Dictionary of Computing - 5th Edition

time slice /ta m sla s/ noun a period of time allocated for a user or program or job

within a multitasking system

time stamp /ta m st mp/ noun a MIDI message that is tagged with a time so that a sequencer can play it at the correct mo-

ment

timing loop / ta m ŋ lu p/ noun a computer program loop which is repeated a number of times to produce a certain time

delay

timing master / ta m ŋ mɑ stə/ noun a clock signal which synchronises all the

components in a system tint /t nt/ noun hue

tiny model / ta ni mɒd(ə)l/ noun a memory model of the Intel 80x86 processor family that allows a combined total of 64 Kb for data and code

title / ta t(ə)l/ noun an identification name given to a file or program or disk title bar / ta t(ə)l bɑ / noun a horizontal bar at the top of a window which displays

the title of the window or application

T junction /ti d' ŋkʃ(ə)n/ noun a connection at right angles to a cable carry-

ing the main signal or power

TMSF time format / ti em es ef ta mfɔ m t/ noun a time format used mainly by audio CD devices to measure time in frames and tracks. Full form tracks, minutes, seconds, frames time format toggle / tɒ (ə)l/ verb to switch something between two states (NOTE: toggles –

toggling – toggled)

toggle switch / tɒ (ə)l sw tʃ/ noun an electrical switch which has only two posi-

tions

token / təυkən/ noun 1. an internal code which replaces a reserved word or program statement in a high-level language 2.

(in a local area network) a control packet which is passed between workstations to

control access to the network

token bus network / təυkən b snetw k/ noun an IEEE 802.4 standard for a local area network formed with a bustopology cable, in which workstations

transfer data by passing a token token-passing / təυkən pɑ s ŋ/ noun

a method of controlling access to a local area network by using a token (NOTE: A workstation cannot transmit data until it

receives the token.)

Token Ring network / təυkən r ŋ

netw k/ noun an IEEE 802.5 standard that uses a token passed from one worksta-

tion to the next in a ring network Token Ring networks are very democratic and retain performance against increasing load.

(NOTE: A workstation can only transmit data if it captures the token. Token Ring networks, although logically rings, are often physically wired in a star topology.) tone dialling / təυn da əl ŋ/ noun a method of dialling a telephone number using sounds to represent the digits of the number (NOTE: This method of dialling is the current standard method of dialling numbers and has generally replaced the older pulse dialling system. A Hayescompatible modem can dial the number ‘123’ using tone dialling with the AT command ‘ATDT123’ or using pulse dialling with the AT command ‘ATDP123’) toner / təυnə/ noun a finely powdered ink, usually black, that is used in laser printers If you get toner on your hands, you can only wash it off with cold water.

(NOTE: The toner is transferred onto the paper by electrical charge, then fixed permanently to the paper by heating.) toner cartridge / təυnə kɑ tr d'/ noun a plastic container which holds powdered toner for use in a laser printer

tool /tu l/ noun (in a graphical front end) a function accessed from an icon in a toolbar, e.g. a circle-draw option

toolbar / tu l bɑ / noun a window that contains a range of icons that access tools Toolbook / tu lbυk/ noun a multimedia authoring tool developed by Asymetrix which uses the OpenScript script language to control objects and actions

toolbox / tu lbɒks/ noun 1. a box containing instruments needed to repair or maintain or install equipment 2. a set of predefined routines or functions that are used when writing a program

Toolbox / tu lbɒks/ noun (in an Apple Mac) a set of utility programs stored in ROM to provide graphic functions toolkit / tu lk t/ noun a series of functions which help a programmer to write or debug programs

tools /tu lz/ noun a set of utility programs such as backup and format in a computer system

ToolTips / tu lt ps/ noun a feature of applications that work under Windows that display a line of descriptive text under an icon when the user moves the pointer over the icon

top down programming / tɒp daυnprəυ r m ŋ/ noun same as structured

programming

top-level domain / tɒp lev(ə)l dəυme n/ noun the part of an Internet address that identifies an Internet domain, e.g. a two-letter country code or a three-letter code such as .edu for education or .com for commercial when used without a country

code.

topology /tɒ pɒləd'i/ noun a way in which the various elements in a network are interconnected (NOTE: The plural is topologies.)

