A computer system is an electronic machine that works at a very high speed to process data according to the instructions earlier given to it. the phrase "process data" could mean to input, retrieve, delete, print and perform arithmetic and logic aspect of data, and store data on storage devices. It also involves the movement of data from one location to another etc.
it means that a computer is a machine that can accept instructions. The instructions to mean is the one that computers can understand but not the ordinary human instructions. To give instructions to computer is the most difficult task in computing because computer ability to perform jobs is dependent on the ability of the programmer to instruct it.
A programmer is the person that can give instructions to computers to accomplish human tasks. the user or the computer operator operates the computer based on the commands provided by the programmers. These commands are issued basically by the use of: keys on the keyboard and by the used of menu and icon objects through the mouse, Others could be by touch screen Technology, Light Pen, Joy