HP 98568A Installation Instruction page 337

HP 7957/58/59S SCSI Disk Drives
6. Record the Address.
Make a note that address 0 (or the alternate address you set in an earlier
step of this installation procedure) has been used and is no longer available
on the interface you selected. Use the "Address Record" form on the
Chapter 6, "Mass Storage" tab for this purpose.
NOTE!
Turn on the power to the disk drive BEFORE turning the
power on to the computer.
Adding Mass Storage Devices 6-111