01. Basic Computer Concepts2

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BASIC COMPUTER

CONCEPTS ANDAPPLICATION



COMPUTERS ANDCOMPUTER SYSTEMS



Contents

Computer 1

History & Evolution of Computer System 2

Major Contributors in Computer Development 3

Components of a Computer System 4



COMPUTER



Computer



Computer

A machine that performs tasks, such ascalculations or electronic communication,under the control of a set of instructions

called a program. An electronic device that accepts,

processes, stores, and outputs into

valuable information data at high speedsaccording to programmed instructions.

Perform a wide variety of activities

reliably, accurately, and quickly.



CLASSIFICATIONS



Mainframe Computers

A very large computer, used by majororganizations such as governments,supermarket chains and very largebusinesses.

The mainframe computer can process vastamounts of data at very high speed. Theyalso have very large storage capabilities.

Mainframes can be physically very large,and can occupy entire rooms.



Mainframe Computers

They can cost many hundreds ofthousands of Dollars to install, maintainand run.

Mainframes can have many smallerterminals, usually desktop screens andkeyboards, connected to them.

Operators can therefore access, transmit,process and receive data, to and from themainframe.



Mainframe Computers

These remote terminals are sometimescalled ‗dumb terminals‘; they cannot

process any data themselves, as this iscarried out in the mainframe.



Mainframe Computers



Networked Computers

In settings where there are a number ofcomputers performing similar tasks, suchas in businesses, educationalestablishments and offices, these smallerself-contained units can be linked togetherwith a cabling system. This is called anetwork.

Networked computers allow work done onone computer to be easily made availableto other users connected to the network.



Networked Computers



Personal Computers

PCs, are small, self-contained units whichare usually located on a user‘s desktop.

They are characterized by a small group ofinterrelated components, which areconnected by special cables.

The PC can be seen in homes, schools,offices, and businesses. Due to its steadilyincreasing processing power and storagecapacity, and its reducing costs, thepersonal computer has become the most

widely used small computer.



Personal Computers



Laptop Computers

Small portable ‗laptop‘ computers are nowin widespread use. Although they areextremely convenient to use in virtuallyany location, they usually cost slightlymore than an equivalent desktop system.

They can do all the jobs that a desktopsystem can do, but their main advantageis that they can be used almost anywhere.



Laptop Computers



Personal Digital Assistant (PDA’s)



OTHER

CLASSIFICATIONS



According to purpose



General-Purpose Computers

These machines have the capability ofdealing with a variety of different problemsand are able to act in response toprograms created to meet different needs.

Has the ability to store different programsof instruction and thus to perform a varietyof operations.



Special-Purpose Computers

Designed to perform one specific task.

Example: Collecting highway tolls, air traffic

control, satellite tracking, industrial process

control, airline reservations.



According to the

type of data handled



Analog Computers

Used for scientific, engineering andprocess-control purposes.

They deal with quantities that are

continuously variable, they give onlyapproximate results.

Example: speedometer in an automobile,

service station gasoline pump



Digital Computers

Machines that specializes in counting. Operates by counting values that are

discrete or separate and distinct.



Hybrid Computers

Combines the measuring capabilities ofthe analog computer and the logical andcontrol capabilities of the digital computer.

Contain special equipment to convertanalog voltages into digital voltages andvice-versa.



MAIN PARTS

OF A PERSONALCOMPUTER



Main parts of a PC



The System Case

The system case houses a number ofinterdependent components.

These consist of a power supply, hard

disk, a CD-rom or DVD drive, a floppy diskdrive, an internal modem, an on/off buttonand various connecters, such as USBspecial connectors called ports, and

connectors for input/output devices suchas the mouse and the monitor.



The System Case

These components and devices are allconnected to a large internal circuit boardcalled a motherboard.

The motherboard supports an array ofmicrochips and electronic components.Mounted on this board is the computer‘s

main processor – the CPU or central

processing unit.



The System Case

Mounted on this board is the computer‘smain processor – the CPU or centralprocessing unit.

Also plugged into special connectors,mounted on the board, are smaller circuitboards assembled with microchips calledRAM or random access memory.



The CPU

The CPU‘s function is to process all of thedata that moves between the various partsof the system.

Modern CPUs operate at a very highspeed and they can perform millions ofoperations per second.

These components, although very small,are immensely complex devices.



The CPU

They are subject to constant developmentand as such are increasing in speed ofoperation and data processing capacity allthe time.

The CPU is considered to be the ‗brain‘ of

the computer.



The Hard Disk

Common capacities range from 20-40megabytes (Mb) with up to as much as250 megabytes in many domesticcomputers.

Multiple installations can increase thiscapacity for high storage requirements.



The Hard Disk



The CD-ROM drive

Modern computers are equipped with aCD-rom drive, which opens out to receivea CD-rom or compact disc.

This is a very cheap and common opticaldisk which can hold a substantial amountof data (800Mb).



The CD-ROM drive

Developments of the standard CD-romhave provided disks that are re-writable(CD-RW), and the very high capacity DVD(8 Gigabytes (GB)) which is capable ofstoring an entire feature film at very highquality.

The disks are fairy robust, they are cheap

and are very portable.



The CD-ROM drive



The Floppy Disk drive

It is important to note that the floppy disk isfast becoming redundant, due mainly to itsslow access speed and very smallcapacity (1.44 Mb). However, many oldercomputers still in service are equippedwith floppy disk drives.

They can also be retro-fitted to newer

computers if required. They are verycheap and the disks cost less than $1 tobuy.



The Floppy Disk drive



The Keyboard and Mouse

The mouse is a simple device that allowsthe user to point a various buttons menusand commands which are displayed on thecomputer monitor.

The selections are executed by the pressof a button mounted conveniently on themouse case.

This is also connected by a cable to thecomputer case. Similarly these too areavailable with ‗wireless‘ connection.



