Computer Basics ( Input Device and Output Device)

Basic Components of a Computer

 

Working of Computer 

•          Computers follow the basic principle of the Input-Process-Output (I-P-O) cycle.

•          Input refers to data or instructions given to the computer.

•          Output refers to the result given by the computer.

•          Process refers to the work done by the computer to obtain the output.

Input Devices

•          The input is given to the computer by means of input devices.

•          Keyboard, Mouse, Scanner, Barcode reader, Web cam, and Microphone are some of the commonly used input devices.

Keyboard and Mouse Connectors

•          The keyboard and mouse are connected to the computer by using PS/2, serial ports or a USB port.

•          The PS/2 keyboard and mouse ports are 6-pin ports.

•          To avoid confusion between the two ports, the system case usually has symbols and colour coding. The green colour port is used for mouse and the purple colour port is used for keyboard.

Keyboard

•          A keyboard is used for typing text into the computer.

•          A computer keyboard is similar to a typewriter keyboard but has some additional keys.

•          The most commonly available computer keyboard has 104 keys.

•          Based upon their connection to the motherboard, keyboards are classified into:

–        PS/2 keyboard

–        USB keyboard

–        Wireless keyboard

Mouse

•          Mouse is an input device.

•          It is used to point at and choose things displayed on the monitor.

•          A mouse may have two or three buttons.

•          The most commonly used ones have two buttons – left mouse button and right mouse button. The left button is the most frequently used button.

•          Based upon their connection to the motherboard, mouse is classified into:

–        PS/2 mouse

–        Serial mouse

–        USB mouse

–        Wireless mouse

•          Based on the technology used, mouse can be broadly classified into two categories. They are namely,

–        Mechanical mouse

–        Optical mouse

•         Wireless Keyboard and Mouse

•          Wireless keyboards and mice are powered by small, light weight batteries.

•          The media used to connect to the computer can be through Radio Frequency (RF) waves, Infra Red (IR) signals or through Bluetooth or Industry standard RF.

•          Wireless mouse or keyboard using infra red signals for communicating with the computer need to be in “line of sight” in order to work. 

•          Wireless mice or keyboard using radio frequencies for communication requires two components: a radio transmitter and a radio receiver.

•         Scanner

•          A scanner is a multimedia input device that uses light to read printed information including text, images and bar codes and transfers it to computer in digital format.

•          Scanners can be categorised as:

–        Flatbed scanners

–        Sheet-fed scanners

–        Handheld scanners

–        Drum scanners

Web Camera

•          Web camera or Webcam is a small camera attached to a computer.

•          Webcams connected to PCs can act as Web-accessible cameras with certain software.

•          Webcam can be used for one-to-one live video communication over the Internet, video conferencing and so on.

•          It can capture short videos in predefined length or still images. The captured files can be saved locally and uploaded to an Internet server.

Microphone

•          A microphone is used to record voice or sound. This recorded sound can be stored in a computer in the form of digital signals.

Barcode Reader

•          A barcode reader is an electronic device which optically scans a barcode and translates the data contained in the barcode pattern into data which can be used by a computer or other equipment.

•          Barcode readers are mostly used in shopping malls.

•          This device scans the barcodes present in the product labels to input the price of the products to the billing machine. It is very useful for quick billing.

Output Devices

•          The system unit processes the input given to the computer and gives the output. This output can either be displayed on the monitor or printed on paper using a printer.

Monitor

•          The monitor looks like a television screen.

•          It is also called Visual Display Unit (VDU)

•          It is used to display information from the computer.

•          There are coloured as well as black and white monitors.

•          The monitor displays text and graphics.

•          Based on the technology used, monitor is classified into two types. They are,

–        Cathode Ray Tube (CRT) monitors

–        Liquid Crystal Display (LCD) monitors

Printer

•          A printer is used for transferring data from the computer to the paper.

•          There are colour printers as well as black and white printers. 

•          The different types of printers are Dot Matrix Printers, Inkjet Printer and Laser Printers

                                                Dot matrix Printer              

 Inkjet Printer Laser Printer

Laser Printer 

Types of Printers

Dot Matrix Printer	Inkjet Printer	Laser Printer
Prints characters in the form of dots	Prints fully formed characters	Prints fully formed characters
Speed: 200-540 characters per second	Speed: 4-8 pages per minute	Speed: 4-20 pages per minute
Not very expensive	Moderately priced	Expensive

Touch Screen

•          A touch screen is a computer display screen that is sensitive to human touch.

•          It allows the user to interact with the computer by touching pictures or words displayed on the screen.

