NonStop S-Series Hardware Installation and FastPath Guide (G06.25+)

Glossary
HP NonStop S-Series Hardware Installation and FastPath Guide—529443-001
Glossary-30
ELF
metal object, such as the enclosure, the person wearing the wriststrap is grounded.
Any static electricity incurred during the procedure is discharged safely to the ground
instead of to electrical components within the enclosure.
ELF. See Executable and Linkable Format (ELF).
emergency power off (EPO). Describes equipment used to automatically disconnect all
electrical power to connected equipment if an emergency occurs. A computer room’s
main EPO system shuts off all room equipment (except for lighting and fire-sensor
equipment) if a fire occurs. An equipment zone EPO shuts off power to all connected
computer equipment if the EPO switch is activated.
emergency power-off (EPO) connector. A two-pin connector on the service side of an HP
NonStop™ S-series system enclosure that allows an external signal to disable the
batteries in the enclosure during emergency conditions. A cable is attached from the
connector to a relay band or push button typically located near the door of a computer
room. Pushing the EPO button removes power from all computer equipment in the
room and prevents the batteries from powering the server after power is removed.
EPO capabilities are required in the United States when a server is installed in a
computer room designed to comply with the special construction and fire protection
provisions of the United States’ national electrical code (or at other sites as required by
local regulations).
EMI. See electromagnetic interference (EMI).
emitter-coupled logic (ECL). A logic that expresses digital signals in differential negative
voltage levels, from -8 volts to -1.8 volts. HP NonStop™ S-series servers containing
ServerNet expansion boards (SEBs) use ECL ServerNet cables. An ECL plug-in card
(PIC) allows the modular SEB (MSEB) and I/O multifunction (IOMF) 2
customer-replaceable unit (CRU) to use ECL ServerNet cables.
emitter-coupled logic (ECL) plug-in card (PIC). A plug-in card (PIC) for the modular
ServerNet expansion board (MSEB) and I/O multifunction (IOMF) 2 customer-
replaceable unit (CRU) that supports the emitter-coupled logic (ECL) interface. See
also emitter-coupled logic (ECL) and plug-in card (PIC).
emitter-coupled logic (ECL) ServerNet cable. A ServerNet cable that uses emitter-
coupled logic (ECL). Before the modular ServerNet expansion board (MSEB) was
introduced, ECL was the only ServerNet cable technology used by HP NonStop™
S-series servers. You can connect an ECL ServerNet cable directly to a ServerNet
expansion board (SEB) or to an MSEB using an ECL plug-in card (PIC).
empty directory. In the Open System Services (OSS) file system, a directory that contains
only an entry for itself and an entry for its parent directory.
empty string. In C and C++ programs, a character string that begins with a null character.
This term is synonymous with null string.
EMS. See Event Management Service (EMS).