Abstract: A method is disclosed. The method includes performing a first read operation at a tape drive, determining if a minimum number of data bytes have been recovered in the first read operation to perform error correcting codes (ECC), performing a second read operation if the minimum number of data bytes to perform ECC have not been recovered, determining if a minimum number of data bytes have been recovered in the second read operation to perform ECC, combining the recovered data bytes from the first read operation and the second read operation to form combined recovered data bytes, determining if a minimum number of data bytes are included in the combined recovered data bytes to perform ECC and performing ECC if the minimum number of data bytes are included in the combined recovered data bytes.

Abstract: In one embodiment, a method and apparatus for isolating marginal recording to media or recording apparatus is disclosed. The method includes generating an experience metric from an interaction between a media mounted in a drive, updating one or more metrics for each of the media and the drive based on the experience metric and one or more prior metrics of the media and the drive, storing the one or more updated metrics to the associated media and drive, and utilizing the one or more updated metrics to predict performance trends of the media and the drive for preventative maintenance purposes. Other embodiments are also disclosed.

Abstract: A method for writing data in a tape drive is provided by the present invention. The present invention provides a method for writing data in a tape drive. The invention include allocating a blank area for transpose writing on a magnetic tap and then writing a first group of data sets on the magnetic tape adjacent to the blank area. The tape drive maintains full operating speed during intervals between writing successive data sets, resulting in spaces between the data sets. At a specified interval, the drive repositions the tape writes a transposed data block to the allocated blank area, wherein the transposed data block contains the same content as the first group of data sets. A new blank area for transpose writing is then allocated adjacent to the recently transposed data block.

Abstract: In one embodiment, a method and apparatus for minimizing unload times in a tape drive system is disclosed. The method includes: writing to a tape in serpentine format; reaching a comparison point on the tape, wherein at the comparison point an actual capacity is compared to an expected capacity; utilizing the comparison at the comparison point to estimate a distance from the comparison point until a guaranteed capacity for the tape is reached; and determining a turn-around point on the tape based on the estimated distance, wherein at the turn-around point a tape drive writing to the tape to stop writing in a first direction and then continue writing in a second direction opposite from the first direction and towards a physical beginning of the tape. Other embodiments are also disclosed.

Abstract: In one embodiment, a method and apparatus for isolating marginal recording to media or recording apparatus is disclosed. The method includes generating an experience metric from an interaction between a media mounted in a drive, updating one or more metrics for each of the media and the drive based on the experience metric and one or more prior metrics of the media and the drive, storing the one or more updated metrics to the associated media and drive, and utilizing the one or more updated metrics to predict performance trends of the media and the drive for preventative maintenance purposes. Other embodiments are also disclosed.

Abstract: A method is disclosed. The method includes performing a first read operation at a tape drive, determining if a minimum number of data bytes have been recovered in the first read operation to perform error correcting codes (ECC), performing a second read operation if the minimum number of data bytes to perform ECC have not been recovered, determining if a minimum number of data bytes have been recovered in the second read operation to perform ECC, combining the recovered data bytes from the first read operation and the second read operation to form combined recovered data bytes, determining if a minimum number of data bytes are included in the combined recovered data bytes to perform ECC and performing ECC if the minimum number of data bytes are included in the combined recovered data bytes.

Abstract: In one embodiment, a method and apparatus for minimizing unload times in a tape drive system is disclosed. The method includes: writing to a tape in serpentine format; reaching a comparison point on the tape, wherein at the comparison point an actual capacity is compared to an expected capacity; utilizing the comparison at the comparison point to estimate a distance from the comparison point until a guaranteed capacity for the tape is reached; and determining a turn-around point on the tape based on the estimated distance, wherein at the turn-around point a tape drive writing to the tape to stop writing in a first direction and then continue writing in a second direction opposite from the first direction and towards a physical beginning of the tape. Other embodiments are also disclosed.

Abstract: A drive and method of identifying write velocity during reading are provided. When a track is being read, the data signal is processed prior to determining the data stream to identify the velocity with which the track data were written. The read channel is adjusted based on the identified velocity to compensate for write channel transfer function variation.

