Recovery of data from optical data disk sectors having missing or defective synchronization information

Claim 1

An optical data disk controller for an optical data disk having tracks adapted to contain data arranged in sectors, comprising: first means for searching a predefined region of a selected sector of data read from said disk for a pattern of bits corresponding to a sync to which a data stream to be read from said sector is to be aligned; second means responsive to said first means for generating a "sync found" signal upon detection of said sync pattern in said predefined region; third means responsive to said first means for generating a "pseudo-sync" signal in an absence of said sync pattern in said predefined region; fourth means responsive to said "sync found" signal or pseudo-sync"signal for byte aligning the data stream to be read from said selected sector; fifth means for detecting resync patterns of bits read from said selected sector to maintain byte alignment throughout the data stream; and sixth means for establishing a first search window having a programmably variable first width for searching for said sync patterns and for establishing a second search window having a programmably variable second width for searching for said resync patterns.

Claim 6

A method of data recovery from an optical data disk storing data in sectors arranged serially along a multiplicity of tracks, each sector having header and data field the method comprising the steps of: (a) searching a selected sector of said data disk to detect a sync pattern of bits designating a portion of said data field from which sector data is to be aligned; (b) in response to detection of said sync pattern in step (a), performing a normal data read operation including byte aligning data taken from said sector data field; (c) in response to non-detection of said sync pattern in step (a), performing a data recovery operation including byte aligning data taken from said sector data field and (d) repeating steps (a)-(c) for any other selected sectors; said data read and data recovery operations including searching said data field within a search window to detect at least one resync pattern of bits designating another portion of said data field from which alignment of said sector data is to be maintained, wherein said search window size is progressively increased during searches for successive resync patterns of bits in each of said data read and data recovery operations.

Claim 7

A method of data recovery from an optical data disk storing data in sectors arranged serially along a multiplicity of tracks, each sector having header and data field the method comprising the steps of: (a) searching a selected sector of said data disk to detect a sync pattern of bits designating a portion of said data field from which sector data is to be aligned; (b) in response to detection of said sync pattern in step (a), performing a normal data read operation including byte aligning data taken from said sector data field; (c) in response to non-detection of said sync pattern in step (a), performing a data recovery operation including byte aligning data taken from said sector data field and (d) repeating steps (a)-(c) for any other selected sectors; said data read and data recovery operations including searching said data field within a search window to detect at least one resync pattern of bits designating another portion of said data field from which alignment of said sector data is to be maintained, wherein said search window size is progressively increased during searches for successive resync patterns of bits in each of said data read and data recovery operations.

Claim 19

A method of data recovery from an optical data disk storing data in sectors arranged serially along a multiplicity of tracks, each sector having header and data field, the method comprising the steps of: (a) searching a selected sector of said data disk to detect a sync pattern of bits designating a portion of said data field from which sector data is to be aligned; (b) in response to detection of said sync pattern in step (), performing a normal data read operation including byte aligning data taken from said sector data field; (c) in response to non-detection of said sync pattern in step (a), performing a data recovery operation including byte aligning data taken from said sector data field; and (d) repeating steps (a)-(c) for any other selected sectors; said data read and data recovery operations including searching said data field to detect at least one resync pattern of bits designating another portion of said data field from which alignment of said sector data is to be maintained, wherein during said normal read operation, resync patterns are searched using a window selectively of a fixed or progressively increasing size for successive resyncs, and wherein during said data recovery operation, resync patterns are searched using a window that is (1) initially fixed and of a predetermined maximum size, and following finding of a mark is (2) reduced to a predetermined minimum size and then increased progressively for successive resyncs.

Claim 20

A method of data recovery from an optical data disk storing data in sectors arranged serially along a multiplicity of tracks, each sector having header and data field, the method comprising the steps of: (a) searching a selected sector of said data disk to detect a sync pattern of bits designating a portion of said data field from which sector data is to be aligned; (b) in response to detection of said sync pattern in step (), performing a normal data read operation including byte aligning data taken from said sector data field; (c) in response to non-detection of said sync pattern in step (a), performing a data recovery operation including byte aligning data taken from said sector data field; and (d) repeating steps (a)-(c) for any other selected sectors; said data read and data recovery operations including searching said data field to detect at least one resync pattern of bits designating another portion of said data field from which alignment of said sector data is to be maintained, wherein during said normal read operation, resync patterns are searched using a window selectively of a fixed or progressively increasing size for successive resyncs, and wherein during said data recovery operation, resync patterns are searched using a window that is (1) initially fixed and of a predetermined maximum size, and following finding of a mark is (2) reduced to a predetermined minimum size and then increased progressively for successive resyncs.