Selective index writing prior to unthreading a magnetic recording tape
AssigneeInternational Business Machines Corporation
InventorsTohru Hasegawa, Masayuki Iwanaga, Yutaka Oishi
Life of this patent
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Abstract
A drive-implemented method according to one embodiment includes determining that unthreading of a tape is to be performed, and in response to the determination that the unthreading of the tape is to be performed, determining whether to write an index on the tape prior to unthreading the tape. In response to a determination to write the index on the tape, the index is written on the tape prior to unthreading the tape. The tape is then unthreaded.
Claims23
A drive-implemented method, comprising:
- determining that unthreading of a tape is to be performed;
- in response to the determination that the unthreading of the tape is to be performed, determining whether to write an index on the tape prior to unthreading the tape, wherein determining whether to write the index on the tape prior to unthreading the tape includes determining whether to write the index in a partition of the tape, the partition being selected from a group consisting of an index partition and a data partition of the tape;
- in response to a determination to write the index on the tape, writing the index on the tape prior to unthreading the tape;
- and
- unthreading the tape.
A computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a controller to cause the controller to:
- determine, by the controller, that unthreading of a tape is to be performed;
- in response to the determination that the unthreading of the tape is to be performed, determine, by the controller, whether to write an index in a data partition of the tape prior to unthreading the tape;
- in response to a determination to write the index in the data partition, instruct, by the controller, writing of the index in the data partition prior to unthreading the tape;
- in response to the determination that the unthreading of the tape is to be performed, determine, by the controller, whether to write the index in an index partition of the tape prior to unthreading the tape;
- in response to a determination to write the index in the index partition, instruct, by the controller, writing of the index in the index partition prior to unthreading the tape;
- and
- instruct, by the controller, a threading mechanism to unthread the tape.
An apparatus, comprising:
- a controller;
- and
- logic integrated with the controller, executable by the controller, or integrated with and executable by the controller, the logic being configured to:
- determine, by the controller, that unthreading of a tape is to be performed;
- determining that unthreading of a tape is to be performed;
- in response to determining that the unthreading of the tape is to be performed, determine, by the controller, whether to write an index on the tape prior to unthreading the tape;
- in response to a determination to write the index on the tape, write, by the controller, the index on the tape prior to unthreading the tape;
- unthread the tape;
- receive, by the controller, a write request after the unthreading;
- rethread, by the controller, the tape;
- and
- write, by the controller, data corresponding to the write request on the tape, wherein the index stored on the tape prior to the unthreading is overwritten with the data corresponding to the write request.
Dependencies are inferred from the claim text.