Browse Prior Art Database

Erase Power Calibration of Magneto-Optic Media

IP.com Disclosure Number: IPCOM000062457D
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Bates, KA: AUTHOR [+4]

Abstract

An automatic control system determines the amount of laser power necessary to erase magneto-optic disk media. Use of this system increases laser lifetime. When an erasable magneto-optic disk is first used in a disk drive, the disk must be formatted. This control system provides an erase calibration procedure which is included as part of that formatting operation. The erase calibration procedure is controlled by a microprocessor, for example, one already resident in the drive. This calibration procedure comprises the following steps: 1. A test band of tracks, not accessible to the user, is laser written using a single frequency square-wave source. These test tracks are written using nominal write power to energize the laser. 2. These written tracks are then laser erased, one at a time.

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Erase Power Calibration of Magneto-Optic Media

An automatic control system determines the amount of laser power necessary to erase magneto-optic disk media. Use of this system increases laser lifetime. When an erasable magneto-optic disk is first used in a disk drive, the disk must be formatted. This control system provides an erase calibration procedure which is included as part of that formatting operation. The erase calibration procedure is controlled by a microprocessor, for example, one already resident in the drive. This calibration procedure comprises the following steps: 1. A test band of tracks, not accessible to the user, is laser written using a single frequency square-wave source. These test tracks are written using nominal write power to energize the laser. 2. These written tracks are then laser erased, one at a time. An increase in laser erase power is used with each new track that is erased. 3. Each time a track is erased, it is thereafter read, and the track's residual signal is measured using a bandpass filter and peak detector. 4. When an amplitude of the residual signal is found that is within specification for an acceptable residual signal, the laser's erase power that was used to erase that track, plus a percentage increase, is stored as an information field on the disk. 5. This value of erase power, as now recorded on that disk, is subsequently retrieved each time that disk is used. Thus, as each different disk is inserted in the drive, the ...