The Keyboard and Mouse



The Monitor or Screen

The monitor is a visual display unit,sometimes referred to as a VDU.

It allows the user to see the task beingperformed by the computer.

The use responds to a visual or graphicalrepresentation of tasks.

The design of this type of human interfacehas become known as a Graphical UserInterface or GUI.



The Monitor or Screen



Peripheral Devices

In order to share your work much of itneeds to be output onto familiar mediasuch as paper. There a wide range ofprinters are available, which are

connected to the computer via cables.

There is also a wide selection of inputdevices available which can be connected

to the computer, such as scanners, digitalcameras, video cameras, microphones.



Peripheral Devices

These are capable of inputting images andsounds into the computer.

Additionally there are speakers, projectors,web cams, joy sticks, track balls, gameconsoles, and graphic tablets alsoavailable.

The devices are all commonly referred toas peripheral devices.



INPUT DEVICES



Keyboard

On most computers the keyboard is theprimary device for inputting data.

It is derived from the familiar typewriterkeyboard and it shares the standardQWERTY key layout.

QWERTY refers to the layout of the first 6keys on the top row of the letter keys onthe keyboard.



Keyboard

When you type or press the keys electricpulse for the corresponding keys are sentto the computer. Instructions andcommands are also given by typing on the

keyboard.



Mouse

The mouse is the most common pointingdevice.

Movements are converted to screenposition as the mouse moved.

Clicking the mouse button selects an icon,opens a file, executes a program orselects a text from a document.

The position of the cursor is alsomanipulated with the use of the mouse.



Track Ball

The trackball is essentially an upside downmouse, with a ball that is rotated within asocket.

Commands can be executed by pressingdown on the ball.

T k B ll



Track Ball

T h P d



Touch Pad

Although the laptop computer can have amouse attached, it usually has a smallrectangular touch sensitive pad positionedbelow the integral keyboard.

The user moves a finger round the padand the arrow responds.

To input a command there are usually oneor two buttons positioned below the pad.



Li ht P /G hi T bl t



Light Pen/Graphic Tablet

The light pen looks like a conventionalpen, and can be a stand alone item whichis used to select objects on the screen bydirectly pointing at them.

A modified version of this device can becombined with a graphic tablet.

This is normally used in conjunction with aflat graphic tablet which resembles anelectronic pad.





Using these tools the user can input databy emulating the actions required to drawwith conventional pen and paper.

To input commands the pen can bepressed down on the surface and variousbuttons can be selected on the surface ofthe tablet.





Fl t b d



Flat bed scanner

This device, as its name suggests, has aflat clear glass surface upon which theimage is placed, usually face down. Thebeam of light passes across the image

and the computer converts the signalreceived to digital information.

The latest scanners available are capable

of scanning all types of media, includingphotographic transparencies.

Fl t b d



Flat bed scanner

B d d



Bar code reader

This device can be seen in the majority ofsupermarkets at the checkout. It is used toscan the bar code on a grocery item. Theoperator simply passes the item in front of

a glass scanner, the bar code isrecognized and the purchase is added tothe grocery bill.

Handheld bar code scanners are alsowidely used.

Bar code reader



Bar code reader

Joystick



Joystick

The joystick is a device mainly used wheninputting information to control a computergame. However its use is not limited to thisrole. As the stick is moved around,

movements are controlled on the screen.

Many joysticks have been developed intoa handheld console with an array of

buttons which can control various actionslike firing weapons from the computergame.

Joystick



Joystick

Digital Camera



Digital Camera

Resembling a conventional camera, thedigital camera does not require film.Instead the camera stores its images on aspecial memory card. The camera can be

connected to a computer; the images aretransferred into the computer‘s memory,

where they can be displayed on the

monitor, edited using photo editingsoftware, or printed using a peripheralphoto printer.

Digital Camera



Digital Camera

Microphone



Microphone

The microphone allows sounds to berecorded on the computer. In addition itcan be used to input speech to control acomputer‘s functions.

The microphone can also be used tocommunicate verbally via the Internet. Inthis application it is usually combined with

a small simple video camera called a webcam.

Microphone



Microphone



OUTPUT DEVICES

Output Devices



Output Devices

An output device is anything which allowsyou to see the results of processingcarried out by a computer.

Also translates information into a formatthat can be understood by the user.

A peripheral device that enables acomputer to communicate information to

human or other machines.

Monitor



Monitor

The monitor or Visual Display Unit (VDU)is similar in design to a television screen,but it has a much sharper picture. This isbecause it is usually viewed from a short

distance.

The conventional monitor is usually placedat eye level in front of the user, with the

keyboard in front of this. The monitor is an interface between the

user and the CPU.

Monitor



Monitor

It displays the work being carried out bythe CPU in a graphical form.

This interface is typically known as aGraphical User Interface or GUI.

The standard monitor uses a cathode raytube (CRT) which is similar in design to atelevision tube. The files seen in the

monitor are called softcopy.

Speakers



Speakers

In order to hear sounds produced by thecomputer a set of speakers can beconnected. In a place where speakerswould annoy others, headphones can

replace them. These can be used to listento the narrative of an educational CD-rom.

They can also be used for entertainment,

by playing high quality music, and theycan be use by computer game players toprovide a multi-media experience.

Speakers



Speakers

Projectors



Projectors

projector takes a video signal andprojects the corresponding image on aprojection screen using a lens system.

All video projectors use a very bright lightto project the image, and most modernones can correct any curves, blurriness,and other inconsistencies through manual

settings.

Projectors



Projectors

Printers



Printers

Another common output device thatgenerates a permanent copy of filesprinted on paper called hardcopy.

There are various types of printeravailable; they are usually designed to bepart of the desktop system, and as suchare generally compact devices.

There are currently four types of printersavailable today: dot matrix printer, ink jetprinter, laser printer and the plotter.