Abstract: A method and system are provided for dynamically shortening a number of error correction codewords to correspond to an amount of user data to be recorded on a recording medium. The system and method determine in advance that the number of bytes of user data will only fill a portion of a codeword matrix, and automatically shortens the size of ECC word segments to match the actual user data fill. This allows an ECC interleave to be completed with only a partial fill of the matrix, thereby reducing the required number of recording passes and associated processing time.

Abstract: A tape drive and method of identifying write velocity during reading are provided. When a track is being read, a lead-in code of the data signal is processed prior to determining the data stream. The lead-in code identifies the velocity with which the track data were written. The equalization/detection channel is adjusted based on the identified velocity to compensate for write channel transfer function variation. The lead-in code is coded in a way that is reasonably immune to write channel transfer function variation such that the lead-in code is comprehended prior to adjusting the equalization/detection channel.

Abstract: An asynchronous method for locating individual blocks of data in a tape drive, without having to read the blocks of data is provided. The invention comprises placing an ID mark adjacent to the data blocks and inter-block gaps on the tape. The ID mark contains a small amount of information about the next respective data block on the tape. The ID mark is encoded such that the same detection mechanism that detects the inter-block gap can also retrieve the ID mark information, without having to process the entire block of data associated with a particular ID mark. The ID mark is symmetrical such that it can be detected and decoded in the forward and backward direction, allowing the tape drive to find a desired block of data by searching either forward or backward, even when the magnetic tape uses a unidirectional data format.

Abstract: A method, apparatus, and computer instructions for writing data to a magnetic media. A first frequency is written on a first track on the magnetic media on a first track width. A second frequency is written on the first track in which a combination of the first frequency and the second frequency encodes a bit of data on the first track. An erase pattern is created on a second track on the magnetic media, the second track being adjacent to the first track in which the bit of data on the first track is readable by a tape drive system having a second track width wider than the track width of the first track.

Abstract: A system and method for recovering from write errors during writing of a moving storage medium suspend write current while allowing the storage medium to continue moving. The system and method continue to format data for writing while the write current is suspended and resequence the data for subsequent storage. Information is recorded to distinguish previously written data from current data with error correction pointers adjusted accordingly. Write errors may be detected in a track following streaming tape system based on data errors from a read back check or based on positioning errors of a read/write head servo system, for example. By allowing the storage medium to continue moving through the error event, the system and method improve speed, capacity utilization, and throughput of the storage and retrieval process.

Abstract: A method, computer program product, and data processing system for recovering corrupted data in a multi-track storage medium, such as magnetic tape, using a Reed-Solomon or other similar error correcting code system, is disclosed. A correction history keeping a tally of actual corrected instances of corruption in the storage medium is established. The “N” tracks requiring the greatest number of actual error corrections are designated as erasures. Any errors in the remaining tracks must be found on an individual basis before being corrected.

Abstract: A system and method for recovering from write errors during writing of a moving storage medium suspend write current while allowing the storage medium to continue moving. The system and method continue to format data for writing while the write current is suspended and resequence the data for subsequent storage. Information is recorded to distinguish previously written data from current data with error correction pointers adjusted accordingly. Write errors may be detected in a track following streaming tape system based on data errors from a read back check or based on positioning errors of a read/write head servo system, for example. By allowing the storage medium to continue moving through the error event, the system and method improve speed, capacity utilization, and throughput of the storage and retrieval process.

Abstract: A method, computer program product, and data processing system for recovering corrupted data in a multi-track storage medium, such as magnetic tape, using a Reed-Solomon or other similar error correcting code system, is disclosed. A correction history keeping a tally of actual corrected instances of corruption in the storage medium is established. The “N” tracks requiring the greatest number of actual error corrections are designated as erasures. Any errors in the remaining tracks must be found on an individual basis before being corrected.

Abstract: A method and system are provided for dynamically shortening a number of error correction codewords to correspond to an amount of user data to be recorded on a recording medium. The system and method determine in advance that the number of bytes of user data will only fill a portion of a codeword matrix, and automatically shortens the size of ECC word segments to match the actual user data fill. This allows an ECC interleave to be completed with only a partial fill of the matrix, thereby reducing the required number of recording passes and associated processing time.