L

Label (computer)
Identifier in a program that may be prefixed to a statement (possibly a compound statement) in a program, which enables the statement to be referenced by other statements in the program. Label identifiers may be either alphanumeric or numeric.

LABEL (computer/DOS)
DOS Command that adds, alters or removes a disk label on a hard or floppy disk. Disk labels can be up to eleven characters that do not include an asterisk, question mark, slash, backslash, vertical bar, period, comma, semicolon, colon, plus sign, hyphen, parenthesis, square bracket, caret, greater-than, or less-than sign, or ampersand. Lowercase is converted to uppercase.

Lag (A/V)
Using traditional tube-style cameras, the "comet tail" distortion that follows a moving object or motion of the camera across a stationary object. It occurs especially with tube-style colour cameras and monochrome vidicon tube cameras, under low light levels.

Lambda Calculus (computer/mathematics)
Lambda calculus is a mathematical formalism developed by the logician Alonzo Church in the 1930s to model the mathematical notion of substitution of values for bound variables. It is used in functional programming, list processing languages, programming linguistics, program verification, syntax, semantics, and pragmatics.

Laminar Flow (computer/microelectronics)
In microelectronic fabrication, a directed stream of filtered air moved constantly across a clean work area, usually parallel to the workbench surface.

LAN Access Method (communications)
LAN access methods such as CSMA/CD, Token Passing, Polling, to transfer data to and from connected clients (computers) on the network (refer to OSI Model, layers 1, 2).

LAN (communications, computer)
Local Area Network - communications network serving several users within a confined area (an area on a floor). A network of personal computers within a confined area that is made up of servers and workstations. File servers, or network servers, are high-speed machines that hold programs and data shared by all users on the network, while workstations act as user terminals. The workstation can be diskless, requiring all software and data to be obtained from the server, or it can have local disk storage for applications that are not shared by others. Users may have their own printers or printers can be connected to servers and shared. Small LANs can allow one computer to be both server and workstation, but performance is improved when the server is an independent station in the network. Multiple servers can be installed for larger networks. Bridges can connect like networks together and gateways can connect one type of network to another, allowing a personal computer network to interconnect with a mini or mainframe network.

Controlling software in a LAN is the network operating system, such as Novell's NetWare, which resides in the server. A component part of the software resides in each workstation allowing applications to read and write data from the server as if it were on the local machine. The physical transfer is performed by the media access method, such as Ethernet or Token Ring, which come in the form of network interface cards (NICs) that plug into each computer. Cabling type can be twisted pair, coaxial, or optical fibre.

LANC (A/V, computer)
Local Application Numerical Control - LANC is the method used by Sony and some other VCR and camcorder producers to remotely control video products - especially for editing purposes. LANC provides two-way communications and other remote control methods, such as Control-S (send control signals only). Information received through the LANC protocol includes HMSF time code information in Sony RC format and tape counter data. Control-L and "5-pin remote" are synonyms for LANC.

LAN Manager (communications/LAN)
Microsoft's local area network operating system that supports both DOS/Windows-based operating systems and personal computers. Microsoft File Sharing Protocol provides the file sharing program application; NetBIOS is the transport protocol; Named Pipes is the IPC (interprocess communications protocol).

LAN Server (communications/LAN)
Local Area Network program from IBM Corp. very similar to Microsoft LAN Manager.

Land Area In Image (computer/microelectronics)
In microelectronic fabrication, the closed spaces in the screen which result in open spaces on the printed image in screen printing.

Landscape Mode (computer/printing)
A printing orientation that prints data across the wider side of the form. It is one of two printing modes available on most printers (the other is portrait mode). In landscape mode, printed lines run parallel to the paper's direction of travel through the printer.

Language Processors (computer)
Early computer development to moderate the communication barrier between people and computing machines. "The development of languages themselves was not recognised immediately, but instead a trend was toward providing codes that would reference specialised routines that were to be drawn from a library of such routines. Only later, when these codes took on the character of alphabetic phrases, did they become known as “languages" (Grace Hopper, 1981). This development led to the requirement for a processor (program) that would convert programs represented by a symbolic code into their equivalent machine language. This process was (and still is) known as Assembly, and the processor was known as the Assembler.

Language Translation (computer)
Process of translation to another computer language involving four stages: (1) lookup process for each word in a source language dictionary to determine properties and possible functions; (2) analysis to determine the function of words and groups of words in a sentence; (3) rearrangement and transformation of the results to conform to the syntax of the target language; (4) substitution of target language equivalents.

LAN Manager (communications, computer)
IBM's network operating system.

