?
Yeah, I'm sure that NASA hired some REAL dumb programmers for this job.
Peter
[link|http://www.debian.org|Shill For Hire]
[link|http://www.kuro5hin.org|There is no K5 Cabal]
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Post #137,987
1/26/04 6:01:55 PM
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It's POCS
plain old common sense.
What is the former failure rate of NASA spacecraft computing?
Somewhere around 0.
What is the failure rate of business computing based of "tested methologies using canned software"? What, 50-60 percent?
You decide.
How many really shitty engineers have I met?
Somewhere around 0.
How many shitty IT types have I met? I mean - no vision, sloppy, slapdash, careless, clueless? No telling - dot lots and lots.
You decide.
NASA's webpage talks abot ISO.Bullshit and TQManglement. It's their "corporate ethos". Before, someone like John Houboult could go straight to the top with an issue if he felt justified. Now, 10 layers of total quality management would be in his way.
You decide.
-drl
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Post #137,988
1/26/04 6:03:14 PM
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Way to not answer the question.
How do you know?
Answer: you don't.
Space is a HARD PLACE TO DO BUSINESS. STUFF BREAKS. GET OVER IT.
Peter
[link|http://www.debian.org|Shill For Hire]
[link|http://www.kuro5hin.org|There is no K5 Cabal]
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Post #138,013
1/26/04 6:18:55 PM
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Re: Way to not answer the question.
Peter, in my other life before bumness descended on me like a broken rover, I was a "software engineer" in the Radar and Instrumentation Lab at Ga. Tech Research Institute. We dealt with hardware all the time (Star Wars). No one had VxWorks or any of that BS. We ran hardware simulations on large 'frames, and then coded directly to the simulator. My part was radar codes. Everything was home grown. It always worked. I wonder why?
-drl
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Post #138,014
1/26/04 6:20:27 PM
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Because it was a simulator :-)
Simulators have a tendency to be like the environment you're coding to.
Wonder why we have bugs on the road but not in the lab? Wonder no more. We can't put a motorway in our lab.
Peter
[link|http://www.debian.org|Shill For Hire]
[link|http://www.kuro5hin.org|There is no K5 Cabal]
[link|http://guildenstern.dyndns.org|Home Page - Now with added Zing!]
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Post #138,020
1/26/04 6:26:29 PM
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Re: Because it was a simulator :-)
This was the standard way of dealing with hardware of any complexity. The Apollo computers were done that way. Intel makes CPUs like that. The hardware has design specs, you feed them in, and run them.
One thing we did was model something like a tank, bounce fake radar from a fake antenna off the fake tank, then calculate the cross section of the return - then go out and deal with an actual radar. The numbers always matched.
-drl
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Post #138,021
1/26/04 6:27:00 PM
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BTW, Pathfinder used VxWorks too ...
... with interesting results:
[link|http://catless.ncl.ac.uk/Risks/19.49.html#subj1|http://catless.ncl.a.../19.49.html#subj1]
--
Chris Altmann
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Post #138,027
1/26/04 6:45:18 PM
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heh,
with hardware, it's always timing :)
Could one reason the "homegrow" solutions have been so good - sometimes things were honed down to the "literally counting clock cycles" level.
-drl
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