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How safe is it to leave my laptop running a build or other time-consuming task when I am traveling? I mostly travel on a two-wheeler, with my laptop in a backpack, strapped vertically to my back (left edge towards Earth, right edge towards sky or vice versa).

I have heard that damage can occur if the hard disk's spinning platter comes in contact with the drive head, but isn't that only a problem with much older hard disks? My laptop was purchased in 2010.

I found two related questions, but I am particular about whether the laptop is safe when positioned vertically.

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With a general purpose laptop is definitely not a good idea. –  galegosimpatico Jan 15 at 12:33
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If you want to do that i would be sure that there is sufficent air to avoid overheating and replace the disk with a SSD. SSD is a flash based memory with no spinning parts just like a external USB stick. –  Ivan Viktorovic Jan 15 at 12:38
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Not to mention that you're probably not going to be getting good ventilation. –  kobaltz Jan 15 at 12:38
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I had a Dell E6410 which I kid you not loved turning itself on from OFF in my bag. It came out scalding hot. I no longer pack and carry it around as I did back then so I don't know if the problem persists but years on it's fine. I'd suggest laptops are less susceptible to overheating than we think, even if it feels concerning to find it hot to the touch. –  deed02392 Jan 15 at 17:16
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Leaving it running a task while travelling? I wouldn't even consider this unless you're using an SSD hard disk. Regular hard disks are very susceptible to shock when they're not running; even more so while they're spinning and reading/writing data. –  Chris Jan 15 at 19:49

7 Answers 7

up vote 19 down vote accepted

The orientation of hard drive was historically considered important.

Seeing that some versions of iPod's have the drive turned around all the time, one would think drive orientation change wouldn't matter.

However from personal experience with desktop drives, the "field" knowledge from multiple PC repair techs I have known over the years, as well as that expressed by other comments in various forums, I've personally taken a cautious view that changing orientation during use could be a real problem.

Specifically the common theme I've heard and experienced is that if you originally formatted the drive when it was horizontal, then using it vertically may make it more prone to read/write errors. Similarly if you originally formatted it while vertical, then it would be problematic when used horizontally. I have used that tidbit of info as an additional precaution while recovering an old drive that started clicking. However in laptop drives it may not be applicable since manufacturers expect the drive to be moved around a lot more than desktop drives. YMMV.

Your laptop drive was likely originally formatted when horizontal, so positioning vertically, especially while running builds because of large amount of reads and writes could be a problem, if the above holds for laptop drives.

Hard drive reader heads aren't exactly an equal length lever on both sides of the fulcrum (pivot). One side of the head is long and thin while the other side is short and heavy, crudely shown below:

[][]=(o)------------e

See a more accurate view of the geometry of the drives, here. This might be interesting as well, knowing that the core drive mechanical structure hasn't really changed in multiple decades.

The design is engineered to have the same weight on both sides of the lever to minimize mechanical energy expended in starting and stopping the motion. Two things happen here..

  1. When rotating the head on another axis besides it's own pivot axis, the head is subject to gyro forces and as a result subject to mechanical stress during motion.

  2. When pivot is vertical (i.e. head motion plane is horizontal) then the pivot has no stress moving it sideways. However when the pivot is horizontal (i.e. the head motion plane is vertical or the drive is vertical) then due to the weight of the head mechanism, the pivot will (due to its weight) put pressure on the bearings it is positioned on due to gravitational pull. No matter how precise the engineering, there will be some measurable effect on the bearings that will only come into play in vertical drives. This I guess, will be enough to cause the head to read the disk surface slightly offset.

Item #1 (gyro effect) could be a significant issue on multiple axes especially when the laptop is in a backpack and moving/bouncing up and down and rocking back and forth on the owner's back as the owner is walking. Though human motion is way slower compared to drive platters or readers' motion, so it may not be as significant as might be expected.

Item #2 could be an issue as well albeit less significant and much more automatically corrected with normal calibration that the modern drives already do.

In either case don't move your spinning drive like a pompom :-)

Regarding heat build up: Others have mentioned the heat accumulation inside the bag. I want to reiterate from personal experience that this can be a HUGE issue, and I'd really advise that you avoid putting a working laptop inside a bag for any longer than 1-2 minutes. Be careful with the sleep button, too. Sleep can fail if an error dialog pops up and you don't realize it. If that happens, your laptop can overheat, CPU protection may kick in, and you could lose your work, or worse.

If you really have to keep your laptop in the bag, see if you're able to get a vertical airpath with at least one air entry in the bag near the bottom and at least one air exit near the top. And make sure your laptop has vents that align with the bag's air entry points, only then will it be safe to leave your laptop in there for any longer than 5 minutes.

Reference:

http://superuser.com/a/50422/212609

Does vertical position affect the lifespan or integrity of a hard drive?

http://serverfault.com/a/14245

http://hardforum.com/showthread.php?t=1512482

http://hardforum.com/showpost.php?s=8249ef649e3616f32823f34b635aeeac&p=1035610869&postcount=2

http://www.tomshardware.com/forum/241026-32-vertical-horizontal-mounted-harddrive#5980965

http://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Archives/Computing/2012_October_3

http://answers.yahoo.com/question/index?qid=20110321205213AAhwSDV

http://www.extremetech.com/extreme/142911-ibm-3390-the-worlds-largest-and-most-expensive-hard-drive-teardown

http://en.wikipedia.org/wiki/File:Harddrive-engineerguy.ogv

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For mechanical drives, the larger the diameter the more susceptible it is to errors from movement and re-orientation. Though these issues can be overcome by the manufacturer allowing wider tolerances for such. Laptop drives are inherently less prone and simultaneously have wider tolerances to allow for movement while operating compared to mechanical desktop drives. –  BeowulfNode42 Jan 16 at 1:38
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Historically, it used to matter. Modern drives (less than 20 years old) use a closed-loop control system to ensure that the heads are positioned accurately. There's no 'tolerances' or 'movement' or 'gravity' at play; the control system ensures that the heads are in the right place regardless of orientation or motion. –  Ian Howson Jan 16 at 4:21
    
