Introduction of computer

Computer:-

Computer is an electronic machine. This machine takes input from the user, processes the given input and generates output in the form of useful information.

Input (data) Output (result)

Data:- Data refer to the raw details that need to be processed to generated some useful

information

Example:-

Student database

Data

Program (instruction):- Program refers to the set of instruction that can be executed by the computer

sequential or non sequential manner. These instructions are written in any high level language such as BASIC, FORTRAN,

COBAL, AND C etc...

Information:-

The processed data and this has been generated as a results based on the instructions given by the user.

Process

Roll No Department Name

A computer includes various devices that function as an integrated system to perform several tasks

1. Central processing unit(CPU) 2. Monitor 3. Keyboard and mouse

Central processing unit (CPU)

It is the processor of the computer that is responsible for controlling and executing instruction in the computer.

It is brain of the computer. Monitor

It is a screen, which displays information in visual form, after receiving the video signal from the computer.

Keyboard and mouse

These are the input devices, which are used by the computer, for receiving input from the user.

Application of computers:

Computers are used in almost every sphere of life such as education, communication and banking...

The user from different locations can easily and quickly communicate with each other with the help of computer.

Education: 1. Computers are used in schools and colleges to teach students in a better and

easy way. 2. The students can get more information about a specific topic or subject using the

internet. 3. Student can fill their application form through online.

Business: 1. Computers are used in different types of businesses to store a large amount of

information in the form of a database. 2. Using computer, business meeting can be held between people sitting at remote

locations through web conferencing. Communication

1. Computers that are connected with each other through internet can be used to transfer data to and from other computer.

2. In order to establish communication between two users, E-mails is of the most common mediums that is used.

3. E-Mail user can send /received text messages, graphic messages and file attachments.

Science 1. Computers are used by various scientists for the purpose of research and

development. 2. They generally make use of computer for research and analysis of new theories. 3. With the help of computer to possibility of predicting natural disasters such as

earthquake and ect… Engineering

1. Computers are used by engineering for the creation of complex drawing and design while working different fields like automobiles and constructions.

Entertainment

1. Computers are used in the entertainment industry for creating graphics and animations.

Banking 1. Very useful proposes e of banking is online banking. 2. The users or customers can transfer and receive money by using computers and

internet. 3. In all banks provide the facility of online bill payment through their websites.

Health

1. Computers are used by doctors to diagnose various kinds of diseases and ailments. Several analog and digital are connected with computers enabling the doctors to monitor the condition of a patient and view the internal organs of the body.

Characteristics of computer:

1. Speed 2. Accuracy 3. Storage capacity 4. Reliability 5. versatility 6. diligence

Speed:

A computer is a fast electronic device that can solve large and complex problem in few seconds.

The speed of a computer generally depends upon its hardware configuration. Storage capacity:

A computer can store huge amount of data in its different storage components in many different formats.

The storage are of computer system is generally dived into two categories 1.Main Memory 2.Secondary Memory

Accuracy: A computer carries out calculations with great accuracy. The accuracy achieved by a computer depends upon its hardware configuration and

the instructions. Reliability:

A computer produces results without any error. Most of the errors generated in the computer are human errors that are created by the user itself.

Versatility: Computers are versatile machines. They can perform many different tasks and can

be used for many different purposes. Diligence:

Computer can perform repetitive calculations any number of time with the same accuracy.

Computer generations: The various computing devices invented that enable people to solved different types of

problems. All these computing devices can be classified into several generations. i. First generation computer ii. Second generation computer

iii. Third generation computer iv. Forth generation computer v. Fifth generation computer

First generation computer

The first generation computers were employed during the period 1940 -1956. These computers used the VACUUM TUBES technology for calculation as well as

for storage and control purposes.

A vacuum tube is made up of glass and contains filament inside it. The filaments when heated generate electrons which eventually help in the

amplification and deamplification of electronic signals.

