Specifications

Chapter 2. Architecture and technical overview 85
2.10 External I/O subsystems
This section describes the external 12X I/O subsystems that can be attached to the
Power 770 and Power 780, listed as follows:
򐂰 PCI-DDR 12X Expansion Drawer (#5796)
򐂰 12X I/O Drawer PCIe, small form factor (SFF) disk (#5802)
򐂰 12X I/O Drawer PCIe, No Disk (#5877)
Table 2-29 provides an overview of all the supported I/O drawers.
Table 2-29 I/O drawer capabilities
The two GX++ buses from the second processor card feed two GX++ Adapter slots. An
optional GX++ 12X DDR Adapter, Dual-port (#1808), which is installed in GX++ Adapter slot,
enables the attachment of a 12X loop, which runs at either SDR or DDR speed depending on
the 12X I/ O drawers that are attached.
2.10.1 PCI-DDR 12X Expansion drawer
The PCI-DDR 12X Expansion Drawer (#5796) is a 4U (EIA units) drawer and mounts in a
19-inch rack. Feature #5796 is 224 mm (8.8 in.) wide and takes up half the width of the 4U
(EIA units) rack space. The 4U enclosure can hold up to two #5796 drawers mounted
side-by-side in the enclosure. The drawer is 800 mm (31.5 in.) deep and can weigh up to
20 kg (44 lb).
The PCI-DDR 12X Expansion Drawer has six 64-bit, 3.3 V, PCI-X DDR slots, running at
266 MHz, that use blind-swap cassettes and support hot-plugging of adapter cards. The
drawer includes redundant hot-plug power and cooling.
Two interface adapters are available for use in the #5796 drawer:
򐂰 Dual-Port 12X Channel Attach Adapter Long Run (#6457)
򐂰 Dual-Port 12X Channel Attach Adapter Short Run (#6446)
The adapter selection is based on how close the host system or the next I/O drawer in the
loop is physically located. Feature #5796 attaches to a host system CEC enclosure with a
12X adapter in a GX++ slot through SDR or DDR cables (or both SDR and DDR cables). A
maximum of four #5796 drawers can be placed on the same 12X loop. Mixing #5802/5877
and #5796 on the same loop is not supported.
A minimum configuration of two 12X cables (either SDR or DDR), two AC power cables, and
two SPCN cables is required to ensure proper redundancy.
Drawer
feature code
DASD PCI slots Requirements for the Power 770
and Power 780
#5796 - 6 x PCI-X GX++ adapter card #1808
#5802 18 x SAS disk drive bays 10 x PCIe GX++ adapter card #1808
#5877 - 10 x PCIe GX++ adapter card #1808