Cache Memory - Cache RAM is fast random-access memory that is used to store data for CPU operations. Level 1 cache RAM is part of the CPU itself; level 2 L2 cache RAM is on separate chips. Conventional L2 cache is connected to the system bus, and the speed of its transactions with the CPU is limited by the system bus speed. Level 2 backside cache a feature introduced with G3 computers is located on the same board as the CPU processor board and is connected directly to the CPU through its own high-speed bus. The L2 backside cache allows the system to run significantly faster than conventional L2 cache. As more and more processors begin to include L2 cache into their architectures, Level 3 cache is now the name for the extra cache built into motherboards between the microprocessor and the main memory-what was once L2 cache on motherboards now becomes L3 cache when used with microprocessors containing built-in L2 caches.

Callback - A security precaution in which a user's preauthorized phone number is verified before allowing the user to connect to a network from a remote location.

Calling Tone - A calling tone is a high-pitched, intermittent sound that can be produced by a modem that is originating a data call. Some international telephone agencies require that your modem emit a calling tone so that a person answering your modem's call can immediately identify your modem as a machine and not a human caller.

Canonical Name - The real name of a server when you've given it a nickname or alias. For example, mail.apple.com might have a canonical name of MailSrv473.apple.com.

Caps Lock - A key that you can lock into place so that subsequent letters you type will come out capitalized. Caps Lock doesn't affect nonalphabet keys.

Carbon - The Carbon APIs can be used to write Mac OS X applications that also run on previous versions of the Mac OS 8.1 or later.

Card - A circuit board that you can plug into a slot inside the Apple IIgs to expand the computer's memory or give it the means to communicate with a hard disk, a braille printer, or some other peripheral device.

Carriage Return - Abbreviated CR. A nonprinting character that tells the computer or printer to end a line of text and start a new one. It's used to end paragraphs. Even though you can't see them, you can delete carriage returns the same way you delete other characters.

Carrier Sense Multiple Access/Collision Avoidance CSMA/CA - A networking protocol that avoids collisions instead of detecting a collision like the algorithm used in Ethernet networks IEEE 802.3 standards.

Carrier - The carrier is the telephone line signal used to transfer data between two connected modems. The sound you hear through the modem's speaker when it connects is the carrier signal.

Case - The outer covering of the computer.

Catalog - A list of all the files on a disk. Also called a directory. A subdirectory-is a directory within a directory that usually contains related documents; used to organize the information on large-capacity disks.

CD - compact disc.

CD-ROM - Abbreviation for compact disc read-only memory. A compact disc can store large amounts of information.

CD-ROM-Compact Disc - Read Only Memory, often shortened to CD. One of the most popular ways to distribute programs today. These discs can hold over 600 megabytes of data and are easily portable.

CD-RW-Short for CD-ReWritable disk, a type of CD disk that enables you to write onto it in multiple sessions. With CD-RW drives and disks, you can treat the optical disk just like a floppy or hard disk, writing data onto it multiple times. Macintosh computers have slot-loading or tray-loading drives.

Cell - The intersection of a row and a column in a spreadsheet. A cell can hold a number, label, function, or formula.

Centralized File Service - File service that is provided by a central server accessed by network users. Distributed file sharing-is a type of file service in which users can share the content of their hard disks with other users on the network.

CFM - Stands for Cubic Feet per Minute. This is how a blower or fan is rated-by the amount of air it can move, measured in CFM.

CGI Common Gateway Interface - A script or program that adds dynamic functions to a Web site. A CGI sends information back and forth between a Web site and an application that provides a service for the site. For example, if a user fills out a form on the site, a CGI could send the message to an application that processes the data and sends a response back to the user.

Character Set - The letters, numbers, and symbols that can be generated by pressing keys on a keyboard.

Character - A letter, number, or other symbol.

Child - A computer that gets configuration information from the shared directory domain of a parent.

Chip - A small silicon wafer containing thousands of microscopic components.

Choose - To pick a command from a menu. Usually you do this after selecting something for the Apple IIgs to act on.

CHRP - Common Hardware Reference Platform.

Circuit Board - Also called the main circuit board-is a large circuit board that holds RAM, ROM, the microprocessor, custom integrated circuits chips, and other components that make the computer a computer.

Circuitry - A network of wires, chips, resistors, and other electronic devices and connections.

Classic - An application environment that allows users to continue to use their systems for everything they already do. Classic applications don't appear in the new Aqua interface.

Class - In object-oriented languages such as Java, a prototype for a particular kind of object. A class definition declares instance variables and defines methods for all members of the class. Objects that have the same types of instance variables and have access to the same methods belong to the same class.

Clear - A key on the numeric keypad. Pressing Clear works the same as pressing Control-X. Pressing Control-X while writing a BASIC program cancels the line you're typing.

Click - To position the pointer on something, then press and quickly release the mouse button.

Client Computer - A computer on a network that receives network services from a server.

Client - A program that requests services from other programs or computers that are functioning as servers or hosts.

Clip Art Application - Electronic pictures that you can clip from one disk or document into another. You can buy disks of clip art and use these professional-quality drawings to illustrate your documents.

Clip Viewer - In iMovie, the tab with the eye at the bottom of the screen that displays video clips arranged in a movie.

Clipboard - A special part of memory that stores the most recent thing you cut. You can paste the contents of the Clipboard into other parts of your document.

Clock Rate - The rate at which bits move from one internal computer component to another.

Close Box - The small box on the far-left side in the title bar of an active window. Clicking a close box closes the window.

