International Business Machines Corporation

Morovat B Tayefeh

John Edward Kulakowski

Rodney Jerome Means

Blair I Finkelstein

Ian E Henderson

David M Oldham

Glen Alan Jaquette

Raymond Yardy

Alan A Fennema

Richard C Schneider

Timothy S Gardner

Julian Lewkowicz

Anthony G Dewey

Hideo Ueno

Paul H Francois

Paul J Dounn

Hideaki Iwasaki

Terry L Kise

Warren L Bletscher, Jr

In a recordable media drive, error processing is implemented in an adjustable read channel equalizer in which gain and bandwidth values can be selectively adjusted. In a write/verify procedure, the gain value is reduced, while the bandwidth is increased, thereby stressing the read channel during verification of written sectors in order to force the failure of marginal sectors. In an error recovery procedure, when a sector error is encountered, the gain value of the adjustable equalizer is initially increased and a sequence of read retries of the failed sector is initiated.

Adjustable read channel equalization for error processing in a

An optical drive provides an internal routine for automatically optimizing the common mode rejection ratio of the magneto-optic data output signal. A microprocessor provides control to a controller module which in turn supplies a plurality of calibration signals to a data detecting portion. The calibration signals modify predetermined parameters of the data detecting portion based upon measuring a predetermined parameter indicative of the common mode rejection ratio. The common mode rejection ratio optimization corrects for mismatches in both the optical elements and in the electronic data circuits.

Common mode rejection control in an optical disk drive

An optical disk drive apparatus includes a magnet-optic optical disk, laser generator, optical system, first and second photodetectors, data detecting and amplifying device connected to the photodetectors and a laser generator control device. The photodetectors each have first and second detecting sections receiving leading and trailing light beam segments, respectively, and each photodetector producing a magnitude proportional output signal. The control device includes a mode setting device for operating in a read only mode using both first and second sections and a read while performing a write mode using only the second sections.

Split detector system for direct read-while-write operation on

A magnetooptic disk has circumferentially-spaced-apart, radially-aligned embossed sector areas which indicate data storage tracks. The sector areas include embossed signals which indicate track following information, and in a second area which trails the track-following information, track-seeking information is carried by the embossed signals. A magnetooptic coating covers the entire disk including the embossed sector areas. Readback clock synchronization signals are recorded over the track seeking area to enable synchronizing a readback phase locked loop such that more of the areas between adjacent sector areas can be used for recording data signals. During track seeking, the track seek controlling embossed signals are read using intensity demodulation, while in track following, during a readback, the clock signals recorded over the embossing are read for synchronizing the readback circuits. During recording, the synchronization signals are recorded over the embossed area dedicated to track seeking.

Data storage member having areas in which intensity-modulated signals

A circuit for simultaneously detecting both MO and ROM signals reflected from an optical disk so that both signals are present and useable without switching from one to the other. The circuit eliminates switching time and switching transients. Two photodetectors are arranged to sense P and S components of polarized light in order to stimulate a differential amplifier and produce an output representative of MO recorded data. A second amplifier is connected to at least one of the photodetectors to produce an output representative of ROM recorded data and also representative of defects in the MO portion of the optical disk.

Simultaneous MO and ROM optical disk signal detection

A magnetooptic storage member is scanned by a single laser beam. The beam intensity is sufficient to heat a localized area of the storage member to be above the Curie temperature for enabling reversing the remanent magnetization of the localized area. Such localized area is subjected to a magnetic bias field for directing which of the remanent directions shall be assumed in the localized area. The storage member and laser beam are relatively moved such that a front or leading portion of the localized area does not reach the Curie temperature. The light reflected from this leading portion, which moves with the laser beam relative to the storage member, is detected for indicating the initial remanent state of the localized area before any changes are made by the combination of the magnetic bias field and the laser beam.

