G

G – Gaffer (A/V, production) to Gyrator (communications, computer/microelectronics)

Gaffer (A/V, production)
Senior electrician on a television or film set.

Gaffer Grip (A/V, production)
Strong clamp used to attach small lighting instruments to pieces of scenery, furniture, doors, and other set pieces: sometimes called a gator grip.

Gain (A/V, communications, computer/microelectronics)
General term used to denote an increase in signal power or voltage produced by an amplifier in transmitting a signal from one point to another. The amount of gain is usually expressed in decibels above a reference level. Antenna gain is a measure of the effectiveness of a directional antenna as compared to a nondirectional antenna. It is usually expressed as the ratio in decibels of standard antenna input power to the power input to a directional antenna that will produce the same field strength in the desired direction. The more directional an antenna is, the higher is its gain. In audio/visual terminology, Gain represents the level of signal amplification for A/V signals: "Riding Gain" means to keep the sound volume at a proper level.

Gain Control (A/V, communications)
Manual or automatic control over the signal power or voltage of an instrument or device.

Gain Up (A/V)
Feature button on some camcorders for extremely low light (picture may get grainy).

Gallium (computer/microelectronics)
Silvery metallic element that is liquid for a wide temperature range: as gallium arsenide, it is an important alternative to silicon in the semiconductor fabrication.

Gallium Arsenide (computer/microelectronics)
Blend of Gallium and trace elements that are grown to produce semiconductor material.

Gallium Arsenide Integrated Circuits (computer/microelectronics)
Compound semiconductor whose unusual electronic properties make it attractive for communications and computer applications, especially for: microwave semiconductor devices, Gunn and Schottky diodes, field effect transistors, and optoelectronic devices such as light emitting diodes and photodiodes. The properties that make gallium arsenide attractive as a microwave device material also make it desirable for high-speed logic circuits. The electron mobility of gallium arsenide is 8 to 10 times greater than that of silicon. The electron velocity of silicon continues to increase as higher electric field are applied, and slowly approaches a saturation drift velocity at very high electric fields, while the gallium arsenide electron velocity decreases slowly at high electric fields. These divergent properties between gallium arsenide and silicon are quite significant for very high-speed, low-power digital circuits. Gallium arsenide also possesses a high-resistivity, semi-insulating substrate which provides isolation between devices without the need for pn junction or hetero-epitaxial isolation (silicon-on-sapphire-SOS). Therefore, circuit density can be greater than with comparable silicon integrated circuit approaches. Also, the insulating substrate reduces interconnect line parasitic capacitance, thereby increasing speed and decreasing dynamic power dissipation.


Games (computer)
Specialised applications simulating various games. The fundamental reason for the ability of computers to play a variety of games is that computers have the ability to represent arbitrary situations and processes through the use of symbols and log operations. For example, one can set up a chess position inside a computer by means of an 8 by 8 array of integers, and tentative moves can be made by computer instructions that change the positions of the numbers in the array. The same symbols could represent checker pieces, or with a slight rearrangement, they could be playing cards for blackjack, bridge, poker, solitaire, or others.

Gamma (A/V, production)
General term describing the tonal reproduction characteristics or gray scale reproduction equivalent of a film or video signal. The word gamma is used differently be film and video technicians. In colour film and printing processes, it is a measure of the contrast in a photographic image or display; the ratio of the density range of a negative to the density range of the original.

Gamma Correction (A/V, production)
Term used in video to describe a process through which a nonlinear output-input characteristic is introduced into the video signal for the purpose of changing the effective value of gamma to correct for a picture monitor's nonlinear gray scale reproduction.

Gannt Chart (computer)
Computer generated bar chart used to depict schedule deadlines and milestones.

Gap (computer)
Space between blocks of data on magnetic tape; also the space in a read/write head assembly over which magnetic energy flows causing the underlying magnetic tape or disk surface to become magnetized in the corresponding direction.

Gapless (computer)
Magnetic tape that is recorded in a continuous stream without interblock gaps.