TOPS /tɒps/ noun software that allows IBM PCs and Apple Macs to share files on a network

touch pad /t tʃ p d/ noun a flat device which can sense where on its surface and when it is touched, used to control a cursor

position or switch a device on or off touch screen /t tʃ skri n/ noun a

computer display which has a grid of infrared transmitters and receivers, positioned on either side of the screen used to control a cursor position (NOTE: When a user wants to make a selection or move the cursor, he or she points to the screen, breaking two of the beams, which gives the position of the pointing finger.)

touch-sensitive keyboard / t tʃsensət v ki bɔ d/ noun a thin, flat mem-

brane type keyboard whose keys are activated by touching and operate without movement (NOTE: It is often used in heavy duty or dirty environments where normal keys would not function correctly.)

TP abbr teleprocessing TPI abbr tracks per inch

trace /tre s/ noun a method of verifying that a program is functioning correctly, in which the current status and contents of the registers and variables used are dis-

played after each instruction step

trace program /tre s prəυ r m/ noun a diagnostic program which executes a program that is being debugged, one instruction at a time, displaying the states and registers

traceroute / tre sru t/ noun a software utility that finds and displays the route taken for data travelling between a computer and a distant server on the Internet

COMMENT: The display shows the different servers that the data travels through, together with the time taken to travel between each server (called a hop). Traceroute works by sending out a time-to-live (TTL) query data

packet to the distant server. It starts by sending out packets with a very low time-to-live, then gradually increases the length of time that the packet can survive until one is returned by the host – this then provides the shortest time it will take to reach the host. If you are trying to view a website you can use traceroute to check which section of the link to the website’s server is the slowest. Windows includes a traceroute utility ‘tracert’. Click the Start button and select the Run option then type in ‘tracert’ followed by the domain name of the distant web server, e.g. tracert ‘www.bloomsbury.com’’

trace trap /tre s tr p/ noun a selective breakpoint where a tracing program stops, allowing registers to be examined tracing / tre s ŋ/ noun a function of a graphics program that takes a bitmap image and processes it to find the edges of the shapes and so convert these into a vector line image that can be more easily manipulated

track /tr k/ noun any one of a series of thin concentric rings on a magnetic disk which the read/write head accesses and along which the data is stored in separate sectors verb to follow a path or track correctly The read head is not tracking the recorded track correctly.

COMMENT: The first track on a tape is along the edge and the tape may have up to nine different tracks on it, while a disk has many concentric tracks around the central hub. The track and sector addresses are set up during

formatting.

track address /tr k ə dres/ noun the location of a particular track on a magnetic disk

trackball / tr k bɔ l/ noun a device used to move a cursor on-screen which is controlled by turning a ball contained in a case

tracking / tr k ŋ/ noun 1. the correct alignment of a read head and the tape in a tape player 2. degradation of a video clip because the action moves too fast to be accurately captured by the camera

tracks, minutes, seconds, frames time format / tr ks m nəts sekəndzfre mz ta m fɔ m t/ noun full form of

TMSF time format

tracks per inch / tr ks p r ntʃ/ noun a measure of the number of concentric data tracks on a disk surface per inch.

Abbr TPI

tractor feed / tr ktə fi d/ noun a method of feeding paper into a printer, in which sprocket wheels on the printer connect with the sprocket holes on either edge of the paper to pull the paper through

traffic / tr f k/ noun the totality of messages and other signals processed by a system or carried by a communications link

Our Ethernet network begins to slow down if the traffic reaches 60 per cent of the bandwidth.

traffic analysis / tr f k ə n ləs s/ noun the study of the times, types and quantities of messages and signals being processed by a system

traffic density / tr f k dens ti/ noun the number of messages and data transmitted over a network or system in a period of time

traffic intensity / tr f k n tens ti/ noun the ratio of messages entering a queue to those leaving the queue within a certain time

trailer / tre lə/ noun the final byte of a file containing control or file characteristics

trailer record / tre lə rekɔ d/ noun the last record in a file containing control or file characteristics

transaction /tr n z kʃən/ noun a single action which affects a database, e.g. a sale, a change of address or a new customer

transaction-driven system /tr nz kʃən dr v(ə)n s stəm/ noun full

form of TDS

transaction file /tr n z kʃən fa l/ noun same as update file

transaction processing /tr nz kʃən prəυses ŋ/ noun interactive

processing in which a user enters commands and data on a terminal which is linked to a central computer, with results being displayed on-screen. Abbr TP

