Frb3; Frb2 - Sun Microsystems Sun Fire V60x Manual

4.9.1

FRB3

FRB3 refers to the FRB algorithm that detects whether the BSP is healthy enough to
run BIOS at all. The BMC starts the FRB3 timer when the system is powered up
experiences a hard reset. The BIOS stops this timer in the power-on self test (POST)
by asserting the FRB3 timer halt signal to the BMC. This requires that the BSP
actually runs BIOS code. If the timer is not stopped within five seconds, and it
expires, the BMC disables the BSP, logs an FRB3 error event, chooses another BSP
(from the set of non-failed processors), and resets the system. FRB3 provides a check
to verify that the selected BSP is not dead on start up and can actually run code. This
process repeats until either the system boots without an FRB3 timeout, or all of the
remaining processors have been disabled. At this point, if all the processors have
been disabled, the BMC will attempt to boot the system on one processor at a time,
irrespective of processor error history. This is called desperation mode.
4.9.2

FRB2

FRB2 refers to the level of FRB in which the BIOS uses the BMC watchdog timer to
back up its operation during POST. The BIOS configures the watchdog timer for
approximately 6 to 10 minutes, indicating that the BIOS is using the timer for the
FRB2 phase of operation.
Note – The BIOS factory default is "Disable BSP" (Boot Strap Processor) on FRB2.
After the BIOS has identified the BSP and saved that information, it will then check
to see if the watchdog timer expired on the previous boot. If so, it will store the Time
Out Reason bits in a fixed CMOS location (token name = cmosWDTimerFailReason)
for applications or a User Binary to examine and act upon. Next, it sets the watchdog
timer FRB2 timer use bit, loads the watchdog timer with the new timeout interval,
and disables FRB3 using the FRB3 timer halt signal. This sequence ensures that no
gap exists in watchdog timer coverage between FRB3 and FRB2.
Note – FRB2 is not supported when the BIOS is in Recovery Mode.
If the watchdog timer expires while the watchdog use bit is set to FRB2, the BMC
logs a Watchdog expiration event showing an FRB2 timeout (if so configured). It
then hard resets the system, assuming Reset was selected as the watchdog timeout
action.
4-20 Sun Fire V60x and Sun Fire V65x Servers—Troubleshooting Guide • November 2003