System and method to compensate for data defects within a magneto-optical computer memory device

• US 6,331,968 B1
• Filed: 11/19/1998
• Issued: 12/18/2001
• Est. Priority Date: 07/30/1996
• Status: Expired due to Fees

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology plc (Seagate Technology Holdings Plc)
• Inventors: Belser, Karl A.
• Primary Examiner(s): Huber, Paul W.
• Application Number:
  US09/196,902
• Time in Patent Office: 1,125 Days
• Field of Search: 369/13, 369/44.32, 369/44.35, 369/44.29, 369/47, 369/48, 369/53, 369/54, 369/58, 369/59, 369/124.01, 369/47.14, 369/47.17, 369/47.18, 369/53.15, 369/53.16, 369/53.17, 369/53.32, 369/53.33, 369/59.11, 369/110, 360/25, 360/67
• US Class Current: 369/47.14
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 6/105 having optical polarisation effects
• CPC Class Codes: G02B 6/126 using polarisation effects G02B6/1226 takes precedence
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures
• CPC Class Codes: G11B 11/10515 Reproducing compensating pit shift G11B11/1053
• CPC Class Codes: G11B 11/10532 Heads
• CPC Class Codes: G11B 11/10534 for recording by magnetising, demagnetising or transfer of magnetisation, by radiation, e.g. for thermomagnetic recording
• CPC Class Codes: G11B 11/10541 for reproducing
• CPC Class Codes: G11B 11/10543 using optical beam of radiation
• CPC Class Codes: G11B 11/10554 the transducers being disposed on the same side of the carrier flying heads G11B11/1058
• CPC Class Codes: G11B 11/10563 Access of indexed parts
• CPC Class Codes: G11B 11/10569 Swing arm positioners
• CPC Class Codes: G11B 11/1058 Flying heads
• CPC Class Codes: G11B 11/10595 Control of operating function
• CPC Class Codes: G11B 20/10009 Improvement or modification of read or write signals
• CPC Class Codes: G11B 20/1866 by interleaving G11B20/1809 takes precedence
• CPC Class Codes: G11B 20/1879 Direct read-after-write methods
• CPC Class Codes: G11B 20/1883 Methods for assignment of alternate areas for defective areas
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 7/0037 : with discs
• CPC Class Codes: G11B 7/00375 : arrangements for detection of physical defects, e.g. of recording layer
• CPC Class Codes: G11B 7/08564 : using galvanomirrors
• CPC Class Codes: G11B 7/08576 : Swinging-arm positioners
• CPC Class Codes: G11B 7/0901 : for track following only G11B7/0925, G11B7/094, G11B7/0941, G11B7/0943, G11B7/0945, G11B7/0946, G11B7/0948 take precedence
• CPC Class Codes: G11B 7/0948 : specially adapted for detection and avoidance or compensation of imperfections on the carrier, e.g. dust, scratches, dropouts G11B7/095 takes precedence
• CPC Class Codes: G11B 7/122 : Flying-type heads, e.g. analogous to Winchester type in magnetic recording
• CPC Class Codes: G11B 7/127 : Lasers; Multiple laser arrays lasers per se H01S
• CPC Class Codes: G11B 7/1362 : Mirrors
• CPC Class Codes: G11B 7/1365 : Separate or integrated refractive elements, e.g. wave plates
• CPC Class Codes: G11B 7/1372 : Lenses
• CPC Class Codes: G11B 7/1384 : Fibre optics
• CPC Class Codes: G11B 7/14 : specially adapted to record on, or to reproduce from, more than one track simultaneously
• CPC Class Codes: G11B 7/22 : Apparatus or processes for the manufacture of optical heads, e.g. assembly
• CPC Class Codes: H02N 1/008 : Laterally driven motors, e.g. of the comb-drive type
• CPC Class Codes: H04B 10/2572 : due to forms of polarisation-dependent distortion other than PMD

Abstract

A system and method to compensate for data defects within a magneto-optical computer memory device comprises a data channel coupled to the memory device for receiving and processing data signals, and a detector channel coupled to the data channel for detecting the data defects and then generating corresponding defect-skipping pulses. The data channel responsively uses the defect-skipping pulses to compensate for the data defects and thus maintain reliability of the data signals.

Claims

1. A system to compensate for data defects in a memory device, comprising:

a data channel coupled to said memory device for receiving and processing data signals, wherein said data channel determines a rotation of a plane of polarization from a sensed light reflected from a surface of a storage medium to retrieve data; and

a detector channel coupled to said data channel for detecting said data defects by analyzing an amplitude of a sensed light reflected from the surface of the storage medium and responsively generating corresponding defect pulses, said data channel receiving said data defect pulses and responsively compensating for said data defects.

2. The system of claim 1, wherein said memory device comprises a magneto-optical disk drive system and corresponding drive circuitry including said data channel and said detector channel.

3. The system of claim 2, wherein said data channel includes an inverting amplifier coupled to a first signal and a first summing amplifier coupled to an output of the inverter for summing the inverted first signal with a second signal to provide an analog signal to a converter device.

4. The system of claim 3, wherein said detector channel includes a second summing amplifier coupled to a detector, wherein said first and second signals are input into said second summing amplifier to provide a reflectivity signal to said detector.

5. The system of claim 4, wherein said detector generates a coast signal when said reflectivity signal crosses a threshold value.

6. A method to compensate for data defects in a memory device, comprising the steps of:

providing data signals to a data channel coupled to said memory device wherein said data channel determines a rotation of a plane of polarization from a sensed light reflected from a surface of a storage medium to retrieve data;

detecting said data defects with a detector channel coupled to said data channel, wherein said data defects are detected by analyzing an amplitude of a sensed light reflected from the surface of the storage medium;

generating defect pulses corresponding to said data defects; and

providing said defect pulses to said data channel to compensate for said data defects.

7. The method of claim 6, wherein said memory device comprises a magneto-optical disk drive system and corresponding drive circuitry including said data channel and said detector channel.

8. The method of claim 6, wherein said step of providing data signals to a data channel comprises the step of providing a first signal to an inverting amplifier and providing a second signal to a first summing amplifier coupled to an output of the inverter for summing the inverted first signal with the second signal to provide an analog signal to a converter device.

9. The method of claim 8, wherein said step of detecting said data defects with a detector channel comprises the step of providing said first and second signals to a second summing amplifier to provide a reflectivity signal to a detector.

10. The method of claim 9, wherein said step of generating defect pulses corresponding to said data defects comprises the step of generating a coast when said reflectivity signal crosses a threshold value.

11. A system to compensate for data defects in a memory device, comprising:

means for providing data signals to a data channel coupled to said memory device, wherein said data channel determines a rotation of a plane of polarization from a sensed light reflected from a surface of a storage medium to retrieve data means for analyzing an amplitude of a sensed light reflected from the surface of the storage medium to detect said data defects with a detector channel coupled to said data channel;

means for generating defect pulses corresponding to said data defects; and

means for providing said defect pulses to said data channel to compensate for said data defects.