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

Glossary
ServerNet Cluster 6780 Operations Guide—525606-002
Glossary-6
Domain Name System (DNS)
Domain Name System (DNS). A system that defines a hierarchical, yet distributed,
database of information about hosts on a network. The network administrator
configures the DNS with a list of hostnames and Internet protocol (IP) addresses,
allowing users of workstations that are configured to query the DNS to specify remote
systems by hostnames rather than by IP addresses. DNS domains should not be
confused with Windows NT networking domains. See also node and ping.
double-wide plug-in card (PIC). A large-form-factor plug-in card (PIC) that occupies two
adjacent PIC slots within a customer-replaceable unit (CRU). See also single-wide
plug-in card (PIC).
download. The process of transferring software from one location to another, where the
transferring entity initiates the transfer.
downtime. Time during which a computer system is not capable of doing useful work
because of a planned or unplanned outage. From the end user’s perspective,
downtime is any time a needed application is not available.
dual-ported. The capability of a ServerNet adapter or peripheral device to receive data and
commands from two sources although only one source might have access at any
particular moment.
E4SA. See Ethernet 4 ServerNet adapter (E4SA).
ECL. See emitter-coupled logic (ECL).
ECL ServerNet cable. A ServerNet cable that uses emitter-coupled logic (ECL). Prior to the
introduction of the modular ServerNet expansion board (MSEB), ECL was the only
ServerNet cable technology used by NonStop S-series servers. The MSEB supports
connection of this cable using an ECL plug-in card. See also emitter-coupled logic
(ECL).
electromagnetic interference (EMI). Forms of conducted or radiated interference that
might appear in a facility as either normal or common-mode signals. The frequency of
the interference can range from the kilohertz to gigahertz range. However, the most
troublesome interference signals are usually found in the kilohertz to low megahertz
range. At present, the terms electromagnetic interference and radio frequency
interference (RFI) are usually used interchangeably.
electrostatic discharge (ESD) protection kit. A kit containing an antistatic mat and a wrist
strap with a cable and clip. A service provider or customer wears the wrist strap while
performing maintenance procedures inside an enclosure. The wrist strap and cable
contain grounding wires so that when the clip is attached to a metal object, such as the
enclosure, the person wearing the wrist strap is grounded, and any static electricity
incurred during the procedure is discharged safely to the enclosure instead of to
electrical components within the enclosure.
EMI. See electromagnetic interference (EMI).