The BID primary command lets you work with the hardware block ID instead of the block numbers within a file. Z Data Tools displays the block ID (including flag byte) for every data block and tape mark. To locate a block with a specific block ID, enter the desired value in the Block-Id field. Enter BID again to return to the block number display. (Working with block IDs may be helpful to move the tape over defective areas which cannot be crossed with other tape positioning commands.)

You can only use BID with Tape Browse (option 4.1).