Glossary for web, etc. U

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UA United Airlines

UCC EDI: Uniform Code Council - US & Canada equivalent of EAN

UCP Universal Computer Protocol - an SMS protocol from ERMES.
Several functions (known as EMI Operations), but the most commonly implemented are:
01 - Call Input (send);
03 - Call Input With Supplementary Services;
30 - SMS Message Transfer (send);
51 - Submit Short Message.

UDP User Datagram Protocol - OSI level 4. Unacknowledged, connectionless.
See also The TCP/IP Guide: UDP Message Format.
The Checksum field in the header is 'optional' (all zero if not used, and all zero case is replaced by all 1s if sumcheck is used).
- See IPPROTO_UDP Socket Options.

ULTRIX UNIX-based OS for Digital Equipment Corporation computers.

UMA Union de Maghreb Arabe: Mauritania, Morocco, Algeria, Tunisia, Libya working towards economic cooperation.

UMB DOS: Upper Memory Block (640K to 1Mb).

UNC Windows 95 Universal Naming Convention - drive letter not reqd

UPS a commercial express delivery service.

UPU Universal Postal Union - UN agency promotes postal agreements.

URI Uniqe Resource Identifier which defines a namespace. May be a URL (usually up to but not including the final /) or a URN.
e.g. Addition of the module name to identifiers within the module so that modules may be combined without any of the internal names clashing.

URL Uniform Resource Locator. Full spec of a URL is: protocol://host:port/pathname#name?parameters
The first part (before the colon) says what to do e.g. htpp: tells the browser to use the HyperText Transport Protocol to get the page from a server.
The second part (up to the question mark, if there is one) defines which HTML file to get. It may consist of a network address (e.g. //www.yahoo.com/) and a path to the file.
The third part is of the form ?id1=aaa&id2=bbb&id3=ccc . . . where id1 etc are identifiers, and aaa etc are values. This part is deciphered by code (such as javascript) within the page, using e.g. document.URL or location.search (which is the part of the URL from (and including) the "?").
The current URL is normally displayed at the top of brower screen, though this may be for a different frame. To display the URL from the HTML script, try e.g.
The URL is <B><SCRIPT>document.write( location.href );</SCRIPT></B> which in this case displays:
The URL is

URLs to locate articles in MSDN are of the form:
mk:@MSITStore:K:\MSDN\vccore.chm::/html/_core_compiler_options_listed_by_category.htm
where K:\MSDN\vccore.chm is a compiled HTML file.

The URL for the next page can be set in several ways:
a) Via the HTML element <a href=" . . . ">xxx</a> where xxx is some text or a picture that the user can click on to get to the next page.

(- The "<A href=...>" tag can be used for other things;

e.g. <A href="JavaScript:SomeFn(...);">...</A> will execute the JavaScript function "SomeFn".

e.g. Click this.)
b) Via location.href=" . . . " in a SCRIP element or following e.g. onclick= in an INPUT element.
c) Via document.location.replace(. . .); - loads the URL over the current history entry. The user cannot then navigate to the previous URL by using browser's Back button.
d) Via History.go( . . . ) or History.back() or History.forward().
e) Also see Scriptlets.

Some common strings in URLs are:

.ac.	academic
.co.	commercial
.ca	Canada
.com	U.S commercial
.de	Germany
.dz	Algeria
.edu	all U.S. educational
.es	Spain
.fr	France
.gov	U.S. govermnent, non-military
.mil	U.S. army, navy etc
.jp	Japan
.net	Network resources (U.S.?)
.org	U.S. general organisations
.sg	Singapore
.uiuc.edu	University of Illinois
.uk	United Kingdom

For links whose action is irreversible, to make the user confirm what they are doing, usethe JavaScript onclick event:

<A href="..." onclick="return confirm('Are you sure?');">...</A>
e.g. Go to There
There.

See A beginner's guide to URLs.

URN - Uniform Resource Name, which defines a namespace.
Usually contains colons. e.g. urn:www-develop-com:student.

URL Identifier - the bit in the URL just before the ?xyz=... part, which determines which HTML file is wanted.

Utilities for networks. See Net; NetStat;

UTP Unshielded Twisted Pair - "Category 5" fast, but may fail ECM. Cetegory 3,4,5 speed 16,20,100Mbps.

USENET News exchange (actually predates the Internet). Usenet Hierarchies: Leftmost part of address is most significant, Ther may be any number of sections to the address:
.

alt	alternative (often very)
bionet	biological matters
bit	from Bitnet mailing lists
biz	commercial topics
comp	everything computer related
gnu	the GNU project
ieee	Institute of Electrical and Electronic Engineers
info	garnered from more mailing lists
k12	run by American children
misc	anything else
news	related to Usenet itself
rec	recreational discussions
sci	scientific matters
soc	all about society
talk	often lengthy exchanges
uk	national newsgroups
xxx.d	discussion of articles or executables in newsgroup xxx
xxx.announce	significant announcements related to xxx

UUCP Unix to Unix copy - replaced by the Internet.

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