Glossary of Computer Terms

Computer Terms Glossary

This page is meant to serve as a guide to the vast quantity of computer terms and acronyms in common use for the casual computer user. It is divided into two main sections, the first is dedicated to the basics and is meant more for beginners, while the second is meant instead to be used as a reference. In reality many of the terms in the second section are still quite common; the first section was deliberately kept as short as possible.

Terms in the second section may be looked up by either using the "find in page" function of your browser, or by appending "#term" (without the quotes and where term is the term of interest) to the "URL" or "go to" section of your browser, keeping in mind that case matters. The best method of searching for a term though is to use the Search Interface that will return not only the specific term sought but also other entries that reference it. Be aware that the terms referenced in the second part of this page will freely assume familiarity with the first part.

If you are instead actually trying to figure out what a particular filename extension means, you might instead try the filename extensions page.

If you want something added or see a problem with something already here (but keep in mind this guide is not meant to be overly technical) please send .


The operator of a computer.


UDP/IP is a protocol for computer networks. It is the faster of the two primary Internet Protocols. UDP stands for User Datagram Protocol.
The Unicode character set is a superset of the ASCII character set with provisions made for handling international symbols and characters from other languages. Unicode is sixteen bit, so takes up roughly twice the space as simple ASCII, but is correspondingly more flexible.
UNIX is a family of OSes, each being made by a different company or organization but all offering a very similar look and feel. It can not quite be considered non-proprietary, however, as the differences between different vendor's versions can be significant (it is still generally possible to switch from one vendor's UNIX to another without too much effort; today the differences between different UNIXes are similar to the differences between the different MS-Windows; historically there were two different UNIX camps, Berkeley / BSD and AT&T / System V, but the assorted vendors have worked together to minimalize the differences). The free variant Linux is one of the closest things to a current, non-proprietary OS; its development is controlled by a non-profit organization and its distribution is provided by several companies. UNIX is powerful; it is fully multitasking and can do pretty much anything that any OS can do (look to the Hurd if you need a more powerful OS). With power comes complexity, however, and UNIX tends not to be overly friendly to beginners (although those who think UNIX is difficult or cryptic apparently have not used CP/M). Window managers are available for UNIX (running under X-Windows) and once properly configured common operations will be almost as simple on a UNIX machine as on a Mac. Out of all the OSes in current use, UNIX has the greatest range of hardware support. It will run on machines built around many different processors. Lightweight versions of UNIX have been made to run on PDAs, and in the other direction, full featured versions make full advantage of all the resources on large, multi-processor machines. Some different UNIX versions include Solaris, Linux, IRIX, AIX, SunOS, FreeBSD, Digital UNIX, HP-UX, NetBSD, OpenBSD, etc.
To upload a file is to copy it from your computer to a remote computer. The opposite is download.
An uninterrupted power supply uses heavy duty batteries to help smooth out its input power source.
A Uniform Resource Identifier is basically just a unique address for almost any type of resource. It is similar to but more general than a URL; in fact, it may also be a URN.
A Uniform Resource Locator is basically just an address for a file that can be given to a browser. It starts with a protocol type (such as http, ftp, or gopher) and is followed by a colon, machine name, and file name in UNIX style. Optionally an octothorpe character "#" and and arguments will follow the file name; this can be used to further define position within a page and perform a few other tricks. Similar to but less general than a URI.
A Uniform Resource Name is basically just a unique address for almost any type of resource unlike a URL it will probably not resolve with a browser.
A really fast type of serial port that offers many of the best features of SCSI without the price. Faster than many types of parallel port, a single USB port is capable of chaining many devices without the need of a terminator. USB is much slower (but somewhat less expensive) than FireWire.
The point of uucode is to allow 8-bit binary data to be transferred through the more common 7-bit ASCII channels (most especially e-mail). The facilities for dealing with uucoded files exist for many different machine types, and the most common programs are called "uuencode" for encoding the original binary file into a 7-bit file and "uudecode" for restoring the original binary file from the encoded one. Sometimes different uuencode and uudecode programs will work in subtly different manners causing annoying compatibility problems. Bcode was invented to provide the same service as uucode but to maintain a tighter standard.