IBM 3401-S03, Appliance Operation Manual, Page: 27 / 82

The chassis has a 19-inch rack mounting that enables it to be installed on to standard 19-inch racks and
uses 5 EIA units of rack space (8.75 inches (222 mm)).
Each drawer contains 42 bays for Disk Drives in Carriers (DDICs). DDICs are top-mounted into the
drawers.
At the rear, the chassis assembly can accept two PSUs (or one PSU + one PSU blank), one SBB compute
module and SBB module blank, and five cooling modules.
Drawers
Each drawer contains 42 slots, each of which accepts a single DDIC containing a 3.5” drive.
Opening a drawer does not interrupt the functioning of the system, and DDICs can be hotswapped while
the enclosure continues to operate. However, drawers must not be left open for longer than 2 minutes,
otherwise airflow and cooling are compromised.
The drawer is designed to support its own weight, plus the weight of any drives, when fully open.
The following safety features are included:
v To reduce the possibility of toppling, only one drawer can be open at any one time.
v The drawer locks into place when opened all the way. To reduce pinching hazards, two latches must be
released before the drawer can be pushed back in.
Data is sent via three baseplanes and a single sideplane that is mounted on the left side of the drawer,
with no redundant path available. Power is sent via three baseplanes and two sideplanes, the sideplanes
ensures a redundant power path to each drive. The right sidpelane provides power to the drives and
does not provide a data path.
Each drawer is locked shut by turning both anti-tamper locks clockwise. Use a screwdriver with a Torx
T20 bit (see Figure 8 on page 10). Each side of each drawer has a series of status LEDs, shown in the
following figure.
Chapter 2. System overview
11