WAGO 750 Series Manual page 244

240 • Glossary
U
uClinux
The uClinux (microcontroller Linux) is a Linux kernel for microprocessors
and microcontrollers without MMU (Memory Management Unit). In 1996
the project started with kernel version 2.0. Since kernel version 2.6, the
major parts have been integrated into the Linux kernel. The development of
the C standard library uClibc was also part of the uClinux project.
Furthermore, several UserLand programs belong to the uClinux distribution.
uClinux runs on many embedded systems. Embedded systems are devices in
which a small computer is encapsulated by the device it controls, for
example a DSL router, DVD player, etc.
UDP protocol
The user datagram protocol is a transport protocol (layer 4) of the ISO/OSI-
reference model which supports data exchange between computers without a
connection. UDP runs directly on top of the underlying IP protocol.
URL
Abbreviation for uniform resource locator.
Address form for Internet files which are mostly applied within the World
Wide Web (WWW). The URL format makes the unambiguous designation of
all documents on the Internet possible by describing the address of a
document or object which can be read by a web browser. URL includes the
transmission type (http, ftp, news etc.), the computer which contains the
information and the path on the computer. URL has the following format:
Document type//Computer name/List of contents/File name.
UTP
The UTP cable is a symmetrical, not-protected cable with twisted colored
wires in pairs. This type of cable, which there is in execution two-in pairs
and four-in pairs, is the dominating type of cable in the floor wiring and the
terminal wiring.
W
Web browser
Program for reading hypertext. The browser allows the various documents to
be viewed in hypertext and navigation between documents.
Word-alignment
Set configuration of the fieldbus coupler/controller for the creation of a
process image. Word-alignment is used to establish the process image word-
by-word (2 bytes).
World Wide Web
HTTP server on the Internet.
WAGO-I/O-SYSTEM 750
Linux Fieldbus Coupler