Abstract: A computer-implemented method according to one embodiment includes identifying code word interleaved (CWI)-4 entries to be re-written to a data storage cartridge, selecting a subset of the CWI-4 entries to be included within a first CWI-4 set, where a plurality of the CWI-4 entries within the subset are associated with a single sub data set (SDS), and re-writing the first CWI-4 set to the data storage cartridge.

Abstract: A method of operating a magnetic tape within a tape drive. The tape drive comprises a tape head, which shows a tape-bearing surface meant to face a front side of a magnetic tape, in operation. The tape-bearing surface comprises a transducer area. This area includes at least one transducer, which is a read or write element configured to read or write to the magnetic tape, respectively. The method may include driving the tape (along a longitudinal direction of circulation thereof above the tape-bearing surface) and concomitantly ejecting a gas flow toward the transducer area. The gas flow ejected impinges on the back side of the driven tape (e.g., opposite to the front side of the tape), so as to locally urge the front side of the tape against the transducer area and thereby read or write to the tape via said at least one transducer.

Abstract: A determination is made whether read/write is enabled within the tape drive storage unit. In response to determining that read/write is enabled, a determination is made whether a temperature within the tape drive storage unit exceeds a threshold value. In response to determining that the temperature within the tape drive storage unit exceeds the threshold value, a determination is made of a direction of travel of a tape media within the tape drive storage unit. In response to determining that the direction of travel is a forward direction, a first cooling device is powered on. The first cooling device lowers the temperature of a first guide roller and the tape media coming off a first tape storage reel prior to the tape media passing by a read/write head within the tape drive storage unit.

Abstract: A method according to one embodiment includes generating a y-position estimate based on a servo readback, and determining a nonlinearity-correction value corresponding to the y-position estimate. The method further includes adjusting the y-position estimate using the nonlinearity-correction value. A computer program product for compensating for nonlinearity in a timing based servo pattern according to another embodiment includes a computer readable storage medium having program instructions embodied therewith. The program instructions are readable and/or executable by a controller to cause the controller to perform the foregoing method. An apparatus according to another embodiment includes a controller configured to perform the foregoing method.

Abstract: A method according to one embodiment includes applying a static head skew to a magnetic tape head, positioning the first reader at a first y-position relative to a servo pattern in a servo band, and measuring y-positions of the second reader relative to the servo pattern in the servo band while the first reader is at the first y-position. A y-position value is calculated for the second reader based on the measured y-positions. The following process is repeated several times: moving the first reader to a next y-position, measuring y-positions of the second reader while the first reader is at the next y-position, and calculating a y-position value of the second reader based on the measured y-position of the second reader. A unique nonlinearity value of the servo pattern in the servo band is calculated for each of the calculated y-position values of the second reader.

Abstract: A method of operating a magnetic tape within a tape drive. The tape drive comprises a tape head, which shows a tape-bearing surface meant to face a front side of a magnetic tape, in operation. The tape-bearing surface comprises a transducer area. This area includes at least one transducer, which is a read or write element configured to read or write to the magnetic tape, respectively. The method may include driving the tape (along a longitudinal direction of circulation thereof above the tape-bearing surface) and concomitantly ejecting a gas flow toward the transducer area. The gas flow ejected impinges on the back side of the driven tape (e.g., opposite to the front side of the tape), so as to locally urge the front side of the tape against the transducer area and thereby read or write to the tape via said at least one transducer.

Abstract: A determination is made whether read/write is enabled within the tape drive storage unit. In response to determining that read/write is enabled, a determination is made whether a temperature within the tape drive storage unit exceeds a threshold value. In response to determining that the temperature within the tape drive storage unit exceeds the threshold value, a determination is made of a direction of travel of a tape media within the tape drive storage unit. In response to determining that the direction of travel is a forward direction, a first cooling device is powered on. The first cooling device lowers the temperature of a first guide roller and the tape media coming off a first tape storage reel prior to the tape media passing by a read/write head within the tape drive storage unit.

