OVERVIEW Today’s world is an information-rich world and it has become a necessity for everyone to know about computers. Purpose of this tutorial is to.

OVERVIEWToday’s world is an information-rich world and it has become a necessity for everyone to know about computers. Purpose of this tutorial is to introduce you about computer and its fundamentals.

After completing this tutorial you will find yourself at a moderate level of expertise in knowledge of computer basics from where you can take yourself to next levels

DEFINITION COMPUTER

• An electronic device that can follow instruction to accept input, process that input and produce information.

• We can define computer as a device that transforms data.

• It can also simply be defined as an electronic machine that takes data, stores it, processes that data and produces information.

Computer is an advanced electronic device that takes raw data as input from the user and processes it under the control of set of instructions (called program), gives the result (output), and saves it for the future use

ADVANTAGES OF A COMPUTER TODAY

High Speed• Computer is a very fast device.• It is capable of performing calculation of very

large amount of data.• The computer has units of speed in microsecond,

nanosecond, and even the picosecond.• It can perform millions of calculations in a few

seconds as compared to man who will spend many months for doing the same task

Accuracy• In addition to being very fast, computers are

very accurate.• The calculations are 100% error free.• Computers perform all jobs with 100%

accuracy provided that correct input has been given.

Storage Capability• Memory is a very important characteristic of

computers.• A computer has much more storage capacity

than human beings.• It can store large amount of data.• It can store any type of data such as images,

videos, text, audio and many others.

Diligence• Unlike human beings, a computer is free from

monotony, tiredness and lack of concentration.

• It can work continuously without any error and boredom.

• It can do repeated work with same speed and accuracy.

Versatility• A computer is a very versatile machine.• A computer is very flexible in performing the

jobs to be done.• This machine can be used to solve the problems

related to various fields.• At one instance, it may be solving a complex

scientific problem and the very next moment it may be playing a card game.

Reliability• A computer is a reliable machine.• Modern electronic components have long

lives.• Computers are designed to make maintenance

easy.

Automation• Computer is an automatic machine.• Automation means ability to perform the

given task automatically.• Once a program is given to computer i.e.,

stored in computer memory, the program and instruction can control the program execution without human interaction.

Reduction in Paper Work• The use of computers for data processing in an

organization leads to reduction in paper work and results in speeding up a process.

• As data in electronic files can be retrieved as and when required, the problem of maintenance of large number of paper files gets reduced.

Reduction in Cost• Though the initial investment for installing a

computer is high but it substantially reduces the cost of each of its transaction.

DISADVANTGES

No I.Q• A computer is a machine that has no

intelligence to perform any task.• Each instruction has to be given to computer.• A computer cannot take any decision on its

own.

Dependency• It functions as per a user’s instruction, so it is

fully dependent on human being

Environment• The operating environment of computer

should be dust free and suitable.

No Feeling• Computers have no feelings or emotions.• It cannot make judgement based on feeling,

taste, experience, and knowledge unlike a human being

Computer Applications in day to day activities

1.Business

Computer is used in business organizations for:

• Payroll calculations• Budgeting• Sales analysis• Financial forecasting• Managing employees database• Maintenance of stocks etc

2.Banking

Today banking is almost totally dependent on omputer.

Banks provide following facilities:• Banks provide online accounting facility,

which includes current balances, deposits, overdrafts, interest charges, shares, and trustee records.

• ATM machines are making it even easier for customers to deal with banks.

• Banking services through mobile phones

3.Insurance

Insurance companies are maintaining a database of all clients with information showing

• procedure to continue with policies• starting date of the policies• next due installment of a policy• maturity date• interests due• survival benefits• Bonus

4.EducationThe computer has provided a lot of facilities in

the education system.• The computer provides a tool in the

education system known as CBE (Computer Based Education).

• CBE involves control, delivery, and evaluation of learning.

• Online learning, online library-books• Downloading learning materials and

simulations.• It is used to prepare a database about

performance of a student and analysis is carried out on this basis.

5.Marketing

In marketing, uses of computer are following:• Advertising - With computers, advertising

professionals create art and graphics, write and revise copy, and print and disseminate ads with the goal of selling more products.

