Compaq AlphaServer DS20, Руководство по обслуживанию

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System Overview 1-37
Monitor
The I
2
C bus monitors the state of system conditions scanned by the power control
logic. There are two registers that the PC logic writes data to:
•
One records the state of the fans and power supplies and is latched when there is a
fault.
•
The other causes an interrupt on the I
2
C bus when a CPU or system fan fails, an
overtemperature condition exists, or power supplied to the system changes from
N + 1 to N or from N to N +1.
The interrupt received by the I
2
C bus controller and passed on to P-chip 0 alerts the
system of a power system event that may or may not cause a power shutdown. In the
event of imminent power loss the controller has 30 seconds to read the two registers
and store the information in the NVRAM on the server feature module. The SRM
console command show power reads these registers.
Fault Display
The OCP display is written through the I
2
C bus.
Error State
Error state is stored for power, fan, and overtemperature conditions on the I
2
C bus.
Configuration Tracking
Each CPU and each logical section of the system board (the PCI bridge, the PCI
backplane, the power control logic, the remote console manager), and the system
board itself has an EEPROM that contains information about the module that can be
written and read over the I
2
C bus. All EEPROMs contain the following information:
•
Module type
•
Module serial number
•
Hardware revision for the logical block
•
Firmware revision