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Comment by btilly | Hacker News Reader

My favorite was a story from the 1980s of a program which would crash depending on the phase of the Moon!

Turned out to be because it was generating a date by calling a general purpose astronomical routine, then parsing the date out of that. The astronomical routine among other things included the phase of the moon, and during some phases you would overflow the buffer that was passed in.

Another classic was a tech support call from the 1990s where the person's computer rebooted every time they flushed the toilet. Turns out that the person was at the end of the electrical line..and on a septic system. Flush the toilet, the septic system came online, causing a power dip, and that was enough to reboot the computer. A UPS fixed that.

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I heard a story about a terminal in a public terminal room that a user was able to consistently log in to if they were sitting down in a chair in front if the terminal, but never if they were standing up.

They thought it might be static electricity, or some mechanical problem, or "problem exists between keyboard and chair", but finally they noticed something else was amiss...

It turns out some joker had re-arranged the 1234567890 keys to be 0123456789, so when the user was standing up, they looked down at the keyboard and typed their password (which contained a digit, of course) by looking at the keys. But when they were sitting down, they touch typed without looking at the keys, and got their password correct!

I have a slightly more boring anecdote. We were making a 2 Mbit/s multiplexer (E1 to POTS and ISDN lines thing) and ISDN lines worked fine during the day in the test lab but they were always dead the next morning. The unit was otherwise running fine the following day but ISDN was stuck. We never got this to repeat at other times. If you booted it at midnight and came to work at 6AM, it was stuck. But it would run OK from 6AM to midnight so it wasn't any buffer overflow or such.

So, eventually, just decided to stay at lab for the night. At 5AM the air conditioning came on (it was shut for the night). The ISDN circuit got stuck.

It was electromagnetic interference from the massive AC unit fan which was not too far above our lab table. Improving the grounding of the ISDN chip helped.

My favorite was the server that couldn't send email further than 500 miles away.

http://www.ibiblio.org/harris/500milemail.html

Didn't someone prove this to be nonsense?

Don't ruin our industry's good anecdotes with reality!!!

The author notes at the outset it's embellished to be entertaining, but nothing in the actual big seemed outlandish. The only thing that struck me as unlikely was that someone would actually work out and notice the radius. But I also know people like that, so I'd give the story the benefit of the doubt.

The user in the story is the chairman of statistics dept.

That story was what got me using GNU Units. Which turns out to be a surprisingly powerful, and very much units aware, calculator.

Want to convert acreage into MWh of annual solar electric potential, or figure out the oil equivalent energy in a nation's poop? Units can do that. And much more.

A BeOS bug story similar to the phase of the Moon:

  Two [BeOS] test engineers were in a crunch. The floppy drive they were currently
  testing would work all day while they ran a variety of stress tests, but the
  exact same tests would run for only eight hours at night.

  After a few days of double-checking the hardware, the testing procedure, and the
  recording devices, they decided to stay the night and watch what happened. For
  eight hours they stared at the floppy drive and drank espresso. The long dark
  night slowly turned into day and the sun shone in the window. The angled sunlight
  triggered the write-protection mechanism, which caused a write failure. A new
  casing was designed and the problem was solved.

https://www.haiku-os.org/legacy-docs/benewsletter/Issue4-22....

> My favorite was a story from the 1980s of a program which would crash depending on the phase of the Moon!

Do you have a name for this program? It sounds a lot like an urban legend - when would you ever find it easier to parse a date out of an astronomical program than to use actual date handing capabilities from the system or a library?

I've never heard of this either but early programmers did creative things to work around limitations. It might not be as complicated as we imagine. The first "computer", the Antikythera, was designed for this very purpose.

Here is a reference to a program that crashed based on the phase of the moon for slightly different reasons: http://www.catb.org/jargon/html/P/phase-of-the-moon.html

The one that I described I first remember hearing about in undergrad. I heard it from an astronomy student. I guess that makes it an urban legend, but a highly believable one. In my experience inexperienced programmers are very good at unexpectedly repurposing whatever they happen to know for new purposes. And in an astronomy department it is easy to find inexperienced programmers with astronomical routines at hand.

More that it was including the phase of the moon in the output and it would crash of the output ended up being too long.

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