ServerNet Cluster 6780 Operations Guide (G06.24+, H06.03+)

Glossary
ServerNet Cluster 6780 Operations Guide—525606-002
Glossary-7
emitter-coupled logic (ECL)
emitter-coupled logic (ECL). A logic that expresses digital signals in differential negative
voltage levels, from -8 volts to -1.8 volts. NonStop S-series servers containing
ServerNet expansion boards (SEBs) use ECL cables. An ECL plug-in card (PIC)
allows the modular SEB (MSEB) to use ECL ServerNet cables.
EMS. See Event Management Service (EMS).
EMS collector. An Event Management Service (EMS) process to which subsystems report
events.
enclosure. Similar to a cabinet in NonStop K-series systems. An enclosure can contain
components of a system or a peripheral. Base enclosures are placed on the floor and
can have other enclosures stacked on top of them. Stackable enclosures can be
placed on top of other enclosures. See also system enclosure.
error number. For the Subsystem Programmatic Interface (SPI), a value that can be
assigned to a return token, or to the last field of an error token, to identify an error that
occurred. SPI defines a small set of error numbers, but most error numbers are defined
by subsystems.
ESD kit. See electrostatic discharge (ESD) protection kit.
Ethernet. A local area network (LAN) that uses the carrier sense multiple access with
collision detection (CSMA/CD) access method on a bus topology and is the basis for
the IEEE 802.3 standard.
Ethernet 4 ServerNet adapter (E4SA). A ServerNet adapter for Ethernet local area
networks (LANs) that contains four Ethernet ports.
Ethernet hub. A multiport repeater typically supporting 10BaseT cabling. Most hubs are
connectors for 8 or 12 cables. Also referred to as a concentrator.
Event Management Service (EMS). A Distributed Systems Management (DSM) product
that provides event collection, event logging, and event distribution facilities. EMS
provides different event descriptions for interactive and programmatic interfaces, lets
an operator or an application select specific event-message data, and allows for
flexible distribution of event messages within a system or network.
event message. Text intended for a system operator that describes a change in some
condition in the system or network, whether minor or serious. The change of condition
is called an event. Events can be operational errors, notifications of limits exceeded,
requests for actions needed, and so on. See also operator message.
Expand line-handler process. A process pair that handles incoming and outgoing Expand
messages and packets. An Expand line-handler process handles direct links and also
binds to other processes using the Network Access Method (NAM) interface to support
Expand-over-X.25, Expand-over-FOX, Expand-over-ServerNet, Expand-over-TCP/IP,
and Expand-over-SNA links. See also Expand-over-ServerNet line-handler process
(Expand/SvNet).