Appendix Glossary C

In the left margin you will find links to the glossary categorised alphabetically. Some of the pages are quite long and may take a few moments to load if you use a modem. This glossary is always being updated.

Glossary - C

C: - This is what the main root drive of a hard disk is called. The "C" drive. The ":" after the letter defines it as a "drive".

C++ - A programming language used for creating DOS, Windows, UNIX, etc. based programs.

Cable Modem - A modem that sends and receives data over television cable lines. Cable modems typically transmit data faster than telephone connections.

Cable Segment - A cable segment is a section of network cable separated by hubs, routers, and/or bridges to create a subnet.

Cache - A cache is a bank of high speed memory that stores the most recently accessed code and data. When the microprocessor requests data that is in the cache, the amount of time to retrieve the data is many times less than the amount of time needed to access main memory. Many microprocessors have a cache inside of the chip itself. In some cases, there is a cache for the cache (known as a 2nd-level cache). A cache may hold code, data, or even recently accessed data on a hard disk. In general, a cache can be created for faster access to any slower device, be it main memory or hard disks.

Cache Memory - A small amount (normally less than 1 MB) of high-speed memory residing on or close to the CPU. Cache memory supplies the processor with the most frequently requested data and instructions. Level 1 cache (primary cache) is the cache closest to the processor. Level 2 cache (secondary cache) is the cache second closest to the processor and is usually on the motherboard.

Camino - the i820 chipset delivered in late 1999 from Intel that supports a number of next-generation features such as faster RAMBUS memory, UDMA/66 hard drives, faster bus speeds, AGP support at 100+ MHz FSB speeds, and so on.

Cancelbot - A program left running on a Web server that automatically deletes messages on newsgroups and message boards. A cancelbot application is often used to filter out spam.

Capacity - The amount of information that can be stored on a hard disk drive. The data is stored in bytes, and capacity is usually expressed in megabytes. Some hard disks can store up to 50gig of information or more, while a floppy disk can only hold 360K, 720K, or 1.2m or 1.4m or 2.8m ... depending on which type you have on hand.

Caps Lock - A key on the left side of the keyboard that, when pressed allows a user to type in caps without depressing the Shift key. When finished, press it again to deactivate it.

Capture - 1. to save a graphic image as a bitmap. 2. in the Windows environment, to transfer an item to the clipboard.

CAS - (Column Address Strobe) - A memory chip signal that latches the column address of a particular location in a row-column matrix.

Cascade - 1. an arrangement of overlapping windows displayed on a computer monitor. 2. the replies in response to a message in a public forum such as a message board.

CASE - (Computer Aided Software Engineering) The use of computers to help with the development of software.

CAS Latency - The ratio between column access time and clock cycle time. CAS Latency 2 (CL2) offers a slight performance increase over CAS Latency 3 (CL3).

Cascading - Connecting hubs together with cable. Sometimes requires a crossover cable or a special setting on the hub to change one port to a cascading function with the ability to connect to another hub instead of an NIC.

Cascading Style Sheets - Templates in which you define the style for a particular HTML element once, link font style or colour, and then use it over and over on any number of web pages.

Case - The case is one of the most important components of the computer. It is the enclosure that all of the system's components are contained it. It is the big grey box sitting on your desk

Case Sensitivity - To distinguish between capital letters (UPPERCASE) and small letters (lowercase).Many Internet addresses are case sensitive.

Category 3 Cabling - A 10BASE-T unshielded twisted-pair cabling type commonly used in today's 10 MBps Ethernet networks.

Category 5 - A network-cabling standard that supports 100 MBps data throughput.

Category 5 cabling - A higher grade of unshielded twisted-pair cabling required for networking applications such as 100 MBps Fast Ethernet. Most commonly pre-wired in buildings wired within the last five years.

Cc - Abbreviation for carbon copy. The double letters refer to copies. When used in an email header, Cc indicates that copies of the message are being sent to more than one address.

CCD - Charge Coupled Device. Sensor used in digital cameras distinguished by semiconductors connected so that the output of one serves as the input of the next.

ccNUMA - (Cache-Coherent, Non-uniform Memory Access) - A flexible architecture that uses modular, low-cost components and offers multidimensional scaling potential to high-end servers.

CD - (Compact Disc) A plastic disc with a metal finish, developed in the 1980s, capable of storing digitised music. A CD stores data on a continuous groove, much like a phonograph record. One CD can store up to 74 minutes of music.