Types of Printers

Dot Matrix Printer



Dot Matrix Printer

Creates letters, numbers, and symbols bystriking the ribbon of the printer to createsmall dots forming the images of thecharacter.

It is the cheapest kind of printer.

However, it is slow and noisy. It alsoproduces low-quality printout.

Dot Matrix Printer



Dot Matrix Printer

Inkjet Printer



Inkjet Printer

The inkjet printer, as its name implies, isequipped with reservoirs, or cartridges, ofcolored ink.

The ink is fed to a series of very finenozzles, which when passed across thepaper shoot minute droplets of ink on thesurface of the paper.

Quality of print is improved by reducing thesize of the dots by using finer qualitynozzles.

Inkjet Printer



Inkjet Printer

Laser Printer



Laser Printer

If a high volume of prints is anticipated thelaser printer has become the printer ofchoice.

Laser printers work in a similar way to aphotocopier.

A laser beam is passed over the surface ofa rotating drum. This places an electrical

charge on the drum in the shape of thetext and graphics.

Laser Printer



Laser Printer

The charged area of the drum attracts avery fine black powder to it called toner.

This toner is then pressed onto the surfaceof the paper as it passes through themachine.

The paper is then heated to seal the toneronto the paper.

This process is carried out very quicklyand quietly.

Laser Printer



Laser Printer

Plotter



Plotter

The plotter is a specialist printer that isusually reserved for applications wherethere are lots of drawn lines to reproduce.

Plotters can be seen in architects‘ offices,

engineering companies, and scientificestablishments.

They are usually used with computer

aided design (CAD) software and mappingsoftware, to produce very large linediagrams.

Plotter



otte



INPUT AND

OUTPUT DEVICE

Touch Screen



This device is a computer screen modifiedto recognize the location of a touch on thesurface of its screen.

By touching the screen you can make aselection or move a cursor.

The simplest type of touch screen is madeup of a grid of lines, which determine the

location of a touch by matching verticaland horizontal contacts.

Touch Screen



Computer Literacy

Computer Literacy



p y

Knowledge and an understanding ofcomputers combined with the ability to usethem.

Denotes some kind of basic understandingto computer concepts and terminologies.

Also refers to the attitude about computers

and the actual ability to do some tasks oruse programs on it.

Computer Literacy



p y

In actuality, computers, like any otherdiscipline, inspire different levels ofexpertise.

On the least specialized level, computerliteracy involves knowing how to turn ona computer, start and stop simpleapplication programs, and save and print.

Computer Literacy



p y

At higher levels, computer literacybecomes more detailed, involving theability of the ―power users‖ to manipulate

complex applications and, possibly, toprogram in languages such as BASIC or C.

At the highest levels, computer literacyleads to specialized—and technical— knowledge of such topics as electronicsand assembly language.

Computer Literacy



p y

Elementary school students work on an assignment

in their school’s computer lab. Some studies show that

when used selectively by trained teachers, computers can

enhance students’ academic performance.

Computer Literacy



y

Computers are important tools in education. By

using a computer, each student is able to develop at his or

her own pace, making the learning process more flexible

and self-directed. As computers and technology play a role

in more aspects of day-to-day life, education with

computers becomes increasingly important.



Programs

Computer Programs



Usually reside within the computer and areretrieved and processed by the computer‘s

electronics. The program results are stored

or routed to output devices, such as videodisplay monitors or printers.

A program can be executed many differenttimes, with each execution yielding apotentially different result depending uponthe options and data that the user gives thecomputer.



Characteristics

Characteristics of Computer



A machine – can only do things

for which it is designed

2Electronic - runs on electrical

energy through its electricalcomponents.

3Automatic – runs continuously

once started.

1

Characteristics of Computer



Can Manipulate Data –

following specific instructions, it canperform arithmetic functions

5Has Memory - the ability to read

and store instructions

6Has Logic Functions – can

produce results after instructions arefed into it

4



Basic WaysComputers are Used

Data Processing



Conversion of data into information for auseful output.

The analysis and organization of data by

the repeated use of one or more computerprograms.

Data processing is used extensively in

business, engineering, and science and toan increasing extent in nearly all areas inwhich computers are used.

Data Processing



Businesses use data processing for suchtasks as payroll preparation, accounting,record keeping, inventory control, salesanalysis, and the processing of bank and

credit card account statements.

Engineers and scientists use dataprocessing for a wide variety of

applications, including the analysis of newproduct designs, the processing of satelliteimagery, and the analysis of data from

scientific experiments

Control



Computers control many mechanicaldevices and processes.

They direct robots in factories, monitor

traffic lights, operate machineries, inhomes, tiny computers embedded in theelectronic circuitry of most appliancescontrol the indoor temperature, operatehome security systems, tell the time, andturn videocassette recorders (VCRs) onand off.

Design and Development



Engineers can design a product and test itby computer before their companies beginto manufacture their products.

Surgeons and design engineerscollaborates top designs and producesartificial joints and limbs.

The computer then analyzes all the data tohelp them create designs that will fit thepatient best.




The plans for this jetturbine engine werecreated with computer-aided design (CAD)

software. Engineers cancheck the architecturaldetails, slicing through anysection of the engine‘s

computer-generatedblueprint or viewing it fromany angle.




Wind pressure on an automobile is simulated by

Computer-Aided Design (CAD) and Computer- Aided Manufacturing (CAM) software. Red (on thenose of the automobile) indicates high pressureswhile blue indicates low pressures.

Data Communication



Data communication is the process ofelectronically sending data from onecomputer to another.

Internet, computer-based globalinformation system. The Internet iscomposed of many interconnectedcomputer networks.

Linking one computer to another makes itpossible for data to be shared and updatedat different locations.

Data Communication



Each network may link tens, hundreds, oreven thousands of computers, enablingthem to share information and processingpower.