LAP: Link Access Protocol (communications)
Consultative Committee for International Telephony and Telegraphy, CCITT protocol set that was originally based on HDLC (high level data link control) in X.25 packet networks.
LAP-B (LAP-Balanced) X.25 packet network
LAP-D (LAP-D channel) ISDN data channel transmission
LAP-M (LAP-Modem) CCITT V.42 using some of LAPD methods
LAP-X (LAP-Half dupleX) Marine, ship to shore transmission

Lapping (computer/microelectronics)
Grinding and polishing such products as semiconductor blanks in order to obtain precise thickness or extremely smooth, flat, polished surfaces.

Laptop Computer
Small portable computer that can weigh less than 10 pounds but may have the equivalent computing power of a regular desk top configuration. Laptop class machines have been overshadowed recently by Notebook Computers that offer the same power and portability, but are less bulky and offer longer battery operating time (less than 5 pounds).

Large Scale Integration: LSI (computer/microelectronics)
Usually denotes arrays of integrated circuits on a single substrate that comprise 100 or more individual active circuit functions or gates.

Laser (communications, computer)
Light Amplification from the Stimulated Emission of Radiation - a device that generates a very uniform (coherent) light that can be precisely focused. It is used in a wide variety of applications, such as communications, electrophotographic printing and optical disk storage. Lasers are used to transmit light pulses over optical fibres which, unlike electrical wires, are not affected by nearby electrical interference. The different classes of lasers include: optically pumped lasers; gas-discharge lasers; pulsed gas lasers, chemical lasers; photo-dissociation lasers; nuclear lasers; gas-dynamic lasers, semiconductor lasers, free-electron lasers; high-power, short-pulse lasers.

In 1957, the laser was conceived and named by Gordon Gould, a graduate student in physics at Columbia University. When Gould filed for patents in 1959, he found that Charles Townes, a Columbia professor, and Arthur Schawlow, who was working for Bell Labs, had already filed for them. The year before, AT&T had, in fact, demonstrated a working laser at Bell Labs. In 1977, after years of litigation, a court awarded Gould rights to the first of three patents and by the end of the 1980s, he owned all three. After almost 30 years of court battles, Gould finally reaped millions in royalties, but spent much of his life without the recognition he deserved.

Laser Bonding (computer/microelectronics)
In microcomputer fabrication, a process which forms a metal-to-metal fastened union, using a laser heat source to join conductors.

LaserJet (computer/printer)
A series of desktop laser printers from Hewlett-Packard. The printer command language used to drive the LaserJets is HP's PCL (printer control language).

Laser Printer (computer/printer)
A printer that uses the electrophotographic method used in copy machines to print a page at a time. A laser is used to "paint" the dots of light onto a photographic drum or belt. The toner is applied to the drum or belt and transferred onto paper. Desktop laser printers use cut sheets of paper as in a copy machine, and large laser printers use either cut sheets or rolls of paper.

Laser Trim (computer/microelectronics)
In microelectronic fabrication, an adjustment (upward) of a film resistor value by applying heat from a focused laser source to remove material.

LaserWriter (computer/printer)
A series of desktop laser printers that were from Apple Computer.

LASTDRIVE (computer/DOS)
DOS Command that sets the maximum number of logical disk drive letters that can be used on the system. This includes drives used with a network as well as logical drives that are used with the SUBST command. Since the table DOS creates is the map to each potential logical drive, to the physical drive or logical path it represents, the user must only choose as many logical drives as they are expecting to use.

LATA (communications)
Local Access and Transport Area - a geographic region that has been set up to recognize local and long distance telephone calls. In general terms, notwithstanding cellular telephone technologies, any telephone call within a LATA is handled by the local telephone company.

Latch (computer)
Microelectronic circuits that maintain flip-flop states (set and/or reset).

Late Binding (computer/Windows)
A method by which a portion of an application, such as a collection of objects or functions, resides in a separate file and is available to the main application when the application is run instead of when it is compiled into an executable file. Windows Dynamic Link Libraries (DLL) are an example of late binding.

Latency (computer, communications)
The rotational delay in reading or writing a record to a direct-access memory device such as a disk. Maximum latency is the time for an entire revolution of the recording surface. Minimum latency is zero delay, by definition. Average latency is half the maximum. In communications terminology, latency would represent the delay of a series of packets of information, once sent from their source to the destination address. In digital video communications latency can cause delays between the frames and the audio and visual portions of the information. Isochronous Transmission mitigates this by insuring that even with latency, all of the packets of information are presented to the destination (end-user) in the precise sequence as originally transmitted.