• At Home Shopping - Home shopping has been made possible through use of computerised catalogues that provide access to product information and permit direct entry of orders to be filled by the customers.

6.Health Care

• Computers have become important part in hospitals, labs, and dispensaries.

• Computers are being used in hospitals to keep the record of patients and medicines.

• It is also used in scanning and diagnosing different diseases. ECG, EEG, Ultrasounds and CT Scans etc., are also done by computerized machines.

Some major fields of health care in which computers are used are:•Diagnostic System - Computers are used to collect data and identify cause of illness.•Patient Monitoring System - These are used to check patient's signs for abnormality such as in Cardiac Arrest, ECG etc.•Pharma Information System - Computer checks Drug-Labels, Expiry dates, harmful drug’s side effects etc.•Surgery : Nowadays, computers are also used in performing surgery.•Lab-diagnostic System - All tests can be done and reports are prepared by computer.

7.Engineering Design

Computers are widely used in Engineering purpose. One of major areas is CAD (Computer aided design). That provides creation and modification of images.

Some fields are:• Structural Engineering - Requires stress and strain

analysis for design of Ships, Buildings, Budgets, Airplanes etc.

• Industrial Engineering - Computers deal with design, implementation and improvement of integrated systems of people, materials and equipments.

• Architectural Engineering - Computers help in planning towns, designing buildings, determining a range of buildings on a site using both 2D and 3D drawings.

8.Military

Computers are largely used in defence. Modern tanks, missiles, weapons etc. Military also employs computerized control systems. Some military areas where a computer has been used are:

• Missile Control• Military Communication• Military Operation and Planning• Smart Weapons

9.Communication

Some main areas are:• E-mail• Chatting• Video-conferencing

10.Government

Computers play an important role in government. Some major fields in this category are:

• Budgets• Sales tax department• Income tax department• Male/Female ratio• Computerization of voters lists• Computerization of driving licensing system• Computerization of health insurance• Weather forecasting

Summary on the uses/application of computer

There are two uses of computer, these are • General purpose computer is design to solve

wide variety of problems. Examples of general purpose computer are

• School computers • Hospital computers • Office computers

Special purpose computer is designed for particular job only to solve problem of restricted nature. Examples of special purpose computer are o Petroleum pumps 1.Traffic lights 2.Programmable pocket calculator 3.Weapons guidance system

COMPUTER GENERATIONS

Generation in computer terminology is a change in technology a computer is/was being used.

First Generation• The period of first generation was 1946-1959. The

computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit).

• These tubes, like electric bulbs, produced a lot of heat and were prone to frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organisations.

The main features of first generation are:• Vacuum tube technology• Unreliable• Supported machine language only• Very costly• Generated lot of heat• Huge size• Need of A.C.• Non-portable• Consumed lot of electricity

Some computers of this generation were:• ENIAC• EDVAC• UNIVAC• IBM-701• IBM-650

Second Generation• The period of second generation was 1959-

1965. • In this generation transistors were used that

were cheaper, consumed less power, more compact in size, more reliable and faster than the first generation machines made of vacuum tubes.

• In this generation, magnetic cores were used as primary memory and magnetic tape and magnetic disks as secondary storage devices.

• In this generation assembly language and high-level programming languages like FORTRAN, COBOL were used.

• The computers used batch processing and multiprogramming operating system.

The main features of second generation are:• Use of transistors• Reliable in comparison to first generation computers• Smaller size as compared to first generation computers• Generated less heat as compared to first generation

computers• Consumed less electricity as compared to first generation

computers• Faster than first generation computers• Still very costly• A.C. needed• Supported machine and assembly languages

Some computers of this generation were:• IBM 1620• IBM 7094• CDC 1604• CDC 3600• UNIVAC 1108

Third GenerationThe period of third generation was 1965-1971. The computers of third generation used integrated circuits (IC's) in place of transistors.

A single IC has many transistors, resistors and capacitors along with the associated circuitry.

The IC was invented by Jack Kilby. This development made computers smaller in

size, reliable and efficient. In this generation remote processing, time-

sharing, multi-programming operating system were used.