CD I - "Compact Disc, Interactive" This is (was) a proprietary format for creating CD-ROM's that was introduced by Philips many years ago. Its purpose was to provide a file structure that would lend itself to use with interactive games and entertainment-based CD titles. Use of a CD-I disc requires a playback device that is specifically designed to interpret these discs, such a device is roughly as easy to find as a working 8-track tape deck. Suffice to say, this disc format did not really catch on.

CD R - "Compact Disc,Recordable" With the proper hardware and software, and specially designed blank recordable discs, one can create a CD-ROM by placing the files of one's choice onto a new volume.

CD Rewritable - "Compact Disc, Rewritable" The Rewritable CD-ROM is a type of CD-R that employs an encoding process that is designed to be reversible. The standard has as yet not been adopted within all hardware and software configurations. It should be noted that CDR and CD-Rewritable are not the same thing (CD-Rewritable has at least nine more letters, for instance).

CD-ROM - "Compact Disc, Read Only Memory" Each CD-ROM can hold up to 650 megabytes of data in any of several volume formats. Once a CD has been written to and finalised, no more data can be stored on that disc. Like any other common disk storage medium, a CD-ROM can be formatted as a Macintosh volume or a Windows volume. A music CD is actually just another way of formatting the data onto a CD-ROM. There are also many other less common formats for CD-ROMs.

CD-ROM Drive - Like an audio CD player, but instead of reading just music, a CD-ROM drive reads computer programs as well as audio.

CD RW - Compact Disc Recordable/Rewritable. These drives, which cost about £200, can record up to 650 megabytes of data onto inexpensive (£1) CDR discs, and can write and erase data from more expensive (£2) CD-RW discs. Anybody with a standard CD-ROM drive (i.e., almost everybody) can read a CDR disc, but only those with a recent enhanced "MultiRead" variety of CD-ROM (or another CD-RW writer) can read CD-RW discs produced by these drives.

Celeron - Intel's first crack at an inexpensive Slot 1 processor. It lacked a so-called Level 2 ("L2") cache, which significantly impeded its performance especially in business applications such as word processing, spreadsheets and other everyday computing tasks. A newer "Celeron-A" design addresses this limitation by providing an L2 cache. Although the Celeron-A has less cache than a Pentium II (128K vs. 512K), the Celeron-A's cache runs at twice the speed, which helps improve performance to within a few percentage points of the more expensive Pentium II equivalent. Slot 1 motherboards expressly designed for Celeron processors are designated as "EX," although a Celeron or Celeron-A can be used with most LX or BX motherboards as well. We recommend the latter (and skip the original Celeron and go for a Celeron-A if possible). To further confuse the issue, Intel, in Jan. 99, released a so-called PPGA (plastic pin grid array) version of the Celeron, a new ZX chipset designed to be used with PPGA-compatible Socket 370 motherboards and stopped identifying all Celerons faster than 300 MHz with an "A" designation, despite the inclusion of the above-mentioned 128K of L2 cache. Celeron chips are not intended for use in multiprocessor systems but can, with some hardware modifications, be adapted for this purpose.

Celeron 2/Coppermine 128 - Intel in Feb. 2000, announced the Celeron 2, also known as Coppermine 128. This variant maintains the 66 MHz FSB limitation and 128K cache of its predecessor, but adds support for the SIMD (SSE) multimedia instructions found in the Pentium III.

CG - (Character Generator) A software application fro creating titles and credits.

CGA - Colour Graphics Adapter. This was the first video system for a personal computer which allowed you to see colour text and graphics. Not very sophisticated. Cartoonlike graphics.

CGI - "Common Gateway Interface" CGI is a means to providing additional functionality on an Internet server by performing program processing on the server side, and then delivering the results to the client side. A CGI solution typically employs a program, such as a PERL script as a "middle man" to process information that the web browser itself is not equipped to handle. It's kind of like the mother bird chewing the food before giving it to her young, although it's a lot less gross.

CGI scripts - Common Gateway Interface. CGI scripts are programs which can generate and send back data, such as HTML documents, pictures, or sound.

Channel - In Internet Relay Chat (IRC) a channel is a virtual arena where users meet to talk on a particular topic. IRC programs such as the BTinternet Chat client will allow you to call up a list of all active channels. In Internet Explorer 4.0, Channels deliver content to your computer's desktop at intervals which you schedule.

