02/17/2012

The great power cut mystery!

Yesterday, 16 February, the airport Swiss-supplied power cut out at around 9h30. The SIG reported micro-cuts a bit later, affecting Grand Saconnex and Meyrin. A coincidence?


As I write this, on Friday evening, there is not yet an explanation of the power cut at the airport. The timing of this cut, reported as from about 9h30 to 11 am, does not match a morning problem detected by SIG, the Geneva Industrial Services, and consisting of two micro-cuts (of perhaps half a second each) at 9h47 and 10h12, in the region of Grand-Saconnex just south of the airport.

I suspect that at least the second micro-cut also affected Meyrin, north of the airport, because it disturbed the computer which ARAG has installed to register the noise in the region of Citadelle, Meyrin. There was also a cut of several hours in the ARAG system which records aircraft arrivals and departures. It seems likely that the micro-cut caused a failure of the computer programs executing these tasks, but did not cause the computers to make a clean shutdown and reboot.

Anyone reading this and who lives near the airport and had a computer, or computers, running at that time may have seen the effects of micro-cuts yesterday, or perhaps other days. It is rather hard to protect against them without spending quite a lot of money on uninterruptible power supplies, which often use a battery backup system, perhaps even with something like diesel generators as a second backup. What is often critical is to make the computer realise that something bad is happened, so that it will shut itself down in an orderly way: computers really hate someone just pulling out the power cable!

More of interest to home computer users should be to guard against power surges, in particular the effect of one caused by a lightning strike. This rule can also be useful for other household equipment (TV, DVD player, etc.), but I would see a computer as more difficult to replace because of the personal information that we have stored in its memory (and hopefully regularly backed up on some protected external device or agency!). Given that we tend to have several devices in parallel with a computer (printer, internet router, external hard disk) we normally buy a multi-socket electricity distributor. Although they can be bought cheaply, it is always best to buy a good one with surge protection: in the shops these are often indicated as particularly suitable for computers: an extra few Swiss Francs could one day save a lot of effort.

To come back to the original subject of this blog, it seems statistically quite likely that the two events (airport general power cut and SIG micro-cuts) had some common factor. Perhaps this will be revealed in due course!

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