Chapter-1 (Computer,Input Devices, Output Devices, Central Processing Unit (CPU))

What is Computer?
 
Computer is an electronic device that is designed to work with Information. The term computer is derived from the Latin termcomputare’, this means to calculate or programmable machine. Computer can not do anything without a Program. It represents the decimal numbers through a string of binary digits. The Word 'Computer' usually refers to the Center Processor Unit plus Internal memory.

History of Computer? 
 
Charles Babbage is called the "Grand Father" of the computer. The First mechanical computer designed by Charles Babbage was called Analytical Engine. It uses read-only memory in the form of punch cards.
Computer is an advanced electronic device that takes raw data as input from the user and processes these data under the control of set of instructions (called program) and gives the result (output) and saves output for the future use. It can process both numerical and non-numerical (arithmetic and logical) calculations.

Digital Computer Definition

The basic components of a modern digital computer are: Input Device, Output Device, Central Processor Unit (CPU), mass storage device and memory. A Typical modern computer uses LSI Chips.  
Four Functions about computer are:
 
accepts data
Input
processes data
Processing
produces output
Output
stores results
Storage
 

What is Input?

Input is the raw information entered into a computer from the input devices. It is the collection of letters, numbers, images etc.

What is Process?

Process is the operation of data as per given instruction. It is totally internal process of the computer system.

What is Output?

Output is the processed data given by computer after data processing. Output is also called as Result. We can save these results in the storage devices for the future use.

Brief Computer Classification?

Computers differ based on their data processing abilities. They are classified according to purpose, data handling and functionality.
 
According to functionality, computers are classified as:
 
• Analog Computer: A computer that represents numbers by some continuously variable physical quantity, whose variations mimic the properties of some system being modeled.
 
• Personal computer: A personal computer is a computer small and low cost. The term "personal computer" is used to describe desktop computers (desktops).
 
• Workstation: A terminal or desktop computer in a network. In this context, workstation is just a generic term for a user's machine (client machine) in contrast to a "server" or "mainframe."
 
• Minicomputer: A minicomputer isn't very mini. At least, not in the way most of us think of mini. You know how big your personal computer is and its related family.
 
• Mainframe: It refers to the kind of large computer that runs an entire corporation.
 
• Supercomputer: It is the biggest, fastest, and most expensive computers on earth.
 
Microcomputer: Your personal computer is a microcomputer.

What is CPU  (Central Processing unit) ?

In terms of computing power, the CPU is the most important element of a computer system. It add and compare its data in cpu chip. A CPU or Processors of all computers, whether micro, mini or mainframe must have  three element or parts primary storage, arithmetic logic unit (ALU), and control unit. Control Unit (CU) - decodes the program instruction. CPU chip used in a computer is partially made out of Silica. on other words silicon chip used for data processing are called Micro Processor.
Central processing unit (CPU) is the central component of the Pc. Sometimes it is called as processor. It is the brain that runs the show inside the Pc. All work that is done on a computer is performed directly or indirectly by the processor.