Smoke damage and hard drives

Discussion in 'hardware' started by guest, Feb 18, 2019.

  1. guest

    guest Guest

    Smoke damage and hard drives
    February 18, 2019
    https://www.welivesecurity.com/2019/02/18/smoke-damage-and-hard-drives/
     
  2. sdmod

    sdmod Shadow Defender Expert

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    I think that the most important information in the article, (although it was all interesting) was to keep regular backups of your disk.
    I would add, away from the pc and stored somwhere safely.
    This is one thing that many of us intend to do regularly but sometimes forget once we have backed up a few times.
    I know that house fire smoke gets absolutely everywhere and I know that from personal experience. Plastics when burned in a domestic setting leave a very fine black powder which will get onto and coat and into virtually everything. This sort of smoke damage is very difficult to clean and extremely time consuming to do it properly and safely.
    I think that the worst kind of smoke damage that I have seen in dektop computers is when repairing pcs belonging cigarette smokers. I've never examined the internals of the drives but on nearly all occasions the fans were gummed up with thick brown tar and often house dust which had made them not function at their correct speeds to cool the components within the system. In this situation the hard disks and other pc components were exposed to constant heat were probably damaged more in that way than smoke getting into the internals. Presumably, solid state dives are not effected in the same way by smoke as platter disks although I imagine that they are effected by heat caused by non working fans.
     
    Last edited: Feb 18, 2019
  3. Bill_Bright

    Bill_Bright Registered Member

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    It is not likely any smoke particles (from house fires or smokers) would get inside a hard drive. While hard drives are NOT "hermetically" (air tight) sealed (as many believe), they do only have one tiny hole to the interior that is used to equalize pressure. And this tiny hole is vent is covered with a very fine filter that will trap smoke particles, moisture in the air, and other contaminates. So as long as the hard drive was not exposed to extreme heat, or doused with a fire hose, they tend to survive fires even when covered in soot.

    Not sure what you mean here. Hard drives don't have fans. Never have.
     
  4. xxJackxx

    xxJackxx Registered Member

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    I think he just meant the case fans.

    I've had to deal with smokers PC's and they are pretty nasty but no hard drive issues that I've seen.
     
  5. itman

    itman Registered Member

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  6. itman

    itman Registered Member

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    I have a bunch of HDDs stored away. Just looked a Seagate Constellation ES.3. It has what appears to be a hole on the top. Closer examination shows it has a shiny surface which I assume is a glass window. So it appears to me the older drives are indeed sealed.

    -EDIT- I was wrong per Seagate documentation:
    https://www.seagate.com/files/www-content/product-content/enterprise-hdd-fam/enterprise-capacity-3-5-hdd/constellation-es-3/en-us/docs/100671511f.pdf



     
    Last edited: Feb 19, 2019
  7. Bill_Bright

    Bill_Bright Registered Member

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    Except he said in the same sentence he was referring to drive internals and gummed up fans. But if he meant case fans, then sure, they can get gummed up.
    Anyone who has done PC maintenance for awhile has had to deal with PCs where the users smoked around them. And yeah, it gets bad - like the inside of a car windshield of heavy smokers. Worse yet is smokers with cats. Cat fur and dander is very oily - much worse than hound dogs and water dogs and they can be pretty bad too. Combine oily cat fur and dander with tobacco smoke residue and you almost need a chisel to scrape it off. In any case, it does not affect the insides of a hard drive because none of that can get in there.
    No - that is not a seal - at least not an air or water tight seal.

    That shiny surface thing you see is a membrane, but it has very tiny holes in it - just enough to allow the air pressures inside and out to equalize. This equalization is essential to prevent internal pressures (or vacuums) from affecting performance as drives heat up or cool down (through use and through exposure to ambient extremes). They are also used when hard drives are used at higher altitudes, such as in airplanes.

    This membrane is used to seal out dust and moisture particles, but not air particles. And if you submerge the drive in a bucket of water, water will eventually get inside too. Drives are NOT hermetically sealed.
     
  8. Keatah

    Keatah Registered Member

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    Not sure what purpose the gas-permeable filter/holes/membranes serve when it comes to the HDD working on an airplane. Other than yo equalize pressure and remove stress on the HDD's cover plate.

    If you put an HDD in a vacuum, the internals will also experience a vacuum. Most all HDD have a published spec for maximum operating altitude.
     
    Last edited: Feb 19, 2019
  9. Bill_Bright

    Bill_Bright Registered Member

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    Huh? As I said multiple times above, the purpose is all about equalizing pressure. Don't forget, not all airplanes have pressurized cabins and for those that do, they are generally maintained at the equivalent of 8000 feet - still pretty thin. And pressurized cabins are not required when flying under 10,000 feet.

    As far as stress on the cover plate, pretty sure pressures are not that great for that to be a factor.
    Oh? Pretty sure that's not true. Just looking at WD Blue, nothing there.

