What is Computer, Network, Hardware, Software & Basic Computer Organization ?

What is Computer?

1.  A computer is a programmable machine that receives input, stores and manipulates data , and provides output in a useful format.
2.  Computer is a machine for performing calculations automatically.
3.  Computer is a electronic machine capable of performing calculations and other manipulations of various types of data, under the control of a stored set of instructions. The machine itself is the hardware; the instructions are the program or software.

What is Computer Hardware?

          Computer hardware refers to the physical parts of a computer and related devices. Internal hardware devices include motherboards, hard drives, and RAM. External hardware devices include monitors, keyboards, mouse, printers, and scanners. The internal hardware parts of a computer are often referred to as components, while external hardware devices are usually called peripherals. Together, they all fall under the category of computer hardware.

What is software?

     A computer cannot do anything on its own. It must be instructed to do a desired job. Hence, it is necessary to specify a sequence of instruction, which a computer must perform to solve a problem. Such a sequence of instructions , written in a language, which can be understood by a computer, is call a computer program.

     The term software refers to the set of computer programs, procedures, and associated, documents (flowcharts, manuals, etc) which describe the programs, and how they are to be used.

     A software package is a group of programs, which  solve a specific problem or perform a specific type of job. For example, a word-processing package may contain programs for text editing, text formatting, drawing graphics, spelling checking etc. 

What is Computer Network? :-

Computer network means interconnected collection of autonomous computers.

• Two computers are said to be interconnected if they are able to exchange information.

• Computers are connected together to share the resources like hardware, software, data.

• The medium of communication (or communication channel) can be copper wire, fiber optics, microwaves, radio waves and communication satellites.

• An autonomous system means all the computers need itself to be master.

• There is no slave.

• If one computer can forcibly start, stop or control another computer, the computers are not autonomous.

• A system with one control unit and many slaves is not a network.

Basic Computer Organization :-

All computer systems perform the following five basic basic operations, for converting raw input data into information, which is useful to their users:

   1. Inputting : The process of entering data and instructions into the computer system.

   2. Storing : Saving data instructions to make them readily available for initial or additional processing, as and when required.

   3. Processing : Performing arithmetic operations (add, subtract, divide, etc.), or logical operations (comparisons like equal to, less than, grater than, etc.) on data, to convert them into useful information.

   4. Outputting : The process of producing useful information or results for the user, such as a printed report or visual display.

   5. Controlling ; Directing the manner and sequence in which all of the above operations are performed.

A block diagram of the basic computer organization is as shown in below figure. In this figure, the solid lines indicate the flow of instruction and data, and the dotted lines represent the control exercised by the control unit.

Central Processing Unit (CPU)

Basic Organization of a Computer System

It displays the five major building blocks (functional units) of a digital computer system, These five units correspond to the basic operations, performed by all computer systems.