01 Basics of Computers

8/12/2019 01 Basics of Computers

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Job Oriented Computer Course Basics of Computers

Rama Krishna Math, Hyderabad Page 1 of 19

I. Basics of Computers

1.1. Introduction

What are computers? What they do? Why would you want to use one?How they evolved? What should you know before using them? Where

they can be used? so on!

Yeah,so m any quest ions in th e mind o f a lay m an and, even, a novice!

Thus, our Course is designed expertly for a beginner to manage an office on his own.

Come on Lets Learn!

1.2. What are Computers?

Computers are machines that perform tasks or calculations according to a set of instructions,

or programs.The word computer is a derived from the termcompute.A computer is electronic equipment, which is capable of creating solutions by

performing complex processing of information without manual intervention and thattoo at a tremendous speed.

Thus, the computer is a general purpose machine that processes data according to a set ofinstructions that are stored internally either temporarily or permanently.

There are various definitions for a computer. It may be defined as above or as any of thefollowing:

A programmable machine that inputs, processes and outputs data.

An electronic device that stores, retrieves and processes data, and can beprogrammed with instructions.

A machine that accepts input, processes it according to specified rules, and

produces output.

Thus the basic stepsin computing are

Input

Process ORProcessing

Output

Store and Retrieve

Now , you got an ideaWhat the computersare!Isnt it?So, lets learn What they do? andWhy you would want to use it?

PROCESSINPUT OUTPUT

STORE&

RETRIEVE


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Basics of Computers Job Oriented Computer Course

Page 2 of 19 RamaKrishna Math, Hyderabad

1.3. What the computer does? Why we need it?

After the evolution of computer, within a short span of time, the entire gamut ofhuman life has changed at an overwhelming pace.

Be it business, academic, defence strategy, budgeting, research, engineering,medicine or space exploration, computers have established themselves as anindispensable part.

Computers play an important role in human lives. The primary purpose of using acomputer is to make life easier.

In the workplace, many people use computers to keep records, analyze data,do research, and manage projects.

The growing popularity of computers has been turned into account by theBusiness World.

In the Academics, the subject of computers is a mandatory part of manyregular courses.

In the field of Medicine, the history of each patient is storedby freeing the doctors

from the burden of storing bundles of paper.

At home, computers are useful for everyone. You can use computers to findinformation, store pictures and music, play games, and communicate with others.

Note The computer commonly used in homes or offices is popularly referred to as

a PCPersonal Computer.

A computer is connected to the Internet (anetwork that links computers around the world)for communicating others (email ElectronicMail), chatting to them(IMInstant Messaging),finding information(Searching), etc.

In the employment arena also, computers haveexercised their influence. The ability to work withcomputers is a necessary pre-requisite for mostof the present job profiles.

1.4. How they are evolved?

After EDVAC (Electronic Discrete Variable Automatic Computer), in 1946, ENIAC (ElectronicNumerical Integrator and Computer)was the first generalpurpose electronic computer.

Physically, ENIACwas enormous, weighing more than 27,000 kilograms andfilling a large room. To process data, ENIAC used about 18,000 vacuum tubes,each the size of light bulb.

Vacuum Tube

EDVAC ENIAC

UNIVAC

Personal Computer (PC)


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1.5. What should we learn first?

We may have considerable expertise only if we learn about the hardwareand software. Computerswork through an interaction of hardwareand software.

1.5.1. Hardware

The computer and all equipment attached to it are called the hardware.

(or)

The physical components of a computer constitute thehardware.

Hardwarerefers to the parts of a computer that you can see and touch,including the case and everything inside it.

The most important piece of hardware is a tiny rectangular chip inside

your computer called the M icroprocessor, which is in

Central Processing Unit (CPU). Itsthe brain of the computer the part

that tr anslates instructions and perf orms calcul ations.

Hardwareitems such as your monitor, keyboard, mouse, printer, and other components, whichare often called Hardware Devicesor Peripherals.

1.5.2. Software

A set of instructions that perform a particular task is called a Program or Software.

(or)The instructions that tell the computer what to do are called software.

