Patent ID: 6958878

Claim:
Data storage logic for controlling a magnetic tape drive for storing data on a magnetic tape data storage media in a plurality of wraps, which comprise a plurality of parallel longitudinally recorded tracks, said magnetic tape drive having at least one input and/or output, having at least one data buffer, and having a plurality of stepped operational speeds for moving said magnetic tape data storage media longitudinally with respect to at least one tape head for transferring data by reading and/or writing data with respect to said magnetic tape data storage media, said magnetic tape drive capable of conducting a backhitch of said magnetic tape data storage media, said data storage logic: estimates the effective data fill and/or empty rate for said at least one data buffer with respect to said input and/or said output; estimates the drive data rate for transferring data with respect to said at least one data buffer and said magnetic tape data storage media at the current stepped operational speed of said magnetic tape drive; estimates, from said effective data fill and/or empty rate for said at least one data buffer and said drive data rate, the time cost to continue to operate said magnetic tape drive at said current stepped operational speed from a target to substatially the next end of wrap; estimates, from said effective data fill and/or empty rate for said at least one data buffer and a data rate for transferring data with respect to said magnetic tape data storage media of at least one higher stepped operational speed of said magnetic tape drive, together with a forced backhitch of said magnetic tape drive, the time cost to force a backhitch of said magnetic tape data storage media and change said stepped operational speed to said higher stepped operational speed and to operate said magnetic tape drive at said higher stepped operational speed from said target to substantially the next end of wrap; and determines the lesser of said time costs.