1.3.2CPU/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.

1.3.3I/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.

Chapter 1 System Overview 1-21