High-level languages were used during this generation.

The main features of third generation are:• IC used• More reliable in comparison to previous two generations• Smaller size• Generated less heat• Faster• Lesser maintenance• Still costly• A.C needed• Consumed lesser electricity• Supported high-level language

Some computers of this generation were:• IBM-360 series• Honeywell-6000 series• PDP(Personal Data Processor)• IBM-370/168• TDC-316

Fourth Generation• The period of fourth generation was 1971-

1980. • The computers of fourth generation used Very

Large Scale Integrated (VLSI) circuits. • VLSI circuits having about 5000 transistors and

other circuit elements and their associated circuits on a single chip made it possible to have microcomputers of fourth generation

• Fourth generation computers became more powerful, compact, reliable, and affordable.

• As a result, it gave rise to personal computer (PC) revolution.

• In this generation time sharing, real time, networks, distributed operating system were used.

• All the high-level languages like C, C++, DBASE etc., were used in this generation.

The main features of fourth generation are:• VLSI technology used• Very cheap• Portable and reliable• Use of PC's• Very small size• Pipeline processing• No A.C. needed• Concept of internet was introduced• Great developments in the fields of networks• Computers became easily available

Some computers of this generation were:• DEC 10• STAR 1000• PDP 11• CRAY-1(Super Computer)• CRAY-X-MP(Super Computer)

Fifth Generation• The period of fifth generation is 1980-till date. In

the fifth generation, the VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components.

• This generation is based on parallel processing hardware and AI (Artificial Intelligence) software

• AI is an emerging branch in computer science, which interprets means and method of making computers think like human beings.

• All the high-level languages like C and C++, Java, .Net etc., are used in this generation.

AI includes:• Robotics• Neural Networks• Game Playing• Development of expert systems to make decisions in real

life situations.• Natural language understanding and generation.

The main features of fifth generation are:• ULSI technology• Development of true artificial intelligence• Development of Natural language processing• Advancement in Parallel Processing• Advancement in Superconductor technology• More user friendly interfaces with multimedia

features• Availability of very powerful and compact

computers at cheaper rates

Some computer types of this generation are:• Desktop• Laptop• NoteBook• UltraBook• ChromeBook

TYPES OF COMPUTERS

Computers are classified according to Size and Power

Microcomputer -Personal Computer (PC)

Personal computer (PC) is a small, relatively inexpensive computer designed for an individual user.

All are based on the microprocessor

technology that enables manufacturers to put an entire Central Processing Unit (CPU) on one chip

PC Types

Classified by size and portability as follows:1.Desktop and tower2.Portable

Desktop or tower?

• These are computers which are placed on a table and do not have battery for power.

• They can be generally classified by their chassis / case (housing). The chassis or case is the metal frame that serves as the structural support for electronic components

• There are two basic flavors of chassis designs–desktop models and tower models

Tower model The term refers to a computer in which the power supply, motherboard, and mass storage devices are stacked on top of each other in a cabinet.

Tower model computers are narrow and tall.

The main advantage of tower models is that there are fewer space constraints, which makes installation of additional storage devices easier.

Desktop modelA computer designed to fit comfortably on top of a desk, typically with the monitor sitting on top of the computer (case).

Desktop model computers are broad and low.

Desktop models designed to be very small are sometimes referred to as slimline models.

TOWER DESKTOP

Portable Computer

• A portable computer is a computer that is designed to be moved from one place to another. Is a mobile computer.

• Portable computers, because of their size, are also commonly known as 'Lunchbox' or 'Luggable' computers. They can also be called a 'Portable Workstation' or 'Portable PC‘

• Has onboard battery which can store power for several hours.

Example:•Laptops •notebooks •Personal Digital Assistants (PDA)•Tablet Computers •Cell Phones

•Personal Digital Assistants (PDA) a handheld device that combines computing, telephone/fax, Internet and networking features. A typical PDA can function as a cellular phone, fax sender, Web browser and personal organizer. PDAs may also be referred to as a palmtop, hand-held computer or pocket computer.

