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Components of a Computer System
A computer is an electronic machine that performs input, processing, storing, and output according to programmed instructions to carry out specific tasks. Formerly, computers were used primarily to do arithmetic computations, hence the term, computer. Consider the primitive form of a computer, a calculator. You input the numbers and the arithmetic operation you need the calculator to perform, for example, “3+5=”, and then the calculator processes the arithmetic expression by adding 3 and 5, stores the result of 8, and outputs the result onto the display area.
The modern computer operates in a similar fashion. Input to a computer can be sent through the keyboard or mouse. The computer then processes the input, stores the result, and displays the result via the monitor, speaker, printer, or other output devices. For example, when you request for a web page by typing in its URL (Uniform Resource Locator), "http://www.icarnegie.com", the computer processes your input by fetching the requested page over the Internet. It then displays the fetched page on your monitor as output.
In general, a computer system can be decomposed into the hardware system, the software system, and the network system. Each of these subsystems will be discussed in more detail in subsequent units of this course. The figure below illustrates the major subsystems in a computer system with some examples.
Figure 1 Components of a computer system
Let us now look at each subsystem and their main functionality.
Hardware System
The hardware system consists of external and internal physical components that enable a computer to accept input, process the input, store data, and produce outputs. Each of the hardware components will be discussed in more detail in Unit 2. Hardware Systems.
The figures below show some external hardware components of a computer.
Figure 2 Hardware components
The diagram below indicates the hardware components inside the system unit. Each of these components plays an essential role in the operation of a computer system.
Figure 3 Components inside the system unit
Hardware components provide the physical interface to a computer system. However, they cannot function without instructions to operate them. These instructions are software programs.
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