Garbage Collection (computer)
Colloquial term used in some database management systems. In most computer programs, fixed regions of memory are allocated for various purposes, such as arrays, constants, temporary storage, etc., before the computation begins. On the other hand, some systems (including database programs) permit dynamic storage allocation, the assignment and reassignment of memory as determined by requirements during the course of the computation. In such systems, garbage collection refers to the automatic process of identifying those memory cells whose contents are no longer useful for the process & then making them available again for another use.

Garbage In - Garbage Out (computer)
Popular acronym for a flawed application of a program or implementation (see GIGO).

Gas Tube (A/V, computer, photonics)
Electron tube that contains gas or vapour at low pressure in which an electrical discharge takes place. Gas tubes are of two general types: cold-cathode tubes, in which the phenomenon known as glow discharge serves to maintain a conducting path between the electrodes, and hot-cathode tubes, in which an arc discharge conducts the current. The cold-cathode glow tubes are characterized by a relatively high voltage drop and a low current, while the hot-cathode arc tubes are characterized by a low voltage drop and relatively high current. Cold-cathode diode tubes are used in glow lamps or as voltage-regulator tubes. Hot-cathode gas tubes are used as simple rectifier tubes (the Tungar or Rectigon, and the Phanotron), while the Thyratron is a control tube having one or two grids between the cathode and anode.

Gate (computer/microelectronics)
Circuit having an output and a multiplicity of inputs with the output energised only when a certain combination of pulses is present at the inputs. An AND-gate delivers an output pulse only when every input is energised simultaneously in a specified way. An OR-gate delivers an output pulse when any one or more of the pulses meet the specified conditions. A gate is also an electrode in a field effect transistor. A gate can also be expressed as a circuit in which one signal serves to switch another signal on and off.

Gate Array (computer/microelectronics)
Integrated Circuit chip that contains unconnected logic elements. The finished chip is obtained by adhering the top metal layer of pathways between the elements. The final masking stage is less costly than designing the chip from basics. Gate array chips usually contain only two-input NAND gates, which can be used singularly or connected with other NAND gates to provide all operations required to perform digital logic.

Gate-AND (computer/microelectronics)
Circuit with all inputs having "1" level signals at input to produce a "1" level output.

Gate-NAND (computer/microelectronics)
Circuit with all inputs having "1" level signals at input to produce a "0" level output.

Gate-NOR (computer/microelectronics)
Circuit with any one input, or more, having a "1" level signal produces "0" level output.

Gate-OR (computer/microelectronics)
Circuit with any one input, or more, having a "1" level signal produces "1" level output.

Gates-Decision Elements (computer/microelectronics)
Circuit having two or more inputs and one output. The output depends upon the combination of logic signals at the input.

Gateway Computer/Workstation (communications, computer)
Computer that connects two different types of communications networks together. It performs the protocol conversion from one to the other. A gateway could connect a branch office computer on a LAN to a centralised file management resource that exists at a head office across the country. A bridge device, on the other hand, connects similar networks together.

Gator Grip (A/V, production)
Strong clamp used to attach small lighting instruments to pieces of scenery, furniture, doors, and other set pieces: also called a gaffer grip.

Gauss (computer, microelectronics)
Unit of magnetic flux density; the flux density that will induce an electromotive force (emf) of 1 abvolt (10 to the minus 8) per centimetre in a wire moving across the field at a velocity of 1 centimetre per second.

Gaussian Distribution (computer/microelectronics)
Random distribution of events that is often graphed as a bell-shaped curve: used to represent a normal or statistically probable outcome.

Gaussian Noise (communications)
Random interference caused by movement of electricity in a line (also called white noise).

GCR: Grey Component Replacement (A/V, printing)
Separation technique for replacing cyan, magenta, and yellow inks with black.

GDI (computer)
Graphics Device Interface - the graphics language used in Microsoft Windows.

Gel (A/V, production)
Generic name for a colour filter put in front of spotlights or floodlights to give the light beam a specific hue. Gel comes from gelatine, the filter material used before the invention of more heat and moisture resistant plastics.

Gender Changer (communications)
Coupling unit that reverses the gender of one of the connectors in order that two cables with male connectors or two cables with female connectors can be joined together.

