Several types of I/O+ boards are available: SBus+ I/O board, Graphics+ I/O board, and PCI+ I/O board.
For easy access to I/O cables, I/O+ boards should be installed in the rear of the cabinet, with CPU/Memory+ boards in the front of the cabinet. I/O+ boards should be installed from the smallest odd-numbered slot (1) to the largest odd-numbered slot (7 or 15). The odd-numbered slots are located at the rear of the cabinet. When located in these slots, the board is oriented so that the component side is up.
Board slot 1 requires an SBus+ or Graphics+ I/O board because this is the only slot that connects with the internal media tray. If slot 1 does not contain an I/O+ board, the drives in the media tray will not function.
If the rear slots are filled, you can use slots at the front of the cabinet. When located in a front slot, the board is oriented so that the component side is down.
All empty card cage slots must contain a load board (Enterprise 6500 server) or filler panel (Enterprise 5500 or 4500 servers).
The SBus+ I/O board with 100 MB/sec Fibre Channel (Figure B-7) includes two SYSIO ASICs that provide two SBuses:
One for two plug-in SBus cards and two GBIC (100 MB/sec Fibre Channel) interfaces
One for one plug-in SBus card and the onboard devices (10/100 Mbit TPE and Single-ended Fast/Wide SCSI)
SBus connector slots 1 and 2 on the SBus+ I/O board can accommodate a double-wide SBus card.
The Graphics+ I/O board with 100 MB/sec Fibre Channel (Figure B-8) includes one SYSIO ASIC that provides a single SBus for two plug-in SBus cards, two GBIC (100 MB/sec Fibre Channel) interfaces, and the onboard devices (10/100 Mbit TPE and Single-ended Fast/Wide SCSI).
The PCI+ I/O board (Figure B-9) has two PCI bus connectors:
Each connector can accommodate a PCI riser card
Each riser card accommodates one PCI short card
In addition, onboard devices on the PCI+ I/O board provide Fast Ethernet (10/100 Mbit) and Fast/Wide SCSI interfacing.
The board contains five subsystems: I/O (PCI Bus), Memory, Bus Interface, FireHose Interface, and Clock Generation. Four of these subsystems: the I/O (PCI Bus), Memory, Bus Interface and internal board interface subsystems include ASICs. The Clock subsystem distributes and generate clocks for the ASICs and PCI Bus Interfaces on the board