Try this one... see if you can figure it out before getting to the end.
The location was a server room, somewhere up on the 4th or 5th floor of an office in Portsmouth (I think it was) by the docks.
One day the main Unix db server falls over. It was rebooted but it happily fell over again and again, so they called out the support company.
The support gadgie... Mark I think his name was, not that it matters... I doubt you've ever met him and its not important anyway. Its not, honest. Look, we'll just stick with Mark for arguments sake, okay? Fine.
So mark gets there a few of hours later (Leeds to Portsmouth you see... its a long way), switches on the server and everything works without error. Typical bloody support really, client gets upset over naff all. He goes through the log files and finds pretty much nothing that would make the box cock up. Mark then gets back on the train (or whatever mode of transport he used to get there, it could have been a lame cow for all I know... look, its not important, okay?) and heads off back up to Leeds after a pointless waste of a day.
Later that evening, the server falls over. Exactly the same story... it won't come back up. Mark goes through all the usual remote support stuff but the client can't get the server to run.
Back on the train, bus, lemon meringue pie, or whatever the fuck it was, and back down to Portsmouth. Lo, the server boots without a problem! Its a miracle. Mark spends a few hours making sure that there's nothing wrong with the O/S or software, and finally heads off back to Leeds.
Sometime around mid day, the server goes down (easy tiger!). This time it seems prudent to get the hardware support people in to replace the server. But no, it falls over again around 10 hours later.
The pattern continues for a few days. Server working, then after about ten hours it falls over and won't run for another 2 hours. The checked the cooling, they checked for memory leaks, they checked everything but came up with nowt. Then it all stopped.
A week without problems... everybody was happy. Happy, that is, until it started again. The same pattern. 10 hours on... 2-3 hours off...
And then somebody (I seem to remember he said that the person had nothing to do with IT) said:
"Its high tide!"
Which was met with blank looks and probably a wavering hand over the intercom to Security.
"It stops working at high tide"
This, it would seem, is a fairly alien concept to IT support staff, who are not likely to be found studying the Tide Alamanac during the coffee breaks.
So they explained that it couldn't be anything to do with the tide, because it was working for a week.
"Last week was neaps, this week its springs."
Here's a bit of jargon busting for those of you who don't have any RYA qualifications. The tides run on a lunar cycle, so every 12.5 hours as the Earth turns, the gravitational pull of the sun and the moon pull the tide
From one side to the other. In a 12.5 hour cycle, you'll start with a high tide, then get a low tide in the middle, and end with a high tide. But as the moon's orbit changes so does the difference in high and low tide. When the moon is between us and the sun or on the opposite side of the planet (full moon and bugger all moon), we get a Springs. These are the highest highs, and the lowest lows. When there's a half moon, we get neaps. The difference between high and low is greatly reduced. The lunar cycle is 28 days, so Springs - Neaps - Springs - Neaps.
Back to the story.
After explaining the gist of tidal movements to a bunch of techies, the techies immediately considered the posibilty of ringing the police. Which seems fair. But it turns out that the gadgie was right. 2 weeks previously, a Navy destroyer or something had moored up nearby. Every time the tide got to a certain height, the crow's nest was in direct line with the floor that the servers were sitting on. It seems that the radar (or radar jamming, or whatever the military have on their toy dinghies) was playing havoc with the computers.