Why Hard Disks Dominate?
By: James Walsh

Hard Disks

Hard Disk drives are commonly referred to as hard drives or hard disk. These are non-volatile and store digitally encrypted data. The data is stored on platters, which rotate rapidly. These platters have magnetic surfaces. In the given context, the word ‘drive’ is meant for devices that are distinctively apart from their medium. Today’s hard disk drives are sealed units, which have a fixed media. This was not the case in early hard disk drives where the media was removable.

The hard disk drives were originally developed for usage in computers. However today, the hard disk technology is used in numerous gadgets such as digital video recorders, digital cameras, and consoles of video games, digital audio players and even mobile phones. The growing needs of various industries led to the development of RAID (redundant array of independent drives), NAS (network attached storage) and SAN (storage area network).

Hard disk drives were not a common feature before 1980, and yet it was not before mid-1990s that they became common place on market shelves. Their capacities are quoted in megabytes or gigabytes. The physical attributes / sizes of a hard disk drive are quoted in inches. These days, 3.5-inch wide hard disk drives are used in most desktop personal computers.

Working Mechanism

The hard disk drives have a spindle system that relies on air pressure within the enclosed casing. When the disk rotates, the air pressure supports the head at an appropriate flying height. For the provision of air pressure, there are small holes in the casing of the hard disk drives, which usually have carbon filters within them.

If the air pressure is too low, then it will not be able to support the flying head which, in turn, may come too close to the disk, and a head crash may take place. This can destroy data. For high altitude operations, barring aeroplanes, there are specially sealed and pressurised disks. In case of hard disk drives using CSS technology, increase in humidity can lead to a head crash.

There is very close spacing between the heads and the disk surface. Thus, any contamination that may take place in either the disk heads or the platters can also be the cause of a head crash. In this case, the head will scrape across the surface of the platters and destroy the thin magnetic film.

The electronics of the hard disks control not only the actuator but also the rotation of the disk. They also perform read and write functions when decided by the disk controller. Most of the modern-day hard disk manufacturers provide S.M.A.R.T. technology which can inform of an impeding failure in advance.

Domination by Hard Disks

Hard disks are the dominant media used in the computer industry. There are several reasons for the continuous domination by the hard disks. Not only are hard disks very small so that they can be easily assigned to a small space but they have also comparatively very high data-carrying capacities. Made of strong metals, they have a sealed casing to avoid particulate pollution.

Not only are hard disks delicate machines within very strong casing, they also offer random access to the data. As the platters rotate at a very high speed the actuator arm can be placed over any part of the recording surface for reading / writing. This speed to access data is the biggest plus point of the hard disk drives.

In the case of tape drives, they offer sequential access, not random, as in the case of hard disk drives. Therefore, they are not able to keep pace with the speed at which the operating system is functioning. In their case the whole tape has to move in front of the magnetic head before access to any file is gained.

Besides this, the high access speed offered by hard disk drives is unmatchable by other media storage devices. The easily available hard disk drives offer anywhere between 5400 to 7200 revolutions per minute. Other storage media does not provide this kind of speed in performance.

Over and above other features is one of reliability. The hard disk drives have a life span of at least five years. To top it all mass production has brought down the cost of hard disk drives so greatly that they are easily within the reach of the common man.

These are some of the reasons for the continued domination by the hard disk drives.

Article Source: http://www.ArticleJoe.com

James Walsh is a freelance writer and copy editor. If you are concerned about data loss and would like more information on www.fields-data-recovery.co.uk“>Data Recovery see www.fields-data-recovery.co.uk

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