Softwarerefers to the instructions, or programs, that tell the hardware what to do.

For example,

a Word Processing Program that you can use to write letters on the computer is a typ e ofsoftware.

The Operating System(OS) like MS Windows is software that manages your computer andthe devices connected to it.

Later, we discuss about Hardware Parts and Software elaborately.

Ti l l now, you are gradual ly becoming famil iar to the computer. Isnt it?So, lets see Where they are usedand theTypes of computers.

1.6. Where they are used?

Already, we have seen the uses of a computer in section 1.3. Specifically mentioning, the computersare used in: -

a) Home Purposes

b) Office Automation

c) Business Accounting

d) Publishing Works (DTP)

e) Schools and Colleges

f) Internet Cafes

g) Traffic-Signaling

h) Defence Purposes

i) Gaming

j) Industries & Factories

and those arejust a few of the appli cations.

Microprocessor Chip (IC)

Hardware (Parts) Software (Programs)

DTPDesktop Publishinge.g. PageMaker, Photoshop,

CorelDraw


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UPSUninterrupted Power Supply

RAMRandom Access Memory

CPUCentral Processing Unit

1.7. Hardware Parts

Hardware is any part of the computer that you can physically touch, pick up, hold, move around theroom etc. Examples of hardware include the monitor, mouse, hard disk, motherboard etc.

The term HARDWARErefers to the physical components of a computer.

The basic configurationof a computer includes

Computer Case

CPU (Mother Board & Pentium chip (IC))

Monitor

Keyboard

Mouse

Printers

Scanners

Disk Drives: USB Drive, CD / DVD, Hard Drive

Memory (RAM)

Speakers

UPS (Uninterrupted Power Supply)

(See in the picture each part in order given)

Before learning about the parts, we first get an idea about

the basic steps in computingand

the block diagram of the computer architecture.

The basic stepsin computing are

Input

Process ORProcessing

Output

Store and Retrieve

The simple Block

diagram of

Computer

Architectureis

Hardware Parts

PROCSSINPUT OUTPUT

STORE&

RETRIEVE

CPU

INPUTDEVICES

OUTPUTDEVICES

SECONDARY

STORAGEDEVICES SSDs

ALU

CU

MMU


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1.8. Input Devices

The Input Devicesare the Devices that input information in the Computer.

Examples

Key Board and Mouse Digital Camera Touch Pad Joystick

Scanner (OCR) Touch Screen Graphics Tablet Microphone

BCR (Bar Code Reader) MICR (Magnetic Ink Character Recognition) Light Pen

You don ' t need in-depth kn ow ledge of each input device but you doneed to recognize, which wo uld be the most s uitable for specif ic types

of data.

Ke board and Mouse Touch Pad Joystick

Di ital Camera

ScannerTouch Screen Gra hics Tablet Microphone

Light PenBar Code

Cheque

Number

Bank

Sort-Code

Account

Number

MICR

OCR Optical Character RecognitionOMR Optical Mark ReaderBCR Bar Code Reader / RecognitionMICR Magnetic Ink Character Recognition

Bar CodeReader /Scanner


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1.10. Output Devices

The Output Devicesare the Devices that output the information from the Computer.

Examples

Monitor(VDU)s

CRT (Cathode Ray Tube) LCD (Liquid Crystalline Display) TFT (Thin Film Transistor)

Printers

DMP (Dot Matrix Printer) LASER Inkjet / Bubble jet

Speaker Plotter Other Output Devices

1.10.1. Monitor

A monitordisplays the information for the user to view them.

The information could be in text or graphical form.

The area in which the information is displayed is called thescreen.

The picture on a monitor is made up of thousands of tiny coloured dotscalled pixels.

There are basically two types of monitors viz.,

CRT Monitors andLCD Monitors.The LCD monitors are being widely used these days.

1.10.2. Printers

Printersare another common output device.

They are used to create a 'hard' copy of your worki.e. something that you can hold, hand to someone else orfile away.

Most printers produce their output on paper.

