NBT Manual

Glossary
NBT Manual—424773-001
Glossary-21
Trivial File Transfer Protocol (TFTP)
Trivial File Transfer Protocol (TFTP). The Internet standard protocol for file transfer with
minimal capability and minimal overhead. TFTP depends only on the unreliable,
connectionless datagram delivery service (UDP), so it can be used on machines like
diskless workstations that keep such software in ROM and use it to bootstrap
themselves.
UDP. See User Datagram Protocol (UDP)
.
User Datagram Protocol (UDP). The Internet standard protocol that allows an application
program on one machine to send a datagram to an application program on another
machine. UDP uses the Internet Protocol to deliver datagrams. Conceptually, the
important difference between UDP and IP is that UDP messages include a protocol port
number, allowing the sender to distinguish among multiple destinations (application
programs) on the remote machine. In practice, UDP also includes a checksum over the
data being sent.
Viewpoint console application. An extensible interactive application for operators, provided
as part of DSM. Viewpoint allows a system or a network to be controlled from a single
terminal. It includes several block-mode display screens for event messages, a block-
mode display for system or network status, a conversational TACL screen, and a facility
called Define Process to maintain sessions with multiple subsystems at the same time.
wait mode. In the Guardian operating system, the mode in which the called procedure waits
for the completion of an I/O operation before returning a condition code to the caller.
Compare nowait mode
.
WA N. See wide area network (WAN)
.
WAN manager process. The WAN manager process starts and manages the WAN subsystem
objects including the ConMgr and WANBoot processes.
WAN subsystem. See wide area network (WAN) subsystem
.
Warning. In DSM interfaces, a condition encountered in performing a command or other
operation, that can be significant but does not cause the command or operation to fail. A
warning is less serious than an error. Compare error
.
well-known port. Any of a set of protocol ports preassigned for specific uses by transport
level protocols (that is, TCP and UDP). Servers follow the well-known port assignments
so clients can locate them. Examples of well-known port numbers include ports assigned
to echo servers, time servers, remote login (TELNET) servers, and file transfer (FTP)
servers.
wide area network (WAN). A network that operates over a larger geographical area than a
local area network (LAN)—typically, an area with a radius greater than one kilometer.
The elements of a WAN may be separated by distances great enough to require
telephone communications. Contrast with local area network (LAN)
.
wide area network (WAN) subsystem. The Subsystem Control Facility (SCF) subsystem for
configuration and management of WAN objects in G-series releases.