Literally, a computer means a tool or an Equipment or a machine which computers. The Computation includes not only calculations but Also all forms of manipulations. For examples, Cooking, composing music, creating art works, Etc. also fall under computation. This definition cover all sort of computing equipments like abacus (used in 3000 BC) Pocket and desk calculators, mainframe, mini and micro computers. In contrast to other machines, a computer is a multi purpose machine.
Computer in the past were devices capable of only accepting Data. Solving problems and supplying the results. But, today a computer Is a device which can process, store and retrieve (i.e. call back from its memory) information automatically.
It should be noted that even though computer is a machine, it is more than a machine. As we later notice, computer is a special machine. So, computer is a new meaning for the concept of machine. As we all know all machine have three essential units, namely, input unit, processor and output unit. Shows these essential units of a machine.