PDAs were largely discontinued in the early 2010s after the widespread adoption of highly capable, in particular iOS and Android-based, smartphones.

iOS is a mobile operating system developed by Apple. It was originally named the iPhone OS, but was renamed to the iOS in June, 2009. The iOS currently runs on the iPhone, iPod touch, and iPod.

SmartphoneA cellphone and handheld computer that created the greatest tech revolution since the Internet. A smartphone can do everything a personal computer can do, and because of its mobility, much more. Although screen size is a limitation, the increasingly higher resolutions make viewing pleasurable and voice recognition can eliminate a fair amount of typing.

An Android phone is a Smartphone running on Google's open-source Android operating system.

tablets

Minicomputer

• A multi-user computer capable of supporting several users simultaneously.

• Used as servers in Local Area Network(LAN

Mainframe

• A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.

• Used in centralized database e.g. Banks.• Also used as servers in Wide Area Network

(WAN).

Supercomputer

• An extremely fast computer that can perform hundreds of millions of instructions per second.

• The most expensive.• Used for:– Weather forecasting– Remote sensing– Biomedical research– Aircraft design – nuclear energy research– Scientific simulation (animations)– analysis of geological data (e.g. in petrochemical

prospecting)

COMPUTER HARDWARE AND SOFTWARE

Hardware

• Hardware represents the physical and tangible components of a computer i.e. the components that can be seen and touched.

• Examples of Hardware are following:• Input devices -- keyboard, mouse etc.• Output devices -- printer, monitor etc.• Secondary storage devices -- Hard disk, CD, DVD etc.• Internal components -- CPU, motherboard, RAM

etc.

Computer Software

Software is a set of programs, which is designed to perform a well-defined function. A program is a sequence of instructions written to solve a particular problem.

There are two types of software• System Software• Application Software

System Software

The system software is collection of programs

designed to operate, control, and extend the processing capabilities of the computer itself. System software are generally prepared by computer manufactures.

System software serves as the interface

between hardware and the end users.

Without systems software installed in our computers we would have to type the instructions for everything we wanted the computer to do!

Some examples of system software are Operating System:i. MacOSii. Windowsiii. Linux

Utilities Utility programs, commonly referred to as just

"utilities," are software programs that add functionality to your computer or help your computer perform better.

These include antivirus, backup, disk repair, file management, security, and networking programs.

Utilities can also be applications such as screensavers, font and icon tools, and desktop enhancements.

Application software

• Application software, or simply applications, are often called productivity programs or end-user programs because they enable the user to complete tasks such as creating documents, spreadsheets, databases, and publications, doing online research, sending email, designing graphics, running businesses, and even playing games!

• Application software is specific to the task it is designed for and can be as simple as a calculator application or as complex as a word processing application.

•An application program (often just called an application or app) performs a particular function for the user. Examples (among many possibilities) include browsers, email clients, word processors and spreadsheets.More examples:• Payroll Software•Student Record Software•Inventory Management Software•Income Tax Software•Railways Reservation Software•Microsoft Office Suite Software e.g. Microsoft Word Microsoft Excel Microsoft Powerpoint

Parts of computer system

Ports

INTERNAL COMPONENTS OF A COMPUTER

Power Supply The power supply as its name might suggest is

the device that supplies power to all the components in the computer. Its case holds a transformer, voltage control, and (usually) a cooling fan. The power supply converts about 100-120 volts of AC power to low-voltage DC power for the internal components to use.

Motherboard The motherboard is the body or mainframe of the computer,

through which all other components interface. It is the central circuit board making up a complex electronic system. A motherboard provides the electrical connections by which the other components of the system communicate

CPU

The Central Processing Unit (CPU; sometimes just called processor) is a machine that can execute computer programs. It is sometimes referred to as the brain of the computer.

Is the brain of the computer.

RAM

Random access memory (RAM) is fast-access memory that is cleared when the computer is power-down. RAM attaches directly to the motherboard, and is used to store programs that are currently running. RAM is a set of integrated circuits that allow the stored data to be accessed in any order (why it is called random).

