Product guide

24
The L440GX+ supports sleep states s0, s1, s4, and s5. With future versions of
Microsoft Windows
®
9X that support ACPI, the BIOS will only support sleep states
s0, s1, and s5. With future versions of Microsoft Windows NT
®
x that support
ACPI, the BIOS will support sleep states s0, s1, s4, and s5.
q s0: Normal running state.
q s1: Processor sleep state. No context will be lost in this state and the
processor caches will maintain coherency.
q s4: Hibernate or Save to Disk: The memory and machine state are saved
to disk. Pressing the power button or other wakeup event will restore the
system state from the disk and resume normal operation. This assumes
that no hardware changes have been made to the system while it was off.
q s5: Soft off: Only the RTC section of the PIIX4 and the BMC are running
in this state.
The system power is off only when the AC power is completely disconnected.
Caution
All server management functionality is concentrated in the BMC. The BMC and
associated circuitry are powered from + 5V_Standby, which remains active when
server power is switched off and the server is still plugged into AC power.
One major function of the BMC is to autonomously monitor system management
events, and log their occurrence in the nonvolatile System Event Log (SEL). These
include events such as overtemperature and overvoltage 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
software running on the server can poll and retrieve the server’s current status.
SEL contents can be retrieved after system failure, for analysis by field service
personnel using server management software tools such as the Server Control
available on the CD-ROM that ships with the server mainboard.
Because the BMC is powered by 5V_Standby, SEL and SDR information are also
available via the Intelligent Management Bus (IMB). An Emergency Management
Card, such as the Intel
®
LANDesk
®
SMM (Server Monitor Module) card available
Server Management
Baseboard Management
Controller (BMC)
Server Management features are implemented using one microcontroller.
Chapter Two System Features
ACPI (continued)