Generations of computers,Types of computers, Input and Output devices

Generations of a computer

Introduction:

v  A computer is an electronic device that manipulates information or data.

v  It has the ability to store, retrieve, and process data.

v  Nowadays, a computer can be used to type documents, send email, play games, and browse the Web.

v  It can also be used to edit or create spreadsheets, presentations, and even videos.

v  But the evolution of this complex system started around 1946 with the first Generation of Computer and evolving ever since.

v  There are five generations of computers.

FIRST GENERATION

·         Introduction:

1.      1946-1959 is the period of first generation computer.

2.      J.P.Eckert and J.W.Mauchy invented the first successful electronic computer called ENIAC, ENIAC stands for “Electronic Numeric Integrated And Calculator”.

·         Few Examples are:

1.      ENIAC

2.      EDVAC

3.      UNIVAC

4.      IBM-701

5.      IBM-650

·         Advantages:

1.      It made use of vacuum tubes which are the only electronic component available during those days.

2.      These computers could calculate in milliseconds.

·         Disadvantages:

• The computers were very large in size.
• They consumed a large amount of energy.
• They heated very soon due to thousands of vacuum tubes.
• They were not very reliable.
• Air conditioning was required.
• Constant maintenance was required.
• Non-portable.
• Limited commercial use.
• Very slow speed.
• Limited programming capabilities.
• Used machine language only.
• Used magnetic drums which provide very less data storage.
• Used punch cards for input.

SECOND GENERATION

·         Introduction:

1.      1959-1965 is the period of second-generation computer.

2.      Second generation computers were based on Transistor instead of vacuum tubes.

·         Few Examples are:

1.      Honeywell 400

2.      IBM 7094

3.      CDC 1604

4.      CDC 3600

5.      UNIVAC 1108

·         Advantages:

1.      Due to the presence of transistors instead of vacuum tubes, the size of electron component decreased. This resulted in reducing the size of a computer as compared to first generation computers.

2.      Less energy and not produce as much heat as the first genration.

3.      Assembly language and punch cards were used for input.

4.      Low cost than first generation computers.

5.      Better speed, calculate data in microseconds.

6.      Better portability as compared to first generation

·         Disadvantages:

1.      A cooling system was required.

2.      Constant maintenance was required.

3.      Only used for specific purposes.

THIRD GENERATION

·         Introduction:

1.      1965-1971 is the period of third generation computer.

2.      These computers were based on Integrated circuits.

3.      IC was invented by Robert Noyce and Jack Kilby In 1958-1959.

4.      IC was a single component containing number of transistors.

·         Few Examples are:

1.      PDP-8

2.      PDP-11

3.      ICL 2900

4.      IBM 360

5.      IBM 370

·         Advantages:

1.      These computers were cheaper as compared to second-generation computers.

2.      They were fast and reliable.

3.      Use of IC in the computer provides the small size of the computer.

4.      IC not only reduce the size of the computer but it also improves the performance of the computer as compared to previous computers.

5.      This generation of computers has big storage capacity.

6.      Instead of punch cards, mouse and keyboard are used for input.

7.      They used an operating system for better resource management and used the concept of time-sharing and multiple programming.

8.      These computers reduce the computational time from microseconds to nanoseconds.

·         Disadvantages:

1.      IC chips are difficult to maintain.

2.      The highly sophisticated technology required for the manufacturing of IC chips.

3.      Air conditioning is required.

FOURTH GENERATION

·         Introduction:

1.      1971-1980 is the period of fourth generation computer.

2.      This technology is based on Microprocessor.

3.      A microprocessor is used in a computer for any logical and arithmetic function to be performed in any program.

4.      Graphics User Interface (GUI) technology was exploited to offer more comfort to users.

·         Few Examples are:

1.      IBM 4341

2.      DEC 10

3.      STAR 1000

4.      PUP 11

·         Advantages:

1.      Fastest in computation and size get reduced as compared to the previous generation of computer.

2.      Heat generated is negligible.

3.      Small in size as compared to previous generation computers.

4.      Less maintenance is required.

5.      All types of high-level language can be used in this type of computers.

·         Disadvantages:

1.      The Microprocessor design and fabrication are very complex.

2.      Air conditioning is required in many cases due to the presence of ICs.

3.      Advance technology is required to make the ICs.

FIFTH GENERATION

·         Introduction:

1.      The period of the fifth generation in 1980-onwards.

2.      This generation is based on artificial intelligence.

3.      The aim of the fifth generation is to make a device which could respond to natural language input and are capable of learning and self-organization.

4.      This generation is based on ULSI(Ultra Large Scale Integration) technology resulting in the production of microprocessor chips having ten million electronic component.

·         Few Examples are:

1.      Desktop

2.      Laptop

3.      NoteBook

4.      UltraBook

5.      Chromebook

·         Advantages:

1.      It is more reliable and works faster.

2.      It is available in different sizes and unique features.

3.      It provides computers with more user-friendly interfaces with multimedia features.

·         Disadvantages:

1.      They need very low-level languages.

2.      They may make the human brains dull and doomed.

Computer Input and Output Devices

Input Devices

v  The devices which are used to give data and instructions to the computer are called Input Devices.