‘At present, users implementing client-server strategies are focusing on decision support systems before implementing online transaction processing and other mission-critical applications.’ [Computing]

transaction record /tr n z kʃənrekɔ d/ noun same as change record transceiver /tr n si və/ noun a transmitter and receiver, or a device which can both transmit and receive signals, e.g. a terminal or modem

transcribe /tr n skra b/ verb to copy data from one backing storage unit or medium to another (NOTE: transcribes – transcribing – transcribed) transducer /tr nz dju sə/ noun an electronic device which converts signals in one form into signals in another the

pressure transducer converts physical pressure signals into electrical signals transfer / tr nsf / verb 1. to change command or control of something All processing activities have been transferred to the mainframe. 2. to copy a section of memory to another location (NOTE: transferring – transferred) noun the process of changing command or control transfer check /tr ns f tʃek/ noun a check that a data transfer is correct according to a set of rules

transfer command / tr nsf kəmɑ nd/ noun an instruction that directs processor control from one part of a program to another

transfer control / tr nsf kən trəυl/ noun a change in the command or control of something, e.g. to another point in the program when a branch or jump instruction within a program is executed transfer rate / tr nsf re t/ noun the speed at which data is transferred from backing store to main memory or from one device to another With a good telephone line, this pair of modems can achieve a transfer rate of 14.4Kbps.

transfer time /tr ns f ta m/ noun the time taken to transfer data between devices or locations

transform /tr ns fɔ m/ verb to change something from one state to another

transformational rules /tr nzfəme ʃ(ə)n(ə)l ru lz/ noun a set of rules

applied to data which is to be transformed into coded form

transient / tr nziənt/ adjective referring to a state or signal which is present for a short period of time noun something which is present for a short period transient area / tr nziənt eəriə/ noun a section of memory for user programs and data

transient error / tr nziənt erə/ noun a temporary error which occurs for a short period of time

transient read error / tr nziənt ri derə/ noun an error, caused by bad data recording, from which a program can recover

transient suppressor / tr nziənt səpresə/ noun a device which suppresses voltage transients

transistor /tr n z stə/ noun an electronic semiconductor device which can control the current flow in a circuit (NOTE:

There are two main types of transistor, bipolar and unipolar.)

transistor-transistor logic /tr nz stə tr n z stə lɒd' k/ noun full form

of TTL

transition point /tr n z ʃ(ə)n pɔ nt/ noun a point in a program or system where a transition occurs

translate /tr ns le t/ verb to convert data from one form into another (NOTE: translates – translating – translated) translation tables /tr ns le ʃ(ə)nte b(ə)lz/ plural noun same as conversion tables

translator /tr ns le tə/, translator program /tr ns le tə prəυ r m/ noun

a program which translates a high level language program into another language, usually machine code. interpreter, compiler

transmission /tr nz m ʃ(ə)n/ noun the process of sending signals from one device to another

transmission channel /tr nzm ʃ(ə)n tʃ n(ə)l/ noun a physical con-

nection between two points which allows data to be transmitted, e.g. a link between a CPU and a peripheral

transmission control protocol

/tr nz m ʃ(ə)n kən trəυl prəυtəkɒl/ noun full form of TCP

transmission control protocol/interface program /tr nz m ʃ(ə)n kəntrəυl prəυtəυkɒl ntəfe s prəυ r m/

noun full form of TCP/IP transmission error /tr nz m ʃ(ə)nerə/ plural noun an error due to noise on the line

transmission medium /tr nzm ʃ(ə)n mi diəm/ noun a means by

which data can be transmitted, e.g. radio or light

transmission rate /tr nz m ʃ(ə)n re t/ noun a measure of the amount of data transmitted in a certain time Their average transmission is 64,000 bits per second (bps) through a parallel connection or 19,200 bps through a serial connection. transmissive disk /tr nz m s v d sk/ noun an optical data storage disk in which the reading laser beam shines through the disk to a detector below transmit /tr nz m t/ verb to send information from one device to another, using any medium such as radio, cable or wire link (NOTE: transmitting – transmitted)

transmitter /tr nz m tə/ noun a device which will take an input signal, process it , e.g. to modulate or convert it to sound, then transmit it by a medium such as radio or light. Abbr TX

transparency /tr ns p rənsi/ noun

(in graphics) the degree to which one image shows another image beneath it transparent /tr ns p rənt/ adjective referring to a computer program which is not obvious to the user or which cannot be seen by the user when it is running transparent GIF /tr ns p rənt d'i a ef/ noun a graphic image stored in the GIF file format with one colour from the palette assigned as a transparent colour