Sensing previously-recorded information while recording or erasing a

A magnetooptic recorder uses a magnetooptic disk for any predetermined number of radially inward tracks which are designated as calibration tracks. One of the calibration tracks is selected as a laser calibration track. The selected track is high powered erased and a test pattern is written on the track. A test pattern is repeated at diverse levels of laser recording power. A test pattern preferably includes or is limited to the highest frequency to be recorded in the ensuing data recordings. The recorded test pattern is read back with the readback signal amplitude being envelope indicated and detected. A table of signal envelope values is created in a digital computer. The values then are fit to a curve using second order polynomial curve fitting techniques. The maximal readback signal amplitude is then selected from the curve corresponding to laser write power used to obtain that maximum signal amplitude and is then selected as a criteria for indicating the laser write power as well as the erase write power.

Calibrating lasers for optical recording using a maximal readback signal

An optical disk recorder is capable of operating with diverse types of optical media. A device initialization procedure is repeated for each receipt of each optical medium. Such procedure includes moving an objective lens to an extreme radial position, defocussing the lens at a most remote position, then calibrating the laser circuits to ensure that the emission of radiation from the laser will not inadvertently destroy signals recorded on the just received medium. Then the medium type is read from the medium and based upon the type indication, various additional calibrating procedures are followed and different sources of laser control values are used for signal exchanging operations between the recorder and received optical medium.

Optical disk recorder for diverse media types and having a predetermined

Rewriteable media, such as magnetooptic record members or disk has its recording controlled such that the recording is certifiable as meeting write once read many characteristics. Controls are introduced for the entire disk for indicating that the rewriteable disk is to be used for certified or vault writing, at least in some radial zones of the disk. Recording or writing operations are limited to those addresssable areas on the certifiable rewriteable medium that have not been previously written. Each of the addressable areas of the medium, in a disk termed, sectors, have a precursor portion called a control area which indicates the status of the sector and is used for preventing overwriting or erasure as well as controlling.

Controls for optical disk relating to accessing and utilization of such

A magnetooptic player reads magnetooptically recorded signals on a disk by using a differential detector. Intermediate areas on a storage member used to store the magnetooptically record signals are sector marks and ID fields formed by undulations in the surface of the disk. Such sector marks and ID fields are read by detecting the intensity modulation in a reading light beam; for detecting such embossed marks and D-ROM disks, one-half of the differential detector is disabled for facilitating such detection in a differentially arranged detector.

Detecting magnetooptic and intensity-modulated optical signals with the

Recording operations for an optical disk recorder are calibrated by adjusting recording power level (light intensity) such that a permissible crosstalk can be detected in adjacent erased tracks. Following the power level calibration, pulse duration or width is calibrated for a predetermined symmetry of recorded pulses along the calibration track. Various sequences and procedures are described. Calibration occurs at a plurality of radially spaced-apart tracks.

Write calibration for magnetooptic disk recorders

A magnetooptic disk has circumferentially-spaced-apart, radially-aligned embossed sector areas which indicate data storage tracks. The sector areas include embossed signals which indicate track-following information, and in a second area which trails the track-following information, track-seeking information is carried by the embossed signals. A magnetooptic coating covers the entire disk including the embossed sector areas. Readback clock synchronization signals are recorded over the track-seeking area to enable synchronizing a readback phase-locked loop such that more of the areas between sector areas can be used for recording data signals. During track seeking, the track seek controlling embossed signals are read using intensity demodulation, while in track following, during a readback, the clock signals recorded over the embossing are read for synchronizing the readback circuits. During recording, the synchronization signals are recorded over the embossed area dedicated to track seeking.

Recording intensity modulated signals and polarization-modulated optical

A magnetooptic recorder player provides for residual data checking and media defect checking. Media defect checking is effected by comparing the reflected light intensity of a modulated optical beam with the input data characteristics. A difference between the input data and the detected light intensities represents asperities in the record media. Residual data is checked by selectively gating MO detected signals during recording, which are intermediate the high intensity light beam pulses used for recording signals. Both the detected residual data and detected media asperities are counted for each addressable record storage area on the medium.

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Tucson, AZ, United States of America

Morovat B Tayefeh