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• Cable Modem:
  A cable modem is a type of Internet connection that is transmitted through a coaxial cable. The benefits of this technology are that you are able to achieve much faster speeds through a cable connection and that most homes are already setup with a cable TV setup, making the Internet connection very simple.
  
  
• Cache:
  A very high speed type of memory that is similar to random access memory (RAM). The difference in RAM and Cache is that the Cache memory is on the server side and the RAM is stored in the computer system. Cache is much faster than RAM but they both serve the same purpose and that is to remember previously accessed information. Most commonly, the Cache memory is to remember the previously visited web page so that the computer itself doesn't have to spend its resources providing the page.
   
  
• Cache RAM: 
  Cache (commonly referred to as SRAM) is responsible for storing frequently requested instructions and data. It is a small block of high-speed memory located between the CPU and the main memory. When your computer processor needs data, it will check the Cache first to see if it is there. If the data is not there, it will retrieve it from the slower main memory.
   
• CADD (Computer Assisted Design and Drafting):
  A graphics software designed to assist users develop on-screen projects, usually rendering in either 2 or 3 dimensional imagery.
   
• Cascade:
  A method of connecting circuits together in series to make the output of one, the input of the next. This kind of end-to-end connectivity is useful in extending the distance of a network.
   
• CATV:
  Community Antenna Television or Cable TV system. Can be all coaxial or HFC (Hybrid Fiber Coax) based.
   
• CD-ROM: 
  (Compact Disc Read-Only Memory) A durable and low cost circular optical storage device widely used to store large amounts of information on a personal computer.
   
• Centronics:
  A 36-pin parallel port interface standard that most printer manufactures conform to.
   
• CGA: 
  Stands for Color Graphics Adapter. Introduced by IBM as their first microcomputer color standard. This graphics card allowed a maximum of four colors at a resolution of 320 x 200 or two colors at 640 x 200.
   
• CGI: 
  The "Common Gateway Interface". CGI provides a gateway for HTML pages to interact with other applications.
   
• Channel:
  A channel in computing is a specific bandwidth and frequency combination.
   
• Chassis:
  The physical framework of a computer system that houses all of the internal devices, wiring, and power supplies. 
   
• CICS:
  "Customer Information Control System". A general purpose IBM mainframe-based transaction management system. CICS is one of IBM's most widely used database / data communications subsystems.
   
  
• Client:
  A client is commonly referred to as a program or a process that requests information from other programs or processes. A web browser is a good example of a client. Another example would be an email client such as Outlook Express.
   
• Clipboard:
  A temporary data (text and graphics) storage facility used when transferring data to a new location.
   
• Clock Speed:
  The clock speed is the frequency which determines how fast devices that are connected to the system bus operate. The speed is measured in millions of cycles per second (MHz or megahertz) and is generated by a quartz crystal on the motherboard which acts as a kind of metronome. Devices that are synchronized with the clock may run faster or slower but their speed is determined by multiplying or dividing a factor by the clock speed.
   
• Clone:
  An imitation or copy of the original. Usually refers to building a computer system that is based on and compatible with another computer company's system.
   
• Cluster:
  In a Windows environment, Cluster refers to the allocated space within files measured in units. A cluster is part of a group of a logical disk sector. Depending on the disk size, a typical cluster size can range from 1 to 64 sectors.
  
  Cluster can also refer to a group of computers networked together and used as a single unit.
   
• Clustering:
  This is a way of connecting two (or more) computers together using clustering hardware so that they share the processing load. If ten computers of equal processing speed are clustered together, you would in a sense have a single computer with ten times the processing capacity. The most common use of this technique is with search engines where it is used to provide speedy search results. A couple of other common uses of clustering can be to increase storage capacities or for networks that require load balancing to increase a networks availability and stability.
   
• CMOS:
  Most commonly, CMOS refers to a battery powered chip that resides on the Motherboard and is responsible for retaining certain system information (date, time and some system setup parameters) when the computer system is turned off.
   
• CMTS:  
  Cable Modem Termination System. Typically, this system is found in a cable companies headend or distribution hub. Its purpose is to provide a high-speed data service to cable subscribers.
   
• COBOL:
  Stands for Common Business Oriented Language. A computer programming language invented during the second generation of computers and designed to meet the needs of business. Although less often used today, it was well-suited for writing programs that process large files and generate reports.
   
  
• Codec: 
  1. Short for Compressor/Decompressor. This technology is used for compressing and decompressing data. Codecs are widely used in both hardware and software. A few examples of codecs are: Cinepak, Indeo and MPEG.
  
  2. Also stands for Coder/Decoder in the telecommunications field. This is a device that encodes or decodes a signal. A common use for this device would be in telephone companies digital and analog networks. It is used to convert binary signals to analog signals.
  
