Bogota, Colombia has an elevation of 2,640m. A cable car in the city (Teleférico de Monserrate) can also take one to an elevation of 3,152m. Given that regular hard drives were usually pressurized to operate in elevations up to 3,000m, was there a high rate of hard drive failures in places like Bogota? Perhaps countries like Colombia had specially manufactured hard drives to deal with the issue?
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6Hard drives are never pressurized as far as I know. All the drives that I can remember are either open drives or have a vent hole. But air pressure/density should still be an issue because the head has less lift and would be closer to the disk.– user3528438Mar 14 at 15:48
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10@user3528438 helium-filled HDDs exist. They must be sealed.– RonJohnMar 14 at 18:18
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14Mechanical hard drives are still in use. Why the question in the past tense?– SebastianMar 15 at 11:27
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5Greetings from the cold Bogotá! Nah, mechanical hard drives work well here. The usual brands and the usual models you find anywhere else will work just as well as anywhere else. Saludos!– Albert CMar 23 at 17:52
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3 Answers
Most modern hard disk drives are not pressurised. They have a "breather" hole (normally with an air filter) to let the internal and external air pressures equalise. They're normally rated to work at 3,000 metres altitude.
There's another requirement that's likely more commercially significant than working in Bogota, which is working in a pressurised airliner. Those have a regulatory requirement to keep the pressure equivalent to 2,400 metres or less, so Bogota at 2,640m is a slightly stricter requirement.
If hard drives are rated to work at 3,000m, they likely have at least a 10% safety margin, so Bogota on a low-pressure day should not be a problem. There are genuinely sealed drives produced, for working at higher altitudes, but they're bound to be much more expensive, given the limited need for them. It looks as if ordinary ones should be fine in Colombia.
Some modern hard drives are sealed and filled with helium. These were developed by Hitachi Global Storage Technologies, now part of Western Digital. Using helium reduces turbulence and friction, allowing narrower recording tracks and thus higher density, although the difference is not huge. Helium-filled drives have to be very thoroughly sealed, since helium is good at escaping, and should be fine at high altitudes.
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7If Backblaze, a company which doesn't go for high end drives, is utilizing sealed helium drives, I'd say the technology is more or less commonplace nowadays, at least for higher capacities. Here is their blog from 2018, discussing sealed helium failure rates. No clue as to their specified attitude though. I checked the datasheets for the listed helium drives, and none of them list operating altitude or pressure.– jaskijMar 15 at 0:24
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1In fact, after further thought, I am going to -1 your answer, because helium filled drives are a normal tech nowadays. So stating that all normal drives have a breather hole is simply not true. Would've if I could, not enough rep here.– jaskijMar 15 at 0:32
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6"If hard drives are rated to work at 3,000m, they likely have at least a 10% safety margin" Note that if the 10% refers to the pressure, then that's quite a bit more than 10% higher altitude. You have to go up to about 3600m for the pressure to be 10% less than the pressure at 3000m. Mar 15 at 0:57
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2@jaskij: Added helium-filled drives, which I had not previously heard about. Mar 15 at 9:29
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1@JohnDallman HDD advancements aren't exciting, and rarely make the news, but as you surely saw, they've been a thing for ten years now.– jaskijMar 15 at 16:31
TL;DR: Rather not.
Given that regular hard drives were usually pressurized
Fixed (!) drives are not pressurized. If they were, there would be no issue. They are usually sealed to avoid any dust intake (*1), but the seals are flexible to allow expansion.
to operate in elevations up to 3,000m,
Since many manufacturer were often US companies the value is often given as 10,000 ft (3,048m). But this is not really a measurement of height, but pressure. Standard pressure for 3,048 m is 697 hPa (*2).
More important, it is not a hard technical limit in any way, but an environmental spec to which the manufacturer guarantees that the drive will always work. It does not give any hint what happens outside that limit.
Even if there is some concern, the margin of error will be at least 20%, so if 697 hPa is guaranteed, then it's safe to assume that nothing will happen up to 20% lower - that is 540 hPa, or a standard height of ca. 4,770 m.
The specific value has most likely been selected to allow regular use in (pressurized) passenger aircraft, which are set per regulation at or below 8,000 ft above sea level.
was there a high rate of hard drive failures in places like Bogota?
No. Never heard of.
- For one, as explained, 10,000 ft are neither a hard limit or a limit at all, but a guaranteed operational condition.
- Second, the seal may at most simply pop, which equalizes pressure - but I'm not sure that coming easy
- Third, even if, there are still filters keeping dust out
On a side note:
- Real pressure depends not only on height, but location, weather and time of day. For example today's real pressure at in Bogota at 11 PM at 2,618 m altitude is 757 hPa, which is more like 2,400 (2,600m would be 737 hPa)
*1 - Modern drives as well to keep whatever gas is used to fill (like Helium) inside.
*2 - All values calculated with the standard formula
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1Mainstream HDDs are not sealed but rather are vented. There is a filter in the vent passage to prevent contamination but the vent does allow pressure equalization between the inside of the drive and the ambient.– jwh20Mar 14 at 17:00
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3@jaskij External hard drives are generally HDD, and it's common for laptops to use them, as well as servers that don't need fast access times. Mar 15 at 1:04
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5@jaskij I disagree--boot drives are usually SSD in good machines but if you want to store a lot spinning rust is still your best approach. Mar 15 at 4:46
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1@LorenPechtel depends on multiple things, but a regular facebook machine doesn't need much storage. Some people argue that if you have enough data to need an HDD, you probably should have a NAS instead. I guess it depends on what you see as a "good" machine, but when a quality 1TB SSD costs 65$, I really see no reason to go for an HDD in a mainstream machine. Gaming PCs might need more, but those often have higher budgets. Video editing, in my book, is not mainstream. I guess it's a question of perspective.– jaskijMar 15 at 16:29
La Paz, Bolivia is higher than Bogota Colombia. In the mid 1970s I was an instructor for Digital Equipment Corporation, and I taught some courses to a customer in La Paz. The customer had bought a large timesharing system with several disk drives.
Those disk drives had been tested at a low pressure chamber in Colorado before being certified as ok to work in La Paz. It's air pressure generated by the Bernoulli effect that keeps the heads from crashing into the recording surface. In effect, this gives them a maximum flying altitude.
