System information

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Eclipse™ 2640 SAN Router Administration and Configuration Manual
Glossary
TTL See transistor-transistor logic.
twisted pair Relatively low-speed transmission medium consisting of two
insulated wires arranged in a regular spiral pattern. The strands are
twisted to improve protection against electromagnetic and radio
frequency interference. The wires may be shielded or unshielded.
U
UDP See user datagram protocol.
UL See Underwriters Laboratories.
ULP See upper level protocol.
unblocked port Devices communicating with an unblocked port can login to the
director or switch and communicate with devices attached to any
other unblocked port (assuming that this is supported by the current
zoning configuration).
Underwriters
Laboratories
UL. A laboratory organization accredited by the Occupational Safety
and Health Administration and authorized to certify products for use
in the home and workplace (D).
unicast Communication between a single sender and a single receiver over a
network.
uniform resource
locator
URL. A URL is the address of a document or other resource on the
Internet.
uninterruptable power
supply
UPS. A buffer between public utility power or another power source,
and a system that requires precise, uninterrupted power (D).
universal port module UPM. A flexible 1 gigabit-per-second or 2 gigabit-per-second module
that contains four generic ports (G_Ports).
UNIX A popular multi-user, multitasking operating system originally
designed to be a small, flexible system used exclusively by
programmers. UNIX was one of the first operating systems to be
written in a high-level programming language, namely C. This meant
that it could be installed on virtually any computer for which a C
compiler existed. Due to its portability, flexibility, and power, UNIX