The Internet has made it possible forpeople all over the world to communicatewith one another effectively andinexpensively.



Uses of Computer

Uses of Computer



2For scientific research - used extensively inscientific research to solve mathematical problems,investigate complicated data, or model systems that aretoo costly or impractical to build

3Used in automobile – Computers in automobiles

regulate the flow of fuel, thereby increasing gas mileage,and are used in anti-theft systems.

To keep record – In business, computers track

inventories with bar codes and scanners, check the creditstatus of customers, and transfer funds electronically

1

Uses of Computer



5For telecommunication - The military employscomputers in sophisticated communications to encodeand unscramble messages, and to keep track ofpersonnel and supplies.

6For Education – Educators use computers to trackgrades and communicate with students; with computer-controlled projection units, they can add graphics, sound,and animation to their communications.

For entertainment – Computers also entertain,

creating digitized sound on stereo systems or computer-animated features from a digitally encoded laser disc, orplay games on gaming consoles like Playstation and Wii

4



Capabilities of Computer




1

Speed – can processdata faster than

any othermachine.

2

Repetitive-ness

– can perform thesame functions or

operationsmillions of times.

3

Accuracy – can produceprecise results




4

Store and

RecallInformation

– stores andrecalls vast

amount of data athigh speed

5

Self-

checking – counts the

number ofcharacters it hasstored and makesure there is no

loss.



Limitations of Computer

Limitations of Computer



Limitations

Depends on prepared instructions

subject to human control

It can’t correct wrong instructions

subject to occasional breakdown



Reasons why computer sometimes fail



Improper controls can lead to sabotagethe company and invasion of privacy

Lack of standard results in problems

Manufacturer fails to supply needed spare,trained technicians, or that particularmachine model is no longer in production.



Evolution of Computers /Earliest Computing

Devices



Earliest Computing Devices



COUNTING BOARD

Known as the ancient abacus used by theBabylonians

ABACUS

Invented by the

Chinese in CE 1200,

considered being the

first computer thatcan perform simple

addition and subtraction operations.




NAPIER’S BONE

A set of eleven rods withnumbers marked on themin such a way that by

simply placing the rodsside by side, products andquotients of large numberscan be obtained.

Called ―bones‖ becausethey were literally madefrom bones or ivory.

Scottish mathematician

John Napier (1550 –1617) created

Napier’s Bones, so-called because

they were made out of ivory or

bone.



PASCAL’S CALCULATOR/PASCALINE

Invented by Blaise Pascal, aFrench philosopher, mathematician, and physicistin 1642, that added and subtracted, automaticallycarrying and borrowing digits from column tocolumn.

It is the first mechanical calculating machine thatcan perform addition and subtraction operations.

Operated by dialing a series of wheels. Approximately the size of a cigar box, could addand subtract numbers containing up to eightdigits.




Left : B laise Pascal

Below : Pascal ine




LEIBNITZ’S CALCULATOR

Invented by Gottfried Leibnitz.

Utilized the same techniques for addition andsubtraction as Pascal‘s device but could also

perform multiplication and division, as well asextract square roots.

DIFFERENCE ENGINE

Invented by Charles Babbage (Father of ModernComputer) with a 20-decimal capacity that couldsolve mathematical problems.




ANALYTICAL ENGINE

Also invented by Charles Babbage that canperform complex mathematical calculations andwas designed to automate a standard procedurefor calculating the roots of polynomials.

The Analytical Engine was developed to meet themathematical needs of the time, and it containedmost of the features found in modern computers.

There was a way to input data, a place for storingdata, a place for processing data, a control unit togive directions, and a way to receive output.




Charles Babbage’s

first machine was actuallythe Difference Engine(pictured here), which wasbegun in 1823. It wasdesigned to calculatedifferences. Work on this

precursor to the AnalyticalEngine continued over aperiod of years, butBabbage eventuallyabandoned it in 1842, whenthe British governmentstopped funding it. TheDifference Engine was laterkept in a museum in SouthKensington, England.




HOLLERITH’S PUNCHED-CARD MACHINE

Invented by Herman Hollerith, a statistician withthe US bureau of the Census, used to helpprocess the results of the 1890 census.

Uses 3 by 5 inch punched cards to record thedata, he constructed an electromagnetic countingmachine to sort the data manually and tabulatethe data.




Herman Hollerith’s tabulating machine, which usedpunched cards to tabulateresults, revolutionized the waystatistics, like census records,

were compiled.



TechnologicalGenerations of Computer

Generations of Computer



4th

3rd

2nd

1st

First Generation1945-1959

First Generation



The VACUUM TUBE was invented in

1906 by an electrical engineer named LeeDe Forest.

During the first half of the twentieth

century, it was the fundamental technologythat was used to construct, televisions, X-ray machines, and a wide variety of other

electronic devices. It is also the primary technology associate

with the first generation of computing

machines

First Generation



The first operational electronic general-

purpose computer, named the ENIAC (Electronic Numerical Integrator and

Computer), was built in 1943 and used

18,000 vacuum tubes. It was constructed with government funding at

the University of Pennsylvania‘s Moore

School of Engineering, and its chief designerswere J. Presper Eckert, Jr. and John W.Mauchly.

First Generation



It used punched cards for input and output

and was programmed with plug board wiring. Another important stored program

machine of this generation was the

UNIVAC (UNIVersal Automatic Computer).It was the first successful commerciallyavailable machine. The UNIVAC was

designed by Eckert and Mauchly.

First Generation



The first commerciallyavailable electronic computer,UNIVAC I, was also the firstcomputer to handle both numericand textual information. Designed

by John Presper Eckert, Jr., andJohn Mauchly, whose corporationsubsequently passed to RemingtonRand, the implementation of themachine marked the beginning ofthe computer era. Here, a UNIVAC




1st

4th

3rd

2nd

Second Generation1960-1964

Second Generation



As commercial interest in computer

technology intensified during the late1950s and 1960s, the second generationof computer technology was introduced

based not on vacuum tubes but onTRANSISTORS .

