Lesson 1: Introduction and Basic Organization
On completion of this lesson you will be able to
i) grasp the introductory concepts of a computer and its working principle
ii) understand the basic elements of a computer system.
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1.2 What is a Computer?
A computer is an electronic machine that stores, retrieves, and manipulates or processes data. It cannot think or reason; it can only carry out instructions given to it. A set of instructions that directs its actions is called a program. Different programs are used to solve different problems. Ability to accept, store, and execute various sets of instructions (or programs) makes the computer the invaluable, allpurpose business tool. The first step of solving a problem by a computer is to develop a suitable computer program and then store in its memory. The computer then carries out the instructions in the program. The instructions of a program generally direct the computer to perform three basic functions over and over again; these functions are input, processing, and output. Collectively, these functions constitute the data processing cycle.
Input: input devices are connected to feed the computer facts or data to be processed.
Processing: the control and storing of data, numerical comparisons, and arithmetic operations are performed on the input data to produce the desired results.
Output: the computer feeds the processed data or information, to the output devices.
i) The computer reads a program and stores it in the memory. The computer executes program instructions to:
ii) Input data from the disk, the keyboard, or other storage media,
iii) process the data and
iv) Output results to the display screen, disk or other media.
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