Chapter 1 System Overview 1-21
1.3.2 CPU/Memory Board Unit
The CPU/Memory Board Unit (CMU) contains CPUMs, memory modules, and a
DDC. The CMU and an I/O units can be combined to construct one or more
domains.
The CMU has the following features:
■ Contains an interconnect LSI module that uses the latest LSI process.
■ Uses Double Data Rate (DDR)II DIMM memory.
■ Supports the DR function that enables hot maintenance and replacement of CMUs
during system operation, and enables addition and deletion of active CMUs
during system operation.
■ A redundant DDC configuration enables continuous operation even if a DDC
fails.
1.3.3 I/O Unit
The I/O unit (IOU) consists of a PCIe bridge control LSI module, a printed circuit
board containing a DDC, a hard disk drive (HDD), PCIe slots, and PCI cassettes for
the IOU. The IOU and the CMU can be combined to configure a server.
The IOU has the following features:
■ It contains eight PCIe slots.
■ The IOU Onboard Device Card_A (IOUA) can be used to connect the in-cabinet
disk drive (2.5-inch SAS interface), the in-cabinet DVD-ROM drive, and a tape
device. The LAN port (1000BASE-T/100Base-TX/100Base-T) mounted on the card
can be used.
■ It supports PCI hot-plug for External I/O Expansion Units and PCIe slots.
■ An External I/O Expansion Unit can be used to connect the IOU to an External
I/O Expansion Unit connection card.
■ Supports the DR function that enables active maintenance and replacement of
IOUs during system operation and enables addition and deletion of active IOUs
during system operation.
■ Insert the PCI Card into one of the supplied cassettes before inserting it into a
built-in PCIe slot in the IOU. A PCI card whose length is up to 177.8 mm (short
size) can be mounted in a slot.
■ A redundant DDC configuration enables continuous operation even if a DDC
fails.