•          Touch screens are used to display the output information on the screen as well as to give input by touching the words or pictures on the screen. Thus it is an input/output device.

•          Touch screens are normally used when information has to be accessed with minimum effort.

Computer Basics

Computer Basics

•          Define a computer

•          Understand the use of computers in everyday life

•          Identify the benefits and limitations of computers

•          Understand the different generations of computers

•          Identify the types of computer systems

•          Identify the basic components  of the computer

•          Understand the working of a computer

•          Know about input and output devices

•          Understand the storage capacity of a computer

•          Explain about the various storage media and disk drives

•          Define software

•          List the types of software

•          List the different types of computer languages

•          What is a Computer?

 A computer can be defined as an electronic device that can accept store 

 and process data to produce the required result according to user direction .

        

Uses of a Computer

Computers are used in:

•          Airline and Railway Reservations

•          Medical Diagnosis

•          Weather Forecasting

•          Payment of telephone and electricity bills

•          Banking

•          Manufacturing products like automobiles, shoes, computer cabinets, etc.

•          Cartoon Film Production

•          Space Research

•          Creation of blueprints for houses

•          Benefits and Limitations of a Computer

•          The various benefits of computers are:

•          Speed – 

     Computers are very fast.

•          Accuracy – 

     Computers are very accurate. If the input is right, they never make mistakes.

•          Diligence – 

     Computers never get tired or bored of doing the same task continuously. They work in the same manner all the time.

•          Storage – 

      A computer can store large amounts of information in its memory.

•          Automation –

      If a task has to be performed several times, the computer needs to be instructed only once and it automatically completes the task.

•          The limitations of a computer are:

•          It cannot perform any task on its own. We need to give the computer instructions on exactly what it has to do. 

•          If an unanticipated situation arises, computers will either produce wrong results or abandon the task all together. They do not have the potential to work out alternate solutions.

•         Generations of Computers

The growth of a computer can be classified into five generations of Computers.

•          First Generation

–        The basic component of the first generation of computers was vacuum tubes. A vacuum tube is an electronic device that permitted the processing of digital signals at a faster speed.

•          Second Generation

–        The second generation of computers used a solid-state device called transistor in the place of vacuum tubes. Transistors were very convenient when compared to vacuum tubes.  They were more efficient and cheaper than the vacuum tubes.

•          Third Generation

–        Though transistors were an improvement over the vacuum tube, they still had some limitations. They had complex circuits with numerous connections between the individual transistors.

–        A major breakthrough was achieved when hundreds of transistors were successfully connected together and placed on a single silicon chip called the Integrated Circuit (IC). The use of IC chips in the place of transistors gave birth to third generation of computers.

•          Fourth Generation

–        LSI technology led to the development of Very Large Scale Integration (VLSI) where millions of transistors could be placed on a single chip called the Microprocessor. This was the basic component of fourth generation of computers. The VLSI chips could perform faster calculations

•          Fifth Generation

–        In this generation, researches are focused on developing “thinking computers”. This technology is referred to as Artificial Intelligence. These computers are called the fifth generation computers. The computers you are using now belong to the fifth generation of computers.

Types of Computers

•          Based on the size, cost and performance, computers can classified  into:

–        Micro computers

–        Mini computers

–        Mainframes

–        Super computers

•          Micro Computers

•          Microcomputers are also called as personal computers (PCs).  These computers use microprocessors.

•          They are small in size and they can perform difficult tasks.

•          They are used mainly for desktop publishing, accounting, statistical analysis, graphics designing and project management.

•          The classification of PCs is as follows:

–        Desktops

–        Portables

•          Laptops

•          Notebooks

•          Palmtops

Mini Computers

•          Minicomputers are small general-purpose computers. These computers can perform more complex tasks and cost more than microcomputers.

•          They are larger in size and they have small to medium storage capacity.

•          They are used for processing data and analysing results of experiments. They are also used for controlling and monitoring production processes.

•          Some examples are PDP 11/42 and VAX 11.

Mainframe Computers

•          Mainframes are more powerful than minicomputers.

•          They have high processing speeds and can store large amounts of data. They are used in wide area networks and support hundreds of users. However, these computers consume more electricity.

•          Some examples are IBM 3000 series and Univac 1180. 

Super Computers

•          Supercomputers are the largest and fastest computers. They are also the costliest computers.

•          They are used in fields like science and defence. These computers are used for designing and launching missiles, weather forecasting, biomedical research, aircraft design and automobile design.

•          There are only a few supercomputers throughout the world. India owns a series of supercomputers called PARAM developed by C-DAC.