Video Card

• Unless the motherboard comes with a built-in video card, we will have to install a separate video card into the computer system. Graphic or video cards are typically needed to deal with PC gaming, high definition video and multiple displays.

Sound Card

• Sound cards enable the computer to output, record and manipulate sound. Now it is common to have a bult-in sound card on motherboards, when talking about personal computers.

Expansion Slots

• The next components are the expansion slots. PCs are customizable and they're modular. If we want our PC to perform some additional function, we can add expansion board and install it in one of these expansion slots.

Hard Disk Drive

• Hard disks are the most popular type of internal storage. A hard disk drive (HDD) is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces. Just about every new computer comes with a hard disk these days unless it comes with a new solid-state drive.

• Hard disk drives are accessed over one of a number of bus types, including parallel ATA(also called IDE), Serial ATA (SATA), SCSI, Serial Attached SCSI, and Fibre Channel.

CD and Floppy drives for storage

In addition, we also have our DVD or CD drives and floppy drives

CD-ROM Drive

There are two types of devices in a computer that use CDs: CD-ROM drive and a CD writer. The CD-ROM drive used for reading a CD. The CD writer drive can read and write a CD.

CD writers are much more popular modern computers than a CD-ROM drive.

Both kinds of CD drives are called optical disc drives because they use a laser light or electromagnetic waves to read or write data to or from a CD.

DVDs (digital versatile discs) Are another popular optical disc storage media format. The main uses for DVDs are video and data storage. Most DVDs are of the same dimensions as compact discs. Just like CDs there are many different variations. DVD-ROM has data which can only be read and not written. DVD-R and DVD+R can be written once and then function as a DVD-ROM.

DVD-Video and DVD-Audio discs respectively refer to properly formatted and structured video and audio content. The devices that use DVDs are very similar to the devices that use CDs.

DVD

Blu-rayBlu-ray is a newer optical disc storage media format. Its main uses are high-definition video and data storage. The disc has the same dimensions as a CD or DVD. The term “Blu-ray” comes from the blue laser used to read and write to the disc. The Blu-ray discs can store much more data then CDs or DVDs. A dual layer Blu-ray disc can store up to 50GB, almost six times thecapacity of a dual layer DVD. Blu-ray discs have similar devices used to read them and write to them as CDs have.

USB FLASH DRIVE

• A USB flash drive, is a data storage device that includes flash memory with an integrated Universal Serial Bus (USB) interface. USB flash drives are typically removable and rewritable, and physically much smaller than an optical disc.

• USB flash drives are often used for the same purposes for which floppy disks or CDs were used, i.e., for storage, data back-up and transfer of computer files.

Network Interface Card

A network interface card (NIC) is a circuit board or card that is installed in a computer so that it can be connected to a network.

CMOS BATTERY

FUNCTIONALITIES OF A COMPUTER

A computer performs basically five major operations or functions irrespective of their size and make.These are:

1. Takes data as input.2. Stores the data/instructions in its memory and use

them when required.3. Processes the data and converts it into useful

information.4. Generates the output.5. Controls all the above four steps.

Input Unit

This unit contains devices with the help of which we enter data into computer.

This unit makes link between user and computer.

The input devices translate the information into the form understandable by computer.

CPU (Central Processing Unit)

- CPU is considered as the brain of the computer. - CPU performs all types of data processing

operations. - It stores data, intermediate results and

instructions(program). -It controls the operation of all parts of computer.

CPU itself has following two components• ALU(Arithmetic Logic Unit)• Control Unit

ALU(Arithmetic Logic Unit)This unit consists of two subsections namely•Arithmetic section•Logic Section

Arithmetic SectionFunction of arithmetic section is to perform arithmetic operations like addition, subtraction, multiplication and division.

All complex operations are done by making repetitive use of above operations.

Logic SectionFunction of logic section is to perform logic operations such as comparing, selecting, matching and merging of data.

Output Unit

• Output unit consists of devices which help users to get information from the computer.

• This unit is a link between computer and users.

• Output devices translate the computer's output into the form understandable by users.