General MIDI: GM (A/V, computer)
Specification for consumer melodic and percussion synthesizers developed by the MIDI Manufacturers Association. GM defines a group of 96 standard voices, duplicating those voices of an arbitrary collection of instruments and a group of MIDI note assignments representing specific nonmelodic percussion instruments (drums). The General MIDI synthesizer specification (GS) is incorporated within the Multimedia Extension to define its standard patch numbers.

General Register (computer/microelectronics)
Internal addressable register in the CPU (central processing unit) which can be used for any temporary storage requirement. A general register can also hold the input (operand) and the output (results) of the various functional units in a computing system. The width of the register is directly related to the width of the operation units, as it appears to the programmer, and does not necessarily reflect the width of the main-memory addressable unit. For example, in newer personal computers, the general registers may be 32 bits wide, although the memory may be addressed in 16-bit units. The functional units may include the arithmetic/logic unit (ALU), the memory, the control unit, and various input-output (I/O) processors. The registers operate at a speed that is directly connected to the speed of the units they serve. Their speed must be such that they do not slow down in any considerable way the functional units connected to them. In this sense they are the highest-speed storage in the hierarchy of stores present in the computer.

General Synthesizer: GS (A/V, computer)
Standard for assigning sounds to patch numbers. Any synthesizer conforming to the GS standard will play the same or similar voice when it receives a particular patch number for one of 128 capital (main) tones. The GS standard provides for 127 additional sets of complementary tones, related to the capital tones in the basic set. Additional tones may be available on more sophisticated expanders or synthesizers.


Generalized Matched Filter (computer, photonics)
Filter that combines versions of the desired object and rejects known noise sources.

Generated Element (A/V, production)
Term used for the major part of microphone: converts sound waves into electrical energy.

Generated Graphics (A/V, production)
Graphics electronically generated and used directly on the air or stored for later retrieval.

Generation (A/V, computer)
In the micro-computer world, a term used to describe micro-computer evolution starting with first generation chips (i.e. 8080 series) to the most recent (i.e. Pentium V).

In the A/V industry, a term used in video production indicating the number of successive re-recordings of original video material, such as that created with a camera or by computer. A videotape created by a camcorder is first generation. If edited directly to a master tape, the master tape is second-generation. Duplicates produced from the master tape are third-generation. The number of non-digital (analog) generations causing deterioration in the image is determined by the quality of the videotape equipment used.

Generator (computer)
Program that creates a program (application generator, macro generator); also a device that creates electrical power or synchronisation signals.

Genlock (A/V, computer)
Circuitry synchronising video for mixing. In a PC, a genlock display adapter converts screen output into a standard NTSC video signal, which is then synchronised with an external video source. It synchronises the video display of a computer to the frame synchronisation signal of NTSC, PAL, or SECAM video. This process allows computer graphics to be viewed on a TV set or recorded with a VCR. Genlock capability is required to add computer titling to video productions. It allows switching from source to source without picture rolling.

Geographic Information System: GIS (computer)
Digital mapping system used for exploration, mapping, dispatching, and tracking.

Geometrical Optics (computer/photonics)
Study of optical systems by means of their geometrical properties. The wavelike nature of light does not come into play.

Geosynchronous Satellite Orbit (communications)
Satellite in orbit approximately 22,300 miles above the earth, moving in the direction of and at the same speed as the earth's rotation: in effect, the satellite remains stationary relative to the earth: sometimes, less accurately, called geostationary.

Germanium Polycrystalline (computer/microelectronics)
In microelectronic fabrication, a primary raw material for making crystal ingots.

GERT (communications, computer)
Graphical evaluation and Review Technique: a procedure for the formulation and evaluation of systems using a network-like approach.
Gesture Based Interface (computer)
In pen-based computer applications, a user interface (such as a stylus) that transforms the gestures or motion, made by the user, to electronic input.

Get (computer)
In programming language, a get statement - a request for the next record in an input file (contrast Get with Put).

Ghost (communications, computer/Windows)
A faint second image that appears close to the primary image on a display or printout. In transmission, a ghost is a result of secondary signals that arrive ahead of or later than the primary signal. Another use of the term is to display a menu option in a dimmed, fuzzy typeface in order to indicate that the option is not currently available. Pull-down menus typically ghost unavailable options (as in Windows).

