Abstract: An improved format is disclosed for storing a randomized data block in a storage device. The data block format includes a data field, an identifier (ID) field for storing an identifier that identifies data stored in the data field, and a randomizer seed field for storing a randomizer seed. An error check character generator generates an ID field error check character utilizing said identifier. The randomizer seed includes the ID field error check character.

Abstract: The control software and hardware in the tape drive control unit creates and manages a multiple level error detection and correction system to protect the data written on the magnetic tape. The helical scan data write circuits operate on the received stream of data records to produce two orthogonal error detection and correction codes on a scan group level. The data write circuit divides the received stream of data records into data segments, each of which contains a predetermined number of data bytes. A first of these scan group error codes is generated on a per data segment basis while a second scan group error is generated across multiple data segments. A third level error correction code is also used to protect an entire scan group rather than data on a per byte basis. The third level error correction code generator produces an error code over a predetermined number of sequentially written scan groups to enable the control unit to reconstruct an entire scan group if its data integrity is compromised.