Launch (computer/Windows)
To start a Windows applications. Windows Program Manager is an application launcher.

Lavaliere (A/V)
Extremely small microphone that can be clipped onto a jacket, tie, blouse, or other piece of clothing: a larger model can be suspended from a neck cord and worn in front of the chest: also called neck or chest microphone.

LCD (A/V, computer)
Liquid Crystal Display - a display technology that is commonly used in digital watches and notebook computers. Because they use less power, LCDs replaced LEDs (light emitting diodes) in watches years ago. Power is used only to move molecules rather than to energize a light-emitting substance. Liquid crystals are rod-shaped molecules that flow like liquid, and are used to direct light between two polarized filters. In their normal state, the crystals direct the light through the polarizers, allowing a natural grey background to show. When energized, they redirect light to be absorbed in one of the polarizers, causing the dark appearance of crossed polarizers to show.

Lead (A/V)
In A/V production, normally considered to be the first sentence of a news story.

Lead Frame (computer/microelectronics)
In microelectronic fabrication, a metal part of a solid state device package which achieves electrical connection between the die and other parts of the systems of which the IC (integrated circuit) is a component. Large scale integrated circuits are welded onto lead frames in such a way that leads are available to facilitate making connections to and from the various solid state devices to the packages.

Leader Numbers (A/V)
Numerals used for accurate cueing of videotape and film during playback. The numbers from 10 to 3 flash at 1-second intervals and are synchronised with short audio beeps.

Lead-In (A/V)
That part of a story text that introduces a sound bit (in electronic news gathering).

Leading (computer/printing)
Term sometimes used to describe the vertical spacing between lines of type.

Leading Decision (computer)
Term sometimes used to describe the loop-ending decision occurring at the beginning of a closed loop (continuously running) routine.

Leadless Inverted Device: LID (computer/microelectronics)
In microelectronic fabrication, shaped, metallized ceramic form used as an intermediate carrier for the semiconductor chip devices, especially adapted for attachment to conductor lands of a thick or thin film network, by re-flow solder bonding.

Leak Detectors (computer/microelectronics)
Applied only to hermitic devices, fine leak detectors are used to detect defects in sealing that are too small to be detected by gross-leak methods.

Leased Line (communications)
Private channel leased from a carrier. Leased lines can be ordered in pairs, providing a four-wire channel for fast full-duplex transmission. The dial-up system provides only two-wire lines. Leased lines can also be conditioned to improve line quality.

Least Significant Bit (computer/microelectronics)
Bit (binary digit) position at the farthest right position of a byte.

Least Significant Digit (computer)
Digit position at the farthest right position of a complete number.

Least-Squares Approximation (computer)
Used in computer-assisted numerical analysis, the least-squares approximation refers to a wide variety of mathematical optimisation problems in which the objective is to make a residual vector small in the sense of minimising the sum of squares of its elements, or to make a residual function small in the sense of minimising the integral of the squared residual function (also called Approximation Theory, Chebyshev Approximation).

LED (computer)
Light Emitting Diode: rectifying semiconductor device which converts electric energy into electromagnetic radiation. The wavelength of the emitted radiation ranges from the green to the near infrared, this is from 550 nm to over 1300 nm (nanometer). Visible light-emitting diodes are used as solid-state indicator lights and as light sources for numeric and alphanumeric displays. Infrared LEDs are used in opto-isolators and in optical fibre transmission systems.

Legend (computer/graphics)
In regard to a graph or schematic, or an architectural drawing (floor plan), text that explains any colours used, any symbols used, and any other label points on the plan.

LEN: Low Entry Networking (communication)
Original IBM SNA (System Network Architecture), peer-to-peer connection between LU 2.1 (3270-type) nodes. LU 6.2 (logical unit) is also supported with LEN.

Lens (A/V)
Optical lens, essential for projecting an optical (light) image of the scene onto the film or the front surface of the camera pickup tube or tubes; lenses come in various fixed focal lengths or in a variable focal length (zoom lenses), and with various maximum apertures.

Lens Format (A/V)
Colloquial term in A/V for grouping of lenses that have focal lengths appropriate to a particular size of camera pickup tube: lenses that fit 1 inch, 2/3rd inch, and the 1/2 inch pickup tube formats.

Lens Prism (A/V)
Prism that, when attached to the camera lens, will produce special effects, such as the tilting of the horizon line, or the creation of multiple images.