Main Features

• Major Innovation - Vacuum Tubes • Main Memory - Punched Cards • Input Output Devices - Punched cards and papers • Languages - Low level machine language • Operating System - No operating system, human operators to set • switches • Size - Main frame for example ENIAC, EDVAC, UNIVAC

Advantages of First Generation

1. Vacuum tubes were used as electronic component. 2. Electronic digital computers were developed for the first time. 3. These computers were the fastest calculating devices of their time. 4. Computations were performed in millisecond.

Disadvantages of First Generation

1. Too large in size. 2. They were unreliable. 3. Induce a large amount of heat due to the vacuum tubes. 4. Not portable. 5. Limited commercial use.

Second Generation Computers:

The second generation computers were employed during the period 1956-1963.

The main characteristic of these computers was the use of transistors in place of vacuum tubes in building the basic logic circuits.

A transistor is a semiconductor device that is used to increase the power of the incoming signal.

It has three connections 1. Emitter 2. Base 3. Collector

The base of the transistor is the gate through which signal, needed to be amplified is send.

The signal sent through the base of transistor is generally a small flow of electrons.

The collector of the transistor is used to collect the amplified signal. The emitter of the transistor act as the output gate for emitting the amplified

signal

Main Features

• Major Innovation - Transistors as main component. • Main Memory - RAM and ROM. • External Storage - Magnetic tapes and Magnetic Disk. • Input Output Devices - Magnetic tapes and Magnetic Disk. • Languages - Assembly language, some high level languages for Example BASIC,

COBOL, FORTRAN. • Operating System - Human handles punched card. • Size - Main frame for example IBM-1401, NCR-300, IBM-600 etc.

Advantages of Second Generation

1. Smaller in size as compares to 1st generation. 2. Much more reliable. 3. Less heat generated. 4. Computation was performing in micro second. Less hardware and maintenance

problem. 5. Could be used for commercial use.

Disadvantages of Second Generation

1. Very costly for commercial use. 2. It still required frequent maintenance. 3. Frequent cooling also required.

Third generation computers:

The third generation computers were employed during the period 1964-1975. The major characteristic feature of third generation computer system was the

use of Integrated Circuits(ICs) The IC technology was also known as microelectronics technology. The ICs are Circuits that combination of various electronic components such as

transistor, resistors, capacitors, etc... onto a single small silicon chip.

Main Features

• Major Innovation - Integrated circuit (ICs) as basic electronic component. • Main Memory - PROM and DRAM. • External Storage - Improve disk (Floppy Disk) • Input and Output Devices - Keyboard for input, monitor for output. • Languages - More high level languages. • Operating System - Complete operating systems were introduced. • Size - Mini, for example: IBM SYSTEM / 360, ICH-360, HONEY WELL-316 etc.

Advantages of Third Generation

1. Smaller in size as compared to second generation. 2. More reliable. 3. Portable 4. Less electricity consumption. 5. Heat generation was rare. 6. General purpose computer.

Disadvantages of Third Generation

1. Air conditioning was required in many cases due to ICs. 2. Very advance technology was required to make the ICs.

Fourth generation computer:-

The fourth generation computers were employed during 1975-1989. The invention of large scale integration (LSI) technology and very Large scale

integration (VLSI) technology led to the development of fourth generation computers. The LSI technology allowed thousand of transistors to be fitted onto one small silicon

chip. The VLSI technology allowed hundreds of thousands of transistor to be filled onto a

single chip The progress in LSI and VLSI technologies led to the development of the microprocessor

Main Features

•Major Innovation - LSIC and VLSIC (Micro Processor) •Main Memory - EPROM and SRAM. •External Storage - Floppy Disk and Hard Disk. •Input and Output Devices - Monitor for output. •Languages - Languages and application software. •Operating System - MS-DOS and PC-DOS •Size - Micro computer e.g. IBM-PC, Apple Macintosh etc.

Advantages of Fourth Generation

1. Smaller in size and much reliable. 2. No cooling system required in many cases. 3. Much faster computation. 4. Portable and cheap. 5. The heat generated was negligible. 6. Totally general purpose computer.

