Abstract: A magnetic field strength detector includes a magnetic field sensing element that outputs voltage as a function of magnetic field strength. In some embodiments, the magnetic field sensing element comprises a coil, and voltage is induced across the coil as a function of the magnetic field strength. A magnetic field strength detector also includes an indicator that alters as a function of the voltage output by the magnetic field sensing element when the magnetic field strength exceeds a threshold. The alteration is substantially irreversible and, in some embodiments, visible. The detector may be used to, for example, measure the strength of a magnetic field generated by a degaussing device, or to confirm that a particular medium was exposed to a magnetic field with a strength adequate to degauss the medium.

Abstract: The invention presents techniques for marking data storage media and responding to disturbances in the marking process. In one embodiment, the invention presents a system that uses a laser to emit a beam to ablate physical marks in a data storage medium. The system includes a sensor such as an optical sensor, configured to detect the position of the data storage medium and to generate a position signal as a function of the position of the data storage medium. An optical device, controlled by an actuator, directs the beam from the laser to an ablation site on the data storage medium as a function of the position signal.

Abstract: Bias recording is used to record servo patterns on magnetic tape. With use of bias recording, a faster recording process may be provided relative to conventional pulse recording processes. A servo pattern recording method includes providing a servo band along at least a portion of a length of a tape. Bursts of a first signal are recorded in a first servo track of the servo band along the length of the tape and a second signal, e.g., a continuous signal, is recorded in at least a second servo track of the servo band along the length of the tape. The second servo track is recorded adjacent to the first servo track and at least one of the first signal and the second signal is recorded using a bias signal at a bias frequency summed with a record signal at a record frequency. A system for carrying out the bias recording of servo patterns is also described.

Abstract: The invention presents techniques for marking data storage media and responding to disturbances in the marking process. In one embodiment, the invention presents a system that uses a laser to emit a beam to ablate physical marks in a data storage medium. The system includes a sensor such as an optical sensor, configured to detect the position of the data storage medium and to generate a position signal as a function of the position of the data storage medium. An optical device, controlled by an actuator, directs the beam from the laser to an ablation site on the data storage medium as a function of the position signal.

Abstract: A multi-track servo recording head assembly records a plurality of identical tracks of servo information longitudinally defined within a very high density servo section along a magnetic recording medium. The servo recording head assembly includes a write transducer for writing a servo signal, as well as an erase transducer that includes two outer erase elements and at least one inner erase element positioned between the two outer erase elements. Each erase element erases alternating portions of the servo signal to create at least one of the plurality of tracks of servo information in the servo section. The outer erase element and the inner erase element are positioned transversely across the servo section, with the inner erase elements having an erase head width that is less than an erase head width of the outer erase elements.

Abstract: A multi-track servo recording head assembly records a plurality of identical tracks of servo information longitudinally defined within a very high density servo section along a magnetic recording medium. The servo recording head assembly includes a write transducer for writing a servo signal, as well as an erase transducer that includes two outer erase elements and at least one inner erase element positioned between the two outer erase elements. Each erase element erases alternating portions of the servo signal to create at least one of the plurality of tracks of servo information in the servo section. The outer erase element and the inner erase element are positioned transversely across the servo section, with the inner erase elements having an erase head width that is less than an erase head width of the outer erase elements.

Abstract: A yoke for supporting a magnetic recording core adjacent a moving recording tape is disclosed. The core has two major surfaces, two side walls, and upper and lower walls. Two wound wire coils are mounted to the core adjacent respective side walls and extend beyond the major surfaces. The yoke includes two opposed major surfaces and a front surface which defines a bearing surface for supporting the recording tape. A narrow slot is formed in the front surface to receive the core. The walls of the narrow slot stabilize the core along the length of the core adjacent the core upper wall. Relief pockets extend between the two major surfaces of the yoke and encompass at least a portion of the narrow slot. The relief pockets permit winding the coils around the core after the core is positioned in the yoke.