IBM F50 RS/6000 7025 - Manual (Page 199)

Installing a SSA Disk Drive in Bank C, D, or E.
Notes:
Banks C, D, and E support hot-swappable disk drives only.
SSA disk drive carriers and SCSI disk drive carriers are not
interchangeable.
9.1 GB drives (1.6 inches high) require two bays for each drive.
Before installing disk drives in bank D or E, you must also order and
install a disk drive backplane at the rear of bank D or E. You must also
order and install an SSA adapter and an SSA cable that connects the
disk drive backplane to the SSA adapters. (To order, contact your
authorized reseller or marketing representative.)
After the backplane is completely installed, you do not have to turn off the
server to install additional hot-swappable disk drives. However, you must
turn off the system when performing the steps that involve installing or
removing backplanes, cables, adapters, memory, and CPU cards
Chapter 5. Installing Options 5-55