Abstract: In one embodiment, a method includes writing a data set to a sequential access medium. The method also includes reading the data set after being written in a read-while-write process to identify faulty encoded data blocks, each of the faulty encoded data blocks including at least one faulty codeword. Moreover, the method includes rewriting a correct version of a first of the encoded data blocks in a first encoded data block set to the rewrite area of the sequential access medium selected from a predetermined subset of logical tracks. The predetermined subset of logical tracks includes D1+D2+1 logical tracks. Only one encoded data block from a particular sub data set is rewritten in a single encoded data block set in the rewrite area.

Abstract: A determination is made whether read/write is enabled within the tape drive storage unit. In response to determining that read/write is enabled, a determination is made whether a temperature within the tape drive storage unit exceeds a threshold value. In response to determining that the temperature within the tape drive storage unit exceeds the threshold value, a determination is made of a direction of travel of a tape media within the tape drive storage unit. In response to determining that the direction of travel is a forward direction, a first cooling device is powered on. The first cooling device lowers the temperature of a first guide roller and the tape media coming off a first tape storage reel prior to the tape media passing by a read/write head within the tape drive storage unit.

Abstract: In one embodiment, a method includes writing a data set to a sequential access medium. The method also includes reading the data set immediately after being written to the sequential access medium in a read-while-write process to identify one or more faulty encoded data blocks, each of the one or more faulty encoded data blocks including at least one faulty codeword having symbols at least 10 bits in size. Moreover, the method includes rewriting a first of the one or more faulty encoded data blocks within a first encoded data block set to a particular logical track in the rewrite area of the sequential access medium selected from a predetermined subset of logical tracks. The predetermined subset of logical tracks includes D1+D2+1 logical tracks. Only one faulty encoded data block from a particular sub data set is rewritten in a single encoded data block set in the rewrite area.

Abstract: A determination is made whether read/write is enabled within the tape drive storage unit. In response to determining that read/write is enabled, a determination is made whether an absolute value of a channel offset exceeds a threshold value. In response to determining that the absolute value of the channel offset exceeds a threshold value, a direction of travel of the tape media is determined. In response to determining that the direction of travel of the tape media is a forward direction, a determination is made whether the channel offset is positive. In response to determining that the channel offset is positive, a left cooling device within the tape drive storage unit is powered on. The left cooling device lowers the temperature of a left guide roller and the tape media coming off a left tape storage reel prior to the media passing by a read/write head.

Abstract: A tape drive-implemented method, according to one embodiment, includes: using information read from one or more servo bands on a magnetic tape to position a magnetic tape head relative to the magnetic tape. An array of data transducers is positioned along the magnetic tape head, the array extending perpendicular to a direction of travel of the magnetic tape. Moreover, a group of servo readers is positioned at each end of the array of data transducers. A distance between each of the immediately adjacent servo readers in each of the groups of servo readers is less than or equal to one third of a prespecified width of each of the servo bands. Furthermore, the distance between each of the servo readers in each of the groups and the prespecified width are both measured in a direction perpendicular to the direction of travel of the magnetic tape.

Abstract: A determination is made whether read/write is enabled within the tape drive storage unit. In response to determining that read/write is enabled, a determination is made whether a temperature within the tape drive storage unit exceeds a threshold value. In response to determining that the temperature within the tape drive storage unit exceeds the threshold value, a determination is made of a direction of travel of a tape media within the tape drive storage unit. In response to determining that the direction of travel is a forward direction, a first cooling device is powered on. The first cooling device lowers the temperature of a first guide roller and the tape media coming off a first tape storage reel prior to the tape media passing by a read/write head within the tape drive storage unit.

Abstract: A determination is made whether read/write is enabled within the tape drive storage unit. In response to determining that read/write is enabled, a determination is made whether an absolute value of a channel offset exceeds a threshold value. In response to determining that the absolute value of the channel offset exceeds a threshold value, a direction of travel of the tape media is determined. In response to determining that the direction of travel of the tape media is a forward direction, a determination is made whether the channel offset is positive. In response to determining that the channel offset is positive, a left cooling device within the tape drive storage unit is powered on. The left cooling device lowers the temperature of a left guide roller and the tape media coming off a left tape storage reel prior to the media passing by a read/write head.