(NOTE: When the image is displayed, any part of the image in this colour will be transparent to allow any image beneath to show through. This feature is used a lot in webpages to place images on a patterned background.)

transparent interrupt /tr ns p rəntntər pt/ noun a mode in which if an in-

terrupt occurs, all machine and program states are saved, the interrupt is serviced, then the system restores all previous states and continues normally

transparent paging /tr ns p rəntpe d' ŋ/ noun software which allows the user to access any memory location in a paged memory system as if it were not paged

transphasor /tr nz fe zə/ noun an optical transistor constructed from a crystal which is able to switch a main beam of light according to a smaller input signal

COMMENT: This is used in the latest research for an optical computer that could run at the speed of light.

transportable /tr ns pɔ təb(ə)l/ adjective which can be carried, though perhaps requiring a vehicle A transportable computer is not as small as a portable or a laptop.

transport layer /tr ns pɔ t le ə/ noun the fourth layer in the ISO/OSI network model that provides a reliable connection and checks and controls the quality of the connection

trap /tr p/ noun a device or piece of software or hardware that will catch something such as a variable, fault or value

trapdoor / tr p dɔ / noun a way of getting into a system to change data, browse or hack

trapezoidal distortion / tr p zɔ dəl d s tɔ ʃ(ə)n/ noun same as keystone distortion

trap handler /tr p h ndlə/ noun a piece of software that accepts interrupt signals and acts on them, e.g. running a special routine or sending data to a peripheral

trashcan / tr ʃk n/ noun (in a GUI) an icon which looks like a dustbin that deletes any file that is dragged onto it

tree and branch network system

/ tri ən brɑ ntʃ netw k s stəm/ noun a system of networking in which data is transmitted along a single output line, from which other lines branch out, forming a tree structure that feeds individual stations

tree of folders / tri əv fəυldəz/ noun a view of all the folders stored on a disk arranged to show folders and subfolders tree selection sort / tri s lekʃənpɔ t/ noun a rapid form of selection in which the information from the first sort pass is used in the second pass to speed up selection

trellis coding / trel s kɒd ŋ/ noun a method of modulating a signal that uses both amplitude and phase modulation to give a greater throughput and lower error rates for data transmission speeds of over 9,600 bits per second

triad / tra d/ noun 1. a group of three elements, characters or bits 2. a triangular shaped grouping of the red, green and blue colour phosphor spots at each pixel location on the screen of a colour RGB monitor

trichromatic / tra krəυ m t k/ adjective RGB

trivial file transfer protocol / tr viəlfa l tr nsf prəυtəkɒl/ noun full

form of TFTP

Trojan Horse / trəυd'(ə)n hɔ s/ noun a program inserted into a system by a hacker that will perform a harmless function while copying information held in a classified file into a file with a low priority, which the hacker can then access without the authorised user’s knowledge troubleshoot / tr b(ə)lʃu t/ verb 1. to debug computer software 2. to locate and repair faults in hardware troubleshooter / tr b(ə)lʃu tə/ noun a person who troubleshoots hardware or software (NOTE: troubleshot)

true /tru / adjective referring to a logical condition representing a non-zero value. Compare false

TrueType / tru ta p/ a trade name for an outline font technology introduced by Apple and Microsoft as a means of printing exactly what is displayed on screen

truncate /tr ŋ ke t/ verb 1. to cut something short 2. to give an approximate value to a number by reducing it to a certain number of digits 3.5678 truncated to 3.56 (NOTE: truncates – truncating – truncated)

truncation /tr ŋ ke ʃ(ə)n/ noun removal of digits from a number so that it is a particular length

truncation error /tr ŋ ke ʃ(ə)n erə/ noun an error caused when a number is truncated

trunk /tr ŋk/ noun a bus or communication link consisting of wires or leads which connect different parts of a hardware system

truth table /tru θ te b(ə)l/ noun a method of defining a logic function as the output state for all possible inputs

truth value /tru θ v lju / noun each of two values, true or false, T or F, 1 or 0, used in Boolean algebra

TSAPI abbr telephony services application programming interface

Tseng Labs / seŋ l bz/ a manufacturer of chipsets used in graphics adapters

TSR abbr terminate and stay resident TSW abbr telesoftware

TTL / ti ti el/ noun the most common family of logic gates and high-speed transistor circuit designs in which the bipolar transistors are directly connected, usually collector to base. Full form transistortransistor logic

