spooky coincidence or disk killer virus?

[Roger Heflin]

Alan Cox wrote:
>> Is this just a sign of superb quality control in the samsung
>> disk factories turning out identical disks that last almost
>> the exact same amount of time in the same CPU case with the
>> same number of power cycles?
> 
> I gad a very similar thing happen with IBM disks and a raid 1 array. That
> near miss taught me a lesson about mixing drives in a raid array.
> 
>> Or is there some spooky virus around that can actually destroy
>> the electronics in disk drives (both disks appear to be so dead
>> they can't even be recognized as disk drives by the BIOS).
> 
> In theory some drives can be firmware flashed and destroyed.   In practice
> there are several more likely things I can think of as well as
> the identical disks case:
> 
> - Power problems
> - Exposure to strong magnetic fields (the firmware is mostly stored on
> disk so if you trash the disk in a big magnetic field it may not register
> in future..)

I would not count on any magnetic field anyone reasonably comes in contact
with doing much of anything to a disk.   The disks already have some of the
most powerful permanent magnets inside of the disk case within < an inch of
the disk.   And degaussing a disk is almost impossible to do by accident,
and in fact it takes a pretty expensive machine to do a proper job of it
(>$100k US).   I know a few years ago somewhere I worked tried to degauss
some 8mm tapes and did not have any luck with any of the handheld degaussers,
all of the tapes still read just fine, and the current disk material is
rated to require close to 10x the magnetic field strength of those tapes, so
are even harder to mess up.

> - Nearby lightning strike damaging electroncis.

That would be more likely, I had one of my users take a machine overseas
(US 110V machine, not an auto voltage power supply) and someone got the
correct local cord and plugged it in without moving the switch to 220.
That took out the PS, one of the 2 hard disks, and a few other things,
with just a bit more voltage it would have likely gotten everything...

> 
> Or it could just be chance....
> 

That is very possible if both disks came from the same batch, I have
seen what good process control does when there was a underlying process
problem that no one knew about...

Usually when I have lost a large portion (or all) of a single lot it
has been a spin-up failure (I assume bad lube, or bad bearings, or a
bad motor, or ???), and they all tend to fail pretty consistently and usually
the ones that have not failed yet consistently fail on the next reboot or power 
up of any machines with that same disks model in them.

                                  Roger