It allows the user to move around at will within the tape, send output to different files, specify different blocksizes and record lengths for different files on the tape, and combine multiple tape files into a single output file. On output, records will be blank padded and blocked to create fixed length tape blocks. The parameter must be separated from the command by exactly one space.
Some commands take numeric parameters and others take alphameric text.
A description of the commands can be obtained by asking for help on any particular command. The keypad keys emulate the 2-character commands. See also EB, UT, and GT commands. This command will not back up before the beginning of the current file. 2 BL Sets the physical blocksize of records read on the tape to the size specified.