1979 IBM 62PC
Marks the beginning of the shrinkage of disks below the then 14-inch standard diameter..

Why it’s important After a decade and a half of 14-inch disk drives the HDD industry began a transition to smaller disks, reflecting the movement to diversification of computer systems and smaller installations.

The first disk drives by IBM and then Bryant used disks with diameters of of 24-inches or larger, e.g. IBM 1301.. In 1963 Librascope introduced a line of fixed head disk drives diameters ranging from 24-inches to 4-inches, including an 8-inch diameter model [Datamation, July 1963, p.77] Also in 1963 IBM announced its 1311using 14-inch diameter disks in a removable disk pack. The industry then coallesed on the 14-inch disk as the defacto standard into the 1980s

IBM 62PC (Piccolo) had a rotary actuator with six 8-inch disks. One of the surfaces was used as a dedicated servo surface. The total capacity was 65MB. The eleven remaining heads stored the users' data and had servo sample information stored with each sector of data.

360,000 units were shipped from Jan 1979 through Feb 1990 mainly as internal storage for a number of IBM system products (e.g., IBM 5520, IBM 8100, IBM Series 1 and System/38) and/or as an attachable DASD subsystems such as the IBM 3310 and 8801. The Model 0680 was an OEM version.

Additional information
Commander, RD and Taylor, JR,"Servo Design for an Eight-Inch Disk File," DISK STORAGE TECHNOLOGY, IBM GA 26-1665-0, Feb. 1980, pp. 90-98
AR Hearn, "Actuator for an eight-inch disk file," ibid, pp. 84-89
Case, W J P, "Piccolo (62PC)" Chapter 7 of History of Disk-File Development at Hursley and Millbrook, IBM Corp., Oct 17, 1990

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