[rgj]

My anecdote:

Around 1993 I had a Commodore Amiga with an A590 external hard drive. A big enclosure that could be connected to the expansion port on the left of an Amiga 500, containing a very precious 20MB hard disk.

One day, it stopped working. I tried everything but I couldn’t get it to work. A friend offered to take a look at it so I put it in my backpack and took the train to my friend. When connected to his A500, the drive worked lime a charm.

When I drove back home in the train I wondered what would be the matter with my A500 since it apparently made my A590 hard drive fail.

However, once I got home and reconnected the drive, it worked. No problem whatsoever.

Until two days later. It failed. You know what’s going to happen, right? Took it to my friend, it worked, took it back and it worked for two more days.

Turns out that disconnecting it, putting it in my bag, walking it around for a while worked just as well.

Turns out that disconnecting it, dropping it from 5cm / 2 inches and reconnecting it, worked just as well.

Which was what I did for the next four years or so. Whenever it stopped working, I disconnected it, dropped it and reconnected it.

Always loved the look on the face of people who witnessed me starting up my Amiga.

[ChuckMcM]

FWIW the failure mode (which was also common in drives for the SPARCStation at the time) was called "stiction." That occurred when the drive parked the heads, after power down, into the landing zone on the platter.

At Sun we took apart a number of failed drives (which could also be recovered sometimes by giving them a sharp twist) and hunted for the root cause. The answer was that over some time the drive heads became smoother and the surface of the landing zone also became smoother. When the tiny edges of the head had been removed by this process, the surface of the head was pretty much optically smooth (very little variation) and when it landed in a part of the landing zone that was similarly smooth the surfaces would push out the air between them and become stuck just by air pressure and surface friction (stiction). The drive would not spin up until the head had lifted off the surface. The firmware issue was that head lift off was checked for so quickly that the power up of the spindle was aborted before anything happened (this was to prevent damage to the head by dragging it along the platter's landing zone). By jostling the drive you could manually cause the platters to rotate and if you found a spot that wasn't completely smooth (or if you managed to have the heads move out of the landing zone) the surface would be rough enough that the head wasn't being held down and it could lift off again.

Seagate gave us a firmware fix which basically waited longer for the heads to lift off allowing the spindle motor to move the platter a bit before giving up. Quantum (the other disk supplier) beefed up the retract solenoid and gave us firmware that would try 'regular' retract and then 'heavy' retract before giving up. For a pretty long time I had a Seagate drive that had been disassembled to the point of exposing the heads and platters so that the effect could be demonstrated to skeptical engineers.

[foobarian]

An IBM tech told me how they sometimes resuscitated drives that wouldn't come up after power cycling. They would spin the drive on the floor for a few seconds and then quickly hooked it back up before the platters stopped moving.

[joshu]

see also: gage block wringing

[trollied]

Enjoyed your story, thank you!

[netsharc]

Might as well share mine: one day the magic smoke[0] left a lot of components on my PC, including the HD with no backups. I saw the board was replacable, so that's what I did: bought an identical disk on eBay, some torx screwdrivers, transplated the good board to the dead disk, and it worked perfectly fine.

[0] http://www.catb.org/jargon/html/M/magic-smoke.html

[hinkley]

I've heard tell that some data recovery companies have a stable of the controller cards from popular drive models. If swapping the card works, you get your data cheap. Beyond that it gets spendy.

[jaclaz]

Only for the record until soome 15 years ago, exchanging boards was easy, later disk PCB's contrain some "adaptive" data into a (soldered) EPROM (or Flash/whatever, anyway a memory chip), so now you have to de-solder the chip from the old board and re-solfer it on the new one.

There are dedicated hardwares+softwares (as an example the "PC-3000") that are capable of re-programming the chip on the new board with data extracted from the chip on the old board or to re-program them anew, but they are very pricey and only data recovery companies can afford them and the connected training/resources.

So:

1) simple card swapping won't work on any disk manufactured since (roughly) 2005 (possibly even earlier)

2) card swapping can still be made BUT you need to "migrate" the chip from the old board, it is usually an 8-pin SMD so it is doable at home, but not exactly easy-peasy if you are not familiar and experienced in dde-soldering and soldering

[londons_explore]

Nearly all drive failures today are either control electronics or bearings.

Control electronics can be replaced. Bearings can be overcome with a higher motor drive current.

Some drives have crypto keys stored in flash - those are harder to fix.

[Stratoscope]

You were lucky that it was only the magic smoke that escaped, and not the pixie dust on the platters.

https://www.google.com/search?q=hard+drive+pixie+dust

[jacobush]

The manual (or some kind of leaflet with it) of the MFM 10 megabyte drive of an IBM XT even mentioned, that the drive could seize up if the bolts were too tightly or unevenly tightened. Sure enough, I had to adjust them one fine day.

[michaelcampbell]

"sticktion" was an issue with some early Mac drives.

[bradknowles]

In 1989, I did an internship with Imprimis, which was later sold to Seagate.

I worked in the Manufacturing Engineering group, and specifically with the Engineers behind the “Wren” line of hard drives. IIRC, up to the Wren V, they had problems with the lubricant sometimes overheating and leaking out of the spindle onto the platters. When the hard drive spun down, the heads would be glued to the media by the lubricant, thus resulting in stiction.

They developed a “thermalwriter“ test process for the drives to put them through heat conditions way beyond what they might experience in the field, and then developed lubricants that could withstand the heat. They were very proud of this process. But there were still lots of old drives out there.

One of the things the clean room would sometimes do is take hard drives from important clients and try to recover them. I saw a lot of nasty failures, many of which were a result of inappropriate techniques being applied to try to temporarily free the heads.

There was a lot of FUD at the time on what would later be called “The Internet”, so one of my first contributions to the community was to take the knowledge of the engineers at the company and developed a FAQ that I posted to the various USENET newsgroups, on the right — and wrong — ways to try to address this issue in the field.

Sometimes I wonder if that FAQ ever survived.

[tartoran]

This reminds me of my first pc, an Amstrad with a whooping 20Mb drive and 5.25 diskette bay. I had so much software on that machine, 20 megabites seemed more than enough at the time. I was a kid at the time and was getting all kinda of shareware games and eventually a virus completely distroyed the harddrive. Some expert did a low level formatting that took overnight and some but to no avail, the virus’s damage couldn’t be undone.

Fun fact: that amstard pc had a pair of AA batteries to keep the cmos powered up and they fit right on top of the box, right where the monitor fit snugly.