Disadvantages of Fourth Generation

1. Very advanced technology was required to fabricate to the ICs.

Fifth generation computer:-

Main Features

• Major Innovations - ULSIC (Ultra large scale integrated circuit) • Main Memory - EEPROM, SIMM and DIMM. • External Storage - Modified magnetic and Optical disks. • Input/output Devices - Keyboard, Pointing Device, and Scanner as input and Monitor

as main output. • Languages - AI (Artificial Intelligence) Expert systems. • Operating System - GUI based e.g. Windows 95, Windows NT. • Size - Very small in size example: Laptop, Note book, Digital Diary, Palm top and

Pocket PC.

This generation is started from 1981 and still continued, new technologies are adopted to fabricate IC chips, such as electron beam, X-rays or laser rays. The Very Large Scale Integration

(VLSI) was developed, so the computer became much smaller than ever before. New memory storage device like bubble memory, optical or memory are being designed. the new computer will be controlled by using human voice and will work by giving command in our own language. Future computer will in some way to be intelligent and capable of making decision.

Advantages of Fifth Generation

1. Very large storage capacity. 2. Long bit processor builds. 3. Artificial Intelligence Language developed.

Classification of computer: There are different types of computer available these days. the function of each types of computer is to process data and provide some output to the users. We can classify computer according to the following three criteria:

1. Based on operating principles 2. Based on applications 3. Based on size and capability

Based on operating principles

The basic of operation performed and methods used to store and process data and information, computers can be classified into the following categories:

1. Analog computers 2. Digital computers 3. Hybrid computer

Analog computer: The analog computers represent data in the form of continuous electrical signals.

It’s having a specific magnitude. These computers are very fast in their operation

and allow several other operations to be carried out at the same time. the results produced by these computers are not very accurate. The electronic circuit employed in modern anlog computer

is generally an operational amplifier (Op-Amp). it is made up of semiconductor integrated circuits.

Digital computer:

The digital computer, also known as the digital information processing system, is a type of computer that stores and processes data in the digital form.

Therefore each type of data is usually stored in these computers in terms 0s and 1s. This output produced by these computers is also in the digital form. The digital computers are also capable of processing the analog signal. The analog

data should be converting to digital form, before being processed by these computers.

Digital computers are generally faster and more reliable than the analog computer system and provide the accurate results.

The digital computer has different hardware components such as

1. Arithmetic Logic Unit (ALU) 2. Control Unit 3. Input / Output Unit 4. Memory Unit

ALU of digital computer is used to perform the various arithmetic operations, such as addition, subtraction, multiplication, division and various logic operation, such as AND, OR, NOT, etc.

Control unit helps in directing the operation of ALU. The memory Unit is used to store the data on temporary or permanent basic. The input units are used to enter the data into computer and the output units are used

to display the information generated by the computer.

Hybrid computer

The hybrid computer is a combination of analog computer and digital computer because it encompasses the best features of both these computers.

The computer used to in hospitals to measure the heartbeat of a patient.

The hybrid computers are also used in scientific applications and various engineering fields.

Based on size and Capability Computers differ from each other in terms of their shape, size and weights. Computers can be classified into the following categories:

1. Microcomputers 2. Mini computers 3. Mainframe computers 4. Super computers

Micro computers:

The microcomputer is used for everything from home computer to a powerful business computer.

A micro computer is defined as the one which has a single microprocessor (a chip). Micro computer system consists of a microprocessor, storage unit, input unit and output

devices, including power supply, connecting cables, an operating system and other software programs.

Advantage of Micro computer

It is the smallest of the compute family. It is several times cheaper than minicomputer.

Micro computers depending upon the kind of application for they are being used are further classified

1. Personal computer 2. Workstation 3. Laptop

Personal computer

It is a single user machine. One machine is used to only one person at a time. Personal computer is also known as desktop computer.

