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Glossary C...


C A powerful compiled programming language, that was designed primarily for systems programming (including the AmigaDOS operating system), but it is also suitable for writing most types of application programs, but can be rather complex to learn. It was originally written back in the early 70's by Kernighan and Ritchie (K&R), two of the developers working on UNIX for AT&T, and many C compilers make a point of being K&R compatible.
C-NET (pronounced "C-net") A powerful Bulletin Board program available for the Amiga.
CACHE (pronounced "cash") High speed memory used to improve system performance, where the data can be stored temporarily, and thereby provide immediate access the next time it is accessed. Becoming increasingly common on hard drives.
CAD (pronounced "cadd") Acronym for Computer Aided Design and is also used by MS-DOS, Windows and Windows NT users as an abbreviation for Ctrl-Alt-Delete
CAD/CAM (pronounced "cadd camm") Acronym for the combined processes of Computer Aided Design and Computer Aided Manufacturing.
CAI (pronounced "C-A-I") Acronym for Computer Aided Instruction.
CAM (pronounced "camm") Acronym for Computer Aided Manufacturing.
CAMS (pronounced "camms") Abbreviation for "Cameras" often used to describe live cameras (i.e. cams or webcams) playing on the Internet.
CAMERA READY A term used for artwork or copy ready for final film production.
CAPTION The descriptive matter printed above or below an illustration.
CARD Another name for a small circuit board. Most cards are meant to be easily inserted and removed from the system.
CARRIAGE RETURN Often referred to as the RETURN key, it is a special ASCII character that is used to go to a new line and return the cursor to the left hand side.
CARRIER A high frequency modulated current of approx 3600 cycles/sec used for the transmission of telephone messages down a wire, onto which voice or data signals are superimposed. Without this carrier, all messages would become get mixed up or otherwise lost. It is particularly noticeable when using a modem in the the form of a connect message which indicates that carrier has been established. If carrier is lost, transmission stops and is often accompanied by a No Carrier message, as seen when a modem is hung-up.
CCITT (pronounced "C-C-I-T-T") Abbreviation for the "Consultative Committee for International Telephone and Telegraphy", a worldwide standards body that was responsible for defining most of the communication protocols that we use today. It is now known as the "ITU-T" instead.
CD (pronounced "C-D") Acronyms for Compact Disc, Current Directory and Change Directory.
CD + G (pronounced "C-D plus G") Acronym for CD plus Graphics, an extension to the original CD Audio standard which added 2 channels of graphics information, such as lyric sheets or mono still images etc.
CD + Midi (pronounced "C-D plus Middy") Acronym for CD plus Midi, an extension to the original CD Audio standard which used midi sequencing data on the 2 additional channels.
CD Audio (pronounced "C-D Audio") The name given to the original "Red Book" standard developed by Philips & Sony for audio CD's. It allows for up to 72 minutes of music per disc.
CD-32 (pronounced "C-D-thirty-two") An Amiga CD games console based on the A1200, but with an internal CD-ROM drive, no serial or parallel ports, and no keyboard, although the latter can be added later if desired. Also optional is the MPEG expansion module which enables Full Motion Video to be played.
CD-Bridge (pronounced "C-D bridge") A variation of the CD-i standard that can be used on CD-i and CD-ROM/XA machines, and is the standard used by Kodak for Photo-CDs.
CD-ROM (pronounced "C-D rom") An extension to the audio CD standard that stores digital data as opposed to music on a CD. The capacity of a CD-ROM is exactly the same as a music CD provides with the maximum recording time of 74 minutes, which is roughly 650 Megabytes, although some CD's have been developed which can store 80 minutes or just over 700MB of data.
CD-ROM/XA (pronounced "C-D rom X-A") An extension to the CD-ROM standard produced in liaison with Microsoft to enable data and sound to be interleaved on a single disc.
CD-i (pronounced "C-D-I") An acronym for CD Interactive developed primarily by Philips that enables full motion video to be played from a 5inch CD.
