UCE
Unsolicted Commercial Email, one form of SPAM.
UDP
Acronym for User Datagram Protocal, a simple connectionless TCP service.
UNIX
A popular multi-user operating system, the name is a play on an even older system, MULTICS.
URL
An acronym for Uniform Resource Locator, URL's are a standardized format for giving a pointer to information available from gopher,WWW, finger and other servers A Primer explaining the use of URL's is available. Defined in RFC 1738, they were extended to include relative (short) URLs in RFC 1808.
Usenet News
A network of systems that exchange articles using NNTP, UUCP, and other protocols to establish public message conferences on some or all of over 10,000 topics or newsgroups. There are many common news readers, some that can run on your home computer via SLIP and the Unix newsreaders, tin, trn, and nn.
USB
Universal Serial Bus. A serial communications standard available on new Macintosh and PC systems, this is a 12Mbps bus. The USB standard provides for up to 127 devices on a single bus, there are fewer than a dozen different USB devices on the market.
UUCP
An acronym for Unix to Unix CoPy, UUCP is a protocol used for the store-and-forward exchange of mail, Usenet News and other files, usually over a modem.
UUEncode
A popular method of exchanging binary files in Mail and via Usenet News the uuencode program converts a binary file into a (larger) file of alphanumeric characters that will not be corrupted when sent as a text file. UUEncode is available as a Unix command as well as MS-DOS and Macintosh versions. To convert the file back to the original binary form you can use the uudecode program or the popular Unix extraction program uuconvert.