COMPUTER PERIPHERALS

Definition• A peripheral is a "device that is used to put

information into or get information out of the computer

• A computer peripheral is any external device that provides input and output for the computer

• A peripheral device connects to a computer system to add functionality. Examples are a mouse, keyboard, monitor, printer and scanner.

• A peripheral device is generally defined as any auxiliary device such as a computer mouse or keyboard that connects to and works with the computer in some way.

Types of Peripherals There are two different types of peripherals: input devices, which interact with or send data to the

computer (mouse, keyboards, etc.) This unit makes link between user and computer. The input

devices translate the information into the form understandable by computer.

output devices, which provide output to the user from the computer (monitors, printers, etc.).

Output devices translate the computer's output into the form understandable by users.

Some peripherals, such as touchscreens, can be used both as

input and output devices.

Computer peripherals, or peripheral devices, are sometimes called "I/O devices" because they provide input and output for the computer. Some peripherals, such as external hard drives, provide both input and output for the computer.

118

2.Input Devices

•Used by a person to communicate to a computer.

Person to computer

119

Output Devices

•Displays information from the computer to a person.

Input devices• keyboard• mouse• touchscreen• pen tablet• joystick• MIDI keyboard• scanner• digital camera• video camera• Microphone• Biometric machines e.g.BVR• Smartphones • Magnetic Ink Card Reader(MICR)• Optical Character Reader(OCR)• Bar Code Reader• Optical Mark Reader(OMR)

Output devices

• monitor• projector• TV screen• printer• plotter• speakers

Both input and output Example:• external hard drives• media card readers• digital camcorders• digital mixers• MIDI equipment

Keyboard

• Keyboard is the most common and very popular input device which helps in inputting data to the computer. The layout of the keyboard is like that of traditional typewriter, although there are some additional keys provided for performing additional functions.

• Keyboards are of two sizes 84 keys or 101/102 keys, but now keyboards with 104 keys or 108 keys are also available for Windows and Internet.

123

Keyboard

• The keyboard allows the computer user to enter words, numbers, punctuation, symbols, and special function commands into the computer’s memory.

Mouse

Mouse is most popular pointing device. It is a very famous cursor-control device having a small palm size box with a round ball at its base which senses the movement of mouse and sends corresponding signals to CPU when the mouse buttons are pressed.

Joystick

• Joystick is also a pointing device which is used to move cursor position on a monitor screen. It is a stick having a spherical ball at its both lower and upper ends. The lower spherical ball moves in a socket. The joystick can be moved in all four directions.

• The function of joystick is similar to that of a mouse. It is mainly used in Computer Aided Designing(CAD) and playing computer games.

Light Pen

• Light pen is a pointing device which is similar to a pen. It is used to select a displayed menu item or draw pictures on the monitor screen. It consists of a photocell and an optical system placed in a small tube. When the tip of a light pen is moved over the monitor screen and pen button is pressed, its photocell sensing element detects the screen location and sends the corresponding signal to the CPU.

Track Ball

• Track ball is an input device that is mostly used in notebook or laptop computer, instead of a mouse. This is a ball which is half inserted and by moving fingers on ball, pointer can be moved. Since the whole device is not moved, a track ball requires less space than a mouse. A track ball comes in various shapes like a ball, a button and a square.

Scanner

• Scanner is an input device which works more like a photocopy machine.

• It is used when some information is available on a paper and it is to be transferred to the hard disc of the computer for further manipulation.

• Scanner captures images from the source which are then converted into the digital form that can be stored on the disc.

• These images can be edited before they are printed. A scanner can be used to input pictures and text into a computer. There are two main types of scanner; Hand-held and Flat-bed.

Digitizer

• Digitizer is an input device which converts analog information into digital form.

• Digitizer can convert a signal from the television or camera into a series of numbers that could be stored in a computer.

• They can be used by the computer to create a picture of whatever the camera had been pointed at.

• Digitizer is also known as Tablet or Graphics Tablet because it converts graphics and pictorial data into binary inputs.

• A graphic tablet as digitizer is used for doing fine works of drawing and image manipulation applications.

