NonStop System Glossary

power interface board (PIB)
1. On the Integrity NonStop server, a board in a NonStop Blade Element that connects the power
supply to the midplane.
2. In NonStop S-series system enclosures with power shelves, a board mounted on the bulkhead
located behind the power supplies in the power shelf. The PIB provides electrical connection
between the power supplies and DC power cables.
power monitor and control unit (PMCU)
A field-replaceable unit (FRU) that connects the batteries to the DC power distribution bus in a
NonStop S-series enclosure and provides a means of disconnecting the batteries for powering off
the system. The PMCU also provides a means for the service processor (SP) to diagnose the condition
of the batteries, fans, and power supplies; to regulate the voltage supplied to the fans; and to
provide the interface to the group ID switches and service light-emitting diodes (LEDs). A group
contains two PMCUs, one for each of the two DC power distribution buses.
power shelf
In NonStop S7400, S7600, and Sxx000 processor enclosures and I/O enclosures containing
I/O multifunction (IOMF) 2 customer-replaceable units (CRUs), an assembly residing below the
chassis consisting of power supplies and supporting circuitry that provides DC power to the
enclosure.
power supply
1. In NonStop S-series system enclosures without power shelves, the component on the processor
multifunction (PMF) customer-replaceable unit (CRU) or the I/O multifunction (IOMF) CRU that
converts standard AC line voltage into the DC voltages needed by the group components in the
enclosure.
2. In NonStop S-series system enclosures with power shelves, the component located in the power
shelf that converts standard AC line voltage into DC voltage and delivers it to the PMF CRUs or
IOMF 2 CRUs in that enclosure, which in turn supply the DC voltages needed by the group
components in the enclosure.
POWER_OFF
Complete loss of AC power after an AC outage surpasses the UPS battery capacity.
POWER_ON
The action taken by the maintenance entity firmware when AC returns while in LOW_POWER or
POWER_OFF mode.
POWER_RETURN
The action taken by the maintenance entity firmware when AC returns before going to LOW_POWER
mode.
PPL
See process-pair list (PPL).
PPP
See Point-to-Point Protocol (PPP).
P 149