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The code worked differently when the moon was full

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Re: The code worked differently when the moon was full

#31

Post by m4rtink »

mhandley wrote: post #12

The phase of the moon really can affect performance. A friend of mine worked on wireless links in Scotland and was struggling with loss at certain times of day, but not exactly the same time every day. When they graphed loss against time, the pattern was really periodic over many days. The periodicity turned out to be 12 hours 25 minutes, which they eventually realized is exactly the time between low tides. The probl…

I heard a story about an astronomer loosing the chance to be the first to report a commet one cold winter night - just as he wanted to send the email to report it, the Internet connection was dead! He ran from the observatory to the nearest place with Internet connectivity, but by the time he sent the email from there, there was already a report from another astronomer elsewhere, a few minutes ago.

Reason for the mysterious network outage ? Thermal contraction! The observatory was connected to the Internet via an optical link to a highrise building in the city that contracted ever so slightly due to the very low temperature, moving the laser beam of the optical link out of alignment, shutting down the connection.

Re: The code worked differently when the moon was full

#32

Post by Dylan16807 »

AceJohnny2 wrote: post #20
AceJohnny2 wrote: post #19

As long as you don't traumatize the hard drives by yelling at them, feat. brendangregg & bcantrill: https://youtu.be/tDacjrSCeq4

Tangentially, my last company made sophisticated routers, dissipating ~3kW of heat. We had hard drives in them for persistent logs. There was a big problem where we needed to upgrade the fans to deal with the heat dissipation, but it was destroying the performance of the spinning disk HDDs due to the vibration of the fans. (these were 2U devices with 5 boards: 2 control-plane boards (1 active, 1 on stand-by for redun…

So I'd say the obvious solution would be suspending the drive on relatively big pieces of rubber, like https://m.media-amazon.com/images/S/aplus-media/sc/a32b42cb-...

If it was a big problem, that must not have been viable? Too cramped?

Re: The code worked differently when the moon was full

#33

Post by enobrev »

a-dub wrote: post #30
drdeadringer wrote: post #23

Reminds me of a story where a company's internet would regularly drop at the same time every day -- let's say 3pm. Nobody could figure it out so they called in an expert. After lots of attempts and figuring, one day the person in question happens to look out the window at the time in question ... and sees a service truck park exactly in line-of-sight between the business and their internet-signal pickup broadcast poi…

i once lived in an apartment in an old building where if you turned on the light in the bathroom the dsl would lose sync. why this would occur i'll never know. (probably old telephone wiring wrapped around old 110v wiring? maybe? or who knows what kind of weird leakage/ground loops may have existed)

Quite a few years ago, I spent many hours making my way up the support tiers at Time Warner in Brooklyn to resolve some connection issues (cable modem). I patiently waded through each tier as they repeatedly asked me to reset my modem and my router and restart my computer and check every cable, etc. The same things I'd already done before (as an on-site tech myself, at the time) and as the previous support person asked me to repeat.

Finally I made it to tier three, with someone who seemed obviously competent. Within about a minute, he checked the power usage on my modem and then historically, and knew immediately that if I moved my modem to another outlet, it would work.

It did. Never had that type of connection issue again.

Re: The code worked differently when the moon was full

#34

Post by fragmede »

mhandley wrote: post #12

The phase of the moon really can affect performance. A friend of mine worked on wireless links in Scotland and was struggling with loss at certain times of day, but not exactly the same time every day. When they graphed loss against time, the pattern was really periodic over many days. The periodicity turned out to be 12 hours 25 minutes, which they eventually realized is exactly the time between low tides. The probl…

The moon is a nightime light source, and a pretty good one at that, every 30 days or so. Even after the invention of the light bulb it continues to light up the night. Thus it's not astrology to suggest that the phase of the Moon could affect things on Earth seeing as how it's what causes tides. (It is astrology to suggest the Moon is causing an effect based on magic though).

Re: The code worked differently when the moon was full

#35

Post by AceJohnny2 »

Dylan16807 wrote: post #32
AceJohnny2 wrote: post #20

Earlier quoted context omitted.

Tangentially, my last company made sophisticated routers, dissipating ~3kW of heat. We had hard drives in them for persistent logs. There was a big problem where we needed to upgrade the fans to deal with the heat dissipation, but it was destroying the performance of the spinning disk HDDs due to the vibration of the fans. (these were 2U devices with 5 boards: 2 control-plane boards (1 active, 1 on stand-by for redun…

So I'd say the obvious solution would be suspending the drive on relatively big pieces of rubber, like https://m.media-amazon.com/images/S/aplus-media/sc/a32b42cb-... If it was a big problem, that must not have been viable? Too cramped?

