Head crash

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A crash head is a hard-disk failure that occurs when the read-write head of the hard disk drive is in contact with the rotating disk, which results in permanent damage and is usually not fixed on the magnetic media on the platter surface. This is most often caused by sudden hard disk movements, such as jolts caused by dropping the laptop to the ground while it is operating or physically shocking the computer.

Video Head crash

Detail kepala

A head usually drives a thin film of moving air trapped on the surface of its plate (some drives from the mid-1990s use a thin liquid layer instead). The distance between the head and the plate is called the flying height. The top layer of the plate is made of a material like Teflon that acts like a lubricant. Underneath was a sputtered carbon layer. These two layers protect the magnetic layer (data storage area) from the most unintentional touch of the read-write head.

The disk read-and-write head is made using a thin film technique that includes materials hard enough to scratch the protective layer. Head crashes can be initiated by forces that provide sufficient pressure on the disk from the head to scratch onto the magnetic storage layer. Small particles of dirt or other detritus, excessive shock or vibration (such as accidentally dropping a running drive), can cause the head to bounce off the disk, destroy a thin magnetic layer in the head area in contact with, and often damage the head in the process. After this initial accident, innumerable fine particles from damaged areas can land to other areas and can cause more head damage as the head moves above the particles, rapidly causing significant damage and loss of data, and making the drive useless. Some modern hard disks incorporate free fall sensors to offer protection against head crashes caused by accidentally dropping the drive.

Maps Head crash

Differences in RPM

Since most modern drives spin at levels between 5,400 and 15,000 RPM, damage caused by magnetic layers can become widespread. At 7,200 RPM, the tip of the plate runs at more than 120 kilometers per hour (75 mph), and when the falling head drags the plate surface, the read-write head is generally too hot, making the drive or at least part of it unusable until the head cools.

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The old head

Older drives usually play much slower and have larger heads flying higher above the medium surface. However, because in many cases, the media is placed in a removable cartridge or pack and because the air filtering is relatively rough, the crashes are quite frequent and always expensive.

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Laptop

Head crashes are a common problem on laptop computers, as they are subject to sudden movement. This leads to technological developments that detect sudden movements and take evasive actions (eg by parking heads), sometimes known as active hard-drive protection or "sudden motion sensing." In a very old laptop design, the hard disk drive head becomes stuck if the laptop loses power, leaving the disk head in a state of no parking and potentially leading to scaling the drive if the laptop is moved. This is now an unusual problem, as modern hard disk drives are designed to be easily carried in the 'self-park' mind in the event of a power failure. Where such events occur in laptops built since 2000, most likely the hard disk controllers inside the drive have failed.

src: upload.wikimedia.org

See also

• Active hard-drive protection
• Click on death

src: www.headcrash-hamburg.com

External links

src: i.ytimg.com

References

Source of the article : Wikipedia