Storage Devices Essay

1582 WordsNov 1, 20117 Pages
ASSIGNMENT#1 ICT PC-WAQAR AHMED BESE-17 A Submitted to: Lec. Bilal Rauf Storage Devices Hard disk(HDD) Hard Disk is a non-volatile, random access, magnetic storage device used in the computers. These were introduced by IBM in 1956. Main purpose of Hard Drive(HDD) is to store data. HDD stores data by the process of magnetic recording. Major Components * Cover * Platters * Head * Power Connector * IDE Connector * Jumper Block * Actuator * Spindle A typical HDD has two electric motors: * Disc motor that spins the discs. * Actuator that positions the read/write head on the disc. Magnetic Recording HDD stores data by magnetizing ferromagnetic materials directionally. The data are read from the disk by detecting the transitions in magnetization and decoding the originally written data. There are different encoding processes, such as: * Modified Frequency Modulation * Group Code Recording * Run-length Limited Encoding A Cobalt based alloy is used as magnetizing material. HDD consists of a spindle which holds the platters. Platters are non-magnetic material and hold recorded data. Platters are usually made of aluminum glass or ceramics. The Platters are spun at very high speeds(15000RPM). Data is written to, and read from platter as it rotates past devices called read-write heads. Read write heads operate very close over the magnetic surface. It detects and modifies the magnetic material under it. Data is stored on this magnetic material i-e disc. The image gives microscopic view of platters. Capacity Storage capacity of HDD is increasing day by day. Nowadays HDDs have a storage capacity of more than 1000 GB = 1 Terabyte. External Hard Drives External HDDs can be detached from computers and can operate as USBs. They work same as ordinary hard

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