A tape drive that can select one or more wraps from any available wraps on a tape medium for writing temporary data upon detecting a flush condition. The one or more wraps selected for writing temporary data can be selected from wraps otherwise reserved for normal writing operations. Selection of the one or more wraps for temporary writing may be based on multiple considerations, including proximity to the wrap of current data writing operations and tape medium degradation. The one or more wraps selected for writing temporary data may be selected with or without regard of their assigned read/write direction. Assigning wraps based on proximity and/or degradation can lead to certain operational advantages including reducing tape write head movement in the transverse direction and spreading tape medium wear more evenly across the surface of the tape medium.

The direction of a WRAP and the logical points on which a file are written influence the efficiency of a recall of the file. Embodiments of the present invention provide methods and systems which can be applied to an upper storage layer and a lower storage layer in a hierarchical storage system. In turn, the migration and recall of a plurality of files, which contain data, are more rapid and efficient by preferring one logical point over another logical point.

An approach for deleting a file from a primary file system. The approach deletes a directory entry, associated with a file, from an in-memory index associated with a secondary file system. The approach updates an index cache associated with a secondary file system, based on the in-memory index. The approach updates a dirty flag, associated with the secondary file system, to a value of TRUE.

A tape drive that can select one or more wraps from any available wraps on a tape medium for writing temporary data upon detecting a flush condition. The one or more wraps selected for writing temporary data can be selected from wraps otherwise reserved for normal writing operations. Selection of the one or more wraps for temporary writing may be based on multiple considerations, including proximity to the wrap of current data writing operations and tape medium degradation. The one or more wraps selected for writing temporary data may be selected with or without regard of their assigned read/write direction. Assigning wraps based on proximity and/or degradation can lead to certain operational advantages including reducing tape write head movement in the transverse direction and spreading tape medium wear more evenly across the surface of the tape medium.

A computer-implemented method, according to one embodiment, includes: receiving a read request for data stored on a magnetic tape, the data having multiple portions. For each portion of the requested data determined as not being located in a cache, a determination is made as to whether performing a locate command or performing a read command a plurality of times will retrieve the portions of the requested data that are not located in the cache in a shorter amount of time. The command determined to retrieve the portions of the requested data that are not located in the cache in the shorter amount of time are issued to a tape drive. Moreover, the portions of the requested data that are not located in the cache are combined with portions of the requested data that are located in the cache. Furthermore, the combined portions are used to satisfy the read request.

A computer-implemented method, according to one embodiment, includes: receiving a read request for data stored on a magnetic tape. For each portion of the requested data, an iterative process is performed. In preferred approaches, the iterative process includes: instructing a tape drive to read the portion of the requested data from the magnetic tape, and determining whether a copy of the portion of the requested data is located in a cache. In response to determining that a copy of the portion of the requested data is located in the cache, the tape drive is instructed to discard the portion of the requested data read from the magnetic tape. However, in response to determining that a copy of the portion of the requested data is not located in the cache, the portion of the requested data read from the magnetic tape is received from the tape drive.

A computer-implemented method, according to one embodiment, includes: determining whether a first amount of time associated with performing a locate operation to advance a magnetic tape from a current position to a beginning of the requested data is less than a second amount of time associated with performing a number of read operations to advance the magnetic tape from the current position to the beginning of the requested data. In response to determining that the first amount of time is less than the second amount of time, a tape drive is instructed to perform the locate operation. In response to determining that the first amount of time is not less than the second amount of time, the tape drive is instructed to perform the number of read operations. The tape drive is also instructed to discard data read from the magnetic tape while performing the number of read operations.

An approach for deleting a file from a primary file system. The approach deletes a directory entry, associated with a file, from an in-memory index associated with a secondary file system. The approach updates an index cache associated with a secondary file system, based on the in-memory index. The approach updates a dirty flag, associated with the secondary file system, to a value of TRUE.

A tape drive that can select one or more wraps from any available wraps on a tape medium for writing temporary data upon detecting a flush condition. The one or more wraps selected for writing temporary data can be selected from wraps otherwise reserved for normal writing operations. Selection of the one or more wraps for temporary writing may be based on multiple considerations, including proximity to the wrap of current data writing operations and tape medium degradation. The one or more wraps selected for writing temporary data may be selected with or without regard of their assigned read/write direction. Assigning wraps based on proximity and/or degradation can lead to certain operational advantages including reducing tape write head movement in the transverse direction and spreading tape medium wear more evenly across the surface of the tape medium.

A computer-implemented method, according to one embodiment, includes: sending one or more instructions to calculate a combined size of fragments included in the fragmented files, sending one or more instructions to designate a portion of cache which corresponds to at least the combined size of the fragments, sending one or more instructions to send a copy of each non-fragmented file from a first drive directly to a second drive in which the second sequential storage medium is loaded, sending one or more instructions to use the designated portion of the cache to accumulate the fragments included in the fragmented files, and sending one or more instructions to send a copy of each of the fragments corresponding to a given fragmented file from the cache to the second drive in response to determining that all of the fragments corresponding to the given fragmented file have been accumulated in the cache.