TTL-compatible / ti ti el kəmpɒt b(ə)l/ adjective referring to MOS or other electronic circuits or components that can directly connect to and drive TTL circuits

TTL logic / ti ti el lɒd' k/ noun the use of TTL design and components to implement logic circuits and gates

TTL monitor / ti ti el mɒn tə/ noun a monitor which can only accept digital signals, so can only display monochrome images or a limited range of colours

TTY abbr teletype

tune /tju n/ verb to set a system at its optimum point by careful adjustment (NOTE: tunes – tuning – tuned)

tunnelling / t n(ə)l ŋ/ noun a method of enclosing a packet of data from one type of network within another packet so that it can be sent over a different, incompatible network

Turing machine / tjυr ŋ mə ʃi n/ noun a mathematical model of a device which could read and write data to a controllable tape storage while altering its internal states

Turing test / tjυr ŋ test/ noun a test to decide if a computer is ‘intelligent’

turnaround document / t nə raυnddɒkjυmənt/ noun a document which is

printed out from a computer, sent to a user and returned by the user with new notes or information written on it, which can be read by a document reader

turnaround time / t nəraυnd ta m/ noun 1. the length of time it takes to switch data flow direction in a half duplex system 2. the time taken to activate a program and produce the result which the user has asked for (US) abbr TAT

turnkey system / t nki s stəm/ noun a complete system which is designed to a customer’s needs and is ready to use

(NOTE: To operate it, the user only has to switch it on or turn a key.)

turtle / t t(ə)l/ noun a device whose movements and position are controllable, used to draw graphics with instructions in the computer language LOGO (NOTE: It is either a device which works on a flat surface (floor turtle) or one which draws on a VDU screen (screen turtle), and is often used as a teaching aid.)

turtle graphics / t t(ə)l r f ks/ plural noun graphic images created using a turtle and a series of commands The charts were prepared using turtle graphics.

TV / ti vi / abbr television

TV-out / ti vi aυt/ noun a connector on a computer or graphics adapter that provides a modulated signal that can be displayed on a standard television or recorded on a video recorder

TWAIN /twe n/ noun an application programming interface standard developed by Hewlett-Packard, Logitech, Eastman Kodak, Aldus, and Caere that allows software to control image hardware

tweak /twi k/ verb to make small adjustments to a program or hardware to improve performance

tweening / twi n ŋ/ noun (in computer graphics) the process of calculating the intermediate images that lead from a starting image to a different finished image Using tweening, we can show how a frog

turns into a princess in five steps.

24/96 / twenti fɔ na nti s ks/ popular standard for high-performance digital audio equipment that provides 24-bit sam-

ples and a sample rate of 96KHz

24-bit sample / twenti fɔ b tsɑ mp(ə)l/ noun single sample of an analogue signal which is stored as three bytes (a 24-bit digital number), meaning that there are 16,777,216 possible levels. 8-

bit sample, 16-bit sample twisted-pair cable / tw st d peə

ke b(ə)l/ noun a cable which consists of two insulated copper wires twisted around each other, to reduce induction and so interference

COMMENT: The EIA specifies five levels of cable for different purposes. The Category 1 standard defines an older-style unshielded twisted-pair cable that is formed by loosely twisting two insulated wires together to reduce noise and interference; this type of cable is not suitable for data transmission. The Category 2 (part of the EIA/TIA 568 specification) standard defines a type of unshielded twistedpair cable that can be used to transmit data at rates up to 4MHz. The Category 3 (part of the EIA/TIA 568 specification) standard defines a type of unshielded twisted-pair cable that can be used to transmit data at rates up to 10MHz; this type of cable is the minimum standard of cable required for a 10BaseT network. The standard suggests that the cable should have three twists per foot of cable. The Category 4 (part of the EIA/TIA 568 specification) standard defines a type of unshielded twisted-pair cable that is the minimum standard of cable required for data transmission rates up to 16Mbit/second on a Token Ring network. The Category 5 (part of the EIA/TIA 568 specification) standard defines a type of cable that can carry data transmitted at up to 100MHz and is suitable for FDDI over copper wire, 100BaseT or other high-speed networks.

twisted-pair Ethernet / tw st d peəi θənet/ noun a star-topology network

that uses twisted-pair cable and transmits

data at 10 Mbps;. Also called 10BaseT two-address instruction / tu ə dres

n str kʃən/ noun an instruction format containing the location of two operands, the result being stored in one of the operand locations