GIF (computer)
Graphic Interchange Format. GIF is the file format (and extension) storing most graphic images in the CompuServe forum libraries.

Giga (communications, computer)
Giga = 1 billion. GHz (GigaHertz) equals one billion cycles per second. 10 Gbytes (gigabytes) equals 10 billion bytes. 12 GHz is 12 billion cycles per second.

Gigaflops (communications, computer)
Giga Floating Point Operations Per Second. One billion FLOPS per second.

GIGO (computer)
Garbage In - Garbage Out: a popular acronym in computing. A more definitive statement of the principle involved may be that: output is a function of the input and the instructions. The implication is that, if the input data is erroneous, or the user is using the application in a poor implementation, or the sequence of instructions is illogical (or all three), then it should not be a surprise if the results make little sense. Only if all parts of the computing activity are applied with good principles can one expect good results.

Giraffe (A/V, production)
Term sometimes used to describe a tripod boom. A medium-sized microphone boom that can be operated by one person.

GIS: Geographic Information System (computer)
Digital mapping application used for exploration, mapping, dispatching, and tracking.

GKS (communications, computer)
Graphical Kernel System - A graphics system and language for creating 2-D, 3-D and raster graphics images. It is a device independent system that allows applications programs to create and manipulate graphics on many display devices. GKS allows applications to be developed on one system and easily moved to another with minimal or no change. GKS is the first true standard for graphics applications programmers and has been adopted by both ANSI and ISO.



Glare Filter (A/V, computer)
A fine mesh screen that is placed over a CRT (cathode ray tube) screen to reduce glare from overhead and ambient light. Also, a glass or plastic filter for the camera lens to reduce glare. This filter can be installed also as a protective device for the camera lens; it is far cheaper to replace a lens filter, than the camera lens, itself.

Glass Switch (computers/microelectronics)
Glassy, solid-state device used to control the flow of electric current. Useful solid-state devices can be made from glassy as well as crystalline semiconductors. Crystals possess long-range order: that is, given the position of any particular atoms and the orientation of the neighboring atoms, the location of any other atom is known, no matter how far away from the atom under consideration. A glass is a special case of non-crystalline class of materials, namely, amorphous solids. These do not exhibit long-range order, although they tend to have the same local structure (short-range order) as the corresponding crystal.

Glassivation (computer/microelectronics)
Deposited layer of glass on top of a metallized wafer or chip; primarily a protective layer.

Glazed Substrate (computer/microelectronics)
In microelectronic fabrication, unfired material in substrate form. Normally, substrates are printed after firing. For specialized processing, green (unfired) substrates are printed.

Glitch (A/V, computer)
Temporary malfunction in hardware. Contrast with a bug, which is a permanent error. Sometimes a bug in a program may cause the hardware to appear as if it had a glitch. It is sometimes difficult to determine whether a problem lies within the hardware or the software.

Global (computer)
Pertaining to a computer program as a whole. Global variables and constants are accessible to, and may be modified by, program code at the module or procedure level.

Global Account (computer/Windows)
For Windows Networking Advanced Server, normal user account in a user's home domain. Most user accounts are global accounts. If there are multiple domains in the network, it is best if each user has only one user account, in only one domain, and each user's access to other domains is accomplished through a domain trust relationship (see local account).

Global Group (computer/Windows)
For Windows Networking Advanced Server, a group that can be used in its own domain, servers and workstations of the domain, and trusting domains. In all these places it can be granted rights and permissions and can become a member of local groups, however, it can contain only user accounts from its own domain. Global groups provide a way to create handy sets of users from inside the domain, available for use both in and out of the domain. Global groups cannot be created or maintained on standalone Window workstations. For Windows Networking, those that participate in a domain, domain global groups can be granted rights and permissions at those workstations, and can become members of local groups (see group, and local group).

