Hard Disk Drive
An IBM hard disk drive with the metal cover removed. The platters are highly reflective. The orange color is not typical of modern drives, which are silvery. A screwdriver bit is placed into one of six screws that clamp the stack of platters and spacers. In the center, below the screws and clamping plate, is the motor that spins the platters.
Date Invented:	September 13, 1956
Invented By:	An IBM team led by Rey Johnson
Connects to: Host adapter (on PCs often integrated into motherboard) via one of PATA (IDE) interface SATA interface SAS interface SCSI interface (popular on servers) FC interface (almost exclusively found on servers)
Market Segments: Desktop Mobile Enterprise Consumer Other/Miscellaneous

A hard disk drive (HDD), commonly referred to as a hard drive, hard disk or fixed disk drive,[1] is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces. Strictly speaking, "drive" refers to a device distinct from its medium, such as a tape drive and its tape, or a floppy disk drive and its floppy disk. Early HDDs had removable media; however, an HDD today is typically a sealed unit with fixed media.[2]
Strictly speaking, an HDD is a rigid-disk drive, although it is probably never referred to as such. By way of comparison, a so-called "floppy" drive (more formally, a diskette drive) has a disc that is flexible. Originally, the term "hard" was temporary slang, substituting "hard" for "rigid", before these drives had an established and universally-agreed-upon name. Some time ago, IBM's internal company term for an HDD was "file".
HDDs were originally developed for use with computers. In the 21st century, applications for HDDs have expanded beyond computers to include digital video recorders, digital audio players, personal digital assistants, digital cameras and video game consoles. In 2005 the first mobile phones to include HDDs were introduced by Samsung and Nokia.[3] The need for large-scale, reliable storage, independent of a particular device, led to the introduction of configurations such as RAID arrays, network attached storage (NAS) systems and storage area network (SAN) systems that provide efficient and reliable access to large volumes of data.

1 Technology 2 Capacity and access speed 3 Form factors 5 Access and interfaces 6 Integrity 7 Manufacturers

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