IBM TS3100 Setup, Operator, And Service Manual page 340

D-16
TS3100 Tape Library and TS3200 Tape Library Setup, Operator, and Service Guide
means that the current direction is away from the physical beginning of
the tape. A 1 means that the current direction is towards the physical
beginning of the tape.
12. Relative LPOS fields (Bytes 30-33) reports the current physical position
on the tape.
13. SCSI Address field (Byte 34) reports the SCSI Bus Address for the drive.
Values returned range from 00h to 0Fh.
14. This field (Byte 35) contains the frame and drive number, passed across
the RS-422 serial interface.