G067. Glow Discharge (computer/microelectronics)
Mode of electrical conduction in gases. Glow discharge commonly occurs under conditions of relatively low pressure. The discharge typically gives off light, so that the region of the discharge appears to glow with considerable intensity. The most important application of the glow discharge is in the so-called voltage regulator or voltage reference tube. This device maintains a relatively constant difference of potential across itself as the current is varied over an appreciable range, and consequently is very useful in cases where a constant reference potential is required.

Gobo (A/V, production)
Scenic foreground piece through which the camera can shoot, thus integrating the decorative foreground with the background action. In film, a gobo is an opaque shield that is used for partial blocking of light (diffuser). For Projectors a gobo with a star-like geometric design would “throw” a star-like perimeter around the actual video or film being projected on a screen.

GOSIP: Government Open System Interconnection Profile (communications)
U.S. government mandate that, as of August 15, 1990, all network procurement must comply with OSI. Testing is performed at the NIST (National Institute of Standards & Technology), which maintains a database of OSI-compliant commercial products.

GOTO (computer/DOS)
DOS Command that redirects execution of commands in a batch file to a different location in the batch file. This command allows the user to change the order of execution of commands in a batch file. It is often combined with the IF command.

Go To Function Key (computer)
In a spreadsheet application, a key used to get to another cell (also called Jump-To).

GPIB (computer)
General Purpose Interface Bus - IEEE 488 standard that connects peripheral devices to a computer and for attaching sensors and programmable instruments. GPIB is a parallel interface that uses a special 24-pin connector. Hewlett-Packard's version is the HPIB.

Graceful Degradation (computer)
System that, after component failure, continues to perform at a reduced level of performance.

Graceful Exit (computer)
Ability to back out of a program problem without having to turn the computer off.

Grade (communications)
The transmission capacity of a line. Grade can refer to a range or class of frequencies that it can handle, for example, telegraph grade (poor), voice grade, data grade, broadband, etc. Also, a grade of cable, for example, for twisted pair cables (levels 3,4,5 etc.): the grade can determine its signalling and shielding capabilities for voice, data and rated speed characteristics for Local Area Networking (10baseT, 100baseT, FDDI, etc.).

Gradient (A/V, printing)
Blend between two colours or shades of grey.

GRAFTABL (computer/DOS)
DOS Command that loads the information DOS needs to print extended characters in graphics mode when using a CGA display mode (colour graphics adapter).


Grain Boundaries (computer/microelectronics)
Regions of intersection of two perfect but orientationally mismatched crystallites. In this region the atomic arrangement deviates from a perfect, periodic lattice.

Grammar Checker (computer)
Application programs that verify grammatical correctness in text.

Grammars (computer/mathematics)
Algebraic system describing the processes by which instance of a language can be constructed. A grammar consists of four elements: (1) a set of metavariables or nonterminal symbols, usually called parts of speech when dealing with natural languages; (2) an alphabet or character set, often called the terminal symbols; (3) a set of rules or productions which describe how a sequence of substitutions can be made for each metavariable; (4) and a special metavariable called the starting or root symbol, which is the starting point for the substitution process. Grammars are most commonly classified into two groups: context-sensitive, and context free. In context-sensitive grammar, the rules are applicable only when a metavariable occurs in a specified context, for example, in the modification of verbs to their plural form. By contrast, in a context-free grammar, any occurrence of a metavariable may be replaced by one of its alternative, irrespective of the other elements in the language.

Grandfather, Father, Son (computer)
Method of storing previous generations of master file data that is continuously updated. The son is the current file, the father is a copy from the previous cycle, and the grandfather is the copy of the file from the cycle before the Father file update.

Graphic Mass (A/V, production)
Any picture element that is perceived as occupying an area within the frame and as relatively heavy or light.

Graphics: Raster and Vector (A/V, computer, M/M)
Two methods are used for storing/maintaining pictures in a computer. The first method, called vector graphics (also known as object-oriented), maintains the image as a series of points, lines, arcs and other geometric shapes. The second method, called raster graphics, resembles TV, where the picture image is made up of dots (or pixels). Understanding these two methods and how they intertwine in today's graphics systems is essential for end-users involved in mastering computer graphics. When a picture is created on a video display screen, it may not be immediately obvious which method is used. When the user tries to manipulate the image, it becomes clear (obvious) which method has been used.

