HEAD CRASH

What is head crash???

A serious disk drive malfunction. A head crash usually means that the head has scratched or burned the disk. In a hard disk drive, the head normally hovers a few microinches from the disk. If the head becomes misaligned or if dust particles come between it and the disk, it can touch the disk.

When this happens, you usually lose much of the data on the hard disk and will need to replace both the head and the disk. For this reason, it is important to operate disk drives, particularly hard disk drives, in as clean an environment as possible. Even smoke particles can cause a head crash.

A head crash in a modern drive. Note circular mark on the platter.

For more detailed information, you can go to http://en.wikipedia.org/wiki/Head_crash

http://en.wikipedia.org/wiki/Hard-disk_failure

A Hard Drive Crash Can Be Bad... Trying To Fix It Yourself Can Be Worse !!!

We rely on our computers more than ever, and when a hard drive crash occurs, years of data can be gone in the blink of an eye. In most cases the data is fully recoverable, but there are some common mistakes people make when attempting to do the job themselves.

If you experience a hard drive crash, it doesn't take much to make a bad situation even worse. In the event of a hard drive crash, in most instances, the data is completely recoverable at first. However, as part of human nature, we often try to avoid the high costs associated with hard drive data recovery in order to find some sort of "quick fix" to a very serious problem. In this report we will go over some of the symptoms of a hard drive crash and the things you can try in the event of a suspected hard drive crash, along with things you should avoid.

What Noise Is The Drive Making???

The first thing to take into account is whether or not the hard drive is making any unusual noises. Often times when there is a problem with the read/write head within the drive or a firmware issue in the logic board a "clicking" sound will be heard. If this is the case, then you should immediately power down the system and refrain from reapplying power. Same thing goes for any unusual sound, whether it's grinding, squealing, our sounds like a "laser gun". If any of these occur you should immediately power the system down, just pull the plug from the wall.

Unfortunately in the situations listed above, there is little that you can do to recover the data yourself. Actually, unless you have a clean room, fully equipped with the right tools and a trained technician there is nothing that can be done. Even hard drive manufacturers avoid this line of work, and many who do offer data recovery services are only sub-contracting the work out to an established data recovery firm.

Never Ever Open Your Hard Drive !!!
If the data on a hard drive has even the most minimal value to you, then it is imperative that you do not open the drive. Data recovery companies often get calls or e-mails from people who felt they had the right equipment and know-how to perform something as serious as a head replacement. Once they've removed the hard drive's protective case, more often than not, the damage is irreparable.

Working with the internal components of a hard drive requires at least a Class-100 clean room. A clean room does not mean a room that you just vacuumed and dusted (believe it or not people say that to us all the time). A clean room is a special work area in which air quality is heavily controlled and it is vital to hard drives during the manufacturing or assembly process.

The air in the room is regulated in term of air particles, temperature and humidity. A Class-100 clean room means there exists no more than 100 particles that are larger than 0.5 microns in one cubic foot of air. Opening a hard drive in air meeting anything less than the standard listed above will mean certain death for your hard drive and any data contained therein.

The Freezer Method

There has been a long running myth about putting your hard drive in the freezer when it crashes in order to revive it just long enough to pull your data off of it. ACS Data Recovery has run this test for fun on many occasions in different scenarios with junk test drives that they have in the lab.

So far they have yet to see this actually produce any positive results. In fact, in one instance they actually began to see the formation of tiny microscopic ice crystals on the platter themselves, which is a definite crash waiting to happen.
See the problem with this theory is, drives are not completely sealed.

Regardless of what you've heard or read, all hard drives have a tiny breather hole (usually marked with a label that says "do not cover"). This hole not only aids in cooling but it also helps to equalize air pressure in the drive when the platters are spinning. On the other side of this hole is a filter, which keeps dirt and debris from getting inside the drive.

However, this filter does not stop heavy amounts of moisture (especially in flood situations) or moisture vapor (such as found in a freezer). This moisture vapor has been known to settle on the platters and when a system is powered up, the read/write head would resemble an airplane flying into a mountain.

For more infomation, you can surf to tis website~ http://www.beststuff.com/computers/a-hard-drive-crash-can-be-bad-trying-to-fix-it-yourself-can-be-worse.html