Abstract: During operation, an electronic device may receive, from a second electronic device, information that specifies or that corresponds to one or more distortions, where the one or more distortions are associated with measurements of a physical parameter that are performed by a sensor in the second electronic device. Then, the electronic device may determine, based at least in part on the information, the one or more distortions. Moreover, the electronic device may compare the determined one or more distortions with historical values of the one or more distortions. Note that the historical values of the one or more distortions may be specified by or may correspond to historical information that is received from one or more third electronic devices. Next, based at least in part on the comparison, the electronic device may selectively authenticate an individual associated with the second electronic device.

Abstract: A technique for determining the recording medium temperature, thereby enabling high track density in Hybrid recording. This allows compensation for changes in the ambient temperature and variations in the laser power over its life. Such a temperature measuring technique also enables laser power shaping of the spot size/thermal contour in the medium, providing smaller spot size definition with a given optical system. Baseline modulation is a sensitive probe of the temperature gradient between a magneto-resistive read element (anisotropic or giant) and the surface of a disk. By calibrating the temperature rise (above ambient) of the read element, this technique can be used to determine the disk surface temperature.

Abstract: A rotary magnetic head device for a helical scanning magnetic recording and reproducing apparatus includes a rotary drum, a thin-film magnetic head (6) protruding from the rotary drum in a diametrical direction for coming into contact with a magnetic tape (7), obliquely wound around part of the outer peripheral surface of the rotary drum, and head control circuit for adjusting the protrusion of the magnetic head (6) in the diametrical direction. The head control circuit includes a feed-forward control arrangement (9) to bring and hold the magnetic head into a protruded position in which the magnetic head exerts a constant normal force on a tape (7) wound around the drum.

Abstract: A recording and/or reproducing apparatus for a magnetic record carrier such as a tape or disk. The apparatus includes a magnetic recording/reproducing head, a guide for positioning the face of the head relative to a recording surface of the record carrier, and an actuator for moving the head relative to the guide in a direction normal to the recording surface. The actuator is driven by a control unit which receives a control signal from a detector upon detection thereby of frictional contact between the face of the magnetic head and the recording surface. That causes the control unit to cause the actuator to move the head so as to increase the distance between the face thereof and the recording surface.

Abstract: A combination is disclosed of a magnetic record carrier and an apparatus for recording a digital information signal in a track on the record carrier. The apparatus includes an input terminal for receiving the digital information signal, an encoding unit for encoding the digital information signal so as to obtain a digital channel signal suitable for recording, and a writing unit for writing the digital channel signal in the track on the record carrier. The writing unit includes at least one write head having a specific gap width. The apparatus is adapted to write the digital channel signal in the record carrier with a bit-length which is smaller than 0.25 .mu.m, and the record carrier has an oblique easy-axis angle between 30.degree. and 42.degree. with regard to the longitudinal direction of the track and in a plane perpendicular to the record carrier.