Production Glossary
Hard Disk Drive
A hard disk drive, sometimes called a hard drive, is a storage mechanism that holds digital information. Hard disk drives were pioneered in 1956 for storing data in an IBM accounting computer. As time passed, hard disk drives were translated into general storage for personal computers. In the 1980s they were considered uncommon and pricey features for home PCs, but it did not take long for the hard drive disk to become fundamental in the make up of a computer.A hard drive’s technology for storing data is very akin to the technology of video and cassette tapes. Instead of tape, hard drives store data on circular platters that are coated with a magnetic recording substance. These platters are typically made out of glass or aluminum. When a computer is turned on, the hard drive platters begin spin around a spindle. The rotation of the platters can get up to 5,400 rpm on a laptop and 7,200 rpm on a desktop. The data that is written on the magnetic platters is accessed by “read-and-write heads”. These heads are located over the magnetic surface at an extremely close range. An arm holds the individual heads for each spinning platter. Another arm, called an actuator, glides the heads in an arc pattern over the platters as the rotate. This ensures that the whole surface of a platter is accessed as it continues to spin. The read-and-write heads are held over the platter by a stream of air that moves at the same speed as the platter itself.
In a hard disk drive, the safety of information stored is important. In order to remain intact, any recorded material must avoid self-demagnetization, or the repelling of magnetic domains. If a magnetic domain is written in close proximity to a fragile element that is magnetized, the recorded material will become corrupt over time.