Keyboard

v  It is the most commonly used input device.

v  It is used to enter data and instructions directly into the computer.

v  There are 104 buttons on the keyboard which are called keys.

Mouse

v  Mouse is another input device which is commonly found connected with the computers.

v  It is basically a pointing device which works on the principle of Point and Click.

Joystick and Game-pad

v  Joystick and game-pad are also input devices which are also input devices which are used to control the movement of object on the screen. J

v  ust like mouse, these are also pointing devices.

v   Mostly they are used for playing games on the computer.

Light Pen

v  Light pen is another pointing type input device.

v  It is a pen shaped device which can be used by directly pointing the objects on the screen.

v  It can also be used for making drawings directly on the monitor screen.

Scanner

v  We can store pictures, photographs, diagrams into the computer with the help of scanner.

v  The scanner reads the image and saves it in the computer as a file.

Touchscreen

v  Touchscreen is a special computer screen that takes the input by sensing the touch of a human finger, gloved hand, stylus, pen or any other pointing device.

v  The user gives instructions to the computer just by touching the screen.

Microphone

v  This is an input device which is used to record sound or voice into the computer system.

v  You can store voice data in the computer by speaking in front of this device.

Trackball

v  A trackball is similar to a mouse but is mounted in a fixed position.

v  The user spins the ball with fingers to move the pointer on the screen.

v  A Trackball technology was used in earlier laptop computer which is now replaced with track-pad.

Output Devices

v  The devices which are used to display the results or information are called Output Devices.

v  You can view the output on the monitor or you can print it on a paper using a printer.

v  Monitor and the printer are the commonly used output devices.

Monitor

v  This is the most common output device connected with the computer to display the processed information.

v  It looks like a TV and is also known as VDU(Visual Display Unit). 

v  Pictures are displayed by using a large number of very small dots on screen called pixels.

v  The number of pixels that a monitor can show on its screen is referred to as the resolution of the screen. 

The two commonly used monitor types are:

1.      Cathode Ray Tube(CRT)Monitor

2.      Liquid crystal Display(LCD)Monitor

Printer

v  This is an important output device of the computer system. 

v  It gives a printed output of the results that appears on the monitor screen.

v  Printed output is also called Hard Copy output because unlike monitor, this output can be preserved even if the computer is switched off.

Speaker

v  Speakers are categorised as output devices.

v  These are used to listen to the music and sounds played by the computer.

v  Normally they come in a pair and have different shapes and sizes.

Plotter

v  We can get the print of a photograph, drawing, image stored in the computer, by using a plotter.

v  It is an output device which provides a high quality of printed output.

v  It is generally used by engineers and architects.

Types of Computer

We can categorize computer by two ways: data handling capabilities and size.

On the basis of data handling capabilities, the computer is of three types:

• Analogue Computer
• Digital Computer
• Hybrid Computer

1) Analogue Computer

v  Analogue computers are designed to process the analogue data.

v  Analogue data is continuous data that changes continuously and cannot have discrete values such as speed, temperature, pressure and current.

v  Analogue computers directly accept the data from the measuring device without first converting it into numbers and codes.

v  Speedometer and mercury thermometer are examples of analogue computers.

2) Digital Computer

v  Digital computer is designed to perform calculations and logical operations at high speed.

v  It accepts the raw data as digits or numbers and processes it with programs stored in its memory to produce output.

v   All modern computers like laptops and desktops that we use at home or office are digital computers.

3) Hybrid Computer

v  Hybrid computer has features of both analogue and digital computer.

v  It is fast like analogue computer and has memory and accuracy like digital computers.

v  It can process both continuous and discrete data.

v  So it is widely used in specialized applications where both analogue and digital data is processed.

v  For example, a processor is used in petrol pumps that converts the measurements of fuel flow into quantity and price.

On the basis of size, the computer can be of five types:

1) Supercomputer

v  Supercomputers are the biggest and fastest computers.

v  They are designed to process huge amount of data.

v  A supercomputer can process trillions of instructions in a second.

v   It has thousands of interconnected processors.

v  Supercomputers are particularly used in scientific and engineering applications such as weather forecasting, scientific simulations and nuclear energy research.

v  First supercomputer was developed by Roger Cray in 1976.

2) Mainframe computer

v  Mainframe computers are designed to support hundreds or thousands of users simultaneously.

v  They can support multiple programs at the same time.

v  It means they can execute different processes simultaneously.

v  These features of mainframe computers make them ideal for big organizations like banking and telecom sectors, which need to manage and process high volume of data.

3) Miniframe computer

v  It is a midsize multiprocessing computer.

v  It consists of two or more processors and can support 4 to 200 users at one time.

v  Miniframe computers are used in institutes and departments for the tasks such as billing, accounting and inventory management.

4) Workstation

v  Workstation is a single user computer that is designed for technical or scientific applications.

v  It has faster microprocessor, large amount of RAM and high speed graphic adapters.

v  It generally performs a specific job with great expertise; accordingly, they are of different types such as graphics workstation, music workstation and engineering design workstation.

5) Microcomputer

v  Microcomputer is also known as personal computer.

v  It is a general purpose computer that is designed for individual use.

v  It has a microprocessor as a central processing unit, memory, storage area, input unit and output unit.

v  Laptops and desktop computers are examples of microcomputers.