Patent classifications
G11B20/1886
Efficient rewrite using larger codeword sizes
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.
STORING MULTIPLE INSTANCES OF A HOUSEKEEPING DATA SET ON A MAGNETIC RECORDING TAPE
An apparatus according to one embodiment includes a controller configured to control writing operations to a magnetic recording tape. The apparatus further includes logic integrated with and/or executable by the controller for causing the controller to write user data to the magnetic recording tape in a user data area of the magnetic recording tape. Furthermore, the logic is integrated with and/or executable by the controller for causing the controller to create a housekeeping data set (HKDS) that includes location information for the user data written in the user data area, and write several copies of the HKDS in a non-user data area of the magnetic recording tape.
Storing multiple instances of a housekeeping data set on a magnetic recording tape
An apparatus according to one embodiment includes a controller configured to control writing operations to a magnetic recording tape. The apparatus further includes logic integrated with and/or executable by the controller for causing the controller to write user data to the magnetic recording tape in a user data area of the magnetic recording tape. Furthermore, the logic is integrated with and/or executable by the controller for causing the controller to create a housekeeping data set (HKDS) that includes location information for the user data written in the user data area, and write several copies of the HKDS in a non-user data area of the magnetic recording tape.
DETECTING DAMAGED AREAS ON MAGNETIC TAPE MEDIA USING DIAGNOSTICS LOCATE
A computer program product, according to one embodiment, includes a computer readable storage medium having program instructions embodied therewith. The program instructions are readable and/or executable by a processor to cause the processor to: determine, by the processor, a first error location on a magnetic tape where a first error occurred. One or more areas on the magnetic tape to be examined are also determined, by the processor, based on the first error location. Independent of a read and/or write operation, relative motion between a tape head and the magnetic tape is induced by the processor, such that the tape head is positioned adjacent to each of the one or more areas in turn. Moreover, each of the one or more areas having a respective number of measured servo errors which exceeds a threshold value are identified, by the processor, as a damaged area of the magnetic tape.
DETECTING DAMAGED AREAS ON MAGNETIC TAPE MEDIA USING DIAGNOSTICS LOCATE
A computer-implemented method, according to one embodiment, includes: receiving, from a tape drive, a first error location on a magnetic tape where a first error occurred, in addition to determining one or more areas on the magnetic tape to be examined based on the first error location. Independent of a read and/or write operation, the tape drive is instructed to induce relative motion between a tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas in turn. Moreover, each of the one or more areas having a respective number of measured servo errors which exceeds a threshold value is identified as a damaged area of the magnetic tape.
Detecting damaged areas on magnetic tape based on measuring number of servo errors
A computer-implemented method for determining a damaged area of a magnetic tape loaded in a tape drive, according to one embodiment, includes: determining a first error location on a magnetic tape where a first error occurred in response to experiencing the first error. Moreover, the method includes determining one or more areas on the magnetic tape to be examined. The one or more areas are determined using a predetermined algorithm which incorporates the first error location. Independent of a read and/or write operation, relative motion is induced between a tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas in turn. Furthermore, each of the one or more areas having a respective number of measured servo errors which exceeds a threshold value is identified as a damaged area of the magnetic tape.
SELECTIVE HARD AND SOFT REWRITES
The present disclosure includes systems and methods for reducing rewrite overhead in a sequential access storage system. The method may comprise writing a data set to a sequential access medium using a magnetic head, wherein the data set comprises a plurality of encoded data blocks, classifying each of the plurality of encoded data blocks on the sequential access medium into one of at least three classes of write quality, and rewriting the encoded data blocks in a rewrite area of the sequential access medium based at least in part on the write quality class. In some embodiments, the at least three classes of write quality may comprise a hard rewrite class for which rewrites are necessary to prevent data loss, a soft rewrite class for which rewrites are desirable but not necessary, and a no rewrite class for which no rewrite is needed or desired.
EFFICIENT REWRITE USING LARGER CODEWORD SIZES
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.
Efficient rewrite using larger codeword sizes
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.
DETECTING DAMAGED AREAS ON MAGNETIC TAPE MEDIA USING DIAGNOSTICS LOCATE
A computer-implemented method for determining a damaged area of a magnetic tape loaded in a tape drive, according to one embodiment, includes: determining a first error location on a magnetic tape where a first error occurred in response to experiencing the first error. Moreover, the method includes determining one or more areas on the magnetic tape to be examined. The one or more areas are determined using a predetermined algorithm which incorporates the first error location. Independent of a read and/or write operation, relative motion is induced between a tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas in turn. Furthermore, each of the one or more areas having a respective number of measured servo errors which exceeds a threshold value is identified as a damaged area of the magnetic tape.