Graphics: Raster Graphics for Printing (computer)
Raster graphics implies the TV-like method that uses dots to display an image on screen. Raster graphics images are created by scanners and cameras and are also generated by paint packages. A picture frame is divided into hundreds of horizontal rows. with each row containing hundreds of dots, called pixels. Unlike TV, which uses a single standard (NTSC), for the entire country, there are dozens of raster graphics standards with new ones coming along all the time. Also unlike TV, which records and displays the dots as infinitely variable shades and colors (analog concept), computer graphics have a finite number of shades and colors (digital concept) based on how large a number is used to represent each pixel. When scanning an image or painting an object into a computer, the image is created in a reserved area of memory called a bit map, with some number of bits corresponding to each dot (pixel). In the simplest monochrome systems, one bit can represent a dot, either on or off. For grey scale (monochrome shades), several bits are required to hold the shade number for each dot. For color, more bits are needed to hold a number for each intensity of red, green, blue in the dot.

The image in the bit map is continuously transmitted to the video screen, dot for dot, a line at a time, over and over. Any changes made to the bit map are instantly reflected on the screen. Since colors are designated with numbers, changing red to green is simply searching for a red number and replacing it with a green number, just as all occurrences of a word can be changed in word processing. Animation is created by continuously copying new sequences from other areas in memory into the bit map, one after the other.

Raster graphics images may take up more space on disk than vector graphics, because storage for each pixel is required even if it is part of the background. A small object in vector graphics format will take up only a few vectors in the display list file.

Graphics: Vector Graphics for CAD Drawing (computer)
Method used by CAD (computer-aided design). As the user draws, each line of the image is stored as a vector (2 end points on an x-y matrix). For example, a square becomes 4 vectors, 1 for each side. A circle is turned into dozens or hundreds of tiny straight lines, the number is determined by the resolution of the drawing. The entire image is commonly stored in the computer as a list of vectors, called a display list. If the display screen used is a vector graphics screen, as in traditional CAD systems, the image is also "drawn" on screen. It is a raster graphics screen (made up of dots). As is the case with personal computers and in most graphics systems today, the vectors are converted into dots in order to display the image on screen. This is called the rasterization of vectors. Vector graphics are used when it is essential to have geometric knowledge about the object created. In a vector system, geometric shapes keep their integrity; a line can be picked, extended or erased; for example, it never turns into just a string of dots in the database. Vector graphics can be transmitted directly to x-y plotters.

Graphics: Screen -vs- Printers (computer)
Desktop laser printers and plotters connected to PCs have higher resolutions than the standard graphics screens used to display images. The resolution of contemporary desktop laser printers can be 300 dots per inch, or 90,000 pixels per square inch. Common display resolutions are less than 10,000 pixels per square inch. That means the jagged lines on a display screen can print more uniformly on a laser printer (no "jaggies").

GRAPHICS (computer/DOS)
DOS Command sets DOS to print graphics screens using the SHIFT-Print Screen Key combination (from the keyboard). If a user wants to print a graphics screen using one of the printers selected by the type parameter or a compatible, the user must execute this command before pressing SHIFT-Print Screen.

Graphics Adapter Board (computer)
Circuit board that enables a personal computer to display pictures or graphs as well as text: also called a graphics board or graphics card.

Graphics-based (A/V, computer)
Displaying text & pictures as graphics images: typically bit-mapped images. A facsimile that is sent to a personal computer is a graphics based image and not a text based image. Contrast with text based, which is what is generated on the screen when typing with a word processor: one you can "edit" - the other you cannot - you must "re-paint". In audio/visual terminology, Graphics represents all two-dimensional visuals prepared for the television screen, including title cards, charts, and graphs.

Graphics Engine (computer)
Specialized chips, or graphics boards, that perform graphics processing independently of the main CPU in the personal computer. They can perform any of a variety of functions, such as generating graphic geometry (display list processing), converting vectors to raster graphics (rasterization of vectors), compression, matrix multiplication (for fast rotation) as well as providing faster data transfer from memory to the display.

