The Basics

Hard Drives are technically Hard –Disc Drives. The term Hard comes from the need to distinguish them from floppy discs that were commonly used. The word drive is not really technical correct because a drive refers to a mechanism which ‘drives’ removable media, such as a tape player or floppy disk drive. A hard drive, contrary to its name contains fixed (non-removable) media, and were initially actually called ‘Fixed Disks’.

Hard disks have a hard plate that holds the magnetic material, rather than the flexible plastic film found in floppies and tapes. They were first used in the 1950s and started as large disks up to 20 inches in diameter holding only a few megabytes.

The way the hard drive essentially works similar to a cassette, using a magnetic recording system. Data is written onto each disk surface (top and bottom) by a separate recording head.

Did you Know …?

The key point and value of magnetic storage is that it is a more permanent means of storage and gives computers the invaluable ability to be easily erased and rewritten, and it will record desired data once the computer is switched off.

There are certain attributes of Hard disks which are used to categorize them

•                    Physical size which is quoted in inches. Almost all hard disks today are of either the 3.5" or 2.5" varieties, used in desktops and laptops, respectively. 2.5" disks         are usually slower and have less capacity, but use less power and are more tolerant of movement.

•                    Capacity, which is now usually quoted in gigabytes. (older hard disks used to quote their smaller capacities in megabytes)

•                    Data rate, measured in bytes per second that the drive can deliver to the CPU. 5 to 40 megabytes per second are commonly observed.

•                     Rotational delay is the time required for the addressed area of the disk to rotate into a position    where it is accessible by the read/write head. Maximum rotational delay is   the time it takes to do a full rotation (as the relevant part of the disk may have just passed the head when the request arrived). Most rotating storage devices rotate at a constant angular rate (constant number of revolutions per second). The maximum rotational delay is simply the reciprocal of the rotational speed. 7200 revolutions per minute is typical for a hard disk drive; its maximum rotational delay will be 60/7200 s or about 8 ms.

 We offer various sized hard disks from 40 – 200 GB with speeds ranging from 5400 rpm to 7200 rpm. Our hard disks come with a three year manufacturer’s warranty.