C

CAD

See also Computer-Aided Drafting (CAD).

Cascading Style Sheets (CSS)

A method for defining a standard Web page template. This may include headings, standard icons, backgrounds, and other features that would tend to give each page at a particular Web site the same appearance. The reason for using CSS includes speed of creating a Web site (it takes less time if the developer doesn't have to create an overall design for each page) and consistency. Changing the overall appearance of a Web site also becomes as easy as changing the style sheet instead of each page alone. CSS is also a standards supported technology, so it represents an easy method for developers to create Web pages that will work in standards-compliant browsers. There are several versions of CSS due to the standards process ”using the most recent version of CSS is usually the best idea.

Cache

A storage area for data, code, or other resources normally associated with memory or a special file on a hard drive. Both hardware and applications rely on the cache to improve performance.

CD

Compact Disc

CD-ROM

See also Compact Disc Read-Only Memory (CD-ROM).

CGI

See also Common Gateway Interface (CGI).

Client

The requestor and recipient of data, services, or other resources from a file or other server type. This term can refer to a workstation or an application. Often used in conjunction with the term "server," this is usually another PC or an application.

CLR

See also Common Language Runtime (CLR).

COM

See also Component Object Model (COM).

Common Gateway Interface (CGI)

One of the more common methods of transferring data from a client machine to a Web server on the Internet. CGI is a specification that defines how a Web server can launch EXEs and communicate with them. A developer normally writes a GCI application using a low-level language such as C or Practical Extraction and Reporting Language (PERL). CGI receives input through the standard input device and output data through the standard output device. There are two basic data transfer types. The user can send new information to the server or can query data already existing on the server. A data entry form asking for the user 's name and address is an example of the first type of transaction. A search engine page on the Internet (a page that helps the user find information on other sites) is an example of the second type of transaction. The Web server normally provides feedback for the user by transmitting a new page of information once the CGI application is complete. This could be as simple as an acknowledgment for data entry or a list of Internet sites for a data query.

Common Language Runtime (CLR)

The engine used to interpret managed applications within the .NET Framework. All Visual Studio .NET languages that produce managed applications can use the same runtime engine. The major advantages of this approach include extensibility (you can add other languages) and reduced code size (you don't need a separate runtime for each language).

Common Object Request Broker Architecture (CORBA)

This protocol describes data and application code in the form of an object. This is the Object Management Group's (OMG) alternative to Microsoft's Component Object Model (COM). Although CORBA is incompatible with COM, it uses many of the same techniques as COM to create, manage, and define objects. CORBA was originally designed by IBM for inclusion with OS/2.

Compact Disc Read-Only Memory (CD-ROM)

An optical storage technology used to store up to 650MB of permanent data. The optical media includes a reflective surface that the reader interprets as a 1. When a special writer burns a hole in the media, the reader sees the corresponding location as a 0. The combination of 0's and 1's forms the basis for interpreting the data.

Compiler

A program that converts English-like statements into machine instructions in an executable or intermediate form. In some cases, the executable code can run without assistance on the host machine (called a native executable). In other cases, the intermediate code requires compilation into an executable form. This secondary form can rely on an interpreter, such as Beginner's All-Purpose Symbolic Instruction Code (BASIC), or runtime engine, such as Java, or it can use a secondary compiler or linker to change an object format into a standard native executable (C).

Component Object Model (COM)

A Microsoft specification for a binary-based, object-oriented code and data encapsulation method and transference technique. It's the basis for technologies such as OLE (Object Linking and Embedding) and ActiveX ( components and controls). COM is limited to local connections.

Computer-Aided Drafting (CAD)

A special type of graphics program used for creating, printing, storing, and editing architectural, electrical, mechanical, or other forms of engineering drawings. CAD programs normally provide precise measuring capabilities and libraries of predefined objects, such as sinks, desks, resistors, and gears.

Connectivity

A measure of the interactions between clients and servers. In many cases, connectivity begins with the local machine and the interactions between applications and components. Local Area Networks (LANs) introduce another level of connectivity with machine-to-machine communications. Finally, Wide Area Networks (WANs), Metro Area Networks (MANs), intranets , and the Internet all introduce further levels of connectivity concerns.

Cookie

One or more special files used by an Internet browser to store site-specific settings or other information specific to Web pages. The purpose of this file is to store the value of one or more variables so that the Web page can restore them the next time the user visits a site. A Web-master always saves and restores the cookie as part of some Web page programming task using a programming language such as JavaScript, Java, VBScript, or CGI. In most cases, this is the only file that a Webmaster can access on the client site's hard drive. The cookie could appear in one or more files anywhere on the hard drive, depending on the browser currently in use. Microsoft Internet Explorer uses one file for each site storing a cookie and places them in the Cookies folder that normally appears under the main Windows directory or within a user specific directory (such as the \Documents and Settings folder). Netscape Navigator uses a single file named COOKIE.TXT to store all of the cookies from all sites. This file normally appears in the main Navigator folder.

CORBA

See also Common Object Request Broker Architecture (CORBA).

Cracker

A hacker (computer expert) who uses their skills for misdeeds on computer systems where they have little or no authorized access. A cracker normally possesses specialty software that allows easier access to the target network. In most cases, crackers require extensive amounts of time to break the security for a system before they can enter it. Some sources call a cracker a black hat hacker.

CSS

See Cascading Style Sheets