LEOS/MEOS (communications, satellite)
Low Earth Orbital Satellite/Medium Earth Orbital Satellite: New communications satellite capability using intelligent satellites approximately the size of refrigerators that are launched in groups and that orbit at 800 (LEOS) and 1, 200 (MEOS) miles above the earth’s surface, generally in a polar orbit. They are much more economical than earlier geosynchronous satellite systems, they are about 1, 000 times more powerful in terms of their capacity and capabilities, and as they are intelligent, they can communicate with each other providing individual voice, data, video capabilities to end-users. The projected speed for each end-user is one gigabit per second.

Less than (<) condition (computer)
Logic function where a computer compares values: if one is less than another.

Letter Quality Printing (computer/printing)
Term used for the quality produced by a printer (equivalent to high quality typewriter).

Level (A/V)
Term used in Audio/Visual: Audio sound volume; or video signal strength (amplitude).

LFO (A/V, communications, computer)
Low Frequency Oscillator - used in synthesisers to modulate a carrier oscillator providing audio effects such as vibrato (frequency modulation) and tremolo (amplitude modulation).

Library (A/V, computer)
Collection of functions compiled as a group and accessible to applications by calling the function name and any required arguments. Windows DLLs is one type of library. A library used by compilers to provide specialised functions, such as floating-point mathematical routines, is another type. In audio/visual productions, filed footage.

Life Ageing (computer/microelectronics)
In microelectronic fabrication, a burn-in test which moderates the elevation of temperature and extends the time period, in order to test overall circuit input.

LIFO (computer)
Last In First Out: queuing method in which the next item to be retrieved is the item most recently placed in the queue (contrast with LIFO).

Light Amplifier (communications, computer, photonics)
Device which produces an enhanced light output when actuated by incident light. Common usage has introduced two restrictions: (1) a light amplifier must be a device which, when actuated by a light image, reproduces a similar image of enhanced brightness: (2) the device must be capable of operating at very low light levels without introducing spurious brightness variations (noise) into the reproduced image. There are two main categories of light amplifiers: Image-Intensifier Tubes; solid-state Image Intensifiers. In addition to their application for night vision, light amplifiers have been useful in fields of science such as astronomy, nuclear physics, and microbiology.

Light-Emitting Diode: LED (A/V, communications, computer)
Rectifying semiconductor device which converts electric energy into electromagnetic radiation. the wavelength of the emitted radiation ranges from the green to the near infrared, that is from 550 nm to over 1300 nm (nanometers). Visible light-emitting diodes are used as solid-state indicator lights and as light sources for numeric and alphanumeric displays. Infrared LEDs are used in opto-isolators and in optical fibre cable transmission systems.

Light Angle (A/V)
Term used in audio/visual: it can be the vertical angle of the suspended lighting instrument, a 45-degree angle is considered normal.

Light Level (A/V)
In audio/visual production, light is measured a number of ways. The fundamentals of light include the Input of electrical energy entering the lamp, that is then converted into light energy (Input): it is measured in watts (W). The amount of light energy leaving a lamp, called Output, is measured in lumens (lm). The quantity of light falling on a nearby surface is called Incidence, and it is measured in footcandles (fc). The amount of light rebounding from that surface, called Reflectance is measured in footlamberts (fl). Difference (Contrast) in brightness between two adjacent surfaces is measured in Ratio.

Input: electrical energy (amount) entering a lamp watts (W)
Output: light energy (amount) leaving a lamp lumens (lm)
Incidence: light (quantity of) falling on a nearby surface footcandles (fc)
Reflectance: light (amount of) rebounding from that surface footlamberts (fl)
Contrast: light difference in brightness between 2 surfaces (measured in Ratio)

Light Panel (A/V, computer)
Surface-area light source that employs the principle of electroluminescence to produce light. Light panels are composed of two sheets of electrically conductive material; one a thin conducting backing and the other a transparent conductive film, placed on opposite sides of a plastic or ceramic sheet impregnated with a phosphor, such as zinc sulphide, and small amounts of compounds of copper or manganese. When an alternating voltage is applied to the conductive sheets, an electric field is applied to the phosphor. Each time the electric field changes, it dislodges electrons from the edges of the phosphor crystals. As these electrons fall back to their normal atomic state, they affect the atoms of the slight "impurities" of copper or manganese, and radiation of the wavelength of light is emitted. In general, higher voltage and higher frequency both result in a brighter panel. Blue, green, red, or yellow light can be produced by the choice of phosphors, and the proper blend of colours produces white light.

Lighting Triangle (A/V)
Same as Photographic Principle: the triangular arrangement of key lights, back lights, and fill lights: also called triangle lighting.

Lightness (computer/printing)
Variation of a hue along the scale from black to white.

