U

UFS (Unix File System)

An alternative to the HFS+ file system format for Mac OS X.

UNIX (UNiplexed Information and Computing System, originally UNICS)

A complex and powerful operating system whose TCP/IP networking protocol is the basis of the Internet.

unmount

To remove a disk’s icon from the Desktop and make the disk’s contents unavailable without deleting the items in that disk permanently.

unshielded twisted-pair (UTP)

The type of cable used in a 10Base-T, 100Base-T, or Gigabit Ethernet network.

upload

The process of sending files from your computer to another computer.

URL (Uniform Resource Locator)

An Internet address. This can be the address of a Web page, a file on an FTP site, or anything else that you can access on the Internet.

Usenet

A worldwide Internet bulletin board system that enables people to post messages and join discussions about subjects that interest them.

user

Someone who can log into your computer with a unique name and a password. A non-techie whose continued existence is tied to the economic survival of geeks everywhere.

user group

An organization that provides information and assistance to people who use computers. For the names and phone numbers of user groups near you, check Apple’s Web page (www.apple.com/usergroups/find.html).

username

A name that can be used to log into a Mac OS X system.

user preferences

Unique settings where users configure the behavior and appearance of applications and system software.