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An old IBM tech told me that hard drives failed when power cycling equipment could be temporarily resuscitated by placing the drive on the floor, twisting it ha

An old IBM tech told me that hard drives failed when power cycling equipment could be temporarily resuscitated by placing the drive on the floor, twisting it hard by hand, then as quickly as possible connecting it back into the machine and powering on. Apparently getting the platters to spin helped them get around a worn out motor that couldn't make the initial spin-up.

bayindirh 3y ago
I would believe them. I have heard a similar story. A data center had to go through a planned power cycle event. All systems were working when they shut down, but ~40% of the disks failed to spin up due to worn down motors. That's a lot of disks.
- vbezhenar 3y ago
  What’s a procedure to avoid it? Reboot machine once a week so disks fail not all at once?
wrycoder 3y ago
Gotta know which way to twist it.
tristor 3y ago
Yes, stiction is a real issue in old hard drives. In fact something that used to work well if you were cold booting an old server even in the mid 90s, with the expectations of an immediate migration, was giving the drives a good sharp slap to help break stiction so they could spin up. The only issue is it could cause a head crash. Another fun trick from back in the day was sticking hard drives in the freezer to cause the platters to shrink enough to dislodge the head and restore the air gap if you had a head crash so you could try to recover the data. As much as I love hardware, I much prefer our current solid state wonderland.
- justsomehnguy 3y ago
  > to shrink enough to dislodge the head and restore the air gap Huh? What I heard is what a cold drive would be a bit more magnetically stable and IMMSMV that surely worked, because I never had a drive with a stuck heads but I did had drives what would just abort the read or return gibberish, but after an hour in the freezer they would read just fine, till they heat up again. That's for the drives mfg after 2000, if that matters.
  - tristor 3y ago
    My understanding may be incorrect, after all the freezing the drives trick is mostly something that was shared among sysadmins like an old wive's tale. Nonetheless, it does work (or did). The way I had always understood it was that if you had a head crash (which was caused by the head physically contacting the platter, overcoming the resistance of the air gap between the head and platter, usually due to physical impact) that the magnetism of the head would prevent it from lifting back up on its own, and that freezing the drive would cause the metal in the platter to contract away from the head, which was restricted in movement by its armature, thereby restoring the air gap and lifting the head away. If you started the drive spinning before it heated, the head would stay out of contact and you could successfully read data (some of it, for awhile). That said, my understanding may be incorrect.
KMag 3y ago
I remember upgrading from a 4.3 GB HD to a 20 GB HD around 2001. I had the old hard drive sitting on my desk, and the new hard drive sitting in the case, both attached to the motherboard via IDE ribbon cables. Most of the way through backing up the 4.3 GB HD to the 20 GB HD, I heard a screech and the old hard drive twisted slightly on the desk... conservation of linear momentum. The drive was visible to the BIOS, but refused to spin up after that. I put the hard drive in a ziplock bag, put it in the freezer to give the parts slightly more clearance from thermal contraction, and slammed the hard drive nice and hard on the desktop to free the stiction. That revived the drive long enough to finish my copy. I did have backups of all of the really important information, but restoring from a stack of floppies is more tedious, slower, and less fun than percussive maintenance on a hard drive. Back when I had an internship working on MEMS gyros for GPS guided mortar rounds, we had to sometimes perform similar percussive maintenance if static electricity had caused the moving parts to contact the substrate. We took the gyro, and smacked it hard on the desk in an "eyeballs out" orientation to give it something like 10 to 100 Gs of acceleration in an attempt to un-stick the MEMS gyro.
- SomeRndName11 3y ago
  Yeah, did same in 1999 or 2000, but we _did_ _not_ take the HDD from the freezer, just pulled the ribbon and power cable through the narrow slit between the door's rubber gasket and the fridge's body.
- KMag 3y ago
  Clearly, I meant conservation of rotational momentum, not conservation of linear momentum.

bayindirh 3y ago

I would believe them. I have heard a similar story. A data center had to go through a planned power cycle event. All systems were working when they shut down, but ~40% of the disks failed to spin up due to worn down motors. That's a lot of disks.

vbezhenar 3y ago
What’s a procedure to avoid it? Reboot machine once a week so disks fail not all at once?

wrycoder 3y ago

Gotta know which way to twist it.

tristor 3y ago

Yes, stiction is a real issue in old hard drives. In fact something that used to work well if you were cold booting an old server even in the mid 90s, with the expectations of an immediate migration, was giving the drives a good sharp slap to help break stiction so they could spin up. The only issue is it could cause a head crash. Another fun trick from back in the day was sticking hard drives in the freezer to cause the platters to shrink enough to dislodge the head and restore the air gap if you had a head crash so you could try to recover the data. As much as I love hardware, I much prefer our current solid state wonderland.

justsomehnguy 3y ago
> to shrink enough to dislodge the head and restore the air gap Huh? What I heard is what a cold drive would be a bit more magnetically stable and IMMSMV that surely worked, because I never had a drive with a stuck heads but I did had drives what would just abort the read or return gibberish, but after an hour in the freezer they would read just fine, till they heat up again. That's for the drives mfg after 2000, if that matters.
- tristor 3y ago
  My understanding may be incorrect, after all the freezing the drives trick is mostly something that was shared among sysadmins like an old wive's tale. Nonetheless, it does work (or did). The way I had always understood it was that if you had a head crash (which was caused by the head physically contacting the platter, overcoming the resistance of the air gap between the head and platter, usually due to physical impact) that the magnetism of the head would prevent it from lifting back up on its own, and that freezing the drive would cause the metal in the platter to contract away from the head, which was restricted in movement by its armature, thereby restoring the air gap and lifting the head away. If you started the drive spinning before it heated, the head would stay out of contact and you could successfully read data (some of it, for awhile). That said, my understanding may be incorrect.

KMag 3y ago

I remember upgrading from a 4.3 GB HD to a 20 GB HD around 2001. I had the old hard drive sitting on my desk, and the new hard drive sitting in the case, both attached to the motherboard via IDE ribbon cables. Most of the way through backing up the 4.3 GB HD to the 20 GB HD, I heard a screech and the old hard drive twisted slightly on the desk... conservation of linear momentum. The drive was visible to the BIOS, but refused to spin up after that. I put the hard drive in a ziplock bag, put it in the freezer to give the parts slightly more clearance from thermal contraction, and slammed the hard drive nice and hard on the desktop to free the stiction. That revived the drive long enough to finish my copy. I did have backups of all of the really important information, but restoring from a stack of floppies is more tedious, slower, and less fun than percussive maintenance on a hard drive. Back when I had an internship working on MEMS gyros for GPS guided mortar rounds, we had to sometimes perform similar percussive maintenance if static electricity had caused the moving parts to contact the substrate. We took the gyro, and smacked it hard on the desk in an "eyeballs out" orientation to give it something like 10 to 100 Gs of acceleration in an attempt to un-stick the MEMS gyro.

SomeRndName11 3y ago
Yeah, did same in 1999 or 2000, but we _did_ _not_ take the HDD from the freezer, just pulled the ribbon and power cable through the narrow slit between the door's rubber gasket and the fridge's body.
KMag 3y ago
Clearly, I meant conservation of rotational momentum, not conservation of linear momentum.