Lightpen (computer)
Common, manual input device on vector graphic video displays for identifying information displayed on the screen for subsequent computer processing. Also a commercial term for a high intensity flashlight with a red beam used as a pointer to a spot on a projected presentation.

Light Plot (A/V)
In audio/visual production, a plan, like a floor plan, showing type, size (wattage), location of the lighting instruments relative to the scene to be illuminated and the general direction of the beams.

Light Ratio (A/V)
In audio/visual production, the relative intensities of key, back, and fill. A 1:1 ratio between key and back lights means that both light sources burn with equal intensities. A 1:½ ratio between key and fill lights means that the fill light burns with half the intensity of the key light. Because light ratios depend on many production variables, they cannot be fixed. A key/back/fill ratio of 1:1:½ is often used for normal triangle lighting.

Lightwave (communications)
Light in the infrared, visible and ultraviolet ranges, which falls between x-rays and microwaves. Wavelengths in this range are between 10 nanometers and one millimeter.

Lightwave System (communications)
Optical system that transmits light pulses over optical fibers; for example the intercity trunks of the telephone companies are rapidly being converted to lightwave systems. Lightwave systems now in production can transmit over 4 billion light pulses per second.

Limbo (A/V)
Audio/Visual term used to describe any set area used for shooting small commercial displays, card easels, and the like, having a plain, light background.

LIM EMS (computer)
Lotus/Intel/Microsoft Expanded Memory Specifications - Same as EMS.

Limiter Circuit (computer, microelectronics)
Electronic circuit used to prevent the amplitude of an electrical waveform from exceeding a specified level while preserving the shape of the waveform at amplitudes less than the specified level. The limiting action takes place by effectively shunting a normal load resistance with a much lower resistance at and above the specified limiting level. Two different types of limiter circuits include diode limiters, and triode limiters.

Line Adapter (communications)
Device similar to a modem, that converts a digital signal into a form suitable for transmission over a communications line and vice-versa. It provides such functions as parallel to serial and serial to parallel conversion, and modulation and demodulation.

Line Art (computer/printing)
Artwork consisting of solid blacks and whites, with no tonal values.

Linear (communications, computer)
Arrangement along one line, one axis, one dimension. Linear operations imply uniformity, equality, regularity; for example, the outputs of a linear system are uniformly based on the inputs. An increase in the input provides and equal increase in output.

Linear Circuit (computer/microelectronics)
Circuit whose output is an amplified version if its input, or whose output is a predetermined variation of its input.

Linearity (A/V, computer/microelectronics)
Relationship that exists between two quantities when a change in one produces a directly proportional change in the other. An amplifier has good linearity when doubling its input signal strength always doubles the output signal strength. A transistor displays good linearity when doubling of the instantaneous base voltage serves to double the instantaneous value of collector current. In television, uniform linearity of scanning is essential for uniform spacing of picture elements in each horizontal line and uniform vertical spacing between scanning lines.

Line Blanking (A/V)
Audio/Visual term for the blanking signal at the end of each horizontal scanning line. It is used to turn off the electron beam during the retrace period, during which the beam returns to begin a new horizontal line: also called horizontal blanking.

Line Driver (communications)
Hardware device used to extend transmission distance between terminals and computers that are connected via private lines: for digital transmission and is required at each end of the line.

Line Frequency (communications)
Number of times each second a wave or repeatable set of signals is sent over a line. In audio/visual terms, the number of horizontal scans per second, normally 15,734.26 times per second for NTSC colour schemes (National Television Systems Committee). Also, in commercial electric power, it can mean power line frequency, i.e. 60 Hertz.

Line Graph (computer/printing)
Graph made by connecting data points with a line (output is normally a printer/plotter).

Line Level (communications)
Signal strength within a transmission channel, measured in decibels or nepers.

Line Load (communications)
Percentage of time a communications channel is used.

Line Monitor (A/V)
Audio/Visual term for the Master Monitor: the monitor that shows only the line-out pictures; the pictures that go on the air or onto videotape.

Line Of Sight (communications)
In transmission systems, signals above the high frequency range (HF) that do not bend; instead they continue to travel in a straight line right through the atmosphere. In order to capture and retransmit these signals, repeaters must be placed at the horizon point (approximately every 30 to 60 miles) : also describes the unobstructed view from the transmitter to the receiver.

Line-Out (A/V)
Audio/Visual term for the line that carries the final video or audio output.

Line Printer (computer/printer)
Printer that assembles all characters on a line at one time and prints them simultaneously.

Line-Up (A/V)
Listing in chronological order of each item in a newscast and including various pieces of production information; also, variously, the "rundown".

