Abstract: A method, apparatus, and storage device are provided for implementing enhanced performance with read before write to phase-change-memory (PCM). Each write to PCM is preceded by a read to avoid write cancellations with urgent reads from nearby locations. For every write, a large block of data is read from PCM, such as an entire partition, prior to the write in PCM. The cache copy of the large block of data is kept in a controller for the duration of write. A read request from the pre-fetched region is provided from the cached copy thereby preventing read interrupt during write operation.

Abstract: A method and apparatus are provided for implementing enhanced data read for multi-level cell (MLC) memory using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding. A data read back for data written to the MLC memory using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding is performed, higher voltage and lower voltage levels are compared, and respective data values are identified responsive to the compared higher voltage and lower voltage levels.

Abstract: A data storage system has a memory circuit that comprises memory cells and a control circuit that receives data bits provided for storage in the memory cells. The control circuit encodes the data bits to generate a first set of redundant bits and encoded data bits, such that the encoded data bits selected for storage in a first subset of the memory cells with first stuck-at faults have digital values of corresponding ones of the first stuck-at faults. The control circuit encodes the first set of redundant bits to generate a second set of redundant bits. The control circuit performs logic functions on the second set of redundant bits and the encoded data bits to generate a third set of redundant bits, such that redundant bits in the third set of redundant bits selected for storage in a second subset of the memory cells with second stuck-at faults have digital values of corresponding ones of the second stuck-at faults.

Abstract: A method and apparatus are provided for implementing enhanced performance with read before write to phase-change-memory. Each write to PCM is preceded by a read and a calculation to discover a location of any bad bits. The write data is converted to a format that can be corrected for a given number of previously undiscovered bit errors, and the writes are unverified.

Abstract: A data storage system includes a memory circuit and a control circuit. The control circuit is operable to receive data bits provided for storage in memory cells of the memory circuit. The control circuit is operable to compare each of the data bits provided for storage in a corresponding one of the memory cells having a stuck-at fault value to the stuck-at fault value. The control circuit is operable to generate encoded data bits by inverting each of the data bits having a different value than the stuck-at fault value of the corresponding one of the memory cells and by maintaining a digital value of each of the data bits having the stuck-at fault value of the corresponding one of the memory cells. The control circuit is operable to prevent any of the data bits from being stored in the memory cells determined to have unstable values. The control circuit is operable to generate redundant bits that indicate at least one operation to perform on the encoded data bits to regenerate the data bits.

Abstract: A data storage system includes a memory circuit having memory cells and a control circuit. The control circuit is operable to receive data bits provided for storage in the memory cells. A subset of the memory cells have predetermined stuck-at faults. The control circuit is operable to compute a binomial coefficient for each of the predetermined stuck-at faults based on a bit position of a corresponding one of the predetermined stuck-at faults within the memory cells. The control circuit is operable to add together the binomial coefficients to generate an encoded number using a combinatorial number system. The control circuit is operable to generate a first set of redundant bits that indicate the encoded number. The first set of redundant bits are used to decode bits read from the memory cells to regenerate the data bits.

Abstract: A data storage system includes a memory circuit and a control circuit. The control circuit is operable to receive data bits provided for storage in memory cells of the memory circuit. The control circuit is operable to compare each of the data bits provided for storage in a corresponding one of the memory cells having a stuck-at fault to a value of the stuck-at fault, and to invert each of the data bits having a different value than the value of the stuck-at fault of the corresponding one of the memory cells to generate encoded data bits. The control circuit is operable to generate redundant bits that indicate the encoded data bits to invert to regenerate the data bits.

Abstract: A data storage system includes a memory circuit comprising memory cells and a control circuit. The control circuit generates a first set of redundant bits indicating bit positions of the memory cells having stuck-at faults in response to a first write operation if a first rate of the stuck-at faults in the memory cells is greater than a first threshold. The control circuit is operable to encode data bits to generate encoded data bits and a second set of redundant bits that indicate a transformation performed on the data bits to generate the encoded data bits in response to a second write operation if a second rate of stuck-at faults in the memory cells is greater than a second threshold. The encoded data bits stored in the memory cells having the stuck-at faults match digital values of corresponding ones of the stuck-at faults.

Abstract: A shingled magnetic recording hard disk drive that uses writeable cache tracks in the inter-band gaps between the annular data bands minimizes the effect of far track erasure (FTE) in the boundary regions of annular data bands caused by writing to the cache tracks. Based on the relative FTE effect for all the tracks in a range of tracks of the cache track being written, a count increment (CI) table or a cumulative count increment (CCI) table is maintained. For every writing to a cache track, a count for each track in an adjacent boundary region, or a cumulative count for each adjacent boundary region, is increased. When the count value for a track, or the cumulative count for a boundary region, reaches a predetermined threshold the data is read from that band and rewritten to the same band.

Abstract: A method and apparatus are provided for implementing enhanced data partial erase for multi-level cell (MLC) memory using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding. A data partial erase for data written to the MLC memory using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding is performed, and a data re-write after the partial erase to the MLC memory is performed using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding. A data partial erase cycle includes a duration and voltage level based upon a degradation of the MLC memory cells.

