The 2311 had 10 individual R/W heads mounted on a common actuator which was moved in and out hydraulically and mechanically detented at the desired track before reading or writing occurred. The 2311 was organized into cylinders, tracks, and records. (A cylinder referred to all surfaces the same track on each of the 5 platters.) Record 0 was reserved for timing.
Because the 2311 was to be used with a wide variety of computers within the 360 product line, its electrical interconnection was standardized. This created an opportunity for other manufacturers to sell plug compatible disk drives for use with IBM computers and an entire industry was born.