Stephen R. Cumpson

Disk recording beyond 100 Gb/in.2: Hybrid recording? (invited)

A new method for recording above 100 Gb/in.2 is discussed. We call this method “hybrid recording,” a form of thermally-assisted recording that combines thermo-magnetic writing and magnetic reading. In order to increase the stability of the recorded information, writing is carried out at an elevated temperature on a medium with a very high coercivity at room temperature. In our proposal write and read heads with extremely narrow trackwidths are used, so the trackwidth is not determined by the optical spot size and the written bits have a rectangular shape, in contrast to the schemes proposed by others. Preliminary experiments are shown. The applicability of today’s granular and MO type media for hybrid recording is discussed. It is calculated that hybrid recording on optimized media can give an increase of the areal density of a factor 2.9 in areal density or 7 dB (2.2×) medium SNR improvement in case of Poisson noise and 11 dB (3.4×) in case of transition noise. Practically a factor of about 2 in density ...

A hybrid recording method using thermally assisted writing and flux sensitive detection

Thermally assisted magnetic recording is seen as a possible route to increased areal recording density while maintaining long information storage times. The term hybrid recording is often used since the technique involves a hybrid of a magnetic and an optical recording system. In this paper we first discuss the recording system, thereafter we present our first recording results performed on conventional longitudinal thin film media. Finally the results are discussed and a direction may be inferred for the development of thin film media to take full advantage of thermally assisted magnetic recording.

The electrical and magnetic response of yoke-type read heads based on a magnetic tunnel junction

Based on model calculations a comparison is made between yoke-type read heads containing a tunnel junction magnetoresistive element (TMRE) and containing a giant magnetoresistive element (GMRE). For typical head design parameters, TMR-based heads are 3-5 times more flux-efficient than GMR-based heads. However, for approximately 1/spl times/1 /spl mu/m/sup 2/ elements, the SNR of TMRE-based heads is not advantageous as long as the junctions tunnel resistance is not drastically reduced below R=1 k/spl Omega/.

A scalable HDD video recording solution using a real-time file system

We present a scalable solution that enables a single mainstream hard disk drive to simultaneously record and play back multiple real-time video streams, in addition to supporting non real-time PC-like applications. Our solution can handle different types of disks, different numbers of streams with different bit rates, and arbitrary non-RT applications at the same time.

Experimental And The Theoretical Studies Of Non-Linear Transition Shift In Metal Evaporated Tape

The results of experimental and theoretical studies of nonlinear transition shift (NLTS) in advanced metal evaporated (ME) tape are noted. Using the harmonic elimination technique the NLTS as a function of linear recording density was measured. Using a calibrated self-consistent recording model the patterns corresponding to the harmonic elimination technique were simulated allowing NLTS to be calculated. Dipulses were also calculated, and carefully fitted, allowing Partial Erasure (PE) to be determined. The variation in NLTS as a function of easy-axis angle in ME tape was also simulated. In agreement with a previous conjecture by J. Mallinson [1989], the NLTS is found to go through zero, For the head and medium considered, the zero occurs at an easy-axis angle of slightly greater than 35 degrees from the longitudinal direction.