Link (communications, computer/Windows)
In communications terms, a physical and/or logical communications medium. In computing terms, to combine one or more object files into a single, executable file structure. This process is called static linking because the object files are made a permanent part of the executable file structure. In DOS, the executable file structure may consist of an executable element and one or more overlay files. Windows dynamic link libraries, on the other hand, are linked to executable files when the executable file is in memory, not when it is created by linking one or more object files. Link is also used to indicate a DDE or OLE connection for a client and server application.

Linkage Editor (computer)
Editor used to combine into a single module a number of program segments that have been independently compiled. The output of the linkage editor is usually a relocate-able binary program suitable for loading by a relocating loader.

Linked Object (computer/Windows)
Representation or placeholder for an object that is inserted into a destination document. The object still exists in the source file and, when it is changed, the linked object is updated to reflect the changes.

Liquid Crystal and Liquid Crystal Display (A/V, computer)
State of matter that mixes the properties of both the liquid and solid states. Liquid crystals may be described as condensed fluid states with spontaneous anisotrophy. They are categorised in two ways: thermotropic liquid crystals, prepared by heating the substance, and lyotropic liquid crystals, prepared by mixing two or more components, one of which is rather polar in character (for example, water). Thermotropic liquid crystals are divided according to structural characteristics, into two classes; nematic and smectic. Liquid Crystals are used in displays in digital wristwatches, calculators, panel meters, and industrial products. They can be used to record, store, and display images that can be projected onto large screens. On Notebook Computers, flat-panel displays are common.

Lip Flap (A/V)
In Audio/Visual production, lip flap occurs when a speaker's lips are shown moving but out of synchronisation with the sound track. In videotape, the speaker's lips are moving but no sound is heard (occurs from sound drop-out).

Lip-Sync (A/V)
Audio/Visual term for the synchronisation of sound and lip movement.

LISP (computer)
List Processing Language: type of language developed for processing non-numerical data (examples include LISP, Logo, Prolog).

List Box (computer/Windows)
Dialog box with a list of items a user may choose with the mouse or cursor. for example, a list of all files in a directory. If all the choices do not fit in the list box, there is a scroll bar.

LIST Chunk (computer/Windows)
RIFF chunk identified by the FOURCC.LIST type. A LIST chunk contains a series of "subchunks" with FOURCCs (such as INFO) listing information about a file (such as the author's name and the creation date).

List Processing Languages (computer)
Computer languages that facilitate the processing of data organised in the form of lists.

Live (A/V)
Broadcasting term that is used with a variety of meanings. A camera or microphone that is turned on is said to be "live". Programming that is not already pre-recorded is "live". The term may also be used to describe the acoustical properties of a studio (a live studio).

Lithography (computer/printing)
Printing process where image area is separated with a technique known as chemical repulsion.

LLC (communications)
Logical Link sublayer of the ISO/OSI model (International Standards Organisation).

Load And Go Compiler (computer)
Running a computer program in two step sequence: translation of the program (compilation) from human-like language into executable machine code; and then the execution of that code.

LOADHIGH (computer/DOS)
DOS Command that loads a program into reserved memory. Loading a program in reserved memory leaves more room in conventional RAM for other programs. Not all programs, however, can be loaded into reserved memory.

Load Line (computer/microelectronics)
Line drawn on the output characteristic curves of a vacuum tube or transistor, used to determine the operating range and the quiescent point (point of zero signal input).

Loaded Line (communications)
Telephone line that uses loading coils to reduce distortion. The loading coils are used to restore high-end voice frequencies but can interfere with data transmissions.

Loader (computer)
Program designed to enter a program from an input device into working memory: to transfer the program held on some external storage medium, into the main memory of the machine in a form suitable for execution.

Local (computer)
Scope of a variable declared within a procedure rather than at the form, module, or global level. Local variables are only visible within the procedure in which they were declared.

Local Account (computer/Windows)
In Windows Networking Advanced Server, a user account provided in a domain for a user whose global account is not in a trusted domain. It is not required where trust relationships exist between domains (see global account and user account).

Local Area Network: LAN (communications, computer)
Communications network servicing several users within a confined area (an area on a floor). A network of personal computers within a confined area that is made up of servers and workstations: the most popular LANs are Ethernet-Type and Token Ring (see LAN).

Local Bypass (communications)
Interconnection between two facilities without the use of the local telephone company.