Graphics Primitive (computer)
An elementary building block, such as a point, line, or arc. In a solid modelling system, a cylinder, cube, and sphere are examples of primitives.

Graphics Processor (computer)
Specialized hardware that performs graphics processing independently of the main CPU (central processing unit). It can perform a number of functions: graphic geometry, converting vectors to rasters, compression, matrix multiplication, and others.

Graphics Program (A/V, computer, M/M)
In computing terminology, the creation and management of pictures. Pictures can be entered into the computer using input devices such as graphics tablets, mice or light pens, and existing pictures can be scanned into the computer using scanners or cameras. Once stored, pictures can be manipulated and copied in many ways. Colours can be changed, objects can be increased and decreased in size, slanted, squeezed and squashed. Frames of video recordings can be combined with drawn objects. Text descriptions can be added to produce charts, reports, brochures and other kinds of presentation materials. Pictures can be printed on graphics printers and plotters, high-resolution computer output microfilm (COM) machines, or photographed with traditional cameras directly from the video display screen. Business graphics software can generate graphic images, such as bar charts, scatter diagrams and pie charts (i.e. Windows Project) directly from the data without drawing efforts. These charts can be enhanced by using graphics tools, such as paint programs. A graphics computer system requires a graphics display screen, a graphics input device (tablet, mouse, scanner, camera.....), a graphics output device (dot matrix printer, laser printer, plotter....) and a graphics software package. The higher the resolution of the graphics output device, the better the printed image looks. The higher the resolution of a display screen, the more realistic the images will appear.

Although a personal computer costs more than a colour TV, it cannot produce animated pictures with the same facility as a TV, nor can it produce a still picture with the same quality as a 35 millimetre slide. One of the reasons for this is that a TV does not store the signal it receives from the broadcasting station; it simply transfers it directly to the screen. Images created in computers are generated and held in memory and then copied to the screen. Personal computer memories haven't been large enough to represent all the dots in a single frame of TV and generate 30 full frames per second to provide realistic animation. Today, realistic (TV-like and better) graphics require expensive add-on peripherals. Animation of realistic images requires extremely powerful processing. Animation software, that can depict the intricate shading of human skin, totally realistic and infinitely adjustable, may still require systems that cost in excess of $25,000.


Graphics Resolution (computer/Windows)
Level of quality at which Windows prints graphics. The higher the resolution, the better the quality of the printed graphics (and the slower the printing out process is).

Graphics Tablet (computer)
Drawing tablet that can be used for sketching new images or tracing old ones, selecting from menus or for moving the cursor around on the screen. The user makes contact with the tablet with a pen-like stylus connected to the tablet by wire.

Graphics Terminal (computer)
Terminal or other type of device that is capable of displaying pictures.

Graphical User Interface: GUI (computer/Windows)
Graphics-based user interface that incorporates icons, pull-down menus and a mouse such as the Windows GUI, that runs under the Operating System

Graph Theory (computer)
Generally, a graph is a collection of points, any pair of which may or may not be joined by a line. Graph theory is the study of these objects. The uses of graph theory in computers is diverse, and include applications such as scheduling in operating systems and elsewhere, resource allocation, flowchart representations, information retrieval, and even sorting. The algorithms developed to solve graph theoretical problems have been found to be also of theoretical interest in the area of computational complexity.

Gravure (A/V, printing)
Printing method based on the intaglio principle, in which the image area is etched below the surface of the printing plate. The media (paper, etc,) picks up the image from the ink “wells”.

Grey Balance (A/V, printing)
Term used in print processing to define the values of cyan, magenta, and yellow needed to produce a neutral grey when printed at normal density.

Grey Component Replacement: GCR (A/V, computer/printing)
Separation technique for replacing cyan, magenta, and yellow inks, with black.

Grey Scale (computer/printer)
In computer graphics, a series of shades from white to black. The more levels of grey scale, the more realistically an image can be displayed especially a scanned photograph. Scanners vary typically from 16 to 256 levels of grey scale. The amount of grey scale that can be created or entered into a computer depends on the memory and disk space that can be reserved. At the common desktop laser printer resolution of 300 dpi, each square inch is made up of 90,000 pixels. At 256 levels of grey scale (one byte per pixel), it takes 90,000 bytes for one square inch of image. Although compression techniques help reduce the size of graphics files, high-resolution grey scale requires huge storage. The most common format is an 8-bit grey-scale providing 256 shades of grey. Four-bit grey scale images with 64 shades are also used.