Personal computers consist of a system unit, keyboard, and internal hard disk storage, display monitor and other peripheral devices.

Workstation

A workstation is a computer intended for individual use that is faster and more capable than a personal computer.

It's intended for business or professional use (rather than home or recreational use). Workstations and applications designed for them are used by small engineering

companies, architects, graphic designers, and any organization, department, or individual that requires a faster microprocessor.

Laptop computer

Laptop computer is a portable computer that can be taken from one place to another place at any time very easily.

It is also known as notebook computer, notepad or mobile computer.

The laptop computer is small size computer that incorporates all the features of a

typical desktop computer.

Mini computer

A minicomputer was first introduced in the year 1960 by digital equipment corporation.

They were called mini computers because of their smaller size than the other computer.

They can handle more data and more input and output than microcomputers. Minicomputers are less powerful than mainframe computers but more powerful

than microcomputer. The minicomputers are supported to the n number of user worked in at a time. Minicomputer can also used as the web servers that can handle thousands of

transactions in a day. Main frame computer

A mainframe computer is a very large computer that is employed by large business organizations for handling major application, such as financial transition processing.

They are capable of handling almost millions of records in a day. The mainframe computers can maintain large database that can be accessed by

remote users with a simple terminal. They are also known as super servers or database servers.

Features of mainframe computer A mainframe computer can have more than 16 microprocessors. The RAM capacity of these computers lies between 128 MB and 8 GB.

Super computer

A super computer is the fastest type of computer that can perform complex operations at a very high speed.

It has solved to more large number of complex calculation and carries out to

accuracy values. Manufactures of super computers

1. IBM International Business Machines 2. Silicon graphics 3. Fujitsu 4. Intel

Example of super computer used in India.

1. CRAY 3 2. Cyber 205 3. NEC SX -3 4. PARAM

CPU

Basic computer organization

The basic computer organization involves the interfacing of different units of the computer and various operations performed between these units.

Some of the basic units of computer organization are: 1. Input unit 2. Memory Unit 3. CPU 4. Output Unit

Input Unit

An input unit is an electronic device, which is used to feed input data and control signal to a computer.

It is known as input device. Input devices are connected to the computer system using cables. The most commonly used input devices

1. Keyboard 2. Mouse 3. Scanner

INPUT UNIT MEMORY UNIT OUTPUT UNIT

CACHE MEMORY

ARITHMETIC

LOGIC UNIT

CONTROL UNIT

REGISTERS

Keyboard A keyboard is a consists of alphanumeric keys, function keys, modifier keys, cursor

movement keys,spacebar,escape key, numeric keypad, and some special keys ,such as page up,page down,home,insert,delete,and end.

A keyboard is used to enter data into a computer. The latest keyboard (Windows keyboard) is available with 104 keys

The alphanumeric keys include the number keys and alphabet keys. The function keys are keys that keys used to searching a file and refreshing the web

page. The modifier keys such as shift and control keys modify the casing style of a

character or symbol. The cursor movement keys include up, down, left and right keys, and are used to

modify the direction of the cursor on the screen. The spacebar key shifts the cursor to the right by one position. The numerical keypad uses separate keypads for number and mathematical

operators.

Mouse The mouse allows the user to select element on the screen, such as tools, icons,

and buttons, by pointing and clicking them. We can also use a mouse to draw and paint on the screen of the computer

system. The mouse is also known as pointing devices.

The mouse consists of two buttons a wheel at the top and a ball at the

bottom When the ball moves the cursor on the screen moves in the direction in

which the ball rotates. The left button of the mouse is used to select an element and the right

button when clicked, displays the special options such as open and explore and shortcut menus.

Scanner

A scanner is an input device that converts documents and images as digitized images.

The digitized images can be produced as black and white images, An image is considered as a collection of dots with each dot representing a

combination of red, green, and blue color.

Memory unit

The Term Computer Memory is defined as one or more sets of chips that store Data/program instructions, either temporarily or permanently

The memory units of computer are classified as primary memory and secondary memory.