Abstract: A data storage system includes a memory circuit comprising memory cells and a control circuit. The control circuit generates a first set of redundant bits indicating bit positions of the memory cells having stuck-at faults in response to a first write operation if a first rate of the stuck-at faults in the memory cells is greater than a first threshold. The control circuit is operable to encode data bits to generate encoded data bits and a second set of redundant bits that indicate a transformation performed on the data bits to generate the encoded data bits in response to a second write operation if a second rate of stuck-at faults in the memory cells is greater than a second threshold. The encoded data bits stored in the memory cells having the stuck-at faults match digital values of corresponding ones of the stuck-at faults.

Abstract: A data storage system includes a memory circuit having memory cells and a control circuit. The control circuit is operable to receive data bits provided for storage in the memory cells. A subset of the memory cells have predetermined stuck-at faults. The control circuit is operable to compute a binomial coefficient for each of the predetermined stuck-at faults based on a bit position of a corresponding one of the predetermined stuck-at faults within the memory cells. The control circuit is operable to add together the binomial coefficients to generate an encoded number using a combinatorial number system. The control circuit is operable to generate a first set of redundant bits that indicate the encoded number. The first set of redundant bits are used to decode bits read from the memory cells to regenerate the data bits.

Abstract: A method and apparatus are provided for implementing enhanced performance for multi-level cell (MLC) memory using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding. A voltage baseline of a prior write is identified, and a data write uses the threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding for data being written to the MLC memory responsive to the identified voltage baseline.

Abstract: A data storage system has a memory circuit that comprises memory cells and a control circuit that receives data bits provided for storage in the memory cells. The control circuit encodes the data bits to generate a first set of redundant bits and encoded data bits, such that the encoded data bits selected for storage in a first subset of the memory cells with first stuck-at faults have digital values of corresponding ones of the first stuck-at faults. The control circuit encodes the first set of redundant bits to generate a second set of redundant bits. The control circuit performs logic functions on the second set of redundant bits and the encoded data bits to generate a third set of redundant bits, such that redundant bits in the third set of redundant bits selected for storage in a second subset of the memory cells with second stuck-at faults have digital values of corresponding ones of the second stuck-at faults.

Abstract: A data storage system includes a memory circuit that has memory cells and a control circuit that is operable to receive data bits provided for storage in the memory cells. The control circuit is operable to receive a first matrix. Each row of the first matrix corresponds to a unique one of the data bits. The control circuit is operable to generate a second matrix having only the rows of the first matrix that correspond to the data bits provided for storage in a subset of the memory cells having stuck-at faults. The control circuit is operable to generate a third matrix having linearly independent columns of the second matrix. The control circuit is operable to encode the data bits to generate encoded data bits and redundant bits using the third matrix.

Abstract: A shingled magnetic recording (SMR) hard disk drive (HDD) essentially eliminates the effect of far track erasure (FTE) in the boundary regions of annular data bands caused by writing in the boundary regions of adjacent annular data bands. The extent of the FTE effect is determined for each track within a range of tracks of the track being written. Based on the relative FTE effect for all the tracks in the range, a count increment (CI) table or a cumulative count increment (CCI) table is maintained for all the tracks in the range. For every writing to a track in a boundary region, a count for each track in an adjacent boundary region, or a cumulative count for the adjacent boundary region, is increased. When the count reaches a predetermined threshold the data is read from that band and rewritten to the same band.

Abstract: A shingled magnetic recording (SMR) hard disk drive (HDD) essentially eliminates the effect of far track erasure (FTE) in the boundary regions of annular data bands caused by writing in the boundary regions of adjacent annular data bands. The extent of the FTE effect is determined for each track within a range of tracks of the track being written. Based on the relative FTE effect for all the tracks in the range, a count increment (CI) table or a cumulative count increment (CCI) table is maintained for all the tracks in the range. For every writing to a track in a boundary region, a count for each track in an adjacent boundary region, or a cumulative count for the adjacent boundary region, is increased. When the count reaches a predetermined threshold the data is read from that band and rewritten to the same band.

Abstract: A method and apparatus are provided for implementing enhanced data partial erase for multi-level cell (MLC) memory using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding. A data partial erase for data written to the MLC memory using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding is performed, and a data re-write after the partial erase to the MLC memory is performed using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding. A data partial erase cycle includes a duration and voltage level based upon a degradation of the MLC memory cells.

Abstract: A method and apparatus are provided for implementing enhanced performance for multi-level cell (MLC) memory using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding. A voltage baseline of a prior write is identified, and a data write uses the threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding for data being written to the MLC memory responsive to the identified voltage baseline.

Abstract: A method and apparatus are provided for implementing enhanced data read for multi-level cell (MLC) memory using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding. A data read back for data written to the MLC memory using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding is performed, higher voltage and lower voltage levels are compared, and respective data values are identified responsive to the compared higher voltage and lower voltage levels.