Service manual

4-10 AlphaServer GS80/160/320 Service Manual
4.3 FRU Power States Defined
With operating system support, these systems can operate in power
states that allow FRUs to be removed and replaced or added while
other parts of the system remain running.
Table 4– 4 Power States
Power State
Logic Voltage 48V Bus Vaux AC Power
Method of Control
Hot-swap On On On On Operating system (OS)
Warm-swap Off On On On OS, SCM, PSM switch
Cold-swap Off Off On On OS, SCM, OCP (PCI powered)
AC off Off Off Off Off OS, OCP, AC circuit breaker(s),
Table 4–4 defines four power states.
• Hot-swap state - Power is on throughout the system and that which will be
swapped out is removed from the operating system resources and is powered
down by an SCM or an operating system command.
• Warm-swap state – This state only exists in a partitioned system. Power is on
and the operating system(s) is running in all partitions but the one containing
the FRU. The operating system in the target partition is shut down, and the
partition is powered off.
• Cold-swap state - Vaux and AC power are on. The operating system is shut
down, and the system is powered off. The SCM console and OCP control this
state (power off / OCP switch in Off position).
• AC off state – The system is down and power is removed by either tripping the
main circuit breaker or circuit breakers of a target FRU.
Table 4–5 shows FRUs that can be swapped when they are in the various power states.
Other parts of the system may be operating while a particular FRU is in one of these
four power states.