Abstract: A moving head disc file for storage of retrievable informational data with one or more tribit tracks recorded on the disc, the tribit tracks being an integral part of the apparatus, the disc file operating under the supervision of a control system and including a tribit signal decoder whose outputs are logic signals coupled to the system controller, particularly aimed at increasing the number of tracks on a moving head magnetic disc file employing "floppy" or flexible discs.

Abstract: A disc file, for the storage of retrievable, informational data in a plurality of concentric, data storage tracks, on a disc rotating at a constant angular velocity, comprises a radially mobile head 44 for data recording or recovery on the disc, a head positioner for positioning the head to interact with selectable tracks on the disc and a variable frequency clock generator for providing data recording or data recovery control signals whose rate of repetition is a linearly increasing continuous function of the radius of interaction of the head with the disc.

Abstract: An apparatus is provided for distinguishing a tribit servo track from other signals appearing on a rotating disk magnetic information storage media. The apparatus comprises circuit elements which detect for the concurrence of several characteristic features which differentiate the servo signal from data, inter-data-track beat-frequency signals, and noise, also picked up by the transducer head. Upon coincidence of all of the characteristic features tested for, along with an indication that the transducer head has been coarsely positioned over the servo track, a tri-bit-present signal is generated. Among the characteristic features tested for are proper timing of synchronization pulses, proper time relation between synchronization pulse and first positioning pulse, and the occurrence of two positioning pulses for every synchronization pulse.

Abstract: A transducer track-centering system for a magnetic information storage disk utilizes the data itself to generate position-correcting error signals. Angularly-disposed magnetic gaps in a two-part transducer head read and write the data in identical components of a V-shaped pattern which straddles the center line of the disk record track. Transducer positioning errors take the form of a time lag between the data read from the separate branches of the V. The time-difference is then used to adjust the transducer position perpendicularly with respect to track center.