3 ms·

Semi-OT, but is there still any situation in modern computers where turning it off would be "unsafe"? I.e. if you yanked the power cord at some specific time, t

by xg15 2y ago

Semi-OT, but is there still any situation in modern computers where turning it off would be "unsafe"? I.e. if you yanked the power cord at some specific time, the system would take irreversible damage? Was this actually a real danger at all at some point? It's obvious that cutting the power without shutdown will lead to data loss of everything not written to persistent storage. But for old PCs, the warning was always that it could also physically damage the PC, e.g. damage the hard drives or something like that. Is this still the case?

BugsJustFindMe 2y ago
> But for old PCs, the warning was always that it could also physically damage the PC I don't remember this being true. I remember it always being about data loss.
- dist-epoch 2y ago
  Older hard-drives didn't automatically park the head on power loss, leaving it in a dangerous position above the platters. Any shock would smack it into the platters.
  - SoftTalker 2y ago
    My first hard drive came with a utility program to park the heads. Was recommended to run it before powering off
    - _carbyau_ 2y ago
      We had an Apricot that I had to type "park" on before turning off.
    - BugsJustFindMe 2y ago
      Huh, now that you mention it, I do think I remember something like that now. Thanks for joggin the noggin.
  - smitelli 2y ago
    That was only for drives with servo-actuated head arms. Think like what the old black-and-white Macs came with. You could tell one of those drives because it sounded like somebody revving a cordless screwdriver when it was being accessed. The quiet clicking-type drives use a magnetic voice coil-type actuator, and the loss of power causes them to want to spring back to the park position.
deleted 2y ago
[deleted]
Ekaros 2y ago
I think it could be harm to components when you are writing in their non-volatile memory. Namely at least motherboard and GPU. Both often have flashable memory for BIOS/UEFI and VBIOS(for GPU). Interrupting power at wrong time when these are being written could result in non-functional components. Some models do offer dual-bios which lowers the risk.
rzzzt 2y ago
SSDs without a capacitor bank that keeps the lights on for a bit more time after poweroff can leave their internal data structures (flash translation layer) in an inconsistent state. The effect ranges from nothing to data loss to bricking.
advisedwang 2y ago
It was less about physical damage, and more about leaving the system in a state that couldn't boot up. In particular, incomplete writes leading to corruption of the windows registry was a frequent problem.
Syonyk 2y ago
Yes, in some cases. The common case for this would be writing the flash chip ("Updating the BIOS"). Some boards are more cautious about this than others, and a lot of "enthusiast" (overclocker) boards have dual BIOS chips, so you can always swap to a working one and then reflash the corrupted one. But very few modern systems will tolerate a power cut in the middle of a firmware update very well, and even if it does, it's often in a "Well, now, create this particular USB stick with exactly this filename on a FAT16 partition, boot it with it plugged into this particular USB port, and it might recover things" sort of method. You'll notice most laptops refuse to update their firmware without the battery reasonably fully charged, and the power adapter plugged in. This is why. And then we get into the definition of "irreversible." Yes, you can recover from this with an external SPI flasher, if you can get the firmware image into the proper state for the SPI flash, or have an image from before. But most people don't have this option. As for hard drives, I'm of the impression that most newer drives will handle a power cut by using the inertia left in the platters and the motor-as-generator long enough to drive the heads back to a safe position, but I've not done any sort of in depth experimentation on it. A drive with a parking ramp for the heads (or a parking track) has those things for a reason, and "scraping the coating as the drive spins up somewhere in the data section" isn't good for drive longevity.
- jmholla 2y ago
  > But very few modern systems will tolerate a power cut in the middle of a firmware update very well, and even if it does, it's often in a "Well, now, create this particular USB stick with exactly this filename on a FAT16 partition, boot it with it plugged into this particular USB port, and it might recover things" sort of method. I recently did this with one of my Thinkpads, doing it during a battery firmware update among others. I wasn't successful in finding such a solution though. Where have you had success in finding some of the more obscure repair techniques?
  - Syonyk 2y ago
    It'll usually be listed in the BIOS upgrade guide. I've only ever seen the "weird recovery methods" on more performance-oriented mainboards - your RGB-heavy "gamer" boards tend to have some sort of recovery method. I don't know of any major OEMs who have such a thing. For a Thinkpad, though, I would wager good money that someone has directions out there for how to do it with a SPI flash clip - BIOS modding Thinkpads is pretty common, and most of the more intensive mods can't be done without an external writer.
jowea 2y ago
I think you can have problems today if you have a power failure mid motherboard firmware/BIOS/UEFI upgrade. Some mobos I heard have some protection or some way to unbrick it but it could be dangerous. And it was a real danger before for the running sofware system, I think modern filesystems are more resilient against this sort of problem. Never heard of actual physical damage though, but I didn't live that era much, can just barely remember the screen in TFA.
int_19h 2y ago
In the 90s (i.e. when Windows first got this splash screen), there was no concern with physical damage - after all, in DOS, just turning it off while at the C:\> prompt was the normal procedure. But the filesystems normally used on PCs at the time didn't have journalling or other mechanisms to prevent metadata damage if the power was turned off in the middle of a metadata update, which made data loss that much more likely even for blocks that were already written.
hulitu 2y ago
> I.e. if you yanked the power cord at some specific time, the system would take irreversible damage? If you do it one time, no. But, I wouldn't try it too many times. (do you know Windows 10 has "online checkdisk" - and doesn't work. Ask me how i found out)

by xg15 2y ago

BugsJustFindMe 2y ago

> But for old PCs, the warning was always that it could also physically damage the PC I don't remember this being true. I remember it always being about data loss.

