Fast locate using imitation reads on tape drives

A computer-implemented method, comprising:

• receiving a read request for data stored on a magnetic tape, the data comprising multiple portions;
• instructing a tape drive to access the requested data on the magnetic tape;
• and
• for each portion of the requested data, performing an iterative process of:
• instructing the tape drive to read the portion of the requested data from the magnetic tape;
• determining whether a copy of the portion of the requested data is located in a cache;
• instructing the tape drive to discard the portion of the requested data read from the magnetic tape in response to determining that a copy of the portion of the requested data is located in the cache;
• and
• receiving, from the tape drive, the portion of the requested data read from the magnetic tape in response to determining that a copy of the portion of the requested data is not located in the cache.

A computer program product comprising a computer readable storage medium having program instructions embodied therewith, wherein the computer readable storage medium is not a transitory signal per se, the program instructions readable and/or executable by a processor to cause the processor to perform a method comprising:

• receiving, by the processor, a read request for data stored on a magnetic tape, the data comprising multiple portions;
• instructing, by the processor, a tape drive to access the requested data on the magnetic tape;
• and
• for each portion of the requested data, performing, by the processor, an iterative process of:
• instructing the tape drive to read the portion of the requested data from the magnetic tape;
• determining whether a copy of the portion of the requested data is located in a cache;
• instructing the tape drive to discard the portion of the requested data read from the magnetic tape in response to determining that a copy of the portion of the requested data is located in the cache;
• and
• receiving, from the tape drive, the portion of the requested data read from the magnetic tape in response to determining that a copy of the portion of the requested data is not located in the cache.

A computer-implemented method, comprising:

• receiving a read request for data stored on a magnetic tape;
• determining whether a first amount of time associated with performing a locate operation to advance the magnetic tape from a second position to a first position is less than a second amount of time associated with performing a number of read operations to advance the magnetic tape from the second position to the first position, wherein the second position corresponds to a current location of a magnetic tape head relative to the magnetic tape, wherein the first position corresponds to a beginning of the requested data;
• instructing the tape drive to perform the locate operation in response to determining that the first amount of time is less than the second amount of time;
• instructing the tape drive to perform the number of read operations in response to determining that the first amount of time is not less than the second amount of time;
• and
• instructing the tape drive to discard the data read from the magnetic tape while performing the number of read operations.

A computer program product comprising a computer readable storage medium having program instructions embodied therewith, wherein the computer readable storage medium is not a transitory signal per se, the program instructions readable and/or executable by a processor to cause the processor to perform a method comprising:

• receiving, by the processor, a read request for data stored on a magnetic tape;
• determining, by the processor, whether a first amount of time associated with performing a locate operation to advance the magnetic tape from a second position to a first position is less than a second amount of time associated with performing a number of read operations to advance the magnetic tape from the second position to the first position, wherein the second position corresponds to a current location of a magnetic tape head relative to the magnetic tape, wherein the first position corresponds to a beginning of the requested data;
• instructing, by the processor, the tape drive to perform the locate operation in response to determining that the first amount of time is less than the second amount of time;
• instructing, by the processor, the tape drive to perform the number of read operations in response to determining that the first amount of time is not less than the second amount of time;
• and
• instructing, by the processor, the tape drive to discard the data read from the magnetic tape while performing the number of read operations.