CHAP - Your CHAP password is used to authenticate your entry when connecting to BTinternet. Each BTinternet account is allocated its own unique CHAP password. Go to My Account if you need to know your CHAP password.

Chat - A program that connects computers on a network for instantaneous, multi-way communication. With chat you can type messages for delivery to a server, which displays the messages instantly so that users who are logged on to the chat service can respond immediately.

Chat Room - Any of a large number of Websites or newsgroups where users can communicate using a keyboard in real time on a wide variety of topics ranging from oceanography to sex, politics, and much more. If you can come up with a topic, there's probably a chat room for you.

Check Box - A box offering particular options that the user may choose or reject.

Chevrolet - Slang for a computer that is just enough to get the job done. The term would typically be applied to a machine that lacks processing power, memory, or the most current features but is capable of performing its assigned tasks.

Chip - A small integrated circuit usually made from silicon or germanium that may hold millions of electronic components. Among the many chips used in computer hardware are microprocessors and memory chips.

Chip Scale Package - (CSP) Thin chip packaging whereby electrical connections are typically through a ball grid array. Chip-scale packaging is used in RDRAM and flash memory.

Chipset - Microchips that support the CPU. The chipset usually contains several controllers that govern how information travels between the processor and other components. The big chips on your motherboard that acts sort of like a "crossing guard". It controls the flow of data throughout the motherboard.

Chkdsk /f - When you type this at a DOS prompt it will "check" your "disk" to see if there is any internal file structures that are damaged in anyway, due to use. The "/f" switch means that it will fix the damage for you.

Chroma Key - Hardware effect that lets you sample out a coloured background, and replace it with something else.

CHS - Cylinders Heads Sectors, is a method of addressing physical parts of a hard disk so that the disk can be used by the system. By setting CHs parameters, you tell the system the capacity of the drive. When setting the CHs parameters, be SURE you don't set them wrong!! If you set the parameters wrong and format the drive, and then notice your error 6 months later and fix the CHs error, you might not be able to read the drive at all.

CISC - Complex Instruction Set Computer. A CISC microprocessor is one in which the number of bytes needed to represent the opcode instruction is not a fixed, regular length (for example, 32-bits each).

CISC/RISC - Complex Instruction Set Computer, refers to the processor technology being used. CISC computers are generally slower than their counterparts, RISC computers Reduced Instruction Set Computer.

Clean Room - An environmentally controlled dust-free assembly or repair facility in which hard disk drives are assembled or can be opened for internal servicing.

Client - A computer connected to a shared resource server or a program that requests data from another computer, called a server. The client, in computer terminology, is the computer that receives information from a server. For example, when one is browsing the web, the computer used to view the pages is acting as an Internet "client," receiving all of the page and graphic information from the server that contains it. The term client is sometimes also used to describe a piece of software that is doing the job of communicating with a remote server, such as an FTP application or an e-mail program.

Client/Server - A network computing system in which individual computers (clients), use a central computer (server) for such services as file storage, printing, and communications.

Clip Art - Artwork available on floppy disk and CD-ROM as well as on the World WideWeb in several file formats to use without the need to pay royalty fees. The creator is paid for the work by either producing and distributing it themselves, or receives payment at the time a deal is struck with a publisher. The publisher then goes on to charge end users a licensing fee. A wide selection of clip art is available on numerous Websites free of charge.

Clipboard - A useful tool that acts as a temporary storage space holding information (both text and graphics) you've cut or copied until you are ready to paste it to it's final destination. In Windows the images or text vanish when the computer is turned off. Macintosh has both a Clipboard that operates in the same way, and a Scrapbook that holds more than one image at a time, and saves held material from one work session to another.

Clock - The component within a computer that keeps track of the date and time.

Clock Generator - An oscillator to which the system "paces" itself with. The clock generator is used to determine the CPU, PCI, and system bus speeds.

Clock Rate - (clock speed) The speed that a computer's microprocessor is able to process information, usually measured in MHz.

Clone - This means an imitation of the original. Most all computers are clones of the first IBM models.

Cluster - A group of sectors on a hard disk drive that is addressed as one logical unit by the operating system.

CLV - (Constant Linear Velocity) In older disk drivers, the changing of the rotation speed in relation to where the data is stored. Because less information is located close to the centre of the disc, it needs to turn faster to access the data. CAV (Constant Angular Velocity) is rapidly replacing this technology.

