“UA” to “UUNET”

UA

See user agent.

UART

(n.) universal asynchronous receiver-transmitter.

UDF

(n.) Universal Disk Format.

UDP

(n.) User Datagram Protocol.

UFS

See UNIX® file system.

UHF

(n.) ultra-high frequency.

UI

See UNIX® International.

UID number

See user identification number.

ulp

See unit in last place.

ULSI

See ultra-large-scale integration.

ultra-large-scale integration

(ULSI) (n.) The process of placing more than 100,000 components on a chip.

unary operator

(n.) An operator having only one operand. You can use the + (plus) and - (minus) unary operators in absolute, relocatable, and arithmetic expressions.

unasserted

(adj.) Characteristic of a signal that terminates an action. Contrast with asserted.

unavailable

(adj.) Characteristic of a window element that cannot be selected in the current context. For example, the OK button is unavailable till you select an item in the list.

undo

(v.) To reverse the effect of the most recently performed operation on an object.

Unicode

(n.) A 16-bit character set that was defined by ISO 10646. All source code in the Java^TM programming environment is written in Unicode.

uniform resource locator

(URL) (n.) A standard for writing a text reference to an arbitrary piece of data in the World Wide Web (WWW). A URL looks like “protocol://host/localinfo.” The data “protocol” specifies a protocol for fetching the object (such as HTTP or FTP). The data “host” specifies the Internet name of the targeted host. The data “localinfo” is a string (often a file name) that is passed to the protocol handler on the remote host.

UniForum

(n.) The Uniforum Technical Committee, formerly the /usr/group, is an association of individuals, corporations, and institutions with an interest in the UNIX® system. This organization provides input to the Portable Operating System Interface for UNIX (POSIX) and other standards committees and consortia to aid in the development of independent industry-driven standards.

unit in last place

(ulp) (n.) In binary formats, the least-significant bit of the significand bit 0 is the unit in the last place.

universal address

(n.) A hexadecimal address of a type of network, such as TCP/IP, that configures the port monitor to check for print requests from print clients on a network.

UNIX® file system

(UFS) (n.) The default disk-based file system under the SunOS^TM 5.0 (minimum) operating system.

UNIX® International

(UI) (n.) A consortium which consists of Sun, AT & T, and other groups that formed to advance a UNIX® System V-based environment, including the Open Look graphical user interface.

UNIX-to-UNIX Copy Program

(UUCP) (n.) A program that uses the UNIX-to-UNIX Copy Protocol.

UNIX-to-UNIX Copy Protocol

(UUCP) (n.) A protocol for communication between consenting UNIX® systems.

unmount

(n.) The process of removing access to a directory on a disk that is attached to a machine or a remote disk on a network. See also mount.

UPA

(n.) UltraSPARC port architecture.

update

(1) (n.) An installation on a system that changes software that is of the same type. Unlike an upgrade, an update might downgrade the system. Unlike an initial installation, software of the same type that is being installed must be present before an update can occur.

(2) (v.) To perform an installation on a system that changes software that is of the same type.

upgrade

(n.) An installation that merges files with existing files and saves modifications where possible.

An upgrade of the Solaris Operating System merges the new version of the Solaris operating system with the existing files on the system's disk or disks. An upgrade saves as many modifications as possible that you have made to the previous version of the Solaris operating system.

upper Stream

(n.) A Stream that terminates above a multiplexer. The beginning of an upper Stream originates at the Stream head or another multiplexer driver.

UPS

(n.) uninterruptible power supply.

upstream

(n.) In STREAMS, a direction of data that flows from a driver toward the Stream head. Also called input side, read-side.

URL

See uniform resource locator.

USB

(n.) Universal Serial Bus.

USD

(n.) U.S. dollars.

user account

(n.) A record of essential user information that is stored on the system. Each user who accesses a system has a user account.

user agent

(UA) (n.) An ISO/OSI application process that acts on behalf of a user or an organization in the X.400 Message Handling System. The UA creates, submits, and receives messages for you.

user-defined

(adj.) Characteristic of a setting or some other customization that you determine.

user ID

(n.) A number that identifies a user to the system.

user identification number

(UID) (n.) The number that is assigned to each login name. The system uses UID numbers to identify, by number, the owners of files and NULL.

user name

(n.) A combination of letters, and possibly numbers, that identifies a user to the system.

UTC

(n.) Universal Coordinate Time (accepted acronym from the French).

UTF-8

(n.) File System Safe Universal Transformation Format.

utility

(n.) A standard program, usually furnished at no charge with the purchase of a computer, that does the computer's housekeeping.

utility window

(n.) In a non-multiple document interface (MDI) with the Java^TM look and feel, a modeless dialog box that typically displays a collection of tools, colors, fonts, or patterns. Unlike palette windows, utility windows do not float. User choices that are made in a utility window affect whichever primary window is active. A utility window is not dismissed when a primary window is dismissed. Utility windows are created by using the JDialog component. See also secondary window.

UTP

(n.) unshielded twisted pair.

UUCP

See UNIX-to-UNIX Copy Program, UNIX-to-UNIX Copy Protocol.

UUNET

(n.) A network that carries electronic newsgroups, aggregates of many electronic messages that are sorted by topic, to thousands of users on hundreds of workstations worldwide.