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Houston, We Have a Software Problem
An anonymous reader writes "The computer system that launches the Space Shuttle is an old, but important, computer system. It is built from mid 70's technology and features SSI chips like 7400's...which are getting hard to find. It has 64k of memory and no room to repair any software bugs. NASA started the CLCS project in 1996 which uses state of the art computer languages, OO methodologies, and hardware. Everything that you could actually hire people off the street for. However, NASA is in a budget crunch with the Space Station cost overruns. It is looking to trim costs to keep the Space Station going. There are stories about CLCS getting cancelled here and these guys say its already cancelled."
Auditing the emulator and the host OS would be a problem - the code they've currently got has a very low rate of bugs, and has been extensively audited. NASA knows everything from the hardware up, exactly what the failure rate is and so forth.
Now, imagine you take modern commodity hardware (which changes periodically - look at how often Intel silently release new steppings of their CPUs). You're not going to have a guarantee of consistency there. You're going to have to boot an OS off it - and even the simplest RTOSes are still much, much bigger than the whole platform currently. Then you need an emulator. Then you need the system. And the only problem you've solved with all that work is the unavailablility of the old hardware - you still have a old machine language on a tiny platform which can't be easily extended for new functionality.
I'm not one to replace things that are working fine, but as I understand it, newer designs could be a whole lot cheaper to operate. So I wonder if pouring more into the Space Shuttle program is the best thing to do.
I'm not saying "let's throw out the space shuttle" but it bothers me that there's apparently nothing in the works with a decent shot at replacing it any time soon. It seems the field of space exploration is becoming antiquated.
This is a very pertinent point that appears to have been lost on the initiators (and now burger flippers) of the replacement-launch-thingy project.
What they have, right there, is one spectacularly reliable piece of software. I suspect it's significantly more bug free than even the microcode in a modern processor, let alone the companion chips, bios, operating system, and virtual machine for some god awful p-code language (not that I'm naming names here).
The question that should have been asked is "how can we make a sustainable process for making extremely reliable control computers?". How to go about cutting custom silicon, tiny os's etc. How to save the happy tax payer hundreds of millions of dollars by reselling these services to people making nuclear power stations, heart pace makers etc. instead of going shopping for big sun boxes.
Oh well, reality strikes again.
Dave
I write a blog now, you should be afraid.