CD-i-Ready (pronounced "C-D-I ready") A variation on CD-i which is basically an audio CD with an extra track so that you can either listen to the music on your hi-fi, or also get images if used in a CD-i machine.
CD-i (pronounced "C-D-I") An acronym for CD Interactive developed primarily by Philips that enables full motion video to be played from a 5inch CD.
CD-i (pronounced "C-D-I") An acronym for CD Interactive developed primarily by Philips that enables full motion video to be played from a 5inch CD.
CD-i (pronounced "C-D-I") An acronym for CD Interactive developed primarily by Philips that enables full motion video to be played from a 5inch CD.
CDTV (pronounced "C-D-T-V") Acronym for Commodore Dynamic Total Vision.
CELL The position at the intersection of a row and column in a spreadsheet.
CENTRAL PROCESSING UNIT The Central Processing Unit or CPU is the heart and nerve centre of every computer. In the case of the Amiga it is one of the Motorola 68000 family of processor chips, which decode and execute the instructions contained in the Application programs.
CENTRE JUSTIFIED TEXT Text centred on the full line, with ragged left and right margins.
CENTRONICS With 2 rows of 18 exposed connectors on each side of a narrow rectangular block surrounded by a metal band, this connector is commonly used on parallel devices such as printers, and has spring clips on the socket. While the connector has remained the same the types of signals sent has varied over time, the first being the Uni-directional (or Centronics) protocol, but now more ECP and EPP modes are more common.
CG (pronounced "C-G") CG can be a bit confusing, as it's used as an acronym for two independent references. The basic meaning is Character Generator, but it is also used as an abbreviation for Compugraphic Fonts, i.e. CGFonts.
CGA (pronounced "C-G-A") Acronym for Colour Graphics Adaptor.
CGI (pronounced "C-G-I") Acronym for Common Gateway Interface.
CHARACTER GENERATOR A character generator (or CG) is simply that - a software program for the Amiga to generate text on the screen, generally for video use. It derives its name from hardware devices manufactured commercially, which generate titles and scrolling text for video use, although most of the latest ones are computer based.
CHIP RAM A term given to the RAM which is accessible to all of the Amiga's custom chips, and must be used if an application program wants to send any data to one of these chips or another application program. Because the Amiga is a multi-tasking machine, and Chip RAM is shared, each task must put a temporary lock on the memory space whenever it is used to prevent another task overwriting it. This effectively means that using Chip RAM is slower than using Fast RAM which does not require locking.
CHROMA-KEYING The process of using specific colour information within a video signal to control the replacement of the image by alternate video information. This is the technique used on TV for the presentation of weather charts and is also used for many backgrounds behind TV presenters. The presenters will typically be positioned in front of a blue background, which is replaced using the chroma-key process by any other video image, that can be static images, moving images or computer graphics. Care must be taken to ensure that the presenters do not wear blue, or it will become transparent, and the images will show through. It is also preferable to avoid bushy hair styles, because they tend to create a blue fuzzy outline around the hair. It is also easier to control than Luma-keying. See also Keying.
CHROMA Refers to the colour information within a video signal, and is the same as "Chrominance". See also LUMA or LUMINENCE, COMPOSITE VIDEO and Y/C.
CHROMINANCE Refers to the colour information within a video signal, and is the same as "Chroma". See also LUMA or LUMINENCE, COMPOSITE VIDEO and Y/C.
CIA CHIP Abbreviation for Complex Interface Adaptor Chip.
CIFS (pronounced "C-I-F-S") Acronym for Common Internet Filesystem Standard.
CIS (pronounced "C-I-S") Abbreviation for Compuserve Information Service.
CISC (pronounced "sisk") Acronym for Complex Instruction Set Computer.