dist-epoch 2y ago
Older hard-drives didn't automatically park the head on power loss, leaving it in a dangerous position above the platters. Any shock would smack it into the platters.
- SoftTalker 2y ago
  My first hard drive came with a utility program to park the heads. Was recommended to run it before powering off
  - _carbyau_ 2y ago
    We had an Apricot that I had to type "park" on before turning off.
  - BugsJustFindMe 2y ago
    Huh, now that you mention it, I do think I remember something like that now. Thanks for joggin the noggin.
- smitelli 2y ago
  That was only for drives with servo-actuated head arms. Think like what the old black-and-white Macs came with. You could tell one of those drives because it sounded like somebody revving a cordless screwdriver when it was being accessed. The quiet clicking-type drives use a magnetic voice coil-type actuator, and the loss of power causes them to want to spring back to the park position.

deleted 2y ago

[deleted]

Ekaros 2y ago

I think it could be harm to components when you are writing in their non-volatile memory. Namely at least motherboard and GPU. Both often have flashable memory for BIOS/UEFI and VBIOS(for GPU). Interrupting power at wrong time when these are being written could result in non-functional components. Some models do offer dual-bios which lowers the risk.

rzzzt 2y ago

SSDs without a capacitor bank that keeps the lights on for a bit more time after poweroff can leave their internal data structures (flash translation layer) in an inconsistent state. The effect ranges from nothing to data loss to bricking.

advisedwang 2y ago

It was less about physical damage, and more about leaving the system in a state that couldn't boot up. In particular, incomplete writes leading to corruption of the windows registry was a frequent problem.

Syonyk 2y ago

Yes, in some cases. The common case for this would be writing the flash chip ("Updating the BIOS"). Some boards are more cautious about this than others, and a lot of "enthusiast" (overclocker) boards have dual BIOS chips, so you can always swap to a working one and then reflash the corrupted one. But very few modern systems will tolerate a power cut in the middle of a firmware update very well, and even if it does, it's often in a "Well, now, create this particular USB stick with exactly this filename on a FAT16 partition, boot it with it plugged into this particular USB port, and it might recover things" sort of method. You'll notice most laptops refuse to update their firmware without the battery reasonably fully charged, and the power adapter plugged in. This is why. And then we get into the definition of "irreversible." Yes, you can recover from this with an external SPI flasher, if you can get the firmware image into the proper state for the SPI flash, or have an image from before. But most people don't have this option. As for hard drives, I'm of the impression that most newer drives will handle a power cut by using the inertia left in the platters and the motor-as-generator long enough to drive the heads back to a safe position, but I've not done any sort of in depth experimentation on it. A drive with a parking ramp for the heads (or a parking track) has those things for a reason, and "scraping the coating as the drive spins up somewhere in the data section" isn't good for drive longevity.

jmholla 2y ago
> But very few modern systems will tolerate a power cut in the middle of a firmware update very well, and even if it does, it's often in a "Well, now, create this particular USB stick with exactly this filename on a FAT16 partition, boot it with it plugged into this particular USB port, and it might recover things" sort of method. I recently did this with one of my Thinkpads, doing it during a battery firmware update among others. I wasn't successful in finding such a solution though. Where have you had success in finding some of the more obscure repair techniques?
- Syonyk 2y ago
  It'll usually be listed in the BIOS upgrade guide. I've only ever seen the "weird recovery methods" on more performance-oriented mainboards - your RGB-heavy "gamer" boards tend to have some sort of recovery method. I don't know of any major OEMs who have such a thing. For a Thinkpad, though, I would wager good money that someone has directions out there for how to do it with a SPI flash clip - BIOS modding Thinkpads is pretty common, and most of the more intensive mods can't be done without an external writer.

jowea 2y ago

I think you can have problems today if you have a power failure mid motherboard firmware/BIOS/UEFI upgrade. Some mobos I heard have some protection or some way to unbrick it but it could be dangerous. And it was a real danger before for the running sofware system, I think modern filesystems are more resilient against this sort of problem. Never heard of actual physical damage though, but I didn't live that era much, can just barely remember the screen in TFA.

int_19h 2y ago

In the 90s (i.e. when Windows first got this splash screen), there was no concern with physical damage - after all, in DOS, just turning it off while at the C:\> prompt was the normal procedure. But the filesystems normally used on PCs at the time didn't have journalling or other mechanisms to prevent metadata damage if the power was turned off in the middle of a metadata update, which made data loss that much more likely even for blocks that were already written.

hulitu 2y ago

> I.e. if you yanked the power cord at some specific time, the system would take irreversible damage? If you do it one time, no. But, I wouldn't try it too many times. (do you know Windows 10 has "online checkdisk" - and doesn't work. Ask me how i found out)