NEC Express5800/120Rd-2, Service Manual

Page: 42 / 362

1-24 System Overview
System Board Management Controller (BMC)
Server management is concentrated in the System Board Management Controller (BMC). The
BMC and associated circuitry are powered from a 5Vdc standby voltage, which remains active
when system power is switched off, but the ac power source is still on and connected.
The BMC supports the Management Workstation Application (NEC MWA), which allows
remote server management via a modem or direct connection to a manager system. Events
monitored by the manager system include over-temperature and over-voltage conditions, fan
failure, or chassis intrusion.
Information on MWA may be found on the EXPRESSBUILDER CD-ROM included with your
server.
One major function of the BMC is to autonomously monitor system management events, and log
their occurrence in the nonvolatile System Event Log (SEL). The events being monitored
include over-temperature and over-voltage conditions, fan failure, or chassis intrusion. To enable
accurate monitoring, the BMC maintains the nonvolatile Sensor Data Record (SDR), from which
sensor information can be retrieved. The BMC provides an ISA host interface to SDR sensor
information, so that software running on the server can poll and retrieve the server's current
status.
The BMC performs the following:
!
Monitors system board temperature and voltage
!
Monitors processor presence and controls Fault Resilient Boot (FRB)
!
Detects and indicates baseboard fan failure
!
Manages the SEL interface
!
Manages the SDR Repository interface
!
Monitors the SDR/SEL timestamp clock
!
Monitors the system management watchdog timer
!
Monitors the periodic SMI timer
!
Monitors the event receiver
!
Controls secure mode, including video blanking, diskette write-protect monitoring, and
front panel lock/unlock initiation
!
Controls Wake On LAN via Magic Packet support.