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by cmonreally123 579 days ago
Why? You increase cost for what? The Boeing example I believe related to this defect which occurs after 51 days of operation: https://www.google.com/amp/s/www.theregister.com/AMP/2020/04...

This seems sane given that the planes don't operate for 51 days constantly (I'm not in aerospace so please correct me, it seems a reboot could occur with refueling without issue)

2 comments

Usually planes are turned around too fast to be waiting for them to fully reboot every time they fuel. Typically they would prefer to keep them running for weeks at a time to minimize any issues or delays with extra steps when the clock is ticking and customers are waiting to board and fly
But they don't reboot them every time they fuel.

Commercial aircraft need continual software updates to operate. They are, in a sense, living, breathing machines. Things like navigation and terrain databases are updated inside of 30 days.

Adding a scheduled reboot is one more item on a checklist that was already being run through.

It's counterintuitive, but performing a reboot as a scheduled maintenance item is far more risk averse than going in and touching code that has been otherwise thoroughly tested and signed off by regulatory authorities.

The chances of introducing a new bug when attempting to repair the former presents additional risk to what amounts to a convenience issue.

Mainframes in the late 80s got so good nobody was rebooting them. Then in the 90s someone's mainframe had the powerbackup generators fail in a power outage and the system went down (a once in 500 year event, but with more than 500 mainframes around the world it was statistacally bound to happen). the system didn't boot correctly and it took months to figure out all how to start all the services it was running that the person who started them left without add them to the startup configs. Now everyone reboots a couple times a year so that when things don't restart correctly the person who knows about them still remembers something about it.
> it took months to figure out all how to start all the services it was running

Having had to migrate a 12 year old dying server this weekend, yeah, I was 24/7 strongly cursing the idiot who didn't document anything[0]. On the plus side I did get to update a bunch of stuff to more modern practices.

[0] You will not be surprised to learn that idiot was me.[1]

[1] My other servers are much better - anything that hasn't yet been properly service'd has its own `RUNME.sh` which runs whatever it is in the correct way.

Yes.

Also in case of emergency, eg after a power loss or whatever, you might have to do a reboot anyway. So you might as well make sure that this code path is well exercised.

I'd rather deal with a ground hog day of the system being for the millionth time in its first day of operation, than dealing for the first time with the system being in its millionth day of operation.

Planes are certainly turned around quickly, so a reboot every time they refuel isn't desirable.

But equally, they dont do this 24x7 - if only because airport curfews and maintainence schedules won't let them.

Rebooting the computer when doing regular maintenance is no big deal.

    > Usually planes are turned around too fast to be waiting for them to fully reboot every time they fuel.
To be clear, this affected the Boeing 787, a plane usually focused on long-haul between medium sized cities. It is incredibly rare to see a long-haul flight turned-around immediately. Normally, they have max two flights per days, and for longer routes, just one route per day. There was plenty of time to reboot. I don't think anyone was ever in danger.

Also, I am starting to grow tired of "anything Boeing does is bad" on HN in the last 6-12 months. The Boeing 787 was a huge hit, both technically and commercially. (I would say the same for the Airbus A350.) I certainly never worked anything as important or cool in my career. The endless booing from the HN peanut gallery adds little new and/or useful information to the discussion. Yes, I expect to be downvoted for this last paragraph.

TIL. I had thought a computer reboot was snappy compared to filling those fuel tanks, that's so counterintuitive to me. That does make it more of an issue then.
Why? Because it's indicative of shit engineering.

"Let's build something that we KNOW will catastrophically fail, because we deliberately ignore to take account limited resource availability of that system."

For a critical systems, that's just lazy and unacceptable.