2D / tu di / object in a graphic image that has only the appearance of width and

height, not depth, so does not look like a solid object

two-dimensional / tu damenʃən(ə)l/ adjective which has two di-

mensions, i.e. flat, with no depth

two-dimensional array /tu damenʃ(ə)nəl ə re / noun an ordered struc-

ture whose elements are arranged as a ta-

ble of rows and columns

two-input adder / tu npυt də/ adjective half adder

two-level subroutine / tu lev(ə)ls bru ti n/ noun a subroutine containing another subroutine

two-part /tu pɑ t/ noun referring to paper with a top sheet for the original and a second sheet for a copy two-part invoices

two-pass assembler / tu pɑ s əsemblə/ noun an assembler which con-

verts an assembly language program into machine code in two passes (NOTE: The first pass stores symbolic addresses, the second converts them to absolute ad-

dresses.)

two-phase commit / tu fe z kə m t/ noun (in a database) a function that ensures that each step of a transaction is correct and valid before committing the changes to the database

two-plus-one-address instruction

/tu pl s w n ə dres/, two-plus-one instruction /tu pl s w n/ noun an instruction containing locations of two operands and an address for the storage of the result

two’s complement / tu zkɒmpl mənt/ noun a complement

formed by adding one to the one’s complement of a binary number, often used to represent negative binary numbers

TX abbr transmitter

type /ta p/ noun 1. printed characters on a page they switched to italic type for the heading 2. the definition of the processes or sorts of data which a variable in a computer can contain verb to enter information via a keyboard I typed in the command again, but it still didn’t work. (NOTE: types – typing – typed)

Type 1 /ta p w n/ noun a set of four wires arranged as two pairs of solid wires surrounded by a braided shield to reduce interference

Type 2 /ta p tu / noun a set of twelve wires arranged as six pairs of wire, used for voice transmission

Type 3 /ta p θri / noun a twisted pair of wires, used for telephone wire

Type 5 /ta p fa v/ noun 100–140 micron diameter fibre optic cable

Type 6 / ta p s x/ noun a set of four separate wires arranged as two pairs, with each wire made up of strands of fine wire Type 8 /ta p e t/ noun a set of four separate wires arranged as two pairs, forming shielded cable with no twists

Type cable /ta p ke b(ə)l/ noun a specification for cables defined by IBM typeface / ta p fe s/ noun a set of characters in a particular design and particular weight Most of this book is set in the Times typeface.

typesetter / ta p setə/ noun a machine which produces very high-quality text output using a laser to create an image on photosensitive paper, usually at a resolution of 1275 or 2450 dpi

type size /ta p sa z/ noun the size of a font, measured in points

type style /ta p sta l/ noun the weight and angle of a font, e.g. bold or italic

UA / ju e / noun (in an X.400 email system) software that ensures a mail message has the correct header information and then delivers it to the message transfer agent which sends the message to its destination. Full form user agent

UART / ju ɑ t/ noun a chip which converts asynchronous serial bit streams to a parallel form or parallel data to a serial bit stream. Full form universal asynchro-

nous receiver/transmitter

UART controller / ju ɑ t kən trəυlə/ noun a circuit that uses a UART to convert serial data from a terminal into a parallel form, then transmits it over a network UBC abbr universal block channel UDP / ju di pi / noun a protocol that is part of TCP/IP that is often used in network management and SNMP applica-

tions. Full form user datagram protocol

UHF / ju e tʃ ef/ noun a range of frequencies normally used to transmit television signals. Full form ultra high frequency

ULA / ju el e / noun a chip containing a number of unconnected logic circuits and gates which can then be connected by a customer to provide a required function. Full form uncommitted logic array ulaw / ju lɔ / noun a method of encoding digital sound samples so that an 8-bit word

can store a 14-bit sound sample Ultimedia / lti midiə/ a trade name for

a multimedia concept developed by IBM that combines sound, video, images and text, and defines the hardware required to run it

ultra- / ltrə/ prefix very large

Ultra-2 SCSI / ltrə tu es si es a / noun an extension to the SCSI hard disk interface that supports either 8-bit data transfers at a rate of 40 Mbits/second or 16-bit data transfers at a rate of 80 Mbits/second (NOTE: This standard can support 15 devices.)