There are three main types of printers:

Laser printers

Inkjet printers

Dot Matrix (impact) printers

VDU Visual Display Unit

CRT Monitor LCD Monitor TFT Monitor

Monitor

LCD Projector

Speech Synthesizer

S eakers Plotter

Bubble JetDMP LASER Printer


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Laser Printer Inkjet Printers Dot Matrix Printers

1. Non-Impact Printers Non-Impact Printers Impact Printers

2. Faster printingRelatively faster than DMP butslower than Laser

Slower relatively

3. High Quality Medium Quality Poor Quality

4. Use Powered Ink, called TONERCartridges contain INK, bothcolour and black and white

Print Head containing grid ofPINS and Carbon Ribbon

5.Colour version and also Blackand White version available

Colour version and also Blackand White version available

Only Single Colour

6. Cost is Expensive Cost is Cheap Cost is Moderate

7. Print Cost is Moderate Print Cost is Expensive Print Cost is Cheap

1.10.3. Plotter

Plotters are a specialist type of printer, which is able to draw high quality images on very largepieces of paper, for example 3 foot wide by 10 foot long.

They are used by engineers, architectsand map-makers to draw plans of buildings, diagrams ofmachines or large scale maps.

A plotter differs from a printer in that it draws images using a pen.

There are plotters now which are 'pen-less'and are usedfor creating high density drawings.

There are four types of Plotters:

Drum Plotter

Micrographic Plotter

Flatbed Plotter

Inkjet Plotter

1.10.4. Speakers

Most computers are fitted with a small internal speaker which can produce beeping sounds toalert you if you make an error.

Computers can also be fitted with a sound card (or chip) which will enable sound to be outputthrough external speakers.

These usually produce a much higher quality soundthan the internal speaker.

1.10.5. LCD Projector

An LCD Projectortakes the input from a computer and shows it on a large screen.

It is commonly used in organizations for displaying PowerPoi nt presentationduring meetings.

Hardware Table

Recollect all the Hardware Partsonce again. Seethe table below: -

Input devices CPU box Output devices Memory devices /drives

KeyboardMouseScanner(OCR)MicrophoneJoystickOMRBCRMICRSmart Card

Cards: Motherboard,VGA, AGP,Sound, LAN

Cords: Mains, Printer,Monitor

SMPSBuses (cables)Ports: Serial, USB,

Parallel, LPTSocketsIC (chips): Processor, ROMTransistorsCapacitorsDiodesResistors

Monitor: CRT, LCD, TFTPrinter: DMP, Laser,

Inkjet, BubbleJet

SpeakerPlotter: Flatbed, DrumLCD ProjectorSpeech Synthesizer

Hard disk driveFloppy disk driveCD / DVD driveTapesFlash Memory (Pendrive, Memory Card)

Note Input / Output devices are also called

as Peripherals


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1.11. Generations of Computers

First generat ion compu ters, starting with the UNIVAC(UNIVersal Automatic Computer)in 1951, usedvacuum tubes, and their memories were made of thin tubes of liquid mercury and magnetic drums.

Second generat ion sy stems, in the late 1950s, replaced tubes withtransistors and used magnetic cores for memories. Size was reducedand reliability was significantly improved.

Third generat ion com puters, beginning in the mid 1960s, used the first

Integrated Circuits (IC) and the first Operating Systems (OS), andDatabase Management Systems (DBMS).

Fourth generat ion computers, starting in the mid 1970s, are madeentirely of chips. The microprocessor and personal computer arespawned.

Even with the millions of people using computers every day, we are stillin the fourth generation.

The f i f th generat ion implies faster hardware and more sophisticated software that uses ArtificialIntelligence(AI) routinely. You will be in the fifth generation, perhaps in the 20152020 time frames.

1.12. Software

After learning What the Hardware parts are! We start know ing about the next most impo rtantpart of the Compu ters i.e. What is Software? an dWhat are its types?

Come on Lets Learn!