Abstract: A determination is made whether read/write is enabled within the tape drive storage unit. In response to determining that read/write is enabled, a determination is made whether a temperature within the tape drive storage unit exceeds a threshold value. In response to determining that the temperature within the tape drive storage unit exceeds the threshold value, a determination is made of a direction of travel of a tape media within the tape drive storage unit. In response to determining that the direction of travel is a forward direction, a first cooling device is powered on. The first cooling device lowers the temperature of a first guide roller and the tape media coming off a first tape storage reel prior to the tape media passing by a read/write head within the tape drive storage unit.

Abstract: In one general embodiment, a method includes receiving data logically organized into a predetermined number of two-dimensional arrays, each two-dimensional array including a plurality of NS codewords positioned orthogonally to a plurality of WS codewords. The method also includes successively writing each of the NS codewords to a data storage medium. A first NS codeword from a first two-dimensional array is written to the data storage medium prior to starting to write a second NS codeword from the first two-dimensional array. Also, the plurality of NS codewords are protected with a stronger encoding than the plurality of WS codewords.

Abstract: A tape drive-implemented method, according to one embodiment, includes: using information read from one or more servo bands on a magnetic tape to position a magnetic tape head relative to the magnetic tape. An array of data transducers is positioned along the magnetic tape head, the array extending perpendicular to a direction of travel of the magnetic tape. Moreover, a group of servo readers is positioned at each end of the array of data transducers. A distance between each of the immediately adjacent servo readers in each of the groups of servo readers is less than or equal to one third of a prespecified width of each of the servo bands. Furthermore, the distance between each of the servo readers in each of the groups and the prespecified width are both measured in a direction perpendicular to the direction of travel of the magnetic tape.

Abstract: In one embodiment, a method includes receiving data to store to a magnetic tape medium using a tape drive, the data being organized into a predetermined number of two-dimensional arrays, each two-dimensional array including a plurality of narrow-spread (NS) codewords positioned orthogonally to a plurality of wide-spread (WS) codewords (relative spread referring to space occupied on the magnetic tape medium when written). The method also includes successively writing each of the NS codewords onto a plurality of tracks of the magnetic tape medium using a first number of channels of the tape drive capable of writing data to tape tracks simultaneously. A first NS codeword from a first two-dimensional array is completely written to the magnetic tape medium prior to starting to write a second NS codeword from the first two-dimensional array. Also, the plurality of NS codewords are protected with a stronger encoding than the plurality of WS codewords.

Abstract: The invention is notably directed to computer-implemented methods and systems for managing datasets in a storage system. In such systems, it is assumed that a (typically small) subset of datasets are labeled with respect to their relevance, so as to be associated with respective relevance values. Essentially, the present methods determine, for each unlabeled dataset of the datasets, a respective probability distribution over a set of relevance values. From this probability distribution, a corresponding relevance value can be obtained. This probability distribution is computed based on distances (or similarities), in terms of metadata values, between said each unlabeled dataset and the labeled datasets. Based on their associated relevance values, datasets can then be efficiently managed in a storage system.

Abstract: In one general embodiment, a method includes applying a static head skew to a magnetic tape head, positioning the first reader at a first y-position relative to a servo pattern in a servo band, measuring y-positions of the second reader relative to the servo pattern in the servo band while the first reader is at the first y-position, and averaging the measured y-positions. The method further includes repeating the following process several times: moving the first reader to a next y-position, measuring y-positions of the second reader while the first reader is at the next y-position, and averaging the y-positions measured by the second reader while the first reader is at the next y-position. The method further includes calculating a unique nonlinearity value of the servo pattern in the servo band for each of the average y-position values, and storing and/or outputting the calculated nonlinearity values.