CMOS - Complementary Metal Oxide Semiconductor. Sensor used in digital cameras whose semiconductors use both negative and positive polarity circuits and require less power than CCDs. This has to do with the special memory inside the computer. This type of memory stores information about the computers configuration and hard drive. It also keeps track of the date and time. This requires a battery to run.

CMYK - "Cyan Magenta Yellow Black" One of the two prevailing colour models in use for electronic publishing. CMYK imaging is the central concept in four-colour printing. This system is based on the principle that all colours can be created by combining the proper amounts of Cyan, Magenta, Yellow, and Black. The CMYK colour model is an "additive" scheme, in which white (or blank) is defined as the absence of all four source colours and all tones are created by adding the appropriate amounts of the necessary colours.

Coax Cable - Thin or thick coax cable used in Ethernet networking. This looks similar to cable TV coax but usually has BNC connectors on the ends.

COBOL - (Common Business Oriented Language) First developed in the 1950s by the US Department of Defense and several early computer manufactures, COBOL is a somewhat wordy computer language used for business data processing. It remains the most widely used programming language today.

Codec - "Coder-Decoder" A software or hardware solution that is responsible for translating stored data between compressed and uncompressed formats.

Collision Detection - The ability of a 3D object to physically react to another 3D object in space and time.

Collisions - Two packets sent over the network simultaneously will collide and be rejected. Ethernet will automatically resend them at altered timing to ensure proper receipt. Many hubs include LEDs to indicate collisions.

Colour Depth - The amount of colour that a computer display is capable of processing. The colour depth of a system will range from Black and White (1-bit) to Millions of Colours (32-bit). Colour depth is expressed in the number of colours or colour bits available per pixel (e.g., 8-bit colour refers to a display that is capable of showing 256 colours, 2-bit colour refers to the amount of colour that you can buy for a quarter). It may help to think of colour depth as the size of the box of crayons that a computer has; the bigger the box, the more shades available of each colour. If possible, try for the big box with the built-in sharpener.

Colour Model - The colour model is the means through which a computer system defines how individual colours within a file will be stored and delivered. The standard colour models in use in electronic publishing today are RGB (Red, Green, Blue) and CMYK (Cyan, Magenta, Yellow, Black). Generally speaking, RGB is used most often for the display screen and CMYK is typically used for print applications. These two colour models take the opposite approach to drawing the page or screen from one another, and when selecting which one will best suit a particular purpose, this should be taken into account.

Coloured Lighting - The first 3D games used simple white light to illuminate objects and cast shadows. With the advent of faster CPUs and 3D hardware acceleration, games now have the raw power to mix different coloured lights to archive more spectacular ambient effects.

Compact Disc Rewritable - A rewritable technology whose media can be written to and erased approximately 1,000 times before failure. Standard 74min CD-RW media can hold up to 500 MB when formatted for fixed-length packet writing.

CompactFlash - A small, lightweight form factor for removable storage cards. CompactFlash cards are durable, operate at low voltages, and retain data when power is off. Uses include digital cameras, cell phones, printers, handheld computers, pagers, and audio recorders.

Compatible - This term refers to a computer that can run DOS software. Mostly all computers are DOS compatible these days.

Compiling - Compiling takes all of the code you wrote and combines it into instructions that the computer can understand.

Composite - An Apple Computer, Inc. term for a memory module that used an older technology and contained more but lower-density chips.

Compression - A means of encoding a digital file so that it occupies a smaller amount of disk space than the data contained within the file. In order to make use of a compressed file, one must employ a codec (coder-decoder). Compression "squeezes" files to save space and transmission time.

Concurrent Rambus - The second generation of Rambus technology. Concurrent Rambus has been used in graphics-based computers, digital TVs, and video game applications (such as Nintendo 64 since 1997).

Consumable - Material that gets used up in the process of creating printed materials. In desktop publishing for instance; the paper, toner, ink, and film would be examples of the consumables. In purely digital communication, like website publishing, there are few, if any, consumables, unless you include the fourteen pizzas that the average webmaster goes through in a week.

Continuity RIMM - (C-RIMM) A Direct Rambus memory module that does not contain memory chips. C-RIMM provides a continuous channel for the signal. In a Direct Rambus system, open connectors must be populated with C-RIMMs.