CLEAR TO SEND Refers to the process of a modem advising a data terminal to transmit its data, but it is more correctly used in reference to pin 5 of the RS-232C interface which is used to pass the signal between the modem and the terminal. Once the signal is detected by the terminal, it will start sending its data to the modem. This is only effective when RTS/CTS hardware hand-shaking is being used.
CLI (pronounced "C-L-I") Acronym for Command Line Interface.
CLICKING Refers to pressing and releasing the left mouse button. Double clicking means pressing and releasing twice in quick succession. The right mouse is not normally clicked as such, but held down for menu selection.
CLIPPING RATE The way by which diskette manufacturers qualify the degree of the return signal on a given diskette. The higher the return signal (known as track average amplitude or TAA), the smaller are the defects on the diskette surface. Smaller defects mean, in general less interaction between head and disk, eg smearing or defect migration, and so may lead to better long term reliability of the diskette. Clipping levels are expressed as a percentage of the return signal (TAA) and its mathematical equation is: "% clip level = worst missing pulse on track / return signal (TAA) x 100%". Clipping levels are set internally on the certifier and are changed by altering some electronic components to the desired percentage level.

As can be seen graphically above, if the return signal (TAA), which is error free, is 100% in value and clipping percentage value is set for 75% then any return signal which falls below the set clipping level is deemed to be unacceptable as a 100% certified diskette at 75% clipping level. Most disks are sold as being certified 100% error free, but this doesn't mean that the disk is perfect - it simply means that the disk was error free at the specified clipping level. If it fails at one level, it may be perfectly acceptable at a lower clipping level. But there is no way you can tell from the disk except when disks are supplied by the manufacturer when they will specify the clipping level. Obviously the higher the clipping level, the longer the disks will last, and there will be less chance of getting read/write errors. What point is there in buying a disk that you can write your valuable data to, only to find that you can't read it back again a short time later. When buying blank disks, don't be tempted to buy cheap disks from non-computer shops as these tend to have clipping levels around 40-45%. Sure they are cheap and seem to work OK, but they will not last long and may even cause damage to the delicate heads inside the disk drive by depositing some of the oxide coating each time they are used, while the cost of having your drives repaired may well outstrip any saving. The recommended minimum clipping level is 60%.
CLOCK This term refers, in computer sense, to the source of the timing signals used by your computers. The operation of the CPU is synchronised by this clock, and is generally measured in Megahertz, for example the 68000 chip is clocked at 7.14 MHz. Clock used in this way is often confused with the Real-Time or Time Of Day clock, which keeps time just like your watch and is also present in most computers. Unfortunately this clock is switched off when you turn off your computer, so yet another clock, known as the Battery-Backup clock is required if you want to reset the TOD clock when the machine in turned on again. The Battery-Backup clock is optional on many Amigas, and must be added separately. For example, the A501 memory expansion card also contains a BBC.
CLONE The name given to look-a-like computers, mainly in the MS-DOS arena which work the same or even better than the IBM PC on which they are based. At one time, clones were considered cheap and nasty imitations, but many of later machines running MicroSoft Windows are pretty much state of the art for MS-DOS machines. There are also a few clones of the Apple Macintosh, but nobody has successfully cloned the Amiga, mainly due to the special custom chips used by the Amiga.
CLOSE GADGET The gadget normally shown as a square box with a dot inside it located at the upper left corner of a window. Clicking on it closes the window.
CMOS (pronounced "C-moss) Acronym for Complementary Metal Oxide Semiconductor.
CO-OPERATIVE MULTI-TASKING A form of multi-tasking where the tasks must co-operate in order for them to work. There are two forms of co-operative multi-tasking. The first is known as time-slicing, where each task is given a pre-allocated length of processing time before control is passed to the next task in turn. After each of the other tasks has used their time slice, the cycle is repeated. The second type is where the active task is selected by the user, and all other tasks remain inactive until re-activated by the user. The latter is the method used by Microsoft Windows®. For instance, if you have several windows open at once, only the task whose window is active will be able will be able to process; all other windows are kept waiting.
