Flight of flexible disk over recording heads

In using flexible disks at high speed (linear speed of the order of 20 m/s) one has to deal with two gas films : one that holds the disk in position and an other that maintains a constant spacing (order 1 μm) between the disk and the head(s). Two devices realizing the first function are described in this paper : one using a nozzle blowing air toward the disk and one using the centrifugal flow between the disk and nearby wall. Concerning the air film between head and disk, an interferometric method was devised to measure the spacing and the deflection of the disk. The geometry and settings of the head are discussed. These results were used in designing the heads of a prototype of a small fixed head digital memory.