International Business Machines Corporation

Yuhko Mori

Takashi Katagiri

Yutaka Oishi

Hirokazu Nakayama

Setsuko Masuda

James Mitchell Karp

Terue Watanabe

Pamela Ruth Nylander-Hill

Takamasa Hirata

Paul Merril Greco

Kevin Dale Butt

Masakatsu Murata

Tomoko Taketomi

A computer program product for implementing write procedures using an estimated best setting in a first run, the computer program product comprising a computer readable storage medium having program instructions executable by a tape drive to cause the tape drive to perform a method comprising: receiving, at the tape drive, a request for a write operation to be performed in the tape drive; determining, by the tape drive, a capacity margin ratio of the tape drive; determining an optimum a write procedure based at least in part on the capacity margin ratio; and invoking the optimum write procedure in response to determining the optimum write procedure. The optimum write procedure is selected from the group consisting of: a backhitch write procedure, a same wrap backhitchless flush (SWBF) write procedure, and a recursively accumulating backhitchless flush (RABF) write procedure.

Write procedure using estimated best setting in first run

A method for detecting at a migration destination medium a change in data during media migration between write once read many (WORM) media according to one embodiment includes writing data for WORM from a migration source medium to the migration destination medium; holding an identifier (ID) of the source medium in a non-user storage area in the destination medium; and holding information indicating a feature of the data in the non-user storage area.

Detecting tampering of data during media migration, and storage device

In one general embodiment, a tape drive system includes: a read channel; a write channel; logic configured to receiving a request for a write operation to be performed in a tape drive; logic configured to determine an optimum a write procedure in response to receiving the request, the determining being based on expected writing times of each of a plurality of write procedures and an expected transaction size of a next write operation; and logic configured to invoke the determined optimum write procedure in response to determining the optimum write procedure.

A computer program product includes a computer readable storage medium having program instructions executable by a tape drive to cause the tape drive to perform a method comprising: receiving, at the tape drive, a request for a write operation to be performed in the tape drive; determining, by the tape drive, an expected transaction size of a next write operation; comparing, by the tape drive, the expected transaction size of the next write operation to each of a first transaction size threshold and a second transaction size threshold in response to receiving the request; determining, by the tape drive, an optimum a write procedure based at least in part on the comparison; and invoking, by the tape drive, the optimum write procedure in response to determining the optimum write procedure.

In one general embodiment, a method includes receiving a request for a write operation to be performed in a tape drive, determining an expected transaction size of a next write operation, comparing the expected transaction size of the next write operation to each of a first transaction size threshold and a second transaction size threshold in response to receiving the request, determining an optimum a write procedure based at least in part on the comparison, and invoking the optimum write procedure in response to determining the optimum write procedure, wherein the first transaction size threshold is greater than the second transaction size threshold, and wherein the optimum write procedure is selected from the group consisting of: a backhitch write procedure, a same wrap backhitchless flush (SWBF) write procedure, and a recursively accumulating backhitchless flush (RABF) write procedure.

A first data group in an access sequence is selected. A distance from a current position of the tape medium is set to be a logical distance value, determined by a calculation function, that is substituted for the physical distance value for the data groups that are located in the specified regions as compared with other data groups located in the alternative specified regions. A second data group in the access sequence is selected. The logical distance value is then determined by multiplying a coefficient based on a physical positioning of each of the data groups in the tape medium, and a percentage of those of the plurality of data groups that have already been selected as the first data group and the second data group.

Reducing total seek time for determining an access sequence of data stored on a tape medium

An apparatus, computer readable medium device, and method for controlling transportation of a tape medium. A determination is made whether to execute a backhitch operation in response to writing a data set to tape from the buffer. If not, a determination is made whether a transaction size at which data is transferred from the buffer to the tape is less than a buffer size. If so, then a determination is made of a a new speed and whether a current speed is different from the determined new speed. If so, then a backhitch is initiated.

Apparatus and method for controlling transportation of tape medium

In one embodiment, a method for dynamically allocating a memory includes dividing a memory into a first portion and a second portion in response to detecting an error condition when reading data from a data storage medium. The first portion is allocated for processing normal read and/or write requests. The second portion is allocated for processing error recovery procedure (ERP) requests. In another embodiment, a computer program product for dynamically allocating a memory includes a computer readable storage medium having program code embodied therewith. The program code is readable/executable by a processor to divide, by the processor, a memory into a first portion and a second portion in response to detecting an error condition when reading data from a data storage medium. The first portion is allocated for processing normal read and/or write requests. The second portion is allocated for processing ERP requests.

Dynamic buffer size switching for burst errors encountered while reading a magnetic tape

In one embodiment, an apparatus for reading data from a data storage medium includes a processor and logic integrated with and/or executable by the processor, the logic being configured to: read data from a data storage medium, the data including a plurality of data sets, determine that an error condition is detected for a data set read from the data storage medium, determine whether the data set was read from the data storage medium using multiple cut and paste (C/P) error recovery procedure (ERP) (C/P ERP Multi), and when the data set was read from the data storage medium using C/P ERP Multi: continue reading data from the data storage medium normally when the detected error condition has been overcome using C/P ERP Multi; otherwise, continue using C/P ERP Multi to read data from the data storage medium until the error condition is overcome.

Single and multi-cut and paste (C/P) reconstructive error recovery procedure (ERP) using history of error correction

A mechanism is provided for tape writing of small transactions. A first file is written as a plurality of fixed-length data sets (DS), the DS number of the final DS in the plurality of DS is stored in memory as #N(DS#N) and the WP number as #M(WP#M), and the final first file and the second file in the DS following the final DS(DS#N, WP#M) containing the first file are packed and written in sequential DS units, and are stored as DS#N, DS#N+1, etc. and WP#M+1 in sequential order in DS containing the second file. The remaining first, second, or third file is packed and DS#N with WP#M is overwritten as DS#N with WP#M+2, and the remaining #N in the DS numbers of the second file and the third file in the subsequent DS are written as DS#N+1, N+2, etc. with WP#M+2, and the DS#N, #N+1, #N+2, etc. with WP#M+2 are stored.

Tape storage device and writing method therefor

In one general embodiment, a method includes receiving a request for a write operation to be performed in a tape drive; determining a capacity margin ratio of the tape drive; determining an optimum a write procedure based at least in part on the capacity margin ratio; and invoking the optimum write procedure in response to determining the optimum write procedure. The optimum write procedure is selected from the group consisting of: a backhitch write procedure, a same wrap backhitchless flush (SWBF) write procedure, and a recursively accumulating backhitchless flush (RABF) write procedure. Systems and computer program products configured to perform similar techniques are also disclosed.

A first data group in an access sequence is selected. Those data groups located in specified regions of the tape medium are separated from other data groups located in alternative specified regions of the tape medium. The distance from the current position of the tape medium is set to be a logical distance value, determined by a calculation function, that is substituted for the physical distance value for the data groups that are located in the specified regions as compared with other data groups located in the alternative specified regions. A second data group in the access sequence is selected. The logical distance value is then determined by multiplying a coefficient based on a physical positioning of each of the data groups in the tape medium, and a percentage of those of the plurality of data groups that have already been selected as the first data group and the second data group.

Various embodiments for improving tape drive efficiency using a processor device are provided. In one embodiment, a method comprises aggregating one of records and filemarks, the aggregating restricted to being performed only on read operations, from a plurality of data segments into at least one single data segment, including sequentially aggregating the one of the records and filemarks into the at least one single data segment.

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Yokohama, Japan

Yuhko Mori