John Bardeen, William B. Shockley, and

Walter H. Brattain invented the transistor atBell Telephone Laboratories in the mid-1940s.

Second Generation



Transistors the plural of transistor, which is a

contraction of TRANS fer resISTOR ;semiconductor device, which has threeterminals; can be used for switching andamplifying electrical signals




2nd

1st

4th

3rd

Third Generation1964-1970



Third Generation



During the third generation of computers,

the central processor was constructed byusing many integrated circuits. It was notuntil the fourth generation that an entire

processor would be placed on a singlesilicon chip—smaller than a postagestamp.

Third Generation



3rd

2nd

1st

4th

Fourth Generation1971-?

Fourth Generation



The fourth generation of computer

technology is based on theMICROPROCESSOR .

Microprocessors employ Large Scale

Integration (LSI) and Very Large ScaleIntegration (VLSI) techniques to packthousands or millions of transistors on a

single chip.

Fourth Generation



The Intel 4004 was the first processor to

be built on a single silicon chip. Itcontained 2,300 transistors. Built in 1971,it marked the beginning of a generation of

computers whose lineage would stretch tothe current day.




4th

3rd

2nd

1st

Gordon Moore

Gordon Moore

I 1965 i d i di d



In 1965 a semiconductor pioneer predicted

that the number of transistors contained ona computer chip would double every year.This is now known as MOORE’S LAW, and

it has proven to be somewhat accurate. Thenumber of transistors and the computationalspeed of microprocessors currently double

approximately every 18 months.Components continue to shrink in size andare becoming faster, cheaper, and moreversatile.



MAJORCONTRIBUTORS

IN COMPUTERDEVELOPMENT

B laise Pascal - 1642



The first mechanicaldigital calculator, thePascal ine .

Joseph Marie Jacquard - 1804

M h i i ith J d‘



Mechanizes weaving with Jacquard‘s

Loom, featuring punched cards. Used punch cards with weaving loom.

Joseph Marie Jacquard - 1804



Jacquard’s loom, featuringpunched cards,revolutionized the weavingindustry.

Charles Babbage- 1822

―F th f



―Father o f

Computer .‖ Inventedthe difference enginewith mechanical

memory to storeresults.

Ada Augusta Lovelace- 1840



Ada Augusta Lovelace- 1840

―Th f i t ‖ S t d



―The f irs t p rog rammer .‖ Suggested

binary system rather than decimal for datastorage.

Considered to be the first computer

programmer even though she was bornbefore computers existed, and theprogram she wrote was for a machine that

was never built.

George Boo le- 1850



George Boo le- 1850

Developed B l l i which later



Developed Boo lean log ic , which later

was used in the design of computercircuitry.

a mathematician whose work in symbolic

logic laid new foundations for modernalgebra, and set the stage forcontemporary computer circuitry and

database search strategy syntax.

Herman Holler i th -1880

―Built the first



Built the first

electromechanical,punched card dataprocessing machine,

used to compileinformation for 1890US census.

John A tanasof f & Cl if ford Berry -1939

Built the ABC



Built the ABC

(Atanasoff – BerryComputer ), theworld‘s first general-

purpose electronicdigital computer tosolve largeequations.

John V. Atanasoff

A lan Tur ing -1943

Used vacuum tube



Used vacuum-tube

technology to buildBritish Colossus , tocounteract the

German CodeScrambling device,

ENIGMA .

Howard A iken -1944

Built the Mark I the first automatic



Built the Mark I, the first automatic

sequence-controlled calculator, used bymilitary to compute ballistics data.



John Von Neumann -1940s

Presented a paper



Presented a paper

outlining thestored-programconcept.

J. Presper Eckert Jr. & John Mauch ly -1947

Built the ENIAC (Electronic Numerical



Built the ENIAC (Electronic Numerical

Integrators and Compu ter ), the secondgeneral-purpose, electronic digitalcomputer; used to compute artillery firing

tables.

J. Presper Eckert Jr. & John Mauch ly -1947



J. Presper Eckert Jr.and John W. Mauchlycombined their engineering

and scientific talents toproduce the ENIAC, whichfirst saw action in U.S. Armyballistics tests in 1947.

Maurice Wilkes -1949

Built the EDSAC (Electron ic Delay



Built the EDSAC (Electron ic Delay

Storage Au tomat ic Calculator ), the firststored program computer.

J. Presper Eckert Jr., John Mauch ly,

and John Neumann -1949

B ilt th EDVAC (



Built the EDVAC (Electron ic DiscreteVar iable Automat ic Compu ter ), thesecond stored program computer.

An Wang -1949

Developed magnet ic co re memory



Developed magnet ic-co re memory .

Jay For rester -1949

Jay Wright Forrester invents three



Jay Wright Forrester invents three

dimensional core memory at theMassachusetts Institute of Technology.(United States)

Grace Hopper -1949

Developed the UNIVAC I compiler



Developed the UNIVAC I compiler .

Coined the term ―computer bug‖ after amoth got into her computer and caused itto malfunction.

Instrumental in developing COBOL(Common Bus iness-Or iented

Language ) programming language.

Grace Hopper -1949



John Backus -1957

One of the group of IBM (International



One of the group of IBM (International

Bus iness Mach ines ) engineersdeveloped FORTRAN (FORmula

TRANslat ion ), an example of a high-level

programming language.

Jack K i lby and Robert Noyce -1959

Developed and perfected the integrated



Developed and perfected the integrated

circuit to be used in later computers. Jack Kilby and Robert Noyce were the

founders of the integrated circuit.

However, they worked independently ofeach other for different companies.