Ultra ATA / ltrə e ti e / noun a version of the AT Attachment hard disk drive interface standard that can support a data transfer rate of up to 33 MBps (NOTE: To manage this high-speed data transfer from the hard disk interface to the rest of your PC, it needs to have a high-speed version of DMA.)

ultra high frequency / ltrə hafri kwənsi/ noun full form of UHF

Ultra SCSI / ltrə es si es a / noun an extension to the SCSI hard disk interface that supports either 8-bit data transfers at a rate of 20 Mbits/second or 16-bit data transfers at a rate of 40 Mbits/second

(NOTE: This standard can support 15 devices.)

ultraviolet erasable PROM / ltrəva ələt re zəb(ə)l pi rɒm/ noun an

EPROM whose contents are erased by exposing to UV light

ultraviolet light / ltrəva ələt la t/ noun full form of UV light

UMTS / ju em ti es/ noun a third generation mobile communication system that supports voice data, and video signals to the handset. Full form universal mobile telecommunications system

unallowable digit / nə laυəb(ə)ld d' t/ noun an illegal combination of bits in a word, according to predefined rules

unarchive / n ɑ ka v/ verb to retrieve a computer file from an archive where it has been stored (NOTE: unarchives – unarchiving – unarchived)

unary operation / ju nəri ɒpəre ʃ(ə)n/ noun a computing operation on only one operand, e.g. the logical NOT operation

unattended operation / nətend dɒpə re ʃ(ə)n/ noun an operation that can proceed without the need for a person to supervise

unauthorised / n ɔ θəra zd/, unauthorized adjective which has not been authorised The use of a password is to pre-

vent unauthorised access to the data.

unbundled software / n b nd(ə)ldsɒftweə/ noun software which is not in-

cluded in the price of the equipment unclocked / n klɒkd/ adjective referring to an electronic circuit or flip-flop which changes state as soon as an input changes, not with a clock signal

uncommitted logic array

/ nkəm t d lɒd' k ə re / noun full form of ULA

uncommitted storage list

/ nkəm t d stɔ r d' l st/ noun a table of the areas of memory in a system that are

free or have not been allocated unconditional / nkən d ʃ(ə)nəl/ ad-

jective which does not depend on any condition being met

unconditional branch

d ʃ(ə)nəl brɑ ntʃ/, unconditional jump / nkən d ʃ(ə)nəl d' mp/, un-

conditional transfer noun an instruction which transfers control from one point in the program to another, without depending

on any condition being met uncorrupted / nkə r pt d/ adjective

referring to a computer file or database that is free of errors or viruses undelete / nd i t/ verb to restore deleted information or a deleted file Don’t worry, this function will undelete your cuts to the letter. (NOTE: undeletes – undelet-

ing – undeleted)

underflow / ndəfləυ/ noun the result of a numerical operation that is too small to be represented with the given accuracy of a computer

underline noun a line drawn or printed under a piece of text. Also called underscore verb to print or write a line under a piece of text (NOTE: underlines – underlining – underlined)

underlining / ndə la n ŋ/ noun a word-processing command which under-

lines text

underscore / ndəskɔ / noun, verb same as underline (NOTE: underscores

– underscoring – underscored) undetected error / nd tekt d erə/

noun an error which is not detected by a coding system

undo / n du / verb to reverse the previous action, normally an editing command

You’ve just deleted the paragraph, but

you can undo it from the option in the Edit menu. (NOTE: undoes – undoing – undid)

unedited / n ed t d/ adjective which has not been edited

unformatted / n fɔ m t d/ adjective

1. referring to a text file which contains no formatting commands, margins or typographical commands It is impossible to copy to an unformatted disk. 2. referring to a disk which has not been formatted The cartridge drive provides 12.7Mbyte of unformatted storage.

unformatted capacity / n fɔ m t d kə p s ti/ noun the capacity of a magnetic disk before it has been formatted unformatted disk / n fɔ m t dd sk/ noun a magnetic disk which has not been formatted (NOTE: Disks must be formatted before use.)

