Operating a Tape Drive During and After a Transition To a Stand-By Mode
AssigneeInternational Business Machines Corporation
InventorShuhei Nadehara
Life of this patent
Estimating the term…
Abstract
In a tape drive during a transition to a stand-by mode, a tape is wound under control of a processor (e.g., CPU) until duration of a time interval between moments when rotational positions of the reels change decreases to a pre-determined threshold. Thereafter, in the stand-by mode, the processor switches control over the tape drive to a low-power logic circuit (e.g., PLC) and enters a power-save mode.
Claims18
A method of operating a tape drive having a first reel, a second reel and a tape wound on said reels, the method comprising:
- performing under control of a processor during a transition from an operational mode to a stand-by mode:
- winding the tape onto the first reel from the second reel;
- monitoring rotational positions of the first and second reels;
- and
- when duration of a time interval between changes in the rotational positions of said first and second reels becomes equal to or smaller than a pre-determined threshold, (i) terminating winding the tape, (ii) entering the stand-by mode, and (iii) switching control over the tape drive to a logic circuit;
- and
- performing under control of the logic circuit during the stand-by mode:
- detecting a change in a rotational position of at least one of the first or second reels from a first position to a second position;
- and
- counter-rotating said at least one of the first or second reels until the rotational position thereof is restored from the second position to the first position.
A tape drive, comprising:
- a first reel;
- a first plurality of sensors of a rotational position of the first reel;
- a second reel;
- a second plurality of sensors of a rotational position of the second reel;
- at least one motor for rotating said reels;
- a processor configured for controlling the at least one motor in an operational mode of the tape drive and during a transition from the operational mode to a stand-by mode of the tape drive;
- and
- a logic circuit configured for controlling the at least one motor in the stand-by mode of the tape drive.
A computer program product for operating a tape drive having a first reel, a second reel and a tape wound on said reels, said computer program product comprising:
- a data storage medium;
- and
- computer program code within the data storage medium, said computer program code including instructions for performing:
- under control of a processor during a transition from an operational mode to a stand-by mode:
- winding the tape onto the first reel from the second reel;
- monitoring rotational positions of the first and second reels;
- and
- when duration of a time interval between moments when rotational positions of said reels change becomes equal to or smaller than a pre-determined threshold, (i) terminating winding the tape, (ii) entering the stand-by mode, and (iii) switching control over the tape drive to a logic circuit;
- and
- under control of the logic circuit during the stand-by mode:
- detecting a change in a rotational position of at least one of the first or second reels;
- and
- counter-rotating said at least one of the first or second reels until the rotational position thereof is restored.
Dependencies are inferred from the claim text.