  3. The transformation of a binary value into a voltage that can be transmitted over a wire. 
   
• Cold Boot:
  A cold reboot also referred to as a hard boot. This occurs when a computer user must switch the computer system off from the main power switch. This process bypasses the normal shut down procedure of the operating system. A cold boot can also be the result of a power failure but is usually performed by the user as a last resort because of either a system failure or a "hung" state.
   
• Collision:
  This is a problem that is a result from two or more device attempting to send a signal along the same channel. The usual result of a collision is a garbled message. All computer networks have in place some sort of mechanism to either prevent collisions altogether or to quickly recover from a collision if they were to occur.
   
• COM: 
  Stands for Component Object Module. This is a Microsoft standard created to allow for the communication of computer components (or objects) on the same computer system. This specification is very useful because of its ability to integrate many distributed application services in one package.
   
• Command Line:
  Commands you type to run an application. You can type commands at an MS-DOS prompt or in the Run dialog box in the Program Manager of Windows. Interfaces in which you type commands rather than choose them from a menu are often called command line interfaces. MS-DOS has a command line interface while the Macintosh does not. 
   
• Compiler:
  This is an application that converts a programming language into a machine language program.
   
• Compression:
  This refers to the reduction of a file size. This technology is very helpful in saving time and space. Example: When e-mailing a large document, using a compression software to reduce the file size will allow the file to be sent and received much faster.
   
• Config.SYS:
  The configuration file for DOS systems. Each time a DOS computer boots up, it reads from the CONFIG.SYS file (if present) and will execute any prewritten commands. A couple of the most common file held within the Config.sys are: BUFFERS= and FILES=. These commands enable the system to specify the buffer size and the number of files that are allowed to open at once. Commands can also be held in the Config.sys that will install device drivers.
   
• Constraint:
  A data rule that limits a searches possibilities through preset algorithms. The constraint could include an algorithm that would rule out certain data relationships allowing the search to proceed much more quickly.
   
• Contrast Ratio:
  This is a dynamic range measurement method. It measures the contrast ratio as it applies to images and text. Detailed images have a higher contrast ratio.
   
• Controller:
  A controller is a device responsible for transferring data from a computer system to peripheral device or in reverse. Each device within a computer system has a dedicated controller. The controllers for a monitor and keyboard are included when you purchase a computer system. If you were to add additional devices, you may be faced with purchasing additional controllers for these new devices. Care must be taken that the proper controller is purchased that can communicate with the systems expansion bus.
   
• Conventional Memory:
  In a DOS environment, this would refer to a memory portion that is made available to DOS programs. In a typical DOS system, there is 1MB (megabyte) of address space available. Conventional Memory is allotted 640K of the address space. The other 384K of memory is used by the system and is called "high memory". Any memory beyond the 1MB is expanded memory.
   
• CPE:
  This refers to ports or other equipment supplied by the manufacture so that the end user can connect to a network. A typically supplied CPE is either a switch or a router.
   
  
• CPM:
  (Cost Per Thousand)
  This is a calculation method involving 1000 advertisement impression displays. The CPM rate of pay is calculated based upon these 1000 impressions. One scenario might be that a person would agree to pay you ten dollars for each time the advertisement displays on your web page or site one thousand times. 
   
• CPU:
  Central Processing Unit. In a microcomputer, a processor on an IC chip (called a microprocessor) that serves as the heart of the computer. It interprets and carries out instructions, performs numeric computations, and controls the peripherals connected to it. Often the entire system unit is called the CPU.
   
• Critical Mass:
  The scale or volume at which processes become self-perpetuating. In Web publishing, it is said that after achieving a certain amount of material and resources, it will create a self-sustaining chain reaction.
   
• CSS: 
  Stands for Cascading Style Sheets. This is a language designed to work with HTML documents on the Web. CSS is generally used to provide a specific appearance or style to a web page or site. A common use for CSS could be that it is written to specify the links rollover color in a web sites navigation structure. CSS is becoming much more widely used by webmasters due to the file size benefit of using style sheets.
   
• Cursor:
  A cursor is a blinking indicator designed to mark the place of text where a person may be working within a document.
   
• Cyberspace: 
  Author William Gibson in his novel Neuromancer describes a more highly developed form of the Internet and who originally coined the term Cyberspace. The word Cyberspace is currently used to describe the whole range of information resources available through computer networks.
   
  
• Cyberpunk: 
  The term Cyberpunk could be used to describe an individual that hacks their way in to computer system with the intent of stealing or destroying the information in the system. It term was actually originated by a science fiction writer that described a lawless futuristic society dominated by computer technology. 

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