Patent ID: 6943976

Claim:
A system for determining positioning in an automated data storage library, said automated data storage library having a plurality of storage shelves for storing data storage media; at least one data storage drive for reading and/or writing data with respect to said data storage media; and at least one robot accessor for transporting said data storage media between said plurality of storage shelves and said at least one data storage drive; said robot accessor having at least one sensor, and said automated data storage library having at least one home position for said at least one robot accessor; said system comprising: at least one reference point located at an expected location in said automated data storage library remote from said robot accessor home position; and at least one processor for operating said at least one robot accessor in accordance with a calibration system, said at least one processor, conducting a rezero operation, moves said robot accessor sensor to said expected location of said at least one reference point; and if said one reference point is sensed by said robot accessor sensor at substantially said expected location, said rezero operation is completed; wherein said at least one processor, during said rezero operation, if said one reference point is sensed by said robot accessor; compares said sensed location of said one reference point to said expected location; if said comparison indicates an offset between said sensed location and said expected location of said one reference point, moves said robot accessor to a second expected location of a second reference point; and if said second reference point is sensed by said robot accessor sensor at substantially said second expected location, updates said calibration system with respect to said one reference point, and said rezero operation is completed.