Hardware components overview

Main contents:
describe the Gigaplane centerplane
describe how and why components are hot-pluggable
describe the purpose and function of the Clock board
describe the difference in chassis designs from one Enterprise model to another
locate all chassis-mounted components and subassemblies
remove and replace all chassis-mounted components and subassemblies

The following describes the features of the 100-MHz-capable Gigaplane:
1,CPU/memory boards are usually in even-numbered slots in the front of E4500,E5500,E6500

systems
2,I/O boards are usually in odd-numbered slots in the back

The Gigaplane is a packet-switched bus with the following features:
1,256-bit data width
2,out-of-order completion
3,control and address buses are used at the same time as the data bus
4,sun enterprise x000 systems use a clock speed of 83MHz
5,sun enterprise x500 systems use a clock speed of 100MHz

The 16-slot Gigaplane runs at 90 MHz if you use only the first 12 slots nearest the clock
board. If you use more than 12 slots, the clock must be reduced to 83MHz. there is no

100MHz in the E6500 system

The clock board consists of the following subsystems:
console bus
clocks
reset logic
JTAG logic and interface port for factory testing only
centerplane connector signals monitoring

PCM(Power/Cooling Module) power supplies are used in Enterprise 3x00,4x00,5x00,and 6x00 systems. there must be a 300W PCM for every two adjacent boards in the system, because the fans inside the PCM are the only cooling for those boards.This means that if a board is added to the system, there must be an associated PCM.if one is not present, it must be added.
The PCMs:
are hot pluggable
supply cooling for two adjacent boards
operate in redundant current share mode(N 1) with up to :
8 on the Enterprise 6x00
4 on the Enterprise 4/5x00
3 on the Enterprise 3x00

PPS:peripheral power supply

The CPU/Memory boards and the I/O boards are hot pluggable under certain conditions. If the operating system detects a hardware failure in the board, the software turns off the green status LED on the board. It might also stop the blinking LED as well, depending on the failure
Note:Hot pluggable is not supported on the sun enterprise 250 and sun enterprise 450

The internal bus is SCSI-II(wide) for the internal disk drives, but operates in SCSI-I(narrow) mode for the removable media bays .Each system has at least one CPU/Memory board, and at least one I/O interface board for disk and removable media communications. Each system has a clock board that synchronizes everything and provides an interface to an ASCII terminal for boot processes and system administration. Each system has multiple power supplies that enable the hot-swap capability. Each system has space for several internal disk drives and the capability to add more