Saturday, February 24, 2024

Drive Failures - Data Recovery with Open-Source Tools (part 2)

This is part 2 of a multi-part series.  See part 1 for the beginning of the series.

Note that this is material from 2010 and earlier that pre-dates the common availability of solid state drives.

Detecting failures

Mechanical failures

Mechanical drive failure is nearly always accompanied by some sort of audible noise.  One common sound heard from failing hard drives is the so-called "Click of Death", a sound similar to a watch ticking (but much louder).  This can have various causes, but it is commonly caused by the read/write head inside a drive being stuck or possibly trying to repeatedly read a failing block.

Another common noise is a very high-pitched whine.  This is caused by bearings in a drive failing (most likely rubbing metal-on-metal), usually as a result of old age.  Anything that moves inside a computer (fans, for example) can make a noise like this, so always check a suspect drive away from other sources of noise to verify that the sound is indeed coming from the drive.

Drive motors failing and head crashes can cause other distinctive noises.  As a rule, any noise coming from a hard drive that does not seem normal is probably an indicator of imminent failure.

Electronic failures

Failing electronics can cause a drive to act flaky, not detect, and occasionally catch fire.

Hard drives have electronics on the inside of the drive which are inaccessible without destroying the drive (unless you happen to have a clean room).  Unfortunately, if those fail, there isn't much you can do.

The external electronics on a hard drive are usually a small circuit board that contains the interface connector and is held onto the drive with a few screws.  In many cases, multiple versions of a drive (IDE, SATA, SCSI, SAS, etc.) exist with different controller interface boards.  Generally speaking, it is possible to transplant the external electronics from a good drive onto a drive with failing electronics in order to get data off the failing drive.  Usually the controller board will need to be off an identical drive with similar manufacturing dates.

Dealing with physical failures

In addition to drive electronics transplanting, just about any trick you've heard of (freezing, spinning, smacking, etc.) has probably worked for someone, sometime.  Whether any of these tricks work for you is a matter of trial and error.  Just be careful.

Freezing drives seem to be especially effective.  Unfortunately, as soon as a drive is operating, it will tend to heat up quickly, so some care needs to be taken to keep drives cool without letting them get wet from condensation.

Swapping electronics often works when faced with electronic failure, but only when the donor drive exactly matches the failed drive.

Freezing drives often helps in cases of crashed heads and electronic problems. Sometimes they will need help to stay cold (ice packs, freeze spray, etc.), but often once they start spinning, they'll stay spinning. Turning a drive on its side sometimes helps with physical problems as well.

Unfortunately, we do have to get a drive to spin for any software data recovery techniques to work.

To be continued in part 3.

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