UNIT – I
INTRODUCTION TO COMPUTERS
Computer :
Computer is an electronic device. It performs Arithmetic, logical, data processing operations. A computer is a machine that manipulates data according to set of instructions.
Program :
Set of instructions to perform particular task is called as program.
Ex: A game is a program, a word processor is a game.
Software :
Collection of computer programs to perform different types of tasks is called as software.
(Or)
Program that tell the computer what to do.
Ex: Operating System, Banking Application, database, Business Application etc.
Types of Computers :
1) Analog Computers
2) Hybrid Computers
3) Main Frame Computers
4) Micro Computers
5) Desktops
6) Laptops
7) Mini Computers
8) Super Computers
1. Analog Computes :
Data will be converted to wave format. An analog computer can perform several mathematical operations simultaneously.
Ex: ECG
2. Hybrid Computers :
A combination of digital and analog computers. Data will be converted to Digital format (0 and 1).
3. Main Frame Computers:
Large organizations use main frame computers for highly critical applications such as bulk data processing.
4. Micro Computers:
A computer with a micro processor and its central processing unit is known as Micro Computer. They don’t occupy space as much as main frame computers. Micro Computers can be called as personal computers.
5. Desktop Computers:
A Desktop intended to be used on a single location. Desktops are widely popular for daily and home use.
6. Laptops:
Similar in Operation to Desktops, Laptop’s are mini authorized and optimized for mobile use. Laptop’s runs on a single battery. They are enabled with an in build Keyboard, Touchpad (acting as mouse) and crystal display.
7. Mini Computers:
In terms of size and processing capacity mini computers are used in work stations.
8. Super Computers :
The highly calculation intensive tasks can be effectively performed by means of super computers.
Ex: weather fore casting, communication applications. Satellite application and defense applications.
Computer System :
A computer is made up of two major components.
1. Hard Ware and
2. Software
A Computer hard ware us physical equipment.
Software is the collection of programs that allow the hardware to do its Job.
Computer Hardware:
A personal computer is made up of multiple physical components of computer hardware.
The Hardware component of computer system consists of 5 parts.
1) Input Device
2) CPU – Central Processing Unit.
3) Primary Storage Device
4) Output Device
5) Auxiliary Storage devices (or) Secondary storage devices.
Input Devices :
The Input device is usually a keyboard where programs and data are entered in to a computer.
Ex: Keyboard, mouse, scanner, touchpad…
CPU :
The CPU is responsible for executing instructions such a arithmetic calculations and comparisons among data and movement of data inside the system
Some times effort to as the brain of the computer
ALU: Arithmetic and logical unit
The major job of ALU is it executes the user instructions, it is the responsible for all kinds of calculations of the user process.
CU: Control Unit
It Controls the every instructions which are send by the user to the system to perform the process.
MU: Memory Unit
It is used to store the information temporarily/permanently.
In the system there are two units present in MU.
a. RAM – Random access memory
b. ROM – Read only Memory
RAM | ROM |
1. It is temporary Memory | 1. It is permanent memory |
2. It is read and write memory | 2. It is read only memory |
3. It is volatile memory | 3. It is Non-Volatile Memory |
4. When the power is off we loose the unsaved information | 4. When the power is off we cannot loose the information |
Primary Storage:
Primary storage also known as Main Memory, is the place where the programs and the data are stored temporarily during the process the data in primary storage are erased when we turn off a system.
Output Devices:
It is used o show the Output.
Ex: Monitor, Printer. Speakers etc.
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