COMPUTER FUNDAMENTALS

INTRODUCTION TO COMPUTERS

History of computer:-

1.      1^st computing device = ABACUS – BC 500 in Babylonians.

2.      1^st mechanical computer (Analytical Engine) – 1822 Charles Babbage

3.      The ENIAC used 18000 vacuum tubes in 1942.

Generation of Computers:-

• 1^st Generation  -  Vacuum tubes
• 2^nd Generation – Transistors
• 3^rd Generation – Integrated Circuits
• 4^th Generation – VLSI (Very Large Scale Integration)
• 5^th Generation – Artificial intelligence.

Classification of IC’s:-

• small scale integration(SSI) – 10 to 100 components
• Medium scale integration (MSI) – 100 to 1000 components
• Large scale integration (LSI) – 1000 TO 10 000 components
• Very large scale integration (VLSI) – 10 000 and above

BLOCK DIAGRAM OF COMPUTER

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INPUT DEVICES

These devices are used for feeding data, programs and commands to the computer.

Eg.  Keyboard, mouse, joystick, light pen, scanner, webcam and all storage devices.

OUTPUT DEVICES

Those devices which are used for capturing or displaying the results are called out put devices.

Eg.  Monitor, Printer, Plotter, speaker and storage devices.

MEMORY

Memory is the place where the current programs, related data and results are stored temporarily.  Current programs are loaded into the memory from the input devices and the results which are stored inside the memory after processing temporarily.  Once a full result is obtained, it will be sent to the output devices. 

MICROPROCESSOR

All the electronics circuits which are needed for making ALU & Control unit are collectively called CPU (Central Processing Unit).  If all the circuits needed for the CPU are coming integrated in a single chip, it is called a micro processor.

                          FUNCTIONAL CLASSIFICATION OF COMPUTERS

Functionally computers can be classified in to four. They are

• Hardware – Physical components or touchable parts of a computer
• Software – Written programs
• Firmware – Combination of hardware and software or Software embedded in hardware
• Live ware – User

SOFTWARE

             

COMMUNICATION LAYERS OF COMPUTER

BIOS (Basic Input Output System)

Bios in ROM contains programs which initializes various LSI chips on the mother board for performing IO(input / output) operations.  These programs can be accessed by OS or by application programs whenever an IO operation to be performed.  In PC’s BIOS                                                               

comes with mother board as firmware.  So, BIOS is an interface between hardware and software. 

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OPERATING SYSTEM

OS is an organized collection of software that controls the overall operation of the computer.  It does the following operations:-

1.       CPU management

2.       Memory management

3.       I/O management

4.       Storage device management

5.     User interface.

APPLICATION PROGRAMS

Application programs are special programs which are meant for operating computer in a special application. 

E.g.  MS word, Excel, Power point, tally, AutoCAD, Photoshop etc.

Computer (Definition)

Computer is an electronic device, which processes alphanumeric data’s with the help of instructions defined in the program.

Data

Any piece of information given into the computer for processing is called data. 

Instruction

It is the single step to be done by computer.

Program

A group  of instructions which are needed for operating the computer in a specific task is called a program. 

Hardware

All  tangible and visible parts of computer are called  hardware. 

Eg.  Ic, capacitors, resistors, cables, pcb (Printed circuit board) etc.

Software

All intangible and invisible parts of computers, which are essential for the working of computer are called software.

Eg.  Os, application programs, device drivers etc.

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