    WD Black - nothing there. products.wdc.com/library/SpecSheet/ENG/2879-771435.pdf

    Seagate Baracuda - nothing there. https://www.seagate.com/www-content/datasheets/pdfs/barracuda-pro-14-tb-DS1901-9-1810US-en_US.pdf

    Got a link to an example? This is something I have researched before in the past too - while I was in the USAF and for a couple clients who were pilots after I got out. I don't recall ever seeing a spec for maximum operating altitude.
     
    Last edited by a moderator: Feb 20, 2019
  10. Keatah

    Keatah Registered Member

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    Spec sheets published these days are designed to impress the layman and enthusiast and not serve as a reference for engineers or systems integrators. Data sheets of yesteryear always included it.

    I wonder at what altitude the air will become too thin to form an air cushion which supports the heads? 5000? 10000? 40000? A complete vacuum - so the head needs no air to support it? Too high a pressure and the head flies too high and won't read or write because of distance. Too low, and it crashes.

    Specs found here will tell you:
    https://www.google.com/search?q=wd+blue+"altitude"+spec
    ..or a direct example..
    https://eshop.macsales.com/item/Western Digital/WD20EZRZ/

    And there are pressurized boxes for taking HDDs above 10,000 - 15,000 which is typically their limit while operating. Air is too thin.
     
  11. Bill_Bright

    Bill_Bright Registered Member

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    Thanks for that.

    Still, since we know those holes are there for pressure equalization, not sure the value of that information for normal users. As I said above, pressurize cabins are required above 10,000 feet (or else the pilots will go into hypoxia (lack of oxygen to the brain). Not a good thing and the passengers would not be too happy about it either! ;) And if someone takes a hard drive to -1,000ft, they are likely in a pressurized diving suit or submersible because there is only 1 place on Earth with dry land below -1000 ft and that is the Dead Sea Depression (at 413m or 1355ft).
    Nope. That's no how drives work. Air does not hold the head off the platters - the mechanical arm is mechanically positioned just above the platters by design and construction.

    If you look at an image of the insides of the drive, if air held up the R/W head, there would have to be several airtight seals encasing each arm (there are 3 arms in this drive) in 3 airtight chambers preventing the pressurize air from escaping past the R/W head. As seen in that image, there are no such seals or sealed chambers.
    Yes - there are definitely air tight enclosures for this. I have seen them for use with some avionics systems. You don't see them in normal aircraft because as noted, the cabins are pressurized - as are cargo holds (so toothpaste tubes, cans and jars of other stuff don't explode at altitude). But they really are not used that often because (1) hard drives are obsolete, power hungry, heavy and big - not to mention subject to damage through vibrations - so solid state devices are used more often and (2) electronics still have to be cooled. Vacuums are great for thermos bottles where you want to retain (or keep out) heat. Not when you want heat to be moved away from heat sensitive devices.
     
  12. mirimir

    mirimir Registered Member

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    What about those helium-filled drives? Or was that just (pardon the ~unintentional pun) smokeware?
     
  13. Keatah

    Keatah Registered Member

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    Every hard disk relies on a cushion of air and the Bernoulli Effect to set the fly height. As do Helium-filled drives.
     
  14. mirimir

    mirimir Registered Member

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    I know that. But helium-filled drives can't have vents, can they?
     
  15. Bill_Bright

    Bill_Bright Registered Member

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    No, you definitely would not want the helium to escape. But since they were announced several years ago, there has not been much news about them. Those that are out there are clearly for data center applications where super high-density drives are desired. And since data centers are not known to go from 0 to 36,000 feet and back down again with equally extreme swings in ambient temperatures, not sure a method of equalizing pressure is a problem. ;)
     
  16. Keatah

    Keatah Registered Member

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    Microsoft's underwater data center..? Probably less than 100 meters deep.
     
  17. Bill_Bright

    Bill_Bright Registered Member

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    And likely pressurized to or near sea levels for human comfort.
     
  18. sdmod

    sdmod Shadow Defender Expert

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    Yes I meant the case fans, probably just worded badly.
    @sdmod 'I think that the worst kind of smoke damage that I have seen in dektop computers is when repairing pcs belonging cigarette smokers. I've never examined the internals of the drives but on nearly all occasions the fans were gummed up with thick brown tar and often house dust which had made them not function at their correct speeds to cool the components within the system.'

    My point being that unusual persistant heat could possible shorten the life of a drive.

    I'm no expert it was just a casual comment.


     
  19. Bill_Bright

    Bill_Bright Registered Member

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    This is absolutely true of all electronics. Temps do not have to get to the "over" heated or "hot" stage to be problematic.

    It is NOT necessary to keep electronics as cool as possible - just comfortably within its specified normal operating range. That is, a CPU, for example, will not have better performance, be more stable or have a longer life expectancy if normally run at 30°C instead of 50°C, when it's maximum allowed temp is well above that 50°C. But if the maximum temp allowed is, for example, 90°C and it is consistently run near that threshhold (but not crossing it), it "should" still be stable and perform fine, but aging "could" be increased.
     
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