All computer processing requires data. Data refers to the raw fact, including numbers, words, images, and sounds given to a computer during the input operation. In the processing phase, the computer manipulates the data to create information. Information refers to data that has been processed into a meaningful and useful form. The production of information by processing data on a computer is called information processing, or sometimes data processing (DP). During the output operation, the information created is put into some form, such as a printed report, that people can use.

1. The computer user inputs data by pressing the keys on the keyboard. 2. The data is then processed by the device called the system unit. 3. The output, or results, from the processing are displayed on the screen of the monitor or printed on the printer, providing information to the user. 4. Finally, the output is stored on a disk for future reference.

In a computer, operations occur through the use of electronic circuits contained on small chips, when data flows along these circuits it travels at close to the speed of light. This allows processing to be accomplished in billionths of a second.

The electronic components in modern computers are very reliable and seldom fail. In fact, most reports about computer errors are usually reacted to other causes, often human mistakes. The high reliability of the components enables the computer to produce accurate results on a consistent basis.

Computers can store enormous accounts of data and keep that data ready available for processing. Using modern storage methods, the data can be quickly retrieved and processed and then restored for future use. 

The speed, reliability, and storage capabilities of the computer make it a powerful tool for information processing.

Before the information processing cycle for a specific job begins, the computer program corresponding to that job is loaded into the computer's memory. Once the program is loaded, the computer can begin to process data by executing the program's first instruction. The computer executes one program instruction after another until the job is complete.

The first three of these operations, input, process, and output, describe the procedures that a computer performs to process data into information. The fourth operation, storage, describes a computer's electronic storage capability. As you learn more about computers, you will see that these four operations apply to both the computer equipment and the computer software. The equipment, or devices, of a computer are classified according to the operations they perform. Computer software is made up of instructions that describe how the operations are to be performed.

Input devices are used to enter data into a computer. Two common input devices are the keyboard and the mouse. As the data is entered on the keyboard, it is temporarily stored in the computer's memory and displayed on the screen of the monitor. A mouse is a type of pointing device used to select processing options or information displayed on the screen. The mouse is used to move a small symbol that appears on the screen. This symbol, called a mouse pointer or pointer, can be many shapes but is often in the shape of an arrow.

The system unit of a computer, which contains the electronic circuits that actually cause the processing of data to occur. The system unit includes the central processing unit, main memory, and other electronic components. The central processing unit (CPU) contains a control unit that executes the program instructions and an arithmetic/logic unit (ALU) that performs math and logic operation. Arithmetic operations include numeric calculations such as addition, subtraction, multiplication, and division. Comparisons of data to see if one value is greater then equal to or less than another is called logical operations. 

Main memory also called RAM (Random Access Memory) or primary storage, temporarily stores data and program instructions when they are being processed.  

Other electronics include components that work with the input, output, and storage devices and optional components that enable the computer to communicate with other computers.

Output from a computer can be presented in many forms. The two most commonly used output devices are the printer and the monitor (the one you are looking at now.) Other frequently used names for the monitor are the screen, or the CRT, which stands for cathode ray tube.

Secondary storage devices sometimes called auxiliary storage devices, store instructions and data when the system unit is not using them. A common secondary storage device on personal computer is a diskette. Another secondary storage is called a hard disk drive. Hard disk drives contain nonremovable disks and provide larger storage capacities then diskettes. (Other storage device: zip drive, tape drive, CD drive, Super drive...etc) 

Collectively, this equipment is called a computer system, or simply a computer. The term computer is also used to refer to the system unit where the actual processing of data occurs. The input devices, output devices, and secondary storage devices that surround the system unit are sometimes referred to as peripheral devices.

Computers are generally classified according to their size, speed, processing capabilities, and price. However, rapid changes in technology make firm definitions of these categories difficult. This year's speed, performance, and price classification of a mainframe might fit next year's classification of a minicomputer. Even though they are not firmly defined, the categories are frequently used and should be generally understood.

Personal computers (PCs, PC also stands for Programmable Controller), also called microcomputers or micros, are the small systems that have become so widely used. Classifications within this category include hand0held, palmtop, notebook, subnotebook, laptop, pen, desktop, tower, and workstation. Hand-held, palmtop, notebook, subnotebook, laptop, and pen computers are considered portable computers. Depending on their size and features, personal computer prices range from several hundred to several thousand dollars. The most expensive personal computers are generally under $10,000. 

Hand-held computers are usually designed for a specific purpose such as meter reading or inventory counting and are used by workers who are on their feet instead of sitting at a desk. 

Palmtop computers often have several built-in or interchangeable personal information management functions such as a calendar to keep track of meetings and events, and address and phone file, and a task list of things to do. Some palmtop computers also have limited capabilities to write correspondence and perform financial analysis. Palmtop computers do not have disk storage devices and usually have a nonstandard keyboard, meaning that the keys are not arranged like a typewriter. 

Notebook Computers are small enough to be carried in a briefcase but are often transported in their own carrying case. Notebooks are general-purpose computers in that they can run most application software packages. They have standard keyboards and usually have at least one disk drive for storage. Notebooks usually weigh between four and eight pounds. 

