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Air traffic failure caused by two locations 3600nm apart sharing 3-letter code

flightglobal.com

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Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code

#251
What brought me to read this article was a confusion: how can two locations related to air traffic be 3600 nanometers apart? Was it two points within some chip, or something?

Only way into the article it dawned to me that "nm" could stand for something else, and guess it was "nautical miles". Live and learn...

Still, it turned out to be an interesting read)

Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code

#252
post #190

Earlier quoted context omitted.

That's not what an exception proving a rule means. It has a technical meaning: a sign that says "free parking on sundays" implies parking is not free as a rule. When used like this it just confuses a reader with rethoric. In this case netflix is just bad at live streaming, they clearly haven't done the necessary engineering work on it.

> That's not what an exception proving a rule means. It has a technical meaning: a sign that says "free parking on sundays" implies parking is not free as a rule. So the rule is "Free parking on Sundays", and the exception that proves it is "Free parking on Sundays"? That's a post-hoc (circular) argument that does not convince me at all. I read a different explanation of this phrase on HN recently: the "prove" in "ex…

The meaning of a word or expression is not a matter of persuasive logic. It just means what people think it means. (Otherwise using it would not work to communicate.) That is why a dictionary is not a collection of theorems. Can you provide a persuasive logic for the meaning of the word "yes"?

https://en.wikipedia.org/wiki/Exception_that_proves_the_rule

Seems like both interpretations are used widely.

Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code

#253
"and it generated a critical exception error. This caused the FPRSA-R primary system to disconnect, as designed,"

as designed here sounds a big PR move to hide the fact they let an uncaught exception crash the entire software ...

How about : don't trust your inputs guys ?

Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code

#256

Earlier quoted context omitted.

But then when somebody else has the issue they make a new bug and any data/investigation from the old one is basically lost. Like what's wrong with having 1000 open bugs?

In becomes functionally impossible to measure and track tech debt. Not all of those issues are tech debt - things which will never be fixed don't matter. Put another way: you're working on a new version of your product. There are 900 issues in the tracker. Is this an urgent emergency where you need to shut down feature work and stabilize? If you keep a clean work tracker where things that are open mean work that shou…

> Not all of those issues are tech debt - things which will never be fixed don't matter.

Except that I've spent a good amount of time fixing bugs originally marked as `won't fix` because they actually became uh "will fix" (a decade later; lol).

> Put another way: you're working on a new version of your product. There are 900 issues in the tracker. Is this an urgent emergency where you need to shut down feature work and stabilize?

Do you not prioritize your bugs?

If the tracker is full of low priority bugs then it doesn't block the release. One thing we do is even if the bug would be high priority; if it's not new (as-in occurs in older releases) it doesn't (by default) block the next release.

> But wait, of those 900 issues are there any that should block the release? Now you have 900 to go through and determine. And unless you won't fix some of them you'll have the same thing in a few months.

You should only need to triage the bug once. It should be the same amount of work to triage a bug into low-priority as it is to mark it as `won't fix`. With (again), the big difference between that if a user searches for the bug they can find it and ideally keep updating the original bug instead of making a dozen new ones that need to be de-duplicated and triaged which is _more work_ not _less work_ for triagers.

> Work planning, triage, and other team tasks are not magic and voodoo, but on my experience the same engineers who object to the idea of "won't fix" are the ones who want to just code all day and never have to deal with the impact of a huge messy issue database on team and product.

If your idea of the product is ready for release is 0 bugs filed then that's something you're going to want to change. Every software gets released with bugs; often known bugs.

I will concede that if you "stop the count" or "stop testing" then yeah you'll have no issues reported. Doesn't make it the truth.

Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code

#258
post #93

Earlier quoted context omitted.

> The general engineering challenge, is how we deal with little-used little-seen functionality (definitely thinking of fault-handling, but there may be other cases) that is totally reasonable when put in place, but has not aged well, and nobody has noticed or realized it, and even if they did it might be hard to convince anyone it's a priority to improve, and the longer you wait the more expensive. The solution to th…

That is "a" solution. Another solution that is very foreign to us in sweng, but is common practice in, say, aviation, is to have that fallback plan in a big thick book, and to have a light that says "Oh it's time to use the fallback plan", rather than require users to diagnose the issue and remember the fallback. This was one of the key ideas in the design of critical systems*: Instead of automating the execution of…

Isn't what you're proposing exactly what led to this being a major problem? The automated systems disabled themselves, so people had to use the manual way, which was much less efficient, and 1,500 flights had to be cancelled.

Re: Air traffic failure caused by two locations 3600nm apart sharing 3-letter code

#259

Earlier quoted context omitted.

Dig into the OpenZFS 2.2.0 data loss bug story. There was at least one ticket (in FreeBSD) where it cropped up almost a year prior and got labeled "look into layer," but it got closed. I'm aware closing tickets of "future investigation" tasks when it seems to not be an issue any longer is common. But, it shouldnt be.

>it shouldnt be Software can (maybe) be perfect, or it can be relevant to a large user base. It cannot be both. With an enormous budget and a strictly controlled scope (spacecraft) it may be possible to achieve defect-free software. In most cases it is not. There are always finite resources, and almost always more ideas than it takes time to implement. If you are trying to make money, is it worth chasing down issues…

the CADT model of software engineering.
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