CO-PROCESSOR A separate processor chip which takes the load off the main CPU, by doing some specific task. For example, the 68881 Motorola Maths Co-processor handles complex mathematical calculations and thus speeds up the computer. The Amiga's custom chips perform a similar role but in a more specialised way, and it is these chips which speed up the Amiga's processing.
CO-SYSOP (pronounced "koh siss op") Abbreviation for Complementary System Operator and is someone who assists in running a BBS. A BBS can have a number of Co-SysOps, where any can be responsible for specified parts of the BBS in conjunction with the SysOp, although they generally have less authority than the SysOp.
COAXIAL CABLE A two wire cable where one cable is surrounded by the other which acts as a screen, commonly used for TV aerials, quality speaker leads etc. It has the benefit of screening out interference and depending on the quality of the inner cable, transmission speeds can be significantly increased.
COBOL (pronounced "koh-boll") Acronym for "COmmon Business Oriented Language".
CODING Another word used instead of "programming".
COLD BOOT Means starting from cold by turning on the computer itself, as though for the first time that day. See also WARM BOOT.
COLOUR GRAPHICS ADAPTOR (abbreviation "CGA") An early standard for colour screens on MS-DOS computers, about the level of kindergarten finger painting. It is the only support provided by most of the MS-DOS emulators available for the Amiga without a graphics card.
COLOUR REGISTER  
COLOUR SEPARATION The division of a multi-coloured original into four basic colours (black, yellow, magenta and cyan) ready for offset or lithographic printing.
COLOUR ZERO The first colour in the Amiga colour palette that is used to key computer graphics onto an external video source. This is the Amiga default method for determining the key. The palette colour can be defined as any single colour within the Amiga's currently selected colour range.
COMMAND LINE INTERFACE
(acronym "CLI")
The Command Line Interface or CLI allows you to communicate directly with AmigaDOS by typing commands to perform the various functions, rather than using the mouse to select predetermined commands by clicking on icons and menus. The mouse is not used with CLI. To access CLI, the gadget for CLI in Preferences must be set to ON. For more information on the CLI and the commands that are available, read the file called "About_CLI".
COMMODORE BUSINESS MACHINES INC (abbreviation "CBM") The American based computer manufacturer best known for their PET, Vic-20 and C-64 machines, who in 1984 bought the evolving Amiga technology from a small group of developers on the verge of bankruptcy, and delivered the Amiga to a commercial reality in 1985. Their involvement continued until 1994 when they too went in liquidation.
COMMODORE DYNAMIC TOTAL VISION (abbreviation "CDTV") Better known as CDTV or Amiga CDTV, it was a CD based Amiga, looking more like a domestic video recorder than a computer, introduced in 1991. While it was basically an Amiga 500 with a CD drive all in a single box, it did not sell as well as Commodore hoped, mainly through the lack of available software, but after the original attempts to prevent computer shops from selling it, it was bound for a tough future, as appliance stores did not really know what they were selling. By the time computer stores got hold of it, the technology was becoming dated and it basically died.
COMMON BUSINESS ORIENTED LANGUAGE (abbreviation "COBOL") A compiled computer language commonly used for business applications that run on most brands of business oriented computers, but not available for any personal computers, despite numerous requests for it.
COMMON GATEWAY INTERFACE (abbreviation "CGI") A set of rules that describe how a Web Server communicates with another piece of software on the same machine, and how the other piece of software (the 'CGI program') talks to the web server. Any piece of software can be a CGI program if it handles input and output according to the CGI standard. Usually a CGI program is a small program that takes data from a web server and does something with it, like putting the content of a form into an e-mail message, or turning the data into a database query. CGI "scripts" are just scripts which use CGI. CGI is often confused with Perl, which is a programming language, while CGI is an interface to the server from a particular program. Perl is an application of CGI, as well as MIVA, Python, PHP3, and other scripting languages.
