240 ï GlossaryWAGO-I/O-SYSTEM 750Linux Fieldbus CouplerUuClinuxThe uClinux (microcontroller Linux) is a Linux kernel for microprocessorsand microcontrollers without MMU (Memory Management Unit). In 1996the project started with kernel version 2.0. Since kernel version 2.6, themajor parts have been integrated into the Linux kernel. The development ofthe 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 inwhich a small computer is encapsulated by the device it controls, forexample a DSL router, DVD player, etc.UDP protocolThe user datagram protocol is a transport protocol (layer 4) of the ISO/OSI-reference model which supports data exchange between computers without aconnection. UDP runs directly on top of the underlying IP protocol.URLAbbreviation for uniform resource locator.Address form for Internet files which are mostly applied within the WorldWide Web (WWW). The URL format makes the unambiguous designation ofall documents on the Internet possible by describing the address of adocument or object which can be read by a web browser. URL includes thetransmission type (http, ftp, news etc.), the computer which contains theinformation and the path on the computer. URL has the following format:Document type//Computer name/List of contents/File name.UTPThe UTP cable is a symmetrical, not-protected cable with twisted coloredwires in pairs. This type of cable, which there is in execution two-in pairsand four-in pairs, is the dominating type of cable in the floor wiring and theterminal wiring.WWeb browserProgram for reading hypertext. The browser allows the various documents tobe viewed in hypertext and navigation between documents.Word-alignmentSet configuration of the fieldbus coupler/controller for the creation of aprocess image. Word-alignment is used to establish the process image word-by-word (2 bytes).World Wide WebHTTP server on the Internet.
