In 1967, the storage group at IBM's San Jose Laboratories...... with developing an inexpensive device to store and ship microcode for mainframe processors and control units. The device......... under $5, be simple to install and replace, had to be easy to ship and needed unquestionable reliability. Existing technologies - such as the magnetic belts used in dictating machines of the time -......, and rejected. The proposed solution was a completely new technology, the floppy disk.
In 1971 the first incarnation of the floppy disk...... into IBM's System 370 mainframe computer. It was a read-only, 8in plastic disk coated with iron oxide, weighing just under 2 oz. and capable of storing about 80KB. A crucial part of its design was its protective enclosure, lined with a nonwoven fabric that continuously wiped the surface of the disk as it rotated to keep it clean.
In 1973, IBM... a new version of the floppy on its 3740 Data Entry System. This... a completely different recording format, the motor spun in the opposite direction and the device now boasted read/write capacity and a storage capacity of 256KB. It was then that the floppy disk market took off. In 1976 - at just about the time that personal computing...... the scene - the 8in form factor was superseded by the 5.25in floppy. That design eventually gave way to the 3.5in diskette, developed by Sony Corp. in 1981.
Floppy drives are notable for the use of open loop tracking: they don't actually look for the tracks, but simply... the head... to the "correct" position. Hard disk drives, on the other hand, have servo motors embedded on the disk which the head uses to verify its position, allowing track densities many hundred times higher than is possible on a floppy disk.
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