Hard disks differ from virtually every other component in the PC in one very critical
respect: when you lose a hard disk you lose more than just hardware--you lose software and
data as well. The hard disk can be replaced, but the data on it often cannot (and it
certainly isn't covered by your warranty). This is why annoying people like me always harp
on users to back up their data.
If for some reason you fail to heed my sage advice 
and do not back up your
important data, it is still sometimes possible to recover it in the event of a hard disk
failure. There are data recovery services that specialize in restoring lost data from hard
disks that have either failed or been corrupted due to software problems (accidental
formatting, viruses, etc.)
Some of these services are pretty amazing--many of them have a very good success rate
and can resurrect data even when it seems like it would be impossible to the casual
observer. They use specialized equipment and software, and typically even have mini clean
rooms that enable them to take the cover off the drive and access the platters directly.
All this wizardry comes at a cost, of course. A full recovery usually starts at a
few hundred dollars and proceeds from there. The cost is high for three reasons: the
equipment is expensive, the people are highly skilled, and the company knows how valuable
the data is or you wouldn't be talking to them. Compared to recreating a year's worth of
data, $2,000 for a recovery is a bargain. Compared to doing routine backups, it's a
colossal waste of money.
One company well-known for performing data recovery is Ontrack.
|
This graph shows the most common causes of data loss
requiring the use of data recovery services, based on actual
Ontrack recoveries in the 1995-1996 timeframe. |
Note: The use of RAID arrays will reduce the likelihood that data recovery
will be required, but can complicated matters if for some reason it is required.
For information on the implications of RAID on data recovery, see this section.
Note: Even though drives
have labels and stickers on them saying that if the drive is opened the warranty will be
voided, this does not apply to professional data recovery. These companies have
arrangements with the major hard disk manufacturers to allow them to work on the drives
without affecting the drive's warranty status. In some cases the recovery company may be
required to send a letter to the drive manufacturer certifying that your particular drive
had recovery performed upon it.
Next: Redundant
Arrays of Inexpensive Disks (RAID)
