Locating data stored on a magnetic medium

A system of locating data stored on a magnetic medium tape that has a beginning longitudinal position with respect to a beginning of the magnetic medium and a lateral position with respect to a first tape reel, the system comprising:

• a recording tool configured to:
• read a set of lateral positions of the magnetic medium tape with respect to the a first tape reel and a concurrent set of corresponding longitudinal positions of the magnetic medium tape with respect to the a beginning of the magnetic medium tape as the magnetic medium comes off the first tape reel during a first unwinding;
• determine that one or more of the read lateral positions read during the first unwinding exceeds a buffer zone between data tracks of the magnetic tape;
• a non-volatile storage medium configured to:
• store a record of the one or more set of lateral positions of the magnetic medium tape and a corresponding set of the concurrent corresponding set of longitudinal positions of the magnetic medium tape;
• and
• a controller configured to:
• perform the first unwinding of the magnetic tape from the first tape reel;
• wind the magnetic tape on to a second tape reel;
• perform a second unwinding of the magnetic tape from the second tape reel;
• read the record of the one or more set of lateral positions of the magnetic medium tape and the corresponding set of the set of concurrent corresponding longitudinal positions of the magnetic medium tape as the magnetic medium comes off a second tape reel during the second unwinding;
• and
• move a tape head laterally during the second unwinding to the lateral positions in response to the reading of the record of the one or more set of lateral positions of the magnetic medium tape and the corresponding set of the set of concurrent corresponding longitudinal positions of the magnetic medium tape.

A device for storing a record of lateral shifts of a magnetic medium tape, the device comprising:

• a tape reel;
• the a magnetic medium tape configured to have its lateral positions with respect to the tape reel and corresponding longitudinal positions with respect to a beginning of the magnetic tape, read during a first unwinding from said tape reel, and further adapted to be re-wound on to the tape reel after said first unwinding;
• a non-volatile storage medium for storing configured to store a record of a set of one or more of the lateral positions of the magnetic medium tape and a corresponding set of concurrent set of the corresponding longitudinal positions of the magnetic medium tape read during the first unwinding from said tape reel, and further configured to have the record of the one or more lateral positions of the magnetic tape and the corresponding set of the corresponding longitudinal positions of the magnetic tape, read during a second unwinding of the re-wound magnetic tape from the tape reel;
• and
• a tape reel cartridge configured to store the tape reel and the magnetic tape.