Bytes 5 through 8 contain the type codes and are used to identify the type of information in the record. The type code indicates the basic data type in a record, and the three sub-types are used to further classify the data and format. Bytes 9 through 12 contain the record length. Volume Descriptor Record - 360 bytes 2. 360 bytes 3.
Binary fields are either unsigned integer values or specified number codes.
The identification burst is recorded on tape by the tape drive and begins at least 1.7 inches before the trailing edge of the BOT marker. It extends no closer than 0.5 inch from the first data block.