One of the most significant developments of the 1970s was the floppy disk. The engineers at IBM who had developed RAMAC and the early disk drives understood their significance. In late 1967, a group known as "Dirty Dozen" left the IBM research lab in San Jose to found Information Storage Systems (ISS) that sold disk drives through Telex. They were followed during next three years by over 200 other engineers who would leave IBM for the new disk drive companies like Memorex and Shugart Associates. After the departure of the Dirty Dozen, IBM assigned David I. Noble the job of designing a cheap and simple device to load operating code into large computers. Called the Initial Control Program Load, it was supposed to cost only $5 and have a capacity of 256 KB. During 1968 Noble experimented with tape cartridges, RCA 45-rpm records, dictating belts, a magnetic disk with grooves developed by Telefunken, but finally created his own solution -- the floppy disk. Called the "Minnow," it was a plastic disk 8 inches in diameter, 1.5 mm thick, coated on one side with iron oxide, attached to a foam pad and designed to rotate on a turntable driven by an idler wheel. A read-only magnetic head was moved over the disk by solenoids and read data from tracks prerecorded on the disk at a density of 1100 bits per inch. The disk was "hard-sectored" with 8 holes around the center to mark the beginning of data sectors. At first, its capacity was only 81.6 KB, but by Feb. 1969 he had doubled the thickness of the plastic base to 3 mm and coated both sides to add more capacity. In June 1969, the Minnow was added to the IBM System 370 and soon began to be used by other divisions in IBM. In 1970, the name was changed to Igar and Noble had a staff of 25 engineers to help him make improvements. By 1971, Igar became the 33FD disk drive and the 8-inch floppy disk became the Type 1 diskette. The speed was 360 rpm, with head access time of 50 milliseconds. The 8 hard sector holes were replaced by a single index hole for "soft sectors" or "IBM sectoring" across 77 tracks. In 1976 the 43FD disk drive was sold with dual heads to read and write to both sides of the diskette. A new model 53FD was added in 1976 that used modified frequency modulation to record double-density on both sides, resulting in a capacity of 1200 KB.
Magnetic Disk Heritage Center in San Jose and the RAMAC anniversary
