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Comment by hosh | Hacker News Reader

I remember reading a counterpoint about this a while back -- sometimes for critical systems, the risk of updates is really high.

For example, NASA still uses hardened 808x systems. On top of that, for space-based systems in an ionized environment, the risk of having hardware developing hardware faults is non-zero, and the kind of things people do for error correction in that environment is insane.

The flip side of this is that, when a technology is widely used, there is a scaling that happens. If you are the sole user of a technology, then part of your cost is maintaining that technology that used to be shared by all the other users of that technology.

And then there's the bigger question: how effective is nuclear deterrence? And I don't mean for the United States of America vs. the rest of the world. I mean for the global, human civilization, and homo sapiens as a species.

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W/ regard to space-based and airborne systems (commercial jets also actually operate in a fairly high radiation environment):

The risk of faults is not only non-zero, it's expected. Google 'single event upset' and 'nor flash soft error. Short version - (SEU) any bit in your RAM, CPU, peripherals, or databus can (and will, eventually) be randomly flipped in a high radiation environment. (Soft Error) - A random cell in your flash may be pushed into an indeterminate voltage range, and will return a different value every time you read it. So, for instance, you may CRC it, think it's good, copy it to RAM, and then the CRC of the RAM copy will fail because you got a different value the second time you read it.

There are ways to deal with this. Google 'lockstep CPU' for information on a common, fairly hardcore approach. Basically you replicate the CPU (and the rest of the hardware) and cross-check every single clock cycle; you essentially have two or more computers in one box doing the work of a single computer.

As you can imagine, this hardware is typically entirely custom, tested more thoroughly than anything you've ever imagined (unless you're in a safety critical industry yourself), and very expensive to design & test. Hardware refresh cycles are typically measured in decades, often governed by component obsolescence.

>If you are the sole user of a technology, then part of your cost is maintaining that technology that used to be shared by all the other users of that technology.

Yeah the guy who maintained the OS was basically the only guy in the country who could so obviously we had to put up with his bullshit lol

Space Cowboys (2000) was along these lines. The cranky guy who was the only one who understood the ancient "OS", being its creator, was played by Clint Eastwood.

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