Before that, we would know about Languages, Instruct ions, Programs

1.12.1. Language

A Computer Languageis

a medium for communicat ion between the user and the hardware,so as to make computer work as per the given instructions

1.12.2. Types of Languages:

Machine language

The Machine Language is in 0s and 1si.e. binary digits.

e.g.: ASCII Code for A is 65. Its equivalent binary code is 01100101

It isMachine understandable language.

This is also calledLow level language.

This is thefirst generation language.

011011011 000110000 (Machine Language)

Assembly language

The Assembly language is written using Mnemonics, which are hexadecimal codes for the

characters and instructions (called asHex codes).e.g.: For the instruction ADD 5, 2

Assembly language code is E9 5, 2 (say E9is Mnemonic/Hex Code for ADD)

Super Computer

PDA

Laptop

Second Generation Computer

ASCII American StandardCode for InformationInterchange

It is code for denoting acharacter in bytes.


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This is also calledMiddle level language.

This is thesecond generation language.

The Assembly language code should be translated in to Machine Language. That translatorsoftware is called as anASSEMBLER.

High level language

The High level language is written using English-like words.

e.g.: Add 2, 5

This is also called User language.

This is the third generation language.

The High level language codeshould be translated in toMachine Language. There are two types

of Translatorsfor translating High Level Language. They are Compilersand Interpreters.

Examples of High level languages

ADA, FORTRAN, BASIC, COBOL, PASCAL, C, DBMS

FORTRAN Formula Translation

BASIC Beginners All Purpose Symbolic Instruction code

COBOL Common Business Oriented Language

DBMS Data Base Management System

e.g.: dBase III+, dBase IV, FoxBASE

Forth generation languages (4GLs)

OOP Object OrientedProgramming

e.g.: C++, Java

RDBMS Relational Data BaseManagement System

e.g.: FoxPro, Sybase,Oracle, Ingress, MS Access

Fifth and Sixth generation language

AI Artificial Intelligence e.g. Robotics

OBDBMS Object Oriented Relational DataBase Management System

e.g. Oracle, java,.NET, etc.

1.12.3. InstructionA Ins t ruc t ion is

a comm and given to a computerto make it process as per the given command

1.12.4. Program

A Computer Programis

a sequence / set of commands or ins t ruc t ions given to a comp uterThose commands must be written in an order.

HHiigghhLLeevveell

LLaanngguuaaggee

MMaacchhiinnee

LLaanngguuaaggee

CCoommppiilleerr

IInntteerrpprreetteerror

AAsssseemmbbllyyLLaanngguuaaggee

MMaacchhiinneeLLaanngguuaaggee

AAsssseemmbblleerr


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1.13. Types of Computers

In the section 1.5, you learned the meaning of terms like 'hardware' and 'software'.

This next section will introduce you to the different types of computer available today.

Handheld Computer

Tablet PCServer System

Various Types of Computers

Super Computer MainframeServer

Personal Computer Laptop PDA


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1.14. Software

Softwareis

a set of programsrelated to a particular job / task

1.14.1. Types of Software

Software

System ApplicationSoftware Software

System Software

The System Softwareis thesoftware (programs) required for the overall maintenanceofthe whole computer system and its parts (i.e. hardware), as well as the applicationsoftware.

e.g.: Types of System Software e.g.

Operating system (OS) MS Windows, DOS, OS/2, etc.

BIOS (Basic Input Output system)

Utilities (Utility Programs) Win Zip, Defragmentation, etc.

Drivers Audio, Motherboard, LAN, etc.

DLLs (Dynamic Link Libraries)

Application software

The Application software are the software required

for the user purposeslike office purpose, publishing purpose, hospitals,banking, traffic control, reservations, payroll, games,

entertainment, communication, etc.

Application software can be classified as

General purpose

Specialist

Tailor-made

1.15. Operating System (OS)

An Operating System is

a set of sp ecial ized p rograms,which is used for the overall performance of

not only the CPU and its partsbut also the whole computer system

and maintenance of the application software.

e.g.: MS DOS (Microsoft Disk Operating System)

Unix

MS Windows

Linux

Mac OS

The operating system is needed to control everything happening in your computer.

It controls the memory, the disks, the peripherals and the application software.

. Without the operating system your computer would just sit there doing nothing .

