The motherboard interconnect for these systems has been greatly simplified. 12-volt power is distributed to the motherboard through a pair of metal bus bars, connected to a Power Distribution Board (PDB). A single flex-circuit connector routes all critical power control and DVD drive signaling over to the PDB. One or two mini-SAS cables connect the motherboard to the disk drive backplane, providing data access to the system hard drives.
Memory Subsystem
In Sun SPARC Enterprise T5120 and T5220 servers, the UltraSPARC T2 processor’s on-chip memory controllers communicate directly to FBDIMM memory through high-speed serial links. The four dual-channel FBDIMM memory controllers can transfer data at an aggregate rate of 32 giga-transfers per second. Sixteen memory socket locations provide sufficient board space for two rows of 667 MHz FBDIMMs per channel.
I/O Subsystem
The UltraSPARC T2 processor incorporates a single, 8-lane (x8) PCI Express port capable of operating at 4 GB/second bidirectionally. This port natively interfaces to the I/O devices through a series of PLX technology PCI Express expander chips, connecting either to PCI Express card slots, or to bridge devices that interface with PCI Express, such as those listed below.
•Disk Controller — Disk control is managed by a single LSI Logic SAS1068E SAS controller chip that interfaces to a four-lane (x4) PCI Express port. RAID levels 0 and 1 are provided as standard.
•Dual GBE — Two x4 PCI Express ports connect to two Intel Ophir dual Gb Ethernet chips, providing four 10/100/1000 Mbps Ethernet interfaces on the rear of each chassis.
•USB and DVD — A single-lane PCI Express port connects to a PLX PEX8111 PCI bridge device. A second bridge chip converts the 32-bit 33MHz PCI bus into multiple USB 2.0 ports. The system’s USB interconnect is driven from those ports. In addition, the DVD is driven from a further bridge chip that interfaces one of the USB ports to IDE format.
To minimize cabling and increase reliability, a variety of smaller boards and riser cards are deployed, appropriate to each chassis. These infrastructure boards serve various functions in the Sun SPARC Enterprise T5120 and T5220 servers.
•Power distribution boards distribute system power from the dual power supplies to the motherboard and to the disk backplane (via a connector board)
•Connector boards eliminate the need for many discrete cables, providing a direct card plug-in interconnect to distribute control and most data signals to the disk backplane, fan boards, and the PDB.