Gene M. Amdahl -1960s

Designed the IBM SYSTEM/360 series



Designed the IBM SYSTEM/360 series

mainframe com pu ters , the first general-purpose digital computers to useintegrated circuits.

Kenneth Olsen -1963

With DEC (Digi tal Equ ipment



With DEC (Digi tal Equ ipment

Corporat ion ) produced the PDP-I, the firstmini-computer.

John G. Kemeny & Thomas E. Kurtz -1965

Developed BASIC



Developed BASIC

(Beginners A l lPurpose Symbol ic

Ins t ruct ion Code )

programminglanguage; true BASICfollowed later.



Ed Roberts -1975

―Father o f Microcompu ter .‖ Designed the



Father o f Microcompu ter . Designed the

first microcomputer, the A ltair 8800 in kitform



Steven Jobs & StephenWozniak -1977

Designed and built the first Apple



Designed and built the first Apple

microcomputer .

Daniel Br ick l in & Bob Franks ton -1978

Designed the VisiCalc (Visib le



es g ed t e s Ca c ( s b e

Calculator) , an electronic spreadsheet.



COMPONENTSOF A COMPUTER

SYSTEM



Computer System

INFORMATION TECHNOLOGY (IT) is the



( )

name given to the use of computersystems to perform a range of tasksrelated to the receipt, production,

manipulation, storage, retrieval, printingand transmission of electronic information.



1. Hardware


SYSTEM

Hardware

Hardware is the name given to the



g

physical parts of the computer, such asthe monitor, the computer (system box),the keyboard, the mouse, and any

connecting cables. The hardware will notfunction as a computer system without theaddition of software.

The tangible parts or all of the physicalequipments that makes up a computersystem.



FunctionalElements of Hardware

Input Device

Devices that permit the



p

communication between the user andthe computer; tools used to feed datainto the computer.

Output Device

Converts the data entered into the



computer into a form that can beunderstood by the user such asprinter reports, visual display or

audible sounds.

Central Processing Unit (CPU)

The brain of the computer. Controls



p

the flow of data throughout thecomputer system.



Central Processing Unit (CPU)

2. The immediate access memory -



The immediate access memory isthe place where the data used bythe ALU is stored.

3. The con tro l uni t - responsible forensuring that all programinstructions are followed in the

correct sequence.

Auxiliary / Storage Devices

Used as physical storages such as ROM



and RAM Chips, floppy disks, hard disks,and compact discs (CD), flash drive or pendrive.

Types of Storage Devices

Primary Storage – a temporary storage



device. It can store and retrieve data at avery high speed.

1. Internal Memory – contained in the silicon

chip and can hold instructions and datawhich the computer is currently working onor information which the CPU needs to work.

Types of Memory

a) ROM

b) RAM

Types of Memory

Random -access memory (RAM)



RAM is installed in the computer on smallremovable circuit boards. Mounted on theseboards is an array of small electronic ‗chips‘

which temporarily hold data when the

computer is switched on.

RAM is considered to be volatile memory inthat it looses any data stored when the

computer is switched off. It is the mainworking memory of the computer and itscapacity to hold data is measured inmegabytes (Mb).

Types of Memory

Read on ly memory (ROM)



ROM is a type of memory that is permanent.When a computer is switched off ROM retainsany stored data, for use when the computer isswitched on again.

ROM is stored on electronic ‗chips‘ which are

permanently installed by the manufacturer,They cannot be removed, and the data

‗burned‘ onto them cannot be altered in anyway by the computer.



Magnetic Disk

A magnetic disk is a Mylar or metallic



platter on which electronic data can bestored.

Floppy Disk (1.44 mb)- also called simply a

diskette or floppy, a small flexible Mylar diskcoated with iron oxide similar to magnetictape on which data are stored.

Zip Disk - This disk is also a type of floppy

disk; it is encased in a hard plastic case and itneeds a special drive. Variations of this diskcan hold 100Mb, 250Mb or even 750Mb.

Magnetic Disk

Hard Disk - The hard disk is a storage device



that is located inside the computer box. It is amechanical device that is capable of storingvery large amounts of data. Typically they canstore many megabytes (Mb) or even

gigabytes (Gb) of data. Modern computerscome equipped with hard disks that can store40 to 80 gigabytes of information. Externalhard disks are available and are connected to

the computer by special cables.

Optical Disk

The optical disk is a technology that uses



intense light called laser beams. LASER isan acronym which means Light

Ampl i f icat ion and Stimulat ion of

Radiat ion . Compact Disc (CD-ROM) -The CD-ROM is

virtually identical to the familiar music CD. Ithas a very low cost, is highly portable and

typically can hold up to 800Mb of data. Thereare read only (CD-R) and read/write (CD-RW)versions commonly in use.

Optical Disk

The CD-R version is a write once/read many



times format and the CD-RW allows multiplerecording and rerecording of data. Much newsoftware is sold loaded onto a CD-ROM. Itdiffers from the preceding storage devices in

that it is an optical and not a magnetic media. Dig ital Versati le Disc (DVD) – A development

of the CD-ROM. It has a very large capacity,and can store many gigabytes of data. TheDVD drive is replacing the CD drive in moderncomputers and as such is fast becoming thestandard storage device. Its cost is comparable

USB Drives

The latest storage drives (Flash Drives)



are solid state devices that are designedto hold very large amounts of data. Theyplug directly into the USB (Universal

Serial Bus) connection socket of amodern computer. They are very smallpen like devices that need no software torun them, so they are truly portable. Theyhave capacities ranging from 128mb up to32Gb.

USB Drives

As they contain a single ―chip‖ encased in



a robust case they are hardwearing andeconomical to purchase. They areread/write devices.

USB Drives



2. Software


SYSTEM



Software

In order for a computer to operate it needs



two types of software: operat ing sys temsof tware and app l ications so f tware .

