International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Charles Raymond Davis

Bruce Alexander Wilson

Kurt A Rubin

Bernhard E Knigge

Peter Michael Baumgart

Gary Allan Herbst

Grace Lim Gorman

Charles Mathew Mate

Martin Y Chen

Roger W Barton

Vincent Marrello

A method according to one embodiment comprises detecting a change in a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk, the change being caused by head-disk contact. A method for detecting head-disk contact according to another embodiment comprises measuring a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk; detecting a change in the rotational velocity, the change being caused by head-disk contact; and correlating the change in rotational velocity with the head-disk contact.

Method and system for detecting a change in a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk

An optical storage system has an information containing film of a material which has a crystallization temperature between 100.degree. C. and 400.degree. C. and can be switched between the amorphous and the crystalline states. Both the amorphous and crystalline states are substantially a single phase where the stoichiometric ratio of the material remains unchanged. Spots on the film is heated with a circular laser beam with a controlled pulse duration and intensity to melt the material in the spots. The spots are quenched at one rate to produce the amorphous state, and in a second revolution of the disk, at a different rate to produce the crystalline state.

Process for optically storing information using materials having a

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San Jose, CA, United States of America

Charles Raymond Davis