A lication Software


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Here are some of the tasks that an operating system performs:

Here are a few of the other tasks:

Sorting out where to store data on disk drives

Dealing with security - user names and passwords

Organising files and folders

Managing data transfer from the CPU to the peripherals e.g. printer, monitor

Deals with saving, deleting, opening, closing files

1.15.1. Types of Operating System

Single User / Single program OS: Only one User and one Program at a timee.g.: MS DOS

Multi User Operating System: No. of Users at a time and one Servere.g.: Unix

Multi program Operating System: No. of Users and No. of Programs at a timee.g.: MS Windows

CUI Operating SystemIn this operating system, we have to type the characters for the commands

e.g.: MS DOS Unix Part of Linux

GUI Operating System

In this OS, all the commands are seen as small picturescalled graphicse.g.: MS Windows OS / 2 Part of Linux

UserAppl.

S/wOS

H/w

CUI Character User InterfaceGUI Graphical User Interface

The OperatingSystem acts as an

INTERFACEbetweenthe user and the

hardware.

Tasks performed by an Operating System (OS)


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1.16. Memory Devices

It is vital that you have a way of saving the document that you are currently working on.

It is also vital that you cansave software applications that you use on your computer.

This section will introduce you to the different types of memory and storage devices.

The data is stored in the storage devices which are calledMemory.

Memory

Primary Secondary

ROM RAM e.g.: Floppy Disk(Read Only (Random Hard disk

Memory) Access CD(Compact Disk)Memory) DVD (Digital Video Disk)

CacheMemory Flash Memory(Pen

Drive, Memory Card)

1.16.1. System Memory (ROM)

ROMis a special kind of memory which stores theinstructions which the computer uses when i t ' boots up' -

the BIOS(Basic Input Output System).

It allows the computer to check

the type of hard disk installed,

the amount of RAM installed,

the type of CPU being used, etc.

Because the data is 'read only', it can be read but not changed

by the user.

The key thing to remember about ROM is that the data is not erased when the computer is switched off

the data is stored permanently, so it is called 'non volatile memory'

The types of ROM are:

PROM Programmable Read Only Memory

EPROM Erasable Programmable Read Only Memory

EEPROM Electrically Erasable Programmable Read Only Memory

UVPROM Ultraviolet Erasable Programmable Read Only Memory

1.16.2. Short Term Memory (RAM)

RAMis a kind of primary memory which can be read

fromor wri tten toby a computer or other devices.

Information stored in RAM is lost when the computer is

turned off.

This is because RAM is called as 'temporary memory' or'volatile memory'.

Most computers are typically sold with 512 MB - 4 GBofRAM installed.

The types of RAM are:

SDRAM Synchronous Dynamic Random Access Memory

DDR Double Data Rate Synchronous Dynamic Random-Access Memory

The data in the RAMis lost may be when:

The computer is crashed

Accidentally the computer is switched off OR

Power Supply is cut

When you rebooted and logged back in,your work was gone forever.

SO BE CAREFUL ! SAVE YOUR WORK FREQUENTLY!

Read Only Memory (ROM)

Random Access Memory (RAM)


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When you are working with any one or more application software*,

their modules are temporarily stored in RAM while they are

processed by the CPU.

One of the factors that CPUs performance and speed are high is the

capacity of RAM. That is, . the more the capacity of RAM, the higher is theperformance of the CPU .

The External or Secondary Storage Devices (SSDs) are

Blu-ray Disc (BD)

Storage Device Comparison

Storage Device Size / Capacity ComparisonSpeed ofaccess to

data

Cost perGigabyteof storage

RAM and ROM 512 MB2 GB Fastest Very Fast

Floppy Disk 1.44 MB (smallest capacity) Faster Expensive

Zip Disk 100 MB Faster Cheaper

CD 650 MB700 MB Faster Cheaper

Flash memory 1 GB32 GB Faster CheaperDVD 4.7 GB Faster Cheaper

Magnetic Tape Over 100 GB Slowest Cheapest

Hard Disk Around 120 GB1 Terabyte (TB) (largest capacity) More Faster Cheapest

Blu-ray Disc 25 GB128 GB Faster Expensive

Storage Capacity Units

1 Bit (b) 0 or 1

1 Byte (B) 8 bits

1Kilo Byte (KB) 1024 Bytes 210

Bytes

1 Mega Byte (MB) 1024 Kilo Bytes 1024 x 1024 Bytes (210

Bytes)