ungroup / n ru p/ verb to convert a single complex object back into a series of separate objects

uni- /ju ni/ prefix one or single unicast / ju nikɑ st/ noun a transmission from a single computing terminal to one other terminal

uniform resource locator

/ ju n fɔ m r zɔ s ləυ keitə/ noun full form of URL

uninstall / n n stɑ l/ verb to remove a piece of software from a computer

uninterruptible power supply

/ n ntər pt b(ə)l paυə sə pla / noun full form of UPS

union / ju njən/ noun a logical function which produces a true output if any input is true

unipolar / ju ni pəυlə/ adjective 1. (referring to a transistor) which can act as a variable current flow control (NOTE: An external signal varies the resistance of the device.) 2. referring to a transmission system in which a positive voltage pulse and zero volts represents the binary bits 1 and 0

unipolar signal /ju n pəυlə s n(ə)l/ noun a signal that uses only positive voltage levels

unique identifier /ju ni k adent fa ə/ noun a set of characters used to distinguish between different resources in a multimedia book

unit / ju n t/ noun 1. the smallest element 2. a single machine, possibly with many different parts

unit buffer / ju n t b fə/ noun a buffer which is one character long (NOTE: Usually used to mean that there are no buffer-

ing facilities)

unit record / ju n t rekɔ d/ noun a

single record of information

universal / ju n v s(ə)l/ adjective which applies everywhere or which can be used everywhere or used for a number of tasks

universal asynchronous receiver/transmitter / ju n v səle s ŋkrənəs r si və tr nz m tə/ noun

full form of UART

universal block channel

/ ju n v s(ə)l blɒk tʃ n(ə)l/ noun a communications channel allowing high speed transfer of blocks of data to and

from high speed peripherals. Abbr UBC universal device / ju n v s(ə)l d

va s/ noun 1. same as UART 2. same as

USRT 3. same as USART

universal mobile telecommunications system / ju n v s(ə)l məυba ltelikəmju n ke ʃ(ə)nz s stəm/ noun

full form of UMTS

universal product code

/ ju n v s(ə)l prɒd kt kəυd/ noun a standard printed bar coding system used to identify products in a shop using a bar code reader or at a EPOS. Abbr UPC

universal programming

/ ju n v s(ə)l prəυ r m ŋ/ noun the writing of a program which is not specific to one machine, so that it can run on several machines

universal resource locator

/ ju n v s(ə)l r zɔ s ləυ keitə/ noun full form of URL

universal serial bus / ju n v s(ə)ls əriəl b s/ noun full form of USB

universal set / ju n v s(ə)l set/ noun a complete set of elements which conform to a set of rules The universal set of prime numbers less than 10 and greater than 2 is 3,5,7.

universal synchronous asynchro-

nous receiver/transmitter

/ ju n v səl s ŋkrənəs e s ŋkrənəs rsi və tr nz m tə/ noun full form of US-

ART

universal synchronous receiver/transmitter / ju n v s(ə)ls ŋkrənəs r si və tr ns m tə/ noun

full form of USRT

UNIX / ju n ks/ noun a popular multiuser, multitasking operating system devel-

oped by AT&T Bell Laboratories to run on almost any computer, from PCs to minicomputers and large mainframes

‘Hampshire fire brigade is investing £2 million in a command and control system based on the new SeriesFT fault-tolerant Unix machine from Motorola.’ [Computing]

UNIX-to-UNIX copy / ju n ks təju n ks kɒpi/ noun a software utility that helps make it easier for a user to copy data from one computer running UNIX via a serial link to another computer running UNIX. Abbr UUCP

unjustified / n d' st fa d/ adjective referring to text which has not been justified

unjustified tape / n d' st fa d te p/ noun a tape containing unformatted text, which cannot be printed until formatting data such as justification, line width and page size has been added by a computer

unlock / n lɒk/ verb to make it possible for other users to write to a file or access a system

unmoderated list / n mɒdəre t dl st/ noun a mailing list that sends any material submitted to the listserv on to all the subscribers without a person reading or checking the content

unmodified instruction / nmɒd fa d n str kʃən/ noun a program

instruction which is directly processed without modification to obtain the operation to be performed

unmodulated / n mɒdjυle t d/ adjective referring to a signal which has not been modulated

unmount / n maυnt/ verb 1. to remove a disk from a disk drive 2. to inform the operating system that a disk drive is no longer in active use

unpack / n p k/ verb to remove packed data from storage and expand it to its former state This routine unpacks the archived file.

unplug / n pl / verb to take a plug out of a socket Do not move the system without unplugging it. (NOTE: unplugging – unplugged)

unpopulated / n pɒpjυle t d/ adjective referring to a printed circuit board which does not yet contain any components or whose sockets are empty unprotected / nprə tekt d/ adjective referring to data which can be modified and is not protected by a security measure