Technical Product Specification

Intel® Server Boards S4600LH2/T2 TPS

Revision 2.0

3. FP status LED and DIMM fault LEDs may not reflect BIOS detected errors.

6.5 Fault Resilient Booting (FRB)

Fault resilient booting (FRB) is a set of BIOS and BMC algorithms and hardware support that allow a

multiprocessor system to boot even if the bootstrap processor (BSP) fails. Only FRB2 is supported using

watchdog timer commands.

FRB2 refers to the FRB algorithm that detects system failures during POST. The BIOS uses the BMC

watchdog timer to back up its operation during POST. The BIOS configures the watchdog timer to indicate that

the BIOS is using the timer for the FRB2 phase of the boot operation.

After the BIOS has identified and saved the BSP information, it sets the FRB2 timer use bit and loads the

watchdog timer with the new timeout interval.

If the watchdog timer expires while the watchdog use bit is set to FRB2, the BMC (if so configured) logs a

watchdog expiration event showing the FRB2 timeout in the event data bytes. The BMC then hard resets the

system, assuming the BIOS-selected reset as the watchdog timeout action.

The BIOS is responsible for disabling the FRB2 timeout before initiating the option ROM scan and before

displaying a request for a boot password. If the processor fails and causes an FRB2 timeout, the BMC resets

the system.

The BIOS gets the watchdog expiration status from the BMC. If the status shows an expired FRB2 timer, the

BIOS enters the failure in the system event log (SEL). In the OEM bytes entry in the SEL, the last POST code

generated during the previous boot attempt is written. FRB2 failure is not reflected in the processor status

sensor value.

The FRB2 failure does not affect the front panel LEDs.

6.6 Sensor Monitoring

The BMC monitors system hardware and reports system health. Some of the sensors include those for

monitoring

• Component, board, and platform temperatures

• Board and platform voltages

• System fan presence and tach

• Chassis intrusion

• Front Panel NMI

• Front Panel Power and System Reset Buttons

• SMI timeout

• Processor errors

The information gathered from physical sensors is translated into IPMI sensors as part of the “IPMI Sensor

Model”. The BMC also reports various system state changes by maintaining virtual sensors that are not

specifically tied to physical hardware.

See Appendix B – Integrated BMC Sensor Tables for additional sensor information