Hacker News Reader

Comment by danans | Hacker News Reader

Years ago, astronaut Chris Hadfield told an audience of software engineers (including me) that the moment the space shuttle was in stable orbit, the crew would pull out laptops and set up an ethernet network for all the scientific work of their expedition, as the space shuttle's own computers, though limited in raw computing power, ran software that was so thoroughly tested that there was every reason not to "upgrade" them in any way to support the scientific work.

View on HN

As a child, a friend's mother was a programmer for the Shuttle (mid-80s to early 90s). Her job sounded awful: a 'science person' (I was a child, remember!) designed a piece of math; an engineer (software?) would take that piece of math and reduce it to an algorithm; my friend's mother would program that algorithm in machine code, in parallel to an assembly listing. Each instruction (and all the data) would be reviewed line-by-line. She had to provide reasoning (roughly a proof) that each instruction correctly implemented the algorithm. My guess is the algorithm went through the same equivalence checking to the 'math'. I don't know how much code she wrote, but it was only a few programs (functions) per year.

That was my view of 'programming', and I wasn't disabused of that until very late 90s.

Sounds lovely. Now I write code with vague requirements that interfaces with ill-specified functions, on tight deadlines. It surprises me that it doesn't contain a lot more bugs. Maybe we just haven't found them yet.

And whatever you wrote And right to the spec， user said it is not what they want. And demo why it is not working or useful ... Of course that is nothing to do with them, that is not what they said or your it guys analysis wrongly. As spec goes ... do not understand it.

To be fair it takes a lot of interaction (and understanding ) to fix it. And you wonder how these operate here.

It’s funny how early experiences color our understanding of a craft. I remember as a boy telling a neighbor that I was interested in art. She worked with computers and, with stars in her eyes, told me how digital plotters could define shapes accurate to n thousands of an inch. For me that was the worst possible selling point, and may have influenced my decision to eschew anything digital for years. ... and now I teach digital art.

so what is bad about that? sounds like a solid process

it's not bad, just not exciting to a child.

i guess we have to all make sure that whatever we do is exciting to a 6 year old.

It makes perfect sense to use computers for research on the shuttle that were not connected in any way to the shuttle systems.

Yes, he made that point to contrast with the common sci-fi trope of using the ship's computers for all purposes.

Yup, I'd prefer NOT to touch the systems of the vehicle that's serving as my lifeboat, life support, and ONLY re-entry option.

Even today with modern avionics there would be no reason why an aircraft's computer systems would need to interface with a general-purpose LAN. Take a look at the control system of a Cirrus Visionjet for instance. It's quite locked down as its own embedded system. For reliability and resiliency reasons it's good to keep some things compartmentalized.

Does SpaceX's Actor Judge system, work around this problem ? I assume the 3 actors are written by different teams for redundancy.

But surely it's the opposite to what you describe that would be remarkable?

Yes, he made the point as a contrast to how ships computers are depicted in sci-fi.

Reply on news.ycombinator.com