Software System—Operating System Software and Application Software
Network 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 1Components of a computer system
Let us now look at each subsystem and their main functionality.
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