COMMON INTERNET FILESYSTEM STANDARD (acronym "CIFS") A specification for a file access protocol developed by Microsoft that is based on the SMB protocol used by Windows and OS/2, for file and printer sharing in a local area network. CIFS is not designed to replace HTTP or FTP, rather, it is supposed to complement them.
COMPACT DISK  (acronym "CD") Acronyms for Compact Disc
COMPILER A means of translating the source code of a program into machine language before it is run. A compiler is mandatory for assembler or C language but is optional for langauges like Basic which use a runtime interpreter. The compiled program is much faster than its interpreted counterpart.
COMPLEMENTARY METAL OXIDE SEMICONDUCTOR (acronym "CMOS") Describes the technology used in the manufacture of computer chips. CMOS chips use very little power, hence their popularity in battery operated portable computers. Their major drawback is that they are not immensely fast. The term is often used in reference to the battery backed up hardware configuration memory on a PC.
COMPLEX INSTRUCTION SET COMPUTER (acronym "CISC") A computer that understands a large number of instructions. Gordon Moore, the co-founder of Intel Corporation, in the 1960's suggested a couple of laws regarding the computer industry. His first law stated "The number of transistors that can be designed into a single chip, will double every 18 months", and this holds true even today. His second law was "That as the transistor count goes up, so does the potential number of different functions that can be designed into it". However the corollary is that as the number of functions rises the number of potential applications goes down, in so much as the chip tends to have become overqualified for tasks it is being asked to perform. As a result CISC processors are fast becoming too specialised, and RISC processors are becoming popular.
COMPLEX INTERFACE ADAPTOR CHIP Better known as the "CIA" chip, it is used to buffer many of the external connectors on the Amiga. There are in fact two CIA chips in every Amiga and are often damaged by incorrect connections, or static electricity, on the mouse/joystick ports or faulty connections on other ports.
COMPONENT VIDEO A video signal is a combination of many specialised signals, but normally it is thought of as being either Composite or Y/C video. Where the basic signals are retained and manipulated discretely this is called "Component Video". See Y/R-Y/B-Y.
COMPOSITE VIDEO A video signal where the Luminence and Chrominance information are stored together. This type of signal is used for most domestic video recorders, and is the type of signal broadcast from television stations. Monochrome screens are able to display a black & white picture, simply by displaying the luminence information and ignoring the chrominance part of the signal.
COMPUGRAPHIC FONTS Compugraphic Fonts represent the shape of each character within the font as a mathematical equation of the outline, using formulae developed and owned by Agfa Compugraphic Ltd. The magnitude of each character can be varied at the printing stage, depending on size, resolution, colour, etc, and this means that the printed character always looks smooth. One big advantage of Compugraphic Fonts is that they are an industry standard, in that they are used by professional typographers, and can be output to dot matrix, laser or photographic processor with no extra hardware. There is however one slight disadvantage, in that printing to dot matrix printers can be rather slow, due to it having to print in graphics mode, but this is more than adequately compensated for by the quality of output. Public Domain compugraphic fonts are unlikely, due to the hefty licencing costs, but disks of fonts are available commercially.
COMPUTER AIDED DESIGN (acronym "CAD") Special software which enables architects and designers to use a computer to help with the design and drawing process.
COMPUTER AIDED INSTRUCTION (acronym "C-A-I") Special software which can be used as a teaching tool to supplement conventional teaching methods, and in some cases can be used in isolation for refresher courses etc.
COMPUTER AIDED MANUFACTURING (acronym "CAM") Special software that can utilise specifications produced by CAD software to control the manufacturing process.
CONCATENATE A commonly used term which means to join things together end-to end. When one file is appended to the end of another to form a larger file, this is referred to as a "concatenation". Some computer documentation may depict concatenation using double bars "||" as in "One||Two||Three" which really means combining all three files into one file in the order shown.