Local Group (computer/Windows)
In Windows Networking, a group that can be granted permissions and rights only for its own workstation, however, it can contain user accounts from its own computer, and (if the workstation participates in a domain) user accounts and global groups both from its own domain and from trusted domains. Local groups provide a way to create handy sets of users from both inside and outside the workstation, to be used only at the workstation. For Windows Networking Advanced Server, a group that can be granted permissions and rights only for the servers of its own domain, however, it can contain user accounts and global groups both from its own domain and from trusted domains (see global group, group).

Local Loop (communications)
Communications line between a customer and the telephone company's nearest switching center of the telecommunications common carrier.

Local Palette (computer)
Windows GDI data object that provides a list of the individual colours required by a specific application. See GDI and Realising the Palette.

Local Printer (computer)
Printer attached to a personal computer that prints only that computer's documents and performs no network printing functions.

Local Store (computer)
In the Central Processing Unit, Arithmetic Logic Unit, a relatively small number of high-speed storage elements, directly referenced by the computer instruction set. In some systems these registers, because of general-purpose usage, are called general registers.

Local Talk (computer)
Hardware associated with Apple Computer's local area network.

Location Sketch (A/V)
Rough, hand-drawn map of the locale of a remote telecast (television broadcast). For an indoor remote, the sketch shows the dimensions of the room and the location of furniture and windows. For an outdoor remote, the sketch indicates the buildings and the location of the remote truck, power source, and the sun during the time of the telecast.

Lockout (computer)
Circumstance where several processes, executing simultaneously, want to access the same data, at the same moment in time. In a system with multiple CPUs, two processors can be idle and then request a new task at the same time. If no precaution is taken, both could access the table where the list of waiting tasks is stored, and both may attempt to initiate the same task.

Lockup Time (A/V)
Audio/Visual term for the time required by a videotape recorder for the picture and sound to stabilize once the tape has been started.

Log (A/V)
In audio/visual terms, the major operational document: issued daily, the log carries such information as a program source or origin, scheduled program time, program duration, video and audio information, code identification (house number for example), the title of the program, the program type, and additional special information.

Logic (computer, microelectronics)
Mathematical arrangement using symbols for relationships and quantities, handled in a microelectronic network of switching circuits or gates, which perform certain functions.

Logical (computer, algebraic notation)
Synonym for Boolean Logic. Logical is a data type having only true or false values. Logical is also used to define a class of operators whose results are only true or false.

Logical Drive (computer)
Sub-partition of an extended partition on a hard drive.

Logical Field (computer)
Field used to keep track of true and false conditions.

Logical Operations (computer)
Comparing operations. The ALU (arithmetic logic unit) compares numbers, letters, or special characters to take alternative action depending on the result of the comparison.

Logical Palette (computer/Windows)
Windows object providing a list of the individual colours required by a specific application.

Logical Record (computer)
Term sometimes used to describe a record written by an application program.

Logic Circuits (computer/microelectronics)
Basic building blocks used to create products that contain digital electronics. Such products include digital computers, video games, voice synthesizers, pocket calculators, and robot controls. Logic circuits, which comprise several basic electronic devices (transistors, resistors, and diodes) were once designed with each device as a separate physical entity (discrete components). Now, very-large-scale (VLSI) integrated devices offer up to several hundred thousand equivalent basic devices on one tiny piece of silicone, typically rectangular with maximum dimensions of a few tenths of an inch. Logic circuits process information encoded as voltage or current levels (on - off, or "1" - "0"). The adjective "digital" derives from the fact that symbols are encoded as one of a limited set of specific values such as "0" or "1".

Logic Design (computer)
Process of specifying an interconnection of logic elements in digital computer hardware so that a desired function can be performed.

Logic Diagram (computer)
Picture representation for the logical functions of AND, OR, NAND, NOR, NOT.

Logic Error (computer)
Flaw in the design, performance, function of the logic of a program.

Logic Flowchart (computer)
Flowchart that represents the flow of logic in a program.

Logic Function (computer)
Combination storage, delay, or sequential function expressing a relationship between variable signal input(s) to a system or device, and the resultant output(s).

Logic Swing (computer/microelectronics)
Voltage difference between the two logic levels: "1" and "0".

Logic Symbol (computer)
Graphic representation of the aggregate of all the parts implementing a logic function.

Login Script (communications, computer)
Predetermined steps performed to customise a network environment, whenever a user logs on.

Logo (A/V)
In audio/visual terms, a visual symbol identifying an organisation (station, network).

Logon Hours (computer/Windows)
For Windows Networking Advanced Server, a definition of the days and hours during which a user account can connect to a server. When a user is connected to a server and the logon hours are exceeded, the user will either be disconnected from all server communications or will be allowed to remain connected but denied any new connections.