Contrast - The intensity and clarity of light and dark values while shown in greyscale either on a display monitor or a printer. The use of distinct black and white values represents high contrast while the use of grey shows lower contrast.

Control Key - This is a key-combination which uses the Ctrl or CONTROL key plus another key depressed while still holding down the control key... It provides an additional level of function keys.

Controller - The chip or circuit that translates computer data and commands into a form suitable for use by the hard drive. Also known as the disk controller.

Controller Card - An adapter containing the control electronics for one or more hard disks. Usually installed in a slot in the computer.

Conventional Memory - This is the basic type of memory in a PC, where DOS runs and all your are located. There can be a maximum of 640K of conventional memory.

Cookies - A cookie is a small piece of information sent by a Web server and stored on your hard disk so it can be read back later. For example your password, user ID, or preferences for a start page may be stored.

Coppermine - The newest version of the Pentium III, this version uses a more efficient manufacturing process, features onboard cache memory running at the full speed of the processor (as opposed to the half-speed design of earlier PII and PIII models) and uses a different "Flip Chip" design.

CPU - "Central Processing Unit" Simply put, the CPU is the part of a computer that does all the computing. It is common to refer to the computer "box," excluding the monitor, keyboard, mouse, and peripherals as the CPU. The computer chip that has primary responsibility for interpreting commands and running programs. The CPU is also known as the processor or microprocessor. Examples (in roughly ascending order of performance) include Pentium, Pentium with MMX, Cyrix M2, AMD K6, Celeron, K6-2, K6-III, Cyrix III, Pentium II, Celeron-A, Duron, Pentium III, Thunderbird, Athlon. In the Mac market, the Power PC 750 processor (sometimes listed as "G3") is a popular CPU found in iMac computers.

Crash - A computer's failure to continue functioning after encountering an error. When a computer crashes, it generally needs to be restarted to clear the error and resume ordinary function. Sometimes only a single application will crash, leaving the other operations of the computer unaffected. To a pessimist, a crash is a grinding halt in productivity, whereas optimists tend to look at it as a glorious opportunity to run and grab a cup of coffee.

CRC - Acronym for Cyclic Redundancy Check. An error detection code that is recorded within each sector and is used to see whether parts of a string of data are missing or erroneous.

Credit Card Memory - A type of memory typically in laptop and notebook computers. Credit card memory is the size of a credit card.

Crossover Cable - A cable in which the receive and transmit lines (input and output) are crossed. Crossover cables are needed to connect hubs together.

Cross Platform - A software application, or hardware, that is able to run with more than one kind of computer such as an IBM or clone and Macintosh. Software that could run on both computers is said to be cross-platformed.

CRT - Cathode Ray Tube, a sort of nickname for your monitor or screen. This CRT was used when the parts of the atom were discovered. Back around 100 years ago.

CTRL - This is the name of the Control Key as it appears on the keyboard.

Ctrl-Alt-Del - Pressing these keys together quickly halts all computer functions. A dialogue box will appear asking the user if she wants to shut down the present application. Contrary to common belief, pressing these keys together does not shut down a computer.

Cursor - The blinking underline on the screen. This marks your position on the screen, showing you where any new text will appear.

Cursor Keys - There are the arrow keys which moves the cursor around the screen.

Cyberspace - The popular term for the arena of the Internet and the virtual environment of connection that it has created. Cyberspace does not refer to an actual place, but a concept. The term is rarely used by those who work the computing industry and is generally reserved for use by individuals and organisations who are trying to convince themselves and others that they actually know what they are saying when they babble about the Internet.

Cycle - the unit of measure which is a single oscillation of a computer's CPU clock. Programs running concurrently are competing for cycles.

Cylinder - When disks are placed directly above one another along the shaft, the circular, vertical "slice" consisting of all the tracks located in a particular position.

Cyrix - A subsidiary of National Semiconductor that designs, develops, manufactures semiconductor products, including microprocessors for the personal computer industry, and analog, mixed-signal and other integrated circuits for applications in a variety of markets, including the information appliances, personal systems, wireless communications, flat panel and CRT display, power management, local and wide area networks, automotive, consumer and military aerospace markets.

Cyrix III - a Socket 370 processor from VIA with 133 MHz FSB support. Cyrix III is pin-compatible with Intel's Celeron.

Cyrix M2 - Least expensive and lowest performing member of the Pentium-compatible family of Socket 7 processors.