Abstract: A thermoelectrically adjustable magnetic head for reading and writing information comprising a read/write core, and position detection cores on both sides thereof generating compensatory output in proportion to the relative positional drift of the magnetic head with position detection and correction device from the center lines of a magnetic disk data tracks by feeding back signals to the magnetic head to rectify said magnetic head's position to the center of said disk data tracks, and in the course of such compensatory operation also eliminates noise generated at the time of recording from the gaps between said tracks.

Abstract: A magnetic disc device includes a moisture removing mechanism within an enclosure of the device. The mechanism employs a reversible desiccating agent which is capable of not only absorbing moisture but also discharging moisture depending on the surrounding conditions. The reversible desiccating agent cyclically absorbs and discharges moisture in response to a change in temperature and a change in humidity due to the intrusion of the moisture from outside the enclosure. The moisture removing mechanism can be used for a long period of time with a small amount of desiccating agent. Thus, it is possible to make the moisture removing mechanism small and to provide it with long life.

Abstract: An off-set signal provided from an off-set detector is stored in a memory. When a head is positioned on a data track, an off-set signal stored in the memory is read out to correct the head position and position the head to the center of the data track, thus effecting accurate reading and writing of data. An off-set generator feeds the servo system with a dummy off-set signal for producing an off-set correction signal, whereby the servo system corrects the off-track of the magnetic head.

Abstract: A control system for positioning a head in a magnetic disk device. The control system including a stepping motor, an index timing sensor for indicating the starting point of a data track, a rectifier for rectifying the servo position information, and a envelope detector for detecting the envelope of the rectified servo information. The servo position information is recorded in at least two data tracks and is formed in a staggered, offset pattern. The outside and inside tracks can serve as reference tracks for use in predicting the expected position of an intermediate track between the reference tracks by the use of linear interpolation.

Abstract: A disk unit including a control unit for controlling the stop position of a positioning electric motor and positioning a magnetic head operatively linked with the positioning electric motor on a predetermined one of data tracks on a magnetic disk, and positioning error adjustment unit for supplying analog signals to the control unit, wherein the analog signals are related to the positioning error detected by the magnetic head. The control unit includes a control circuit for causing an exciting current which goes high during a time interval T1 and goes low during a time interval T2 during a period T to flow in a first exciting coil of the motor and for causing exciting current which goes low during the same time interval T1 and goes high during the same time interval T2 to flow in another exciting coil adjacent to the first coil, as a function of the magnitude of the aforementioned analog signal; the duration of the time intervals T1 and T2 with respect to the period T is adjusted by the control unit.