|C H A P T E R 4|
Sun Fire System Components
The Sun Fire E6900/E4900 systems share many of the same components. These components are the CPU/Memory boards, the I/O assemblies, the Repeater boards, and the System Controller boards.
The CPU/Memory board is the same across the Sun Fire E6900/E4900 systems. This board supports up to four UltraSPARC IV/IV+ CPU modules, and eight banks of memory, two banks per CPU with four DIMM sockets per bank, for a total of 32 DIMMs.
All DIMMs must be the same capacity and size within a bank, and must not be intermixed on a board.
The Sun Fire E6900/E4900 systems support PCI I/O devices.
The I/O assemblies are logically and physically the same for the Sun Fire E6900/E4900 systems. The basic PCI/PCI+/PCI-X I/O assembly will have six slots for standard PCI/PCI+/PCI-X (33-MHz) device boards, plus two slots for PCI-66 (66-MHz) device boards. PCI-X device boards will also operate at 100MHz for PCI I/O slots 2, 3, 4, 5, 6, and 7.
The Sun Fire E6900/E4900 systems are designed to be repaired and upgraded easier and faster than previous systems. This is due to the placement of active ASICs mounted on the Repeater boards. With two Repeater boards installed in the system, an alternate path is available through the second board, if one board fails.
The Repeater boards provide two functions: redundancy for reliability, and a higher bandwidth. The system can operate with only one Repeater board. The Repeater board acts as a switch and connects multiple CPU/Memory and I/O boards together. The three components are the Address Repeater (AR), the Sun Fire system data controller (SDC), and the data crossbar (DX).
In standard operation, the Sun Fire E6900 system has four Repeater boards which are used to route ten buses (six CPU and four I/O). If one of the Repeater boards fails, the system can continue to operate in a degraded mode with one pair of adjacent Repeater boards. The data width is cut in half and the two Repeater boards will route the ten buses.
Because the Sun Fire E4900 system supports only two Repeater boards, the two Repeater boards operate together to route five buses (three CPU and two I/O). If one of the Repeater boards fails, the data width is cut in half and one Repeater board can route the five buses.
The system controller board contains the system clock and a service processor. The processor on the board is a microSPARC IIep with its own POST/OBP flash PROM and memory. The processor also has a 33-MHz PCI/PCI+/PCI-X bus with two devices on it. The system controller board also has a 10/100BASE-T Ethernet connection and an Ebus interface for a variety of devices. These include a TOD/NVRAM device, flash PROM for extra NVRAM space, a large flash PROM to hold the OS code, and one 16552 dual serial port device.
One System Controller board is required per system. The Sun Fire E6900 comes with two system controllers for redundancy. You can install a second System Controller board in the Sun Fire E4900 System if desired. With two System Controller boards, if one System Controller board fails, the other System Controller board can take control of the system without causing a disruption in the main system operation.
The System Controller board performs the following main functions:
The system controller provides five ports: domain A console, domain B console, domain C console, domain D console, and the system controller shell. The system controller shell provides the following:
The system controller software sequences the booting of the system by:
The system controller software provides tools for changing the configuration of the system, and it also logs errors.
With two System Controller boards installed in Sun Fire E6900/E4900 systems, the second board is a redundant System Controller board. Each System Controller board can check the health and status of the other System Controller board. If the main System Controller board (SC0) fails, the redundant System Controller board (SC1) takes over operations without causing a disruption of the system operation.
The system controller provides a virtual key switch for each domain. The key switch command controls the position of the virtual key switch for each domain.
The system controller provides a Solaris software console for each domain. The Ethernet or serial port of the System Controller board is the physical connection for the Solaris software console. The serial port can support only one console at a time. However, the Ethernet port can support many consoles simultaneously. The system controller multiplexes these physical connections to provide console services for each domain and for the system controller.
The Sun Fire system TOD/NVRAM chip is located on the System Controller board. The system controller multiplexes the physical TOD chip to provide TOD services for each domain and for the System Controller board. The system controller also provides for synchronizing the TOD between the main System Controller board and the redundant System Controller board.
The Sun Fire system has a large number of sensors that monitor temperature, voltage, and current. The system controller polls these devices periodically. If thresholds are exceeded, the system controller shuts down various components to prevent damage.