Abstract: In a magnetic disc storage system and a magnetic disc therefor, the disc having opposed surfaces, at least one of the surfaces being coated with a magnetic material, the disc being adapted to be mounted on a spindle for rotation relative to a magnetic transducer positioned for recording data on and retrieving data from the disc, a plurality of concentric annular tracks being defined on the surface of the disc, each of the tracks being divided into a plurality of sectors, each sector having associated therewith prerecorded servo data for identification thereof, the improvement wherein the servo data for each sector comprises a unit distance track identification code recorded three times in succession, the code changing between adjacent sectors of adjacent tracks, and a clock shift check code recorded immediately following the last recorded one of the track identification codes, the same clock shift check code being recorded for each sector of every track.

Abstract: An automatic-reversing tape deck arranged such that the magnetic tape advancing direction is automatically reversed when the tape is wholly wound during operation and then the operation is continued with the tape being advanced in the reversed direction, in which tape-advancement-direction changing signals are repeatedly generated by a circuit if the tape gets unable to advance because of a certain failure or accident, and the tape advancing operation is stopped when several tape-advancement-direction changing signals are counted by a counter. In this tape deck, wasteful power dissipation and harmful heat generation in the mechanism for changing the tape-advancement-direction can be avoided.

Abstract: A magnetic transducer for reading magnetic information from a magnetic support such as a disc or tape which moves before it, comprises a magnetic circuit formed of two thin layer polar pieces having a gap at one end and means coupled magnetically to the circuit for transformation of magnetic flux loss of information into an electric signal. The pole pieces comprise at the level of the gap a central part bounded by two lateral parts spaced such that the magnetic coupling between the central parts is very much less than the magnetic coupling between the corresponding lateral parts of the pieces. The gap disposed between the central parts is larger than the gap of the lateral parts. There is a substantial reduction in Barkhausen noise and parasitic edge effects over conventional transducer constructions which is obtained by making the thickness of the pole pieces of the transducer substantially greater in the area of the geometric path Lpm than at the lateral portions beyond Lpm.

Abstract: Disclosed is a magnetic head comprising a support member having a plane faced by a magnetic recording medium; an electromagnetic converter mounted on the support member, and provided with an amorphous magnetic film which is possessed of an axis of easy magnetization extending in a prescribed direction along the plane of the film.The amorphous magnetic film occupies such a position on the support member that a magnetic flux sent forth from the recording medium passes through the amorphous magnetic film in the prescribed direction.

Abstract: An improved servo encoding scheme and demodulation circuit for control of the position of a read/write head with respect to a magnetic recording disk is disclosed. First and second signals of like polarity are recorded preceding each data field on the sector of the disk. The signals are summed to provide automatic gain control to the servo loop to compensate for variations in read-back amplitude, while the difference between the two signals is measured and used to provide an indication of departure of the head from the center of the disk track.

Abstract: A linear actuator for translating accessing transducers such as read/write heads along a straight line path of travel relative to a rotating magnetic disk includes a carriage, a flat coil mounted to the disk and having an effective winding extending transversely at the rear end of the carriage, one pair of rollers mounted at right angles to each other at one side of the carriage in rolling engagement upon a cylindrical guide rail, two pairs of rollers similarly mounted at the other side of the carriage in rolling engagement upon a second guide rail. The second guide rail is fixedly mounted to a base frame; the other guide rail is pivotally mounted parallel to the other rail and is biased by a spring to preload the single pair of rollers against the pivotal rail. A pair of block magnets are mounted at the rear end of the base frame with a gap therebetween that is aligned with the path of travel of the effective winding.

Abstract: This is a magnetic tape transport primarily for the automatic threading and replay of cassette-mounted tapes that were originally produced upon the same transport or upon a different recording transport having a single rotating head and guide around which the tape is wrapped in a substantially 360-degree omega path. To be adapted for replay of the cassette-mounted tapes, the replay transport differs from the omega-wrap recording transport in having two diametrically opposite rotating heads and a substantially 180-degree tape wrap, and the heads rotate at half the rotational speed of the omega-wrap transport head. The threading means are of the differential air-pressure type.

Abstract: A cleaning device for magnetic tape heads comprises a mylar tape on which is deposited a layer of a low-tack adhesive. A dacron fabric is bonded to the mylar tape by the adhesive layer. This dacron tape acts as a mechanical cleaning surface when it is moved across the contact surface of the tape head. The adhesive layer operates both to secure individual strands of the fabric rigidly in place so as to support the strands properly when they are in contact with the tape head, and also to capture and control the movement of magnetic particles dislodged from the tape head by the strands of the fabric. Alternate embodiments provide ridges for defining a pattern of raised projections extending away from an underlying base.