UDP:-

Abbreviation for User Datagram Protocol. The connection-less, transport-level protocol used in the TCP/IP suite of protocols, usually bundled with IP-layer software. Because UDP does not add overhead, as does connection-oriented TCP. UDP is often used with SNMP (Simple Network Management Protocol) applications.

UNIX Client:-

Any computer running UNIX that connects to the network.

UNIXWare:-

A version of the UNIX operating system, based on UNIX System V release 4.2, available from Novell. UNIXWare is available in two versions:

• Personal Edition: A two user system that supports up to two processors.

• Application Server: A multi user, server system that can scale up to twelve processors.

UNIXWare also supports multiple threads, and uses preemptive multitasking. In 1993, Novell acquired UNIX System Laboratories, Inc. from AT&T, and as part of the deal, secured all rights to the System V Release 4.2 source code.

Unshielded Twisted-Pair Cable: -

Abbreviated UTP. Cable that contains two or more pairs of twisted copper wires: see the accompanying illustration. The greater the number of twists, the lower the crosstalk. UTP is offered in both voice grade and data grade. The advantages of UTP include ease of installation and low cost of materials. Its drawbacks are limited signaling speeds and shorter maximum cable-segment lengths.

Upgradeable Computer:-

 A computer system specifically designed to be upgraded as technology advances. The amount of circuitry that must be changed when you make the upgrade and the method of upgrading differ from one upgradeable computer to another. At a minimum, you must replace the processor; at most, you need to change nearly all the circuitry installed in the computer. In some systems, the use of a ZIF socket to hold the main processor makes an upgrade easy; in oilier systems, replacing I he main processor can be extremely difficult.

Uplink:-

The transmission of information from an earth station to a communications satellite.

Upload:-

In communications, sending a file or files from one computer to another over a network or via a modem. For example, you might upload a file to a network server or a bulletin board system.

URL:-

Abbreviation for Uniform Resource Locator! pronounced "earl" or "you-are-ell". A method of accessing Internet resources. URLs contain information about both the access method to use and also about the resource itself, and are used by Web browsers to connect you directly to a specific document or home page on the World Wide Web, without you having to know where that resource is located physically. A sample URL might look this:

http: //www.ibm.com/search

The first part of the URL, before the colon, specifies the access method. On the web, this is usually HTTP (for hypertext transmission protocol), but you might also see file, FTP, or Gopher instead. The second part of the URL, after the colon, specifies the resource. The text after the two slashes usually indicates a server name and the text after the single slash defines the directory or individual file you will connect to. If you are linking to a document, it will usually have the file name extension.html, the abbreviation for hypertext markup language.

URLs are always case-sensitive so pay particular attention to uppercase and lowercase letters and to symbols as well.

USENET:-

Contraction of USE Network. An international, non-commercial network, linking many thousands of UNIX sites. Although there is a very close relationship between the Internet and USENET, they are not the same thing by any means. USENET predates the Internet in the early days.  Information was distributed by dial-up connections and UUCP software. Not every Internet computer is part of USENET, and not every USENET system can be reached from the Internet. Like the Internet, USENET has no central governing body: USENET is run by the people who use it. With well over ten thousand newsgroups, USENET is accessed by millions of people every day, in more than one hundred countries.

USENET newsgroups:-

 The individual discussion groups within USENET. USENET newsgroups contain articles posted by other Internet and USENET subscribers; very few of them contain actual hard news. Most newsgroups are concerned with a single subject; the range of subjects available through USENET is phenomenal-there are over ten thousand newsgroups from which to choose. If people are interested in a subject, you are sure to find a newsgroup for it somewhere.

Newsgroups are like the online forums found on CompuServe or America Online; you can post your own articles and browse through similar items posted by others. When you reply to a post, you can reply to the newsgroup so that other subscribers can read your reply, or you can respond directly to the originator in a private-e-mail message.

If you see the word "binary" in a newsgroup name, that newsgroup specializes in pictures. The picture files are first converted to text with the UNIX uuencode utility;

you will need a copy of the UNIX utility uudecode to turn this text hack into a graphical image you can view.

User Account: -

A security mechanism used to control access to a network or to a multi-user computer system, established and maintained by the network administrator. Elements of a user account include password information, rights, and information about the groups to which the user belongs.

User Group:-

A group of users of a specific-computer or software package who meet to share tips and listen to industry experts. Some PC user groups hold large, well-attended monthly meetings, run their own bulletin board systems, and publish newsletters of exceptional quality.