METHOD AND APPARATUS FOR CONTROLLING MOTION OF STORAGE MEDIA

摘要

A method of controlling relative motion of a data storage medium on which data is stored in data groups comprising tracks extending across the storage medium and a rotatable transducer for reading data from the storage medium includes determining from the data groups a start reread data group at which a data reread process is to start following detection of a read error condition in a preceding data read process. The method also includes obtaining a reread track reference value for use in controlling that relative motion during the data reread process using a track reference value difference stored in at least one track of at least one data group that is to be reread during the data reread process and a track reference value that was used in controlling that relative rotation during the preceding data read process.