139

Digital cameraA digital camera can store many more pictures than an ordinary camera. Pictures taken using a digital camera are stored inside its memory and can be transferred to a computer by connecting the camera to it. A digital camera takes pictures by converting the light passing through the lens at the front into a digital image.

Microphone

• Microphone is an input device to input sound that is then stored in digital form.

• The microphone is used for various applications like adding sound to a multimedia presentation or for mixing music.

143

Microphones - Speech Recognition

•Use a microphone to talk to your computer

•Add a sound card to your computer•Sound card digitizes audio

input into 0/1s •A speech recognition program can

process the input and convert it into machine-recognized commands or input

144

Audio Input: Speech Recognition• Speech recognition is a type

of input in which the computer recognizes words spoken into a microphone.

• Special software and a microphone are required.

• Latest technology uses continuous speech recognition where the user does not have to pause between words.

145

Microphones - Speech Recognition

Magnetic Ink Card Reader(MICR)

• MICR input device is generally used in banks because of a large number of cheques to be processed every day.

• The bank's code number and cheque number are printed on the cheques with a special type of ink that contains particles of magnetic material that are machine readable.

• This reading process is called Magnetic Ink Character Recognition (MICR).

• The main advantages of MICR is that it is fast and less error prone.

Optical Character Reader(OCR)

• OCR is an input device used to read a printed text. OCR scans text optically character by character, converts them into a machine readable code and stores the text on the system memory.

Bar Code Readers

• Bar Code Reader is a device used for reading bar coded data (data in form of light and dark lines).

• Bar coded data is generally used in labelling goods, numbering the books etc.

• It may be a hand held scanner or may be embedded in a stationary scanner.

• Bar Code Reader scans a bar code image, converts it into an alphanumeric value which is then fed to the computer to which bar code reader is connected.

Optical Mark Reader(OMR)

• OMR is a special type of optical scanner used to recognize the type of mark made by pen or pencil.

• It is used where one out of a few alternatives is to be selected and marked.

• It is specially used for checking the answer sheets of examinations having multiple choice questions.

1.Pointing stick

2.Touch pad

3.Touch screen

Output devices

156

Monitors

• A monitor is a peripheral device which displays computer output on a screen.

• Screen output is referred to as soft copy.• Types of monitors:

– Cathode-ray tube (CRT)– Liquid Crystal Display (LCD or flat-panel)

CRT LCD

157

Monitors• CRT – cathode ray tube• electron gun shoots a stream of electrons at a specially

phosphor-coated screen• on impact, the phosphor flares up for a fraction of a second• electron gun sweeps across the screen many times a second

• LCD – liquid crystal display • one of several types of “flat-panel” displays• forms output by solidifying crystals and “backlighting” the

image with a light source– Some TV sets are CRTs and many desktop monitors

use this technology – LCD is primarily used for laptops and other portable

devices and TV (flat screen).

158

Video Display Terminology• Pixel – picture element (smallest unit of an

image, basically a single dot on the screen)

• Resolution – number of pixels in the image – Common resolution size is 1024x768 – Refresh rate

• how often a CRT’s electron gun rescans • LCD displays do not use an electron gun, so

do not perform refreshing

The CRT electron gun “shoots” 3 electrons at the screen representing the amount of red, green and blue for the pixel

160

Printers

• Ink Jet Printer– least expensive, color, slower with a higher per page cost

than laser printers • Laser Printer– More expensive, faster, lower per page cost than ink jet,

161

Printers

• A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.

162

Types of Printers

• Inkjet printer, also called a bubble-jet, makes characters by inserting dots of ink onto paper

• Letter-quality printouts • Cost of printer is inexpensive

but ink is costly

• Laser printer works like a copier

• Quality determined by dots per inch (dpi) produced

• Color printers available • Expensive initial costs but

cheaper to operate per page

Inkjet Laser

164

Plotter

• A plotter is a printer that uses a pen that moves over a large revolving sheet of paper.

• It is used in engineering, drafting, map making, and seismology.

Projector

• A projector is an output device that can take images generated by a computer and reproduce them on a large, flat (usually lightly colored) surface.

• For example, projectors are used in meetings to help ensure that all participants can view the information being presented