Logon Script (computer/Windows)
Typically a batch file, a logon script runs automatically every time the user logs on. It can be used to configure a user's working environment at every logon, and it allows an administrator to affect a user's environment without managing all aspects of it. A logon script can be assigned to one or more user accounts.

Logon Script Path (computer/Windows)
When a user logs on, the computer authenticating the logon locates the specified logon script (if one has been assigned to that user account) by following that computer's local logon script path ( C:\WINNT\SYSTEM32\REPL\IMPORT\SCRIPTS ) (see logon script).

Logon Workstations (computer/Windows)
For Windows Networking Advanced Server, workstations where a user is allowed to log on.

Logotype (computer/printing)
In printing terminology, a graphic used to create an organisation's visual identity.

Long Haul Modem (communications)
Device used to communicate over long distances (contrast to short haul modem).

Longitudinal Video Recording System (A/V)
LVR: video recorder that records multiple parallel tracks longitudinally along a tape. Over 200 video heads stacked on top of each other produce video tracks on ¼ inch tape.

Longitudinal Redundancy Check (communications)
Use of a set of parity bits for a block of characters such that there is a parity bit for each bit position in the characters.

Loop (A/V, computer, M/M)
Compound program flow-control structure causing statements contained between the instructions designating the beginning and end of the structure to be repeatedly executed. When a given condition is satisfied, program execution continues at the source-code line after the loop-termination statement. In musical terminology, looping means the repetition of a particular group of measures of a composition.

Long Shot (A/V)
Object seen from far away or framed very loosely. The extreme long shot shows the object from a great distance.

Lost Cluster (computer)
Records in a disk cluster set that have lost their file designations. The DOS Command, CHKDSK can turn lost clusters into files that can be saved or deleted.

Loudspeaker (A/V)
Device that converts electrical signal energy into acoustical energy, which it radiates into a bounded space, such as a room, or into outdoor space. The essential characteristic of the signal energy must be preserved in the energy-conversion process: the shorter term "speaker" is also used. The term unit, as in horn unit or driver unit, is applied to devices having a motor and diaphragm but lacking acoustic elements such as a horn to complete the speaker. The term speaker system is used for a plurality of speaker units and the associated accessories, horns, cabinets, and electrical networks required for an integrated, high quality, high fidelity, stereo sound system.

Low Angle Dolly (A/V)
Dolly used with high hat to create a camera mount for particularly low shots.

Low Band (A/V)
Frequency of video information: low band recorders operate in low frequency range, adequate for monochrome pictures (b&w) but introduces excessive video noise in colour.

Low Level Format (computer)
For disk formatting, a low level format initialises a disk and sets the physical properties of the disk, sector layouts, based on the personal computer's hardware controller.

Low Level Language (computer)
Programming language close to machine language: for example, Assembler Language.

Lower Thirds (A/V)
In audio/visual production, graphics that use the bottom portion of the television picture to add information to the picture: for example, captions, identifications, etc.

Low Key (A/V)
Audio/Visual term used to refer to low-intensity overall, yet selective illumination: the background for low-key illumination is generally dark.

LPT Port (computer/Windows)
On a personal computer, the parallel port connection (usually LPT1) where the cable can be plugged in with the other end attached to the local printer. Windows supports parallel ports LPT1, LPT2, and LPT3.

LPI (computer/printer)
Printing term for Lines Per Inch (linear measurement).

LSI (computer, microelectronics)
Common abbreviation for Large Scale Integration (see large scale integration).

LU: Logical Unit (communications, computer)
On a network, the end-users, application programs, or other devices: also communications under IBM's SNA is another example of an LU.

LU 6.2 (communications, computer)
Protocol that helps enable a peer-to-peer communications under IBM's SNA (System Network Architecture, IBM minicomputer and mainframe network architecture).

Lumen (A/V, computer)
Unit of measurement of the flow (rate of emission) of light. A wax candle generates 13 lumens while a 100 watt bulb generates 1,200 lumens. The intensity of light is measured in candelas. A wax candle generates one candela.

Luminance (A/V, computer)
One of the characteristics defining a colour in the Hue-Saturation-Luminance (HSL) system. Luminance is the collective intensity (lightness) of the colour defined by hue and saturation. In broadcasting, signal containing the black and white image is referred to as the luminance signal.

Luminance Channel (A/V)
In Audio/Visual production, a separate channel with colour cameras that deals with brightness variations and allows colour cameras to produce a signal receivable on a black-and-white television. the luminance signal may be taken out of the green channel or electronically combined from the three chrominance signals.