A few years ago I had a camera with a little 500mb hard drive. One of the warnings about that camera was that it should not be used above 10,000 feet in elevation. It used air as a buffer/cushion between the disk and the head, and if the air was too thin, it could cause problems.
Is that the case with some other hard drives as well? I don’t think they are sealed or completely ‘air tight’.
I ask because I recently put a Toshiba netbook to rest. Two hard drives failed in about one year. Thing is, it seemed to work fine at lower altitudes, but was erratic as hell at my house at 11,200 feet. It worked fine in an office environment at 9200 feet, but at my house, it kept locking up until finally biting the dust. The only difference in environment that I can think of is altitude.
I was under the impression that all (most?) hard drives rely on an air cushion to keep the head from smacking into the plates. As for an altitude limit, living in the midwest, it’s not something we give much though to, so I don’t know anything about that.
All modern hard disks (indeed since about the mid 70’s) work this way. There is no other viable mechanism to maintain the very low and tightly specified head clearance over the disk surface. In general it is a very robust way to make a disk, even when operating they can sustain quite high accelerations before the head touches the platter. If you look carefully at any disk you will find a little vent hole. Often they have a “Do not cover” label next to them. Under the hole is a very fine filter, and then it vents into the cavity containing the platters and heads. This equalises the pressure inside and out.
Off the cuff, I suspect your suspicions are correct, and indeed the problems could well be sheeted home to the altitude. Laptop drive are generally less robust, and likely have finer tolerances, so it is reasonable that they are more sensitive. Also, and this may be the critical point, laptops are often moved when the disk is operating. The thinner air will result in less ability to cope with accelerations that might cause the head to touch the platter.
11,200 feet is .61 atm, whilst 9,000 is 0.68 atm. So over a 10% difference in pressure. Aerodynamic lift is proportional to the density, and here that is proportional to the pressure. So you are at 60% of the sea level margins.
Of course disks operate all the time at 8,000 feet, since that is the altitude that most jet planes are pressurised at. One suspects that is the determining requirement laptop disks need to cope with.
Seriously, you live at 11,200 feet? Colour me impressed. We don’t have anywhere that high in the entire continent.
Interesting. I suppose that the reason I’ve never had problems with desk tops is that they don’t get moved around.
My Wife is pretty fed up with the net book, and would never use it. She suggested that we get a lap top (which I don’t really want). And it would not fix our fundamental problem of altitude.
I’ll look into flash solid state ‘disks’. MusicCat Not sure if such a thing can be used in a vanilla netbook, or if I would have to buy a machine from scratch. I suspect the later.
As long as you get one using the correct form factor for your laptop, you shouldn’t have any problems switching to solid state drives (also make sure you have a way to re-install the operating system).
Good point. I kept wondering what the differnces was between work and my house. The only thing I could come up with was altitude. And then I remembered the warning on the disk for the camera.
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<snip>Seriously, you live at 11,200 feet? Colour me impressed. We don’t have anywhere that high in the entire continent.<snip>
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Yep. For 20 years now. Don’t need air conditioning that’s for sure, and winters can be a bit rough. Saw a few snowflakes yesterday. Sky sure is blue though.
If anyone would like to recommend a SSD, or a ruggedised net book, I sure would like to hear your opinions.
I recall an article about iPod failure on the Tibet train. To allow the lowlanders to travel to Lhasa, it used oxygen enrichment (not pressurization, as some articles implied). It went over passes that were around 13,000 feet.
Most hard drives are rated to about 12,000 feet. They are sealed, but have very tiny pressure relief holes to allow gradual acclimatization while filtering out dust. The head “floats” on a cushion of air between head and disk, dragged along by the spinning disk. At the higher altitudes, (12,000 feet or more) this is too thin, the head scrapes the disk, time for new disk.
Apparently a lot of disk hardware tended to fail on this Tibet train. However, computers are commonly used in Lhasa itself with no problem, which IIRC is about 10,500 feet.
Interesting. I suspect the problem is that portable computers do get joseled around a bit more while they are running. Never had this problem with a desk top.
Gonna look into SSD. I’ve always been interested in it any way.
I suspect that on my net books that have had hard drive failures, daily going from 9200 feet to 11200 feet does not alow it to get acclimized. I often take it down to 5200, and sometimes 800. Too much of a ride I suspect.
yeah, jostling probably helps disk crashes by bouncing the disk head. Laptops, yes; iPods, even more jostling.
Acclimatized does not mean “get used to”. Just that disks are not totally sealed (deliberately), so in a matter of a few minutes or hours the pressure inside will reflect the pressure outside. If the pressure is too low, the head does not “float” properly, and a crash from jostling is likely. Too low air pressure, and you don’t even need to jostle. But, I have dropped a running iPod 3 feet onto carpet at sea level, and it did not crash, as far as I have seen in the years since.
