The first part is hardware - the physical, electronical devices that are thought of and recognized as "computers". The second part is software - the programs that control and coordinate the activities of the computer hardware and that direct the processing of data.
Computer software can be divided into two very broad categories - system software and application software.
System Software
The user interacts with application software. System software enables the application software to interact with the computer hardware. System software is "background" software that helps the computer manage its own internal resources.
The most important system software program is the operating system, which interacts between the application software and the computer. The operating system handles such details as running ("executing") programs, storing data and programs, and processing data.
Application Software
Application software might be described as "end-user" software. Application software performs useful work on general-purpose tasks such as word processing and cost estimating.
Application software may be packaged or custom-made.
1. Packaged software is programs prewritten by professional programmers that are typically offered for sale.
2. Custom-made software, or custom programs, are programs written for a specific purpose and for a specific organization. Using computer languages, programmers create this software to instruct the company computer to perform whatever tasks the organization wants. A program might compute payroll checks, keep track of goods in the warehouse, calculate sales commissions, or perform similar business functions.
"Basic applications" are general-purpose programs. These programs are widely used in nearly all career areas. One of these basic applications is a browser to navigate, explore, and find information on the Internet. The two most widely used browsers are Microsoft's Internet Explorer and Netscape's Communicator.
There are more advanced applications that are more specialized than the basic applications. They are widely used within certain career areas. One of the most exciting advanced applications is multimedia, which integrates video, music, voice, and graphics to create interactive presentations.
Microcomputer hardware - the physical equipment - falls into five categories. They are the system unit, input devices, secondary storage, output devices, and communications devices.
The System Unit
The system unit is electronic circuitry housed within the computer cabinet. The two most important components of the system unit are.
1. The central processing unit (CPU) controls and manipulates data to produce information. A microcomputer's CPU is contained on a single integrated circuit or microprocessor chip. These chips are called microprocessors.
2. Memory, also known as primary storage or random access memory (RAM), holds data and program instructions for processing the data. Memory is sometimes referred to as temporary storage because it will be lost if the electrical power to the computer is disrupted or cut off. Memory is located in the system unit on tiny memory chips.
Input Devices
Input devices translate data and programs that humans can understand into a form that the computer can process. The most common input devices for microcomputers are the keyboard
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