What Does a ‘hard Disk Crash’ Really Mean?
The data residing on hard drives can be categorised into two types. The first is the operating system and various software programmes which usually reside together on a single partition. The operating system harnesses the power of the silicon processor and runs the programmes as desired by the user. The other type of data comprises the actual files that are worked upon by the user.
How a Hard Disk Works
A hard disk looks like a small metal box no bigger than a man’s palm. Inside is a vertical stack of metal or glass platters which is mounted on a spindle motor. The platters are coated with a thin layer of magnetic paint which constitutes the actual data-recording surface. The data on the platters is written and accessed by a read / write head that is mounted at the end of a long actuator arm.
The head is actually an electromagnet that creates or modifies magnetic imprints on the platters. These imprints are then interpreted by the operating system as digital data. The platters have an under side and a top side. Both these sides carry data, with a separate head for each. Thus a hard disk that has four platters would be having eight different heads.
Hard disks have very high capacities. The commonly available ones are capable of storing up to 240 GB of data. Though having many sophisticated and precision parts inside, hard disks are designed to last for years altogether without giving any problem to the user.
Hard Disk Crash
Hard disk crash is the most dreaded situation for any computer user. It leads to complete data loss. The computer just refuses to boot up or gives error messages – the so-called “blue screen of death.” When the hard disk is switched on, the data-carrying platters begin to be spun rapidly by the spindle motor at a speed of 5,400 or 7,200 revolutions per minute (RPM), though there are some hard drives which spin at a staggering 15,000 RPM.
When the platters have picked up enough speed during the booting-up process, the actuator arm moves over them. The head stays afloat a sub-micron-level above the platters due to the air currents generated by the wildly spinning platters. The head then goes about doing its business of reading and writing data all over the platters following the commands of the operating system.
The vertical distance between the read / write head and the spinning platters is miniscule. When a dust particle or any other microscopic contaminant gets wedged between them, the head gets jammed and is unable to move. It scratches the data-recording surface as the platters continue to spin. This is called a head crash.
The head makes contact with the platters in a head crash and damages the data permanently by furrowing the recording surface. That is why it is advised to shut off the computer immediately the moment a head crash is suspected. A scratching sound coming from the hard disk is a strong indication that the head of the drive has failed or it is bouncing off the platters.
When a hard disk crashes, there is nothing much the user can do because the DIY recovery software is useless in this case. The only solution is to immediately contact a professional data recovery company for urgent repairs. The company engineers would take the disk to their clean room which has its air totally cleaned of all dust particles and other contaminants by powerful filters.
The disk is disassembled and repairs carried out. If the disk platters have been damaged, then all possible data files are extracted using special equipment and copied onto another media (usually a CD or DVD) which is then handed over to the customer.
Professional data recovery is quite an expensive affair. It requires a lot of meticulous lab work over several hours or days by trained professionals. To escape the consequences of a head crash, the easiest way is to keep a regular backup of all your important files that are residing on the hard disk.
There are many types of data storage media available today. Optical disks such as CDs and DVDs as well as USB drives are sufficient for most individual users. For those who churn out a large number of data daily, there are portable hard disks which make taking backups a breeze because they come with automatic data-backup software.
James Walsh is a freelance writer and copy editor. If you are concerned about data loss and would like more information on Data Recovery see http://www.fields-data-recovery.co.uk
Article Source: ArticlesBase.com - What Does a ‘hard Disk Crash’ Really Mean?