CONFIG FILE Many programs use a special configuration file that they read at startup, which contains customisation parameters for the way you want the program to function. These files are generally created from within the program if you use the config option and select "save". Some programs do not use any configuration files, but are customised using the TOOLTYPES parameters in the icon file (.info).
CONFIG.SYS FILE A batch file on MS-DOS PC's which contains details about how the machine is to be setup, and is one of the first files it looks at during boot-up.
CONTROLLER Electronic circuitry that allows communication between a CPU and a device such as a disk drive.
CONVENTIONAL MEMORY Due to the way the MS-DOS machne has developed over the years, it retains a peculiar way of organising its memory, in that the early PC's could use only 640K of memory. When 286 PC's came along, wanting to use 2Mb or more of memory, the original 640K was called "conventional memory", as opposed to high memory, expanded memory or extended memory. These terms have almost been forgotten now.
CONVOLUTION A mathematical process which compares an image pixel with its neighbours and then processes it according to certain defined criteria in order to produce a whole range of image processing effects such as blur, sharpen, etc.
COPPER A co-processor built into the Denise chip that can change certain aspects of the Amiga's screen display, (e.g. colour palette or resolution) at any point on the screen.
CPU (pronounced "C-P-U") Acronym for Central Processing Unit.
CRASH A really serious bug which prevents a program from working, and may even cause the whole machine to work incorrectly such that it stops responding to your commands.
CROPPING To trim a graphic image to a reduced size by removing parts of the image.
CRT (pronounced "C-R-T") Cathode Ray Tube or CRT, refers to the type of display screen used by the Amiga on which you are most likely to be reading this. It works by shoot- ing streams of electrons precisely and rapidly at the coloured phosphors on the inner surface of the screen, causing it to emit light for a brief instant. Because the image fades very quickly, it must be refreshed 25 times per second otherwise the flicker would make viewing difficult.
CTRL-A-A (pronounced "control A-A") Refers to pressing the CTRL key, the Left Amiga key, and the Right Amiga key simultaneously while the computer is running resulting in a warm boot. Also known as the Klingon handshake.
CTRL-ALT-DELETE The three figured salute often given by MS-DOS and Windows 3.1 users to reboot their PC's. Under Windows 95/98 etc users are given the option of ending a particular task or rebooting the computer, while NT users need it to log-on and log-off their computers. A strange mixture of uses for the same st of keys by the same software company - Microsoft.
CTS (pronounced "C-T-S") Acronym for Clear To Send.
CURRENT DIRECTORY (abbreviation "CD") The currently selected directory, where the operating system will expect to find files where no pathname has been specified.
CURRENT WINDOW Refers to the window that is currently active, and in most instances the the frame of the window will be highlighted.
CUSTOM CHIPS A number of special purpose chips which some computers use to relieve the CPU of common processing requirements. All of the major functions in the chips are DMA driven, meaning that streams of data are moved between the custom chips and display RAM under DMA control, requiring no intervention by the CPU. Typically the custom chips provide very fast manipulation of graphics and audio data in the display RAM, and with the exception of the Amiga where they come as standard, are normally fitted to expansion cards that you can purchase separately.
Amiga: Each custom chip has its own function and application with names that are pseudo acronyms for what they do, for example GARY and GAYLE are variations of the Gate Array chip while others are AGNUS, ALICE, ANDREA, BUSTER, DENISE, LINDA, LISA, MARY, MONICA, and PAULA.
CYLINDER A term used to describe the same relative track on multiple surfaces of a disk or diskette. It's significant because data stored in multiple tracks can be accessed without having to reposition the read/write head, thereby speeding up the access. For example, a 3.5 inch diskette might be divided into 80 cylinders during the formatting process each containing 2 tracks, 1 track on each surface. Hard disks on the other hand will have more than platter with a separate read/write head for each surface. If a hard drive has say 6 platters, that means 12 surfaces or tracks per cylinder, and it can read data from any of the tracks without moving the read/write heads.

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