Abstract: A method and system are disclosed for efficiently reading and processing multiple data blocks stored in a removable data storage medium within a data storage system, wherein each data block includes a header portion containing selected parameters necessary to identify and process an associated data block, and a data portion. Each data block is accessed within the removable data storage medium utilizing track logic circuitry and then coupled to a data block buffer for temporary storage. A header processing logic circuit is interposed between the track logic circuitry and the data block buffer and is utilized to initiate processing of only the header portion of each data block prior to storage of the data block within the data block buffer. After completion of processing of the header portion of a data block and completion of storage of that data block within the data block buffer, the data block is efficiently processed utilizing selected parameters contained within the header portion.

Abstract: A magnetic tape drive simultaneously senses on a magnetic tape three evenly spaced-apart servo track areas for servoing a multi-track magnetic head to follow a concurrent set of data tracks on the magnetic tape. The data tracks are arranged into a plurality of track groups. Each track group has a first and second subgroup of data tracks. The first subgroup of tracks are scanned in a first relative motion of the magnetic tape and magnetic head as a forward direction (tape is being spooled from a supply tape reel). The second subgroup of tracks are scanned in a second relative motion of the magnetic tape and magnetic head that is opposite in direction to the first relative direction and is a forward direction of scanning. While writing data in any one of the plural track groups, a servo dropout affecting most of the servo track areas is detected and indicated as a servo error. Writing is aborted. The relative position of the magnetic tape and head is detected at both longitudinal ends of the servo dropout.