Operating system software

The basic software that controls a computer.



When your computer starts it goes through aseries of steps. What is happening during thisinitial period is that the computer is loadingthe operating system software. This software

is sometimes supplied preinstalled by themanufacturer, and its basic function is tooperate the computer, organize the softwarethat operates the peripheral devices, and

provide a platform on which to operate theapplications software that the user mayrequire.

Operating system software

3 Major Functions



1. It coordinates and manipulates computerhardware

2. It organizes files on a variety of storage media.

3. It manages hardware errors and the loss of data.

Examples: Windows XP, OS X, Linux, Unix

Windows Vista.



End user

Someone who works with the computer



and uses the information generated by thecomputer.



DATAPROCESSINGCONCEPTS

Data Processing

Data processing is a series of planned



actions and operations acting uponinformation to achieve a desirable outputand result.

In computer science, the analysis andorganization of data by the repeated useof one or more computer programs.

Uses of Data Processing

Data processing is used extensively in



business, engineering, and science and toan increasing extent in nearly all areas inwhich computers are used.

Businesses use data processing for suchtasks as payroll preparation, accounting,record keeping, inventory control, salesanalysis, and the processing of bank andcredit card account statements.

Uses of Data Processing

Engineers and scientists use data



processing for a wide variety ofapplications, including the processing ofseismic data for oil and mineral

exploration, the analysis of new productdesigns, the processing of satelliteimagery, and the analysis of data fromscientific experiments.



Devices used for data processing

1. Manual-Mechanical Device



A simple mechanism powered by hand. required some sort of physical effort from the

user when used.

• Example : Abacus, slide rule

2. Electromechanical Device

powered by an electric motor and usesswitches and relays.

• Example : Household electrical appliance, desk

calculators, punched-card

Devices used for data processing

3. Electronic Device



as principal components circuit boards,transistors or silicon chips and the like.

• Example : computer, ATM



Types of data processing

Electromechanical Data Processing



This type of data processing uses unit recorddevices. This often referred to as punch carddata processing.

Examples of unit record devices are thesorters, collators, reproducers, interpreters,tabulators, calculators, keypunch machinesand keys verifiers. Each device has some sort

of control panel of switches, which will directits predetermined operations.



DATAPROCESSINGOPERATIONS

Data processing operations

Recording



refers to the transfer of data to some form ordocument. It relates to the documentation ofintermediate figures and facts resulting fromcalculations.

Veri fy ing

refers to the careful checking of the recordeddata for any errors.

Dupl icat ing

refers to the reproduction of the data intomany forms or documents.



Data processing operations

Stor ing



refers to placing similar data into files forfuture reference.

Retrieving

refers to recovering stored data and/orinformation when needed.

Feedback

refers to the comparison of the output(s) andthe goal set in advance, any discrepancy isanalyze, corrected, and fed back to properstage in the processing operation.



INTERNET

Internet

Computer-based global information



system composed of many interconnectedcomputer networks. Each network maylink tens, hundreds, or even thousands ofcomputers, enabling them to shareinformation and processing power.

The Internet has made it possible forpeople all over the world to communicatewith one another effectively andinexpensively.

Internet

Unlike traditional broadcasting media,



such as radio and television, the Internetdoes not have a centralized distributionsystem.

Instead, an individual who has Internetaccess can communicate directly withanyone else on the Internet, postinformation for general consumption,retrieve information, use distantapplications and services, or buy and sellproducts.



Uses of Internet

Many individuals use the Internet for



communicating through electronic mail (e-mail), retrieving news, researchinginformation, shopping, paying bills,banking, listening to music, watchingmovies, playing games, and even makingtelephone calls.



History



Timothy Berners-Lee, a British computer scientist,developed the World Wide Web during the 1980s.

History

In the 1980s, as large commercial

i b t TCP/IP t b ild



companies began to use TCP/IP to buildprivate internets, ARPA investigatedtransmission of multimedia—audio, video,and graphics—across the Internet.

Other groups investigated hypertext andcreated tools such as Gopher that allowedusers to browse menus, which are lists ofpossible options.

History

In 1989 many of these technologies were

bi d t t th W ld Wid W b



combined to create the World Wide Web.Initially designed to aid communicationamong physicists who worked in widelyseparated locations, the Web becameimmensely popular and eventuallyreplaced other tools.

Also during the late 1980s, the U.S.government began to lift restrictions onwho could use the Internet, andcommercialization of the Internet began.

History

In the early 1990s, with users no longer

t i t d t th i tifi ilit



restricted to the scientific or militarycommunities, the Internet quicklyexpanded to include universities,companies of all sizes, libraries, public andprivate schools, local and stategovernments, individuals, and families.



Computer Virus

Computer Virus

A self-duplicating computer program that

d f t t t



spreads from computer to computer,interfering with data and software. Just asbiological viruses infect people, spreadingfrom person to person, computer virusesinfect personal computers (PCs) andservers, the computers that control accessto a network of computers

Computer Virus

Some viruses are mere annoyances, but

th d i d Vi



others can do serious damage. Virusescan delete or change files, steal importantinformation, load and run unwantedapplications, send documents viaelectronic mail (e-mail), or even cripple amachine‘s operating system (OS), the

basic software that runs the computer.



HOW INFECTIONS OCCUR

How Infections Occur

A virus can infect a computer in a number

f It i fl di k



of ways. It can arrive on a floppy disk orinside an e-mail message. It canpiggyback on files downloaded fromthe World Wide Web or from an Internetservice used to share music and movies.

Or it can exploit flaws in the waycomputers exchange data over anetwork.


So-called blended-threat viruses spread

i lti l th d t th ti



via multiple methods at the same time.Some blended-threat viruses, for instance,spread via e-mail but also propagate byexploiting flaws in an operating system.