Grey Scale (A/V, production)

Scale indicating intermediate steps from TV black to TV white: maximum range is ten greyscale steps; good range is seven steps; poor range is five steps.
Greater Than (>) Condition (computer)
Comparison operation that determines if one value is greater than another.

Green Book (computer/Windows, M/M)
Philips N.V. Green Book specification on CD-I format. CD-I (Compact Disk-Interactive) refers to a class of CDs primarily designed to be viewed on conventional television sets by means of a CD-I player. CD-I players incorporate at least 1 megabyte of memory (RA), special pointing devices, and remote-control systems. CD-I players also may be used for training and other commercial and industrial applications.

Green Ceramic (computer/microelectronics)
In microelectronic fabrication, an unfired ceramic material.

Green Substrate (computer/microelectronics)
In microelectronic fabrication, an unfired material in substrate form. Normally substrates are printed after firing. In special circumstances, green (unfired) substrates are printed.

Grid (computer)
A preset group of imaginary vertical and horizontal lines used to assist in aligning the position of graphic objects. In Visual Basic, the intersection of the imaginary lines are shown as dots on forms in design mode. Control objects will automatically align their outlines to these dots if the snap-to-grid option is implemented.

Ground Plane (computer/microelectronics)
Common ground electrical path for power and/or signals.

Group (computer/Windows)
Collection of programs in Program Manager. Grouping the programs makes it easier to find when the user wants to invoke or activate them.

Group (computer/Windows Networking)
In User Manager, an account containing other accounts called members. The permissions and rights granted to a group are also provided to its members, making groups a convenient way to grant common capabilities to collections of user accounts. For Windows Networking, groups are managed with User Manager. For Advanced Server, groups are managed with User Manager for Domains (see built-in, global, local, user account).

Group Icon (computer/Windows)
Graphic that represents a Program Manager group that is minimized. Double-clicking the group icon opens the group window.

Group Memberships (computer/Windows Networking)
Groups to which a user account belongs. Permissions and rights granted to a group are also provided to its members. The actions a user can perform in Windows Networking are determined by the group memberships of the user account the user is logged on to.

Group Name (computer/Windows Networking)
Unique name identifying a local or global group to Windows Networking. A group's name cannot be identical to any other group name or user name of its own domain or workstation (see global group, local group).
Group Ware (computer)
Workgroup or collaborative computing applications.

Group Window (computer/Windows)
In Program Manager, a window that displays the program-item icons in a group. These items can be applications or data files associated with applications.

Guard Band (A/V, communications)
In audio visual, the space between tracks on videotape that prevents cross talk between adjacent tracks. In communications, a frequency that insulates one signal from another. In analog telephone the low band is 0-300 Hz, the high band is 3300-4000 Hz.

GUIDE (computer)
International association of users of large-scale IBM computers, formed in 1956 as an informal computer users group with members from 44 companies. The name GUIDE originated as an acronym: Guidance of Users of Integrated Data Processing Equipment.

Gutter (computer/printing)
In typography and printing processes, the space between two columns.

Gyrator (communications, computer/microelectronics)
Linear, passive, two-port electric circuit element whose transmission properties are such that it is effectively a half wavelength longer for one direction of transmission than for the other direction of transmission. Thus, a gyrator is a device that causes a reversal of signal polarity for one direction of propagation but not for the other. This device is novel, since it violates the theorem of reciprocity (Reciprocity Principle). Until the early 1950's, all known linear passive electrical networks obeyed the theorem of reciprocity. Several different types of nonreciprocal networks, however, are now widely applied, principally at microwave frequencies. These devices are used to control the direction of signal flow and to protect or isolate components from undesired signals. One application of a three-port nonreciprocal network, called a circulator, is to permit connection of a transmitter and a receiver to the same antenna. This is accomplished with minimum interference and virtually no power loss of either the transmitted or received signal.