Exactly, there was no room for the rubber dampeners that were the obvious solution, and much frustration from the engineers that this wasn't planned ahead.

Re: The code worked differently when the moon was full

#36

Post by ColinWright »

mhandley wrote: post #12

The phase of the moon really can affect performance. A friend of mine worked on wireless links in Scotland and was struggling with loss at certain times of day, but not exactly the same time every day. When they graphed loss against time, the pattern was really periodic over many days. The periodicity turned out to be 12 hours 25 minutes, which they eventually realized is exactly the time between low tides. The probl…

For those who are interested, this is why you usually have two dishes/aerials, vertically displaced, so that when one has destructive interference between the direct and reflected signals, the other has constructive interference. I learned something about this when writing data compression and encryption software for radar surveillance systems, where there were multiple radars over a moderate coverage area, all sending data via microwave links over water back to the Command and Control Centre.

Re: The code worked differently when the moon was full

#37

Post by Socketier »

a-dub wrote: post #30
drdeadringer wrote: post #23

Reminds me of a story where a company's internet would regularly drop at the same time every day -- let's say 3pm. Nobody could figure it out so they called in an expert. After lots of attempts and figuring, one day the person in question happens to look out the window at the time in question ... and sees a service truck park exactly in line-of-sight between the business and their internet-signal pickup broadcast poi…

i once lived in an apartment in an old building where if you turned on the light in the bathroom the dsl would lose sync. why this would occur i'll never know. (probably old telephone wiring wrapped around old 110v wiring? maybe? or who knows what kind of weird leakage/ground loops may have existed)

This happened to me as well, only with DSL. The strip lights on the bathroom mirror (newly installed) would disconnect the internet when turned on.

Such a weird thing to troubleshoot when you have a few people living in the same house.

Re: The code worked differently when the moon was full

#38

Post by acdha »

I heard a great story a while back for a digitization project where historic content was being provided by many libraries around the world, including one in Russia.

The quality of the scanned books was excellent, except for a weird distortion every so often where part of the page would be shifted partway through as if someone had shifted half the page in Photoshop. This was only noticed in books over a certain size so people were checking to see if there was some kind of mechanical problem with the scanner (these were robots with automatic page turners so it was plausible that there could be something which was only an issue past a certain position), trying to figure out of there was some way that the software had some kind of memory leak or other issue which would explain the long and inconsistent intervals.

Eventually they were on a long-distance phone call to Moscow and not turning up anything when there was a loud rumble in the background. “What was that?” lead to the realization that the library's scan center was close to a subway tunnel. The vibration of a passing train was enough to cause a glitch but only if you happened to be scanning at the exact time it went by: the reason longer books were noticed was simply because having more pages meant that at any point in time a long book was more likely to be sitting in the scanner and the technicians running the scanner were apparently tuning out the trains as background noise. This was reportedly the first project they'd done with one of the scan robots which can process an entire book unattended so it was plausible that smaller past projects simply hadn't been scanning frequently enough to hit this problem or that some previous technician had noticed and immediately redone the page.

Re: The code worked differently when the moon was full

#39

Post by bgirard »

m4rtink wrote: post #31
mhandley wrote: post #12

The phase of the moon really can affect performance. A friend of mine worked on wireless links in Scotland and was struggling with loss at certain times of day, but not exactly the same time every day. When they graphed loss against time, the pattern was really periodic over many days. The periodicity turned out to be 12 hours 25 minutes, which they eventually realized is exactly the time between low tides. The probl…

I heard a story about an astronomer loosing the chance to be the first to report a commet one cold winter night - just as he wanted to send the email to report it, the Internet connection was dead! He ran from the observatory to the nearest place with Internet connectivity, but by the time he sent the email from there, there was already a report from another astronomer elsewhere, a few minutes ago. Reason for the mys…

When I started dating my wife she lived in a shared student residence. She would tell me that her internet didn't work when her room was cold. She had to wait for her space heater to heat up the the room. I didn't believe her at first but it turned out be true. She lived there for a year so I observed it several times. Never did find out what the problem is. I don't know if thermal contraction could effect solders between ~10C -> 22C.

Re: The code worked differently when the moon was full

#40

Post by xsmasher »

vidanay wrote: post #26

We once had a customer who would call us in a panic a couple of times a year saying our inspection equipment was experiencing unusually high false rejects and they were generating very high scrap rate. By the time we got a technician on site the next day, everything was working flawlessly and the customer couldn't reproduce the problem either. This went on for almost three years with various levels of escalation to t…

This is like a real-world equivalent of the "cleaning lady unplugged the machine" urban legend.
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