Traditionally, even if a virus found its way

t t it ld t t ll i f t



onto a computer, it could not actually infectthe machine—or propagate to othermachines—unless the user was somehowfooled into executing the virus by openingit and running it just as one would run alegitimate program.


But a new breed of computer virus can

infect machines and spread to others



infect machines and spread to othersentirely on its own. Simply by connecting acomputer to a network, the computerowner runs the risk of infection. Becausethe Internet connects computers aroundthe world, viruses can spread from oneend of the globe to the other in a matter of

minutes.



Types of Viruses

There are many categories of viruses,

including parasitic or file viruses



including parasitic or file viruses,bootstrap-sector , multipartite, macro,and script viruses. Then there are so-called computer worms, which havebecome particularly prevalent.

A computer worm is a type of virus.

Types of Viruses

However, instead of infecting files or

operating systems a worm replicates from



operating systems, a worm replicates fromcomputer to computer by spreading entirecopies of itself.

Strictly speaking, a computer virus isalways a program that attaches itself tosome other program. But computer virushas become a blanket term that also refersto computer worms.

Parasitic or file viruses

Parasitic or file viruses infect executable

files or programs in the computer These



files or programs in the computer. Thesefiles are often identified by the extension.exe in the name of the computer file.

File viruses leave the contents of the hostprogram unchanged but attach to the hostin such a way that the virus code is runfirst.

Bootstrap-sector viruses

Bootstrap-sector viruses reside on the first

portion of the hard disk or floppy disk



portion of the hard disk or floppy disk,known as the boot sector.

These viruses replace either the programs

that store information about the disk'scontents or the programs that start thecomputer.

Typically, these viruses spread by meansof the physical exchange of floppy disks.

Multipartite viruses

Multipartite viruses combine the abilities of

the parasitic and the bootstrap sector



the parasitic and the bootstrap-sectorviruses, and so are able to infect eitherfiles or boot sectors.

These types of viruses can spread if acomputer user boots from an infecteddiskette or accesses infected files.

Macro viruses

Other viruses infect programs that contain

powerful macro languages (programming



powerful macro languages (programminglanguages that let the user create newfeatures and utilities).

These viruses, called macro viruses, arewritten in macro languages andautomatically execute when the legitimateprogram is opened.

Script viruses

Script viruses are written in script

programming languages such as VBScript



programming languages, such as VBScript(Visual Basic Script) and JavaScript.These script languages can be seen as aspecial kind of macro language and areeven more powerful because most areclosely related to the operating systemenvironment.

Script viruses

The 'ILOVEYOU' virus, which appeared in

2000 and infected an estimated 1 in 5



2000 and infected an estimated 1 in 5personal computers, is a famous exampleof a script virus.



Virus like programs

There are other harmful computer

programs that can be part of a virus but



programs that can be part of a virus butare not considered viruses because theydo not have the ability to replicate.

These programs fall into three categories:Trojan horses, logic bombs, anddeliberately harmful or malicioussoftware programs that run within a Web

browser.



Logic bomb

A logic bomb infects a computer‘s

memory but unlike a virus it does notli i lf



memory, but unlike a virus, it does notreplicate itself.

A logic bomb delivers its instructions when

it is triggered by a specific condition, suchas when a particular date or time isreached or when a combination of lettersis typed on a keyboard.

A logic bomb has the ability to erase ahard drive or delete certain files.

Malicious software programs

Malicious software programs that run

within a Web browser often appear in Javal t d A ti X t l



within a Web browser often appear in Javaapplets and ActiveX controls.

Because those controls and applets

require that certain components bedownloaded to a user‘s personal computer

(PC), activating an applet or control mightactually download malicious code.



HISTORY

History

In 1949 Hungarian American

mathematician John von Neumann atth I tit t f Ad d St d i



mathematician John von Neumann, atthe Institute for Advanced Study inPrinceton, proposed that it wastheoretically possible for a computerprogram to replicate.

This theory was tested in the 1950s at BellLaboratories when a game called Core

Wars was developed, in which playerscreated tiny computer programs thatattacked, erased, and tried to propagate

History

In 1983 American electrical engineer Fred

Cohen at the time a graduate studenti d th t i t d ib lf



Cohen, at the time a graduate student,coined the term v i rus to describe a self-replicating computer program.

In 1985 the first Trojan horses appeared,posing as a graphics-enhancing programcalled EGABTR and as a game calledNUKE-LA. A host of increasingly complex

viruses followed.



History

The VBS_LOVELETTER script virus,

also known as the Love Bug and theILOVEYOU i t d M li



also known as the Love Bug and theILOVEYOU virus, unseated Melissa asthe world's most prevalent and costly viruswhen it struck in May 2000.

By the time the outbreak was finallybrought under control, losses wereestimated at U.S.$10 billion, and the

Love Bug is said to have infected 1 inevery 5 PCs worldwide.

History

In 1995 the first macro language virus,

WinWord Concept was created In 1999th M li i d b



WinWord Concept, was created. In 1999the Melissa macro virus, spread by e-mail, disabled e-mail servers around theworld for several hours, and in somecases several days.

Regarded by some as the most prolificvirus ever, Melissa cost corporations

millions of dollars due to computerdowntime and lost productivity.

History

The year 2003 was a particularly bad year

for computer viruses and worms



for computer viruses and worms. First, the Blaster worm infected more than

10 million machines worldwide by

exploiting a flaw in Microsoft‘s Windowsoperating system. A machine that lackedthe appropriate patch could be infectedsimply by connecting to the Internet.



History

SoBig spread via e-mail, and before the

outbreak was 24 hours old MessageLabsa popular e mail filtering company



outbreak was 24 hours old, MessageLabs,a popular e-mail filtering company,captured more than a million SoBigmessages and called it the fastest-spreading virus in history.

I J 2004 h h M D

01. Basic Computer Concepts2

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