Closed Network - A feature provided by some third-party wireless networking base stations. A closed network does not display the network name in the Control Strip. Instead, a user has to know the specific network name.

Coaxial Cable - An electrical cable consisting of a central wire surrounded by a second tubular wire made of braided mesh, both of which have the same center point, or axis, hence the name coaxial. Separated from the central wire by insulation, the tubular wire shields electronic impulses traveling along the central wire. In turn, the tubular wire is surrounded by insulation.

Cocoa - An object-oriented framework in Mac OS X that provides development tools and services that allow applications to interact with one another and take advantage of a variety of advanced libraries. Cocoa applications look the same as Carbon applications to end users.

Codec - Any technology for compressing and decompressing data. Codecs can be implemented in software, hardware, or a combination of both.

ColorSync - The color management technology integrated into Mac OS X. ColorSync ensures that the color you see is the same from your digital image onscreen to the image on the paper printed by your printer. ColorSync uses industry standard technologies such as ICC profiles and sRGB color spaces.

Column - In a relational database, the dimension of a table that holds values for a particular attribute. For example, a table that contains employee records might have a column titled LAST_NAME that contains the values for each employee's last name. Attribute-In Entity-Relationship modeling, is an identifiable characteristic of an entity. For example, lastName can be an attribute of an Employee entity. An attribute typically corresponds to a column in a database table.

Combo - An optical drive that writes CD-R discs; writes CD-RW discs; reads DVD-ROM discs; and reads CD-ROM discs.

command mode - In command mode, the modem interprets data from the computer as AT commands, instead of transmitting the data to the remote modem. When you first open a telecommunications application, the modem is automatically placed in command mode. When you establish a connection with another modem, your modem switches to on-line mode. Before entering an AT command, you must use the +++ command to return the modem to command mode.

Command - An instruction given to a computer by menu selection or keystroke.

Command key - The Apple Key (K) on the keyboard located next to the Space Bar. Pressed with other keys to perform special actions. Functionality is similar to that of the Control key on a Windows PC.

Communications Software - An application that makes it possible to exchange information with other computers.

Compatibility - The condition under which devices can work with each other.

Component - An object of the WOComponent class that represents a web page or a reusable portion of one.

Composite - A video signal that includes both display information and the synchronization and other signals needed to display it. There are monitor ports on the Apple IIgs for an NTSC composite monitor one that accepts signals that conform to the standards set by the National Television Standards Committee and for an analog RGB monitor.

Compression - The process of reducing the data size of a file.

Computer Account - A list of computers that have the same preference settings and are available to the same users and groups.

Computer - A machine that processes words and numbers faster than a food processor can slice potatoes. Not particularly creative or intuitive, but very good at repetitive tasks.

Configuration - A general-purpose computer term that can refer to the way you have your computer set up that is, the devices you have attached to it or to the way you have your computer set up to send information to a printer, a modem, or some other peripheral device.

Conform Film - To cut and arrange an original camera negative to match edits made in a digital editing system. Also, to assemble video or audio according to an Edit Decision List EDL. See cut list and EDL.

Conform Video - To change the frame rate of a video clip. For example, you can use the Cinema Tools Conform feature to change the frame rate of a PAL 25 fps video clip to film's 24 fps rate. You can also conform a clip to its current frame rate, ensuring there are no frame rate errors within it.

Connect Time - The amount of time you spend accessing an information service.

Console - The Console application lets you see technical messages from the Mac OS X system software and Mac OS X applications. If you are programming or troubleshooting a problem, these messages may be useful.

Contrast Knob - A control on your video display that lets you adjust the contrast between the light and dark on the screen.

Control Panel Program - A program built into the Apple IIgs that lets you set the time of the built-in clock and tailor certain aspects of your computer system to suit your individual preferences like the color of text and background on the screen, the volume of the built-in speaker, and more.

Control - A key on the Apple IIgs keyboard that, when pressed in conjunction with another key, makes the other key behave differently. It controls the operation of other keys.

Controller Card - An interface card that tells your Apple IIgs how to work with one or two disk drives.

Co-Processor - A microprocessor on a card that overrides or works with the microprocessor on the main circuit board.

Copy-Protect - To prevent someone from duplicating the contents of a disk. Write-protect-Means to prevent changes to the contents of a disk by covering the write-enable notch on a 5.25-inch disk or by sliding the small, plastic tab to uncover the square hole on a 3.5-inch disk.

CPU - Central processing unit, a type of microprocessor. In current Power Mac, iMac, PowerBook, and iBook computers, the CPU is a PowerPC G3 or G4 chip. Earlier models contained PowerPC 601, 603, 604, 604e and Motorola 680x0 chips.

Crash, Freeze - A system malfunction of the operating system, application, or hardware device that locks up the computer, which then has to be restarted. A freeze is a system error that causes the cursor to lock in place.

CRM - Communications Resource Manager.

CRT - cathode ray tube, a video display device.

Cursor - Also known as a pointer, usually arrow or cross shaped, which is controlled by the mouse, trackpad, trackball, stylus, or joystick.

Cut and Paste - To move something from one place in a document to another. It's the computer equivalent of using scissors to clip something and glue to paste the clipping somewhere else.

Cut List - A text file that sequentially lists the edits that make up your program. The negative cutter uses the cut list to conform the original camera negative. The cut list is a subset of the film list you can export from Final Cut Pro using Cinema Tools.

Cut - To remove text or pictures from a document by using the Cut command. The most recent clipping is stored on the Clipboard so you can paste it somewhere else if you want.

CVS - Concurrent Versions System, a programming code management system.