History of the Hard Disk

The history of hard disks began in 1955 with the IBM 305 computer.

For many years, hard disks were large, cumbersome devices, more suited to use in the protected environment of a data center or large office than in a harsh industrial environment (due to their delicacy), or small office or home (due to their size and power consumption). Before the early 1980s, most hard disks had 8-inch (20 cm) or 14-inch (35 cm) platters, required an equipment rack or a large amount of floor space (especially the large removable-media drives, which were often referred to as "washing machines"), and in many cases needed high-amperage or even three-phase power hookups due to the large motors they used. Because of this, hard disks were not commonly used with microcomputers until after 1980, when Seagate Technology introduced the ST-506, the first 5.25-inch hard drive, with a capacity of 5 megabytes.

The capacity of hard drives has grown exponentially over time. With early personal computers, a drive with a 20 megabyte capacity was considered large. As of early 2007, desktop hard disks typically have a capacity of 100 to 500 gigabytes, while the largest-capacity drives are 1 terabyte.

1950s - 1970s

The IBM 350 Disk File, invented by Reynold Johnson, was introduced in 1956 with the IBM 305 computer. This drive had fifty 24 inch platters, with a total capacity of five million characters. A single head was used for access to all the platters, making the average access time very slow. It is possibly influenced by Drum memory devices, which were invented in 1932.

The IBM 1301 Disk Storage Unit Control System Mechanical International System, announced in 1961, introduced the usage of a separate head for each data surface.

The first disk drive to use removable media was the IBM 1311 drive, which used the IBM 1316 disk pack to store two million characters.

In 1973, IBM introduced the IBM 3340 "Winchester" disk system, the first to use a sealed head/disk assembly (HDA). Almost all modern disk drives now use this technology, and the term "Winchester" became a common description for all hard disks, though generally falling out of use during the 1990s. Project head designer/lead designer Kenneth Haughton named it after the Winchester 30-30 rifle after the developers called it the "30-30" because of its two 30 MB spindles.

1980s - PC era

Internal drives became the system of choice on PCs in the 1980s. Most microcomputer hard disk drives in the early 1980s were not sold under their manufacturer's names, but by OEMs as part of larger peripherals (such as the Corvus Disk System and the Apple ProFile). The IBM PC/XT had an internal hard disk, however, and this started a trend toward buying "bare" drives (often by mail order) and installing them directly into a system.

External hard drives remained popular for much longer on the Apple Macintosh and other platforms. Every Mac made between 1986 and 1998 has a SCSI port on the back, making external expansion easy; also, "toaster" Macs did not have easily accessible hard drive bays (or, in the case of the Mac Plus, any hard drive bay at all), so on those models, external SCSI disks were the only reasonable option. External SCSI drives were also popular with older microcomputers such as the Apple II series, and were also used extensively in servers, a usage which is still popular today. The appearance in the late 1990s of high-speed external interfaces such as USB and FireWire has made external disk systems popular among regular users once again, especially for users who move large amounts of data between two or more locations, and most hard disk makers now make their disks available in external cases.

Hard disk makers started marketing to end users as well as OEMs in the mid-1990s, and hard disks became available on retail store shelves.

There were external hard disks available for 16-bit computers Amiga and Atari ST but very small percentage of Amiga and Atari ST users obtained them. There was also hard disk available for the most popular 8-bit computer, Commodore 64, but only few people ever bought it.