@IanHowson Newer drives also have significantly smaller targets to find to place the data in or read from. With any mechanical system there is no such thing as perfect fit, no slack, or no play in the mechanical parts. The systems used to monitor where the drive heads are currently located are also subject to some inaccuracies. HDD manufacturers use advances in positioning accuracy to allow for the data to occupy a physically smaller location resulting in much the same robustness as older drives but with increased speed and capacity. I use tolerances to describe the complete system accuracy. –  BeowulfNode42 Jan 16 at 5:42
    
@BeowulfNode42: You're missing the point. The small sizes are exactly why modern drives use the closed-loop system. It's now simply impossible to hit the right sector by guessing. Modern systems guess, check where they ended up, estimate how far off they are, and guess closer. That's why it's called a closed loop. Reorientation doesn't matter: the closed loop system design just means that the first estimation differs, which pretty much fixes every first-order effect. IOW, it's hard to exactly hit track #103925 from zero, but it's a lot easier when you're already on #103924. –  MSalters Jan 16 at 10:31

Another aspect is the battery connection. I have seen interruptions caused by impacts to the laptop. In that case your SW will very likely crash, unless the duration of the power failure is extremely short.

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There are two issues here with putting it in a backpack:

  1. Moving parts that are prone to vibrating/moving.
  2. Hot parts that need cooling.

The first can be easily solved: use a SSD instead of a HDD, empty the CD/DVD drive. A SSD has no moving parts, and it performs better too. The fans are also a moving component, but can handle the movement.

The second is a bigger problem.. overheating damages the hardware. Fans need to be able to push cool air through the device. Keep inlets and outlets unobstructed, and dont put the device in a confined space. Hardware damage may manifest itself by otherwise good software running unstable, or the device malfunctioning altogether.

So: Therefor i would say never leave you laptop on while in a backpack. Except for when it is hybernated/sleeping and the fans are off.

And just to be sure, check in the system BIOS that it is configured to power off (or clock down) automatically when temperatures get to high.

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With all the precautions in the world, eventually something will distract you or displace your machine while you are on the move. Speed bump. Phone call. Shady looking passerby. Suddenly, you notice that it's time to get on or off a bus or train. It doesn't take much.

Accordingly, it doesn't take much to fry a laptop's processor. If you are already doing something processor intensive and shove it into a backpack, weird things can happen.

You can start a shutdown or hibernate, stuff it into your bag, and then happen to pull the thing back out 30 minutes later later and find that a modal dialog interrupted your shutdown. Your bag will be warm, and your rig will be red-hot. They're not designed for it.

In summary, if you ever stow your laptop, it's best that you know for sure that it's fully OFF, or fully hibernated in the least.

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Compilation + insulation may end in deflagation? ;p –  Journeyman Geek Jan 16 at 8:31
    
Just so there is no confusion, "hibernated" is fully off. –  ldigas Jan 16 at 10:18

First, on ventilation, that sounds solvable. You are outside moving. Just do something that makes sense. Don't use a waterproof bag for example. Get something that can breath, partially unzipped. What is the outside temp, etc. Also, newer lap tops generate a lot less heat. Find out what process technology was used for the CPU that will give you a clue. For the hard drive, you can find out the G shock rating of the drive and look up what that means. The first high G value HDDs have been around a while but are dependent on drive size. (some are 1") They were used in early ipods, cam corders, etc. Other common sense things, avoid speed bumps and curbs even if it means taking a longer route home. Finally, expect it to fail at some point in time. Keep the source files on a thumb drive. Actually, just compile from that 'second drive' and even move the OS there. You can boot and compile from the thumb drive and just remove the HDD and stick it on a shelf until you decide to buy an SSD. I'm guessing you are a college student on a bike without a lot of cash. Been there!

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In general that's not a good idea.

Hard drives with active protection systems will park the head on sudden shock (and these are more common than they used to be) and SSDs are nearly insensitive to shock. There seem to be more than one implementation of this, so you'll need to check with your hard drive model to be sure.

That said, your system will likely cook in a closed bag - especially when building files. Its also probably not healthy for your cooling system, and your overheating system may shut down midway through.

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A lot of the shock protection systems are also intended to park during 'freefall' events (so when being dropped) and would not protect the system at all from the kind of shock you'd get in a pannier negotiating a typical road/cycle route. –  James Snell Jan 15 at 16:22
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I lost one laptop to overheating by leaving it to re-encode a videofile while in a laptop bag. The passively cooled GPU literally burned. –  Martin Beckett Jan 15 at 16:46
    
@JamesSnell Some do, though, which is why you need to check. HP's one (if enabled) will park heads with the slightest movement when the lid is closed. But continuous start/stops isn't good for the drive either. –  Bob Jan 15 at 22:14

I think that the spinning hdd will take damage with high-G movements, as the reading needle can accidently scratch the disk plates (the strong magnets prevent this from low-G movements).

Apart from this, the battery time and ventilation should be your main concern. When I do this myself, I only do it for shorter travels (max. 1 hour) and place my laptop in the bag with the ventilation opening upwards and the backpack slightly open to enable it to cool just a little.

If it gets to warm, my laptop goes to sleep, so no real damage happens though...

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