IBM Midrange System DS4000 Series Hardware Manual page 91

Enhanced Disk Drive Modules (E-DDMs)
The hot-swap drive bays that are accessible from the front of your storage subsystem are
shown in Figure 3-49.
Hot-swap drive bays
Slot 1
(left-most)
Figure 3-49 DS5020 hot-swap drive bays
The DS5020 supports both Fibre Channel (FC) and SATA E-DDMs intermixed in the storage
subsystem drive chassis. The DS5020 supports up to sixteen 4 Gbps FC or 3 Gbps SATA
E-DDMs.
SATA E-DDMs have an ATA translator card (interposer card) that converts the Fibre Channel
protocol interface of the DS5020 drive channel or loop into the hard drive SATA protocol
interface. It also provides dual paths to the SATA drive for drive CRU path redundancy. Each
drive, ATA translator card, and carrier assembly is called SATA E-DDM CRUs. The Fibre
Channel E-DDMs consist of the Fibre Channel and the carrier assembly (drive tray).
Install E-DDM CRUs in the 16 drive bays on the front of the storage subsystem from the
leftmost slot (slot 1) to the rightmost slot (slot 16). When an E-DDM is installed, the drive and
tray slot designation is set automatically. The hardware addresses are based on the
enclosure ID, which is set by the controller software, and on the E-DDM physical location in
the storage subsystem.
The DS5020 storage subsystem drive channel operates at a 4 Gbps Fibre Channel interface
speed. Even the 3 Gbps SATA E-DDMs operate at 4 Gbps Fibre Channel speed.
Note: Even though the DS5020 has a 2 or 4 Gbps Fibre Channel Link Rate switch that can
be used to set the drive channel speed at 2 Gbps, the link rate speed must be set to 4
Gbps. The DS5020 supports only 4 Gbps FC speed in the drive channel.
The Link Rate switch on the DS5020 storage subsystem and all storage expansion
enclosures connected to it must have the same setting.
Chapter 3. IBM System Storage DS4000 and DS5000 hardware
Speed selector Slot 16
(2 or 4 Gbps) (right-most)
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