NonStop NS-Series Planning Guide (H06.04+)

Control, Configuration, and Maintenance Tools
HP Integrity NonStop NS-Series Planning Guide—529567-005
B-23
AC Power-Fail States
AC Power-Fail States
These states occur when a power failure occurs and an optional HP model R5500 XR
UPS is installed in each cabinet within the system:
System State Description
NSK_RUNNING NonStop operating system is running normally.
RIDE_THRU OSM has detect a power failure and begins timing the outage. AC
power returning terminates RIDE_THRU and puts the operating
system back into an NSK_RUNNING state. At the end of the
predetermined RIDE_THRU time, if AC has not returned, OSM
executes a PFAIL_SHOUT that results in the system going to
LOW_POWER.
HALTED Normal halt condition. Halted processors do not participate in
power-fail handling. A normal power-on also puts the processors
into the HALTED state.
LOW_POWER Halted-state services (HSS) informs the p-switch that it is in
LOW_POWER state and then waits until the p-switch removes
optic power.
POWER_OFF Loss of optic power from the p-switches occurs, or the UPS
batteries suppling the NonStop Blade Element modules are
completely depleted. When power returns, the system is
essentially in a cold-boot condition.