Abstract: A method for recording high frequency signals representing data with simultaneous readout of low frequency information, such as servo information prerecorded on a magnetic disk, comprises the step of modulating with the data a carrier signal having a repetition frequency displaced significantly from the baseband of the data. The nonlinearity of the recording channel converts the modulated signal spectrum into the low frequency baseband so that the data is magnetically recorded while the low frequency prerecorded information is read out.

Abstract: An integrated read/write head assembly incorporates a thin film inductive write head subassembly comprising first and second pole pieces that define a write transducing gap, and a magnetoresistive read subassembly disposed in the write gap. The first write pole piece is extended so as to provide a planar conductive path from the terminal connections or studs to the magnetoresistive read subassembly, thereby forming a uniform surface for deposition of the magnetoresistive read subassembly.

Abstract: For the point-by-point interferometric measuring of surfaces which are scanned along lines, or which are subjected to a processing procedure (e.g. etching) a focused laser beam is directed with oblique incidence as a measuring beam onto the respective measured points. The respective height of a measured point determines the path difference (phase difference) between the measuring beam and a reference beam which has been suitably split off the input beam. The oblique incidence (angle of incidence .gtorsim.80.degree.) makes it possible to measure interferometrically very rough surfaces. The measuring range may be extended if the reference beam is directed at an oblique angle of incidence, differing only slightly from that of the measuring beam onto the surface to be examined.

Abstract: A self-loading magnetic head air bearing slider is formed with a taper across the full width at its leading edge. The air bearing slider has two rails along its sides and a recess between the rails. The structure of the rails is preferably flared to provide an improved pressure profile thereby to allow fast liftoff from a disk surface.

Abstract: A magnetic head slider and actuator assembly has an air bearing magnetic head slider that is coupled to an electrical coil. Permanent magnets are positioned in a stationary frame to provide a magnetic field adjacent to the coil. When current is supplied to the coil, it moves within a slot in the frame between the permanent magnets and transports the head slider accordingly. In this way, the magnetic head slider is actuated to access data tracks on a magnetic disk.

Abstract: The air bearing surface of a self-loading magnetic head slider has two side rails and a recessed section therebetween. The air bearing surface has a cylindrical or parabolic crowned shape to effectuate very small spacing between the trailing end of the slider, which supports magnetic transducer means in flying relation to a moving magnetic medium.

Abstract: Ferrite read and write modules of a magnetic head assembly that are aligned and positioned within a nonferrite housing are clamped by a leaf spring between the walls of the housing. The leaf spring compensates for thermal mismatch between the ferrite modules and the housing, and compensates for stress fluctuation that occurs with temperature change. The clamping force of the leaf spring is precisely controlled.

Abstract: In a data recording system employing an AC bias signal that is superimposed on the data signal, the AC bias signal is phase modulated to compensate for the difference in the phase angle between the alternating bias and the data signals. The frequency of the AC bias signal is no greater than ten times the frequency of the data signal.

Abstract: The temperature of a magnetic head assembly is reduced by active heat transfer accomplished by a thermoelectric cooling element positioned between and in contact with the head assembly housing and the head assembly. The housing serves as a heat sink from which thermal energy is diffused.

Abstract: A conductive wire useful with a magnetic head assembly is formed from a zirconium/copper alloy core, which is plated with a corrosion resistant conductive metal, such as gold. The wire is preferably covered with insulation, such as polyurethane.

Abstract: An apparatus for processing data employs a modification of a zero modulation code. The zero modulation code has a waveform that is symmetrical about a zero signal level within narrow defined limits. Each data digit, 1 or 0, is encoded into two NRZI digits. A relaxed run length limitation allows use of a (d,k) code of (1,4), where (d) is the minimum number of 0 digits between 1 digits and (k) is the maximum number of 0 digits between 1 digits, without violating the frequency and charge constraints. Only five charge states and only one bit lookahead is needed in order to encode data in the (1,4) code.