1 Giga Byte (GB) 1024 Mega Bytes 1024 x 1024 x 1024 Bytes (230

Bytes)

1 Tera Byte (TB) 1024 Giga Bytes 1 MB x 1 MB (240

Bytes)

*We learnApplication Software

in later sessions.

Hard Disk

Floppy Disk Flash Memory

(Pen Drive / MemoryStick

Compact Disk (CD) Digital Versatile / Video

Disk(DVD)


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Wide Area Network (WAN)

1.16.3. What is a network?

A Computer Networkis

formed by joining computers together,and it allows computers or users to transfer files,

to share software and dataand share one printer.

1.16.4. Types of Networks

Local Area Network (LAN)

When the computers are fairly close to one another,

say, in a single office or two buildingsthat are separated by a road,

they can bejoined together either by cables or wireless means.

These computers then form a Local Area Network (LAN).

Once the computers are connected together into a LAN,

many people (users) can share and use the same resourcesat the same time.They can share files, software, hard disks andperipherals such as a printer or CD-ROM.

Users can also use the LANto communicate with each otherby e-mail.

Data can be transmitted very quickly between networkedcomputers.

To log onto a LAN, you usually need a user name and password.

Wide Area Network (WAN)

By linking LANs together, the network is no longer local to one building,it is now spread over a wide area.

It is known as a Wide Area Network (WAN).

So basically a WAN is where individual computers or LANs which are a long distance apart from each otherare connected together.

Many modern companies have offices, shops or factories in various locations around the country, and forlarge corporations, across the world.

Even though staff works in different places, they often need to beable to access the sameinformation no matterwhere they are.

They generally will notshare hardware orsoftware, unlike a LAN.

Do you know!

. The largestWAN in existenceis the Internet .

The user nameidentifies you to the fileserver so that it can 'serve' you the

correct files.

The passwordensures that the username really does belong to you.

Networks


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1.17.2. Firewall

A firewall is a program or a hardware device that can be used to help protect a network from hackers whomight try to break in and gain access to your data.

Internet Terminology

ISP : ISP stands for 'Internet Service Provider'. An ISP is a company that provides Internet access.

Web Pages: A web pageor webpage is a document or information resource that is suitable for theWorld Wide Web and can be accessed through a web browser and displayed on a

monitor.

Web page is a method of viewing both text and pictures on the same page.

Web pages are created using a special programming language called HyperText MarkupLanguageor HTMLfor short.

Web Browsers: A web browser is a software application for retrieving, presenting, and traversinginformation resources on the World Wide Web.

The basic function of a web browser is to all ow you to view text, images, videos fr om web pages.

There are a number of web browsers available. The most popular are Internet Explorer, Firefox,Safari, Operaand Netscape.

Google is NOT a Web Brow ser; it is rather a Search Eng ineWeb Site : A website, also written as Web site, web site, or simply site, is a collection of related

web pages containing images, videos or other digital assets .

A website is hosted on at least one web server, accessible via a networksuch as the Internet.

Browse/Surfing: Searching for Information on the internet or simply exploring the internet iscommonly referred to Surfingor Browsing.

URL : Abbreviation of Uniform Resource Locator; it is the global address of documents andother resources on the World Wide Web.

Blog : A blog(a blend of the term web log) is a type of website or part of a website supposedto be updated with new content from time to time .

Search Engine : A Seach Engine is essentially a database program, which finds out informationand catalogues all web pages on the Internet according to keywords, about aspecific topicyou enter into the search box provided.

Web Pa es

Mostly used Web Browsers

OperaSafariNetscapeFirefoxInternet Explorer


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For doubts if any contact the author: tmk.sir @ gmail.com

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