Subnotebook computers are smaller versions of notebook computers and generally weigh less then four pounds. To save weight and space, some subnotebooks do not have disk drives and use special-purpose memory cards for storage. 

Laptop computers are larger versions of notebook computers that weigh between eight and fifteen pounds. The extra weight comes primarily from large-capacity disk storage devices and larger display screens. 

Pen computers are specialized portable computers that use a pen-like device to enter data. Sometimes the pen is used to write information on a special input screen and sometimes it is used as a pointing device to select a processing choice presented on the screen. Pen systems have successfully replaced many applications that previously required the user to fill out a form or checklist. The unique feature about pen system is the special software that allows the system to recognize handwritten input. One type of small pen input system is called a personal digital assistant or personal communicator. These hand-held devices are designed for workers on the go and often have built-in communications capabilities that allow the PDA to use voice, fax, email or data communications. Apple's Newton PDA has built-in intelligence that assists the user in making entries. 

Desktop computers are the most common type of personal computer and are designed to fit conveniently on the surface of a desk or workspace. Desktop computers have separate display screens. 

Tower computers are personal computers in an upright case. A full-size tower case provides more room for expanding the system and adding optional equipment. The most powerful personal computers are sometimes only available in tower cases. A mini-tower case, approximately half the size of a full tower case, usually has less expansion room than a desktop computer but takes up less room. 

Workstations are expensive high-end personal computers that have powerful calculating and graphics capabilities. Workstations are frequently used bye engineers to aid in product design and testing. The term workstation is sometimes used to refer to a personal computer or terminal connected to a network.

Mainframe computers are large systems that can handle hundreds of users, store large amounts of data, and process transactions at a very high rate. Mainframes usually require a specialized environment including separate air conditioning, cooling, and electrical power. Raised flooring is often built to accommodate the many cables connecting the system components underneath. The price range for mainframes is from several hundred thousand dollars to several million dollars.

Supercomputer are the most powerful category of computers and, accordingly, the most expensive. The capability of these systems to process hundreds of millions of instructions per second is used for such applications as weather forecasting, engineering design and testing, space exploration, and other jobs requiring long, complex calculations. These machines cost several million dollars.

Most end users do not write their own programs. In some corporations, the information-processing department develops custom software programs for unique company applications. Programs required for common business and personal applications can be purchased from software vendors or stores that sell computer products. Purchased programs are often referred to as application software package, or simply software package.

FAQ Frequently asked question. Lists of FAQs help users learn about a particular topic on the net. 

Flame Slang term for an aggressive or rude message. 

FTP File Transfer Protocol. Method of transferring files from one computer to another. 

GOPHER A menu based system for exploring the NET. 

IRC Internet Relay Chat. Interactive discussion among multiple users. 

MOSAIC Graphical users interface that user hypertext links. 

NET Abbreviation for the Internet. 

NEWGROUPS Discussion groups on various topics. 

PPP Point-to-Point Protocol. A type of Internet connection. 

SLIP Serial Line Internet Protocol. A type of Internet connection. 

Surfing Slang term for browsing the Net. 

TCP/IP Transmission control Protocol/Internet Protocol. Primary communications protocol used on the NET. 

TELNET A terminal emulation communications protocol that allows users to login to other computer systems. 

URL Uniform Resource Locator. The Internet addresses where a document can be found. 

Usenet An informal group of systems that exchange news on a variety of topics. 

Veronica A search tool used with Gopher. 

WAIS Wide Area information Service. A system for finding information in Net Database. 

WWW World Wide Wed. A linked hypertext system used for accessing Net resources.

The process of loading an operating system into main memory is called booting the system. The actual information displayed will vary depending on the make of the computer and the equipment installed. The following steps explain what happens during the boot process on an IBM compatible personal computer that operates using DOS (Disk Operating System).

(You can find more about this by opening DOS Prompt, and type the command HELP)

Single Program operating systems allow only a single user to run a single program at one time. This was the first type of operating system developed. Older personal computers used this typed of operating system. For example, a single program operating system allowed you to load only one application, such as a spreadsheet, into main memory. To work on another application, such as work processing, you would exit the spreadsheet application and load the word processing program into memory.

Multitasking operating system allows more than one program to run at the same time on one computer. Even though the CPU is only capable of working on one program instruction at a time, its capability to switch back and forth between programs cakes it appear as though all programs are running at the same time. For example, with a multitasking operating system, the computer could be performing complex spreadsheet calculation and at the same time be downloading a file from another computer while the user is writing a memo with the work-processing program. 

Multitasking operating system on personal computers can usually support a single user running multiple programs. Multitasking operating systems on some personal computer and most minicomputers and mainframes can support more than one user running more than one program. This version of a multitasking operating system is sometimes call a timesharing or multi-user operating system. These operating system also allow more than one user to run the same program. For example, a whole sale distributor may have dozens of terminal operator entering sales orders using the same order entry program on the same computer. (Most Operation System is Multitasking today. Such as Windows, Mac OS 7.0+, etc.)