INTRODUCTION TO

COMPUTERS

23-7-2014

Introduction to Computers

Its an electronic Device that is used for information Processing.

Computer.. Latin word.. compute

Calculation Machine

A computer system includes a computer, peripheral devices, and software

Accepts input, processes data, stores data, and produces output

Input refers to whatever is sent to a Computer system

Data refers to the symbols that represent facts, objects, and ideas

Processing is the way that a computer manipulates data

A computer processes data in a device called the central processing unit

(CPU)

How Computer Works

DEFINITION OF COMPUTER

• Computer can be defined as “An electronic and electromechanical device capable of receiving data, processing the data inputted, and generating the output in the form of information”. In the definition, we come across some terminologies such as electronic, electromechanical device etc.

• An electric device is that device which runs by electricity.

• An electromechanical device is one which performs mechanical movements upon receiving the electricity. Whatever we are inputting into the computer will be treated as Data and whatever has been generated by computer will be treated as Information.

CHARACTERISITICS OF A COMPUTER

Main characteristics of the computer can be summarized as:

1. Speed: Computer is very fast and accurate device. It can process millions

and millions of instructions within

seconds.

2. Accuracy: Computer results are highly accurate.

3. Memory: Computers have a large amount of memory to

hold a very large amount of data or information.

4. Programmed Intelligence: Computer themselves as such are dumb

terminals. But they are programmed in such a way that they can perform

those operations which have been fed into them in the form of executable

programs.

CHARACTERISITICS OF A COMPUTER

5. Diligence: Computer is free from problems like lack of

concentration, and confusions etc. Computer may never be confused like

humans.

6. Versatility: We can perform many different types of tasks on computer.

One moment it might be busy in calculating the statistical date for annual

performance evaluation of a business organization and next moment it

might be working on playing movies.

7. Power of Remembrance: Unlike humans, computer can store things for

unlimited period of time.

TYPES OF COMPUTER-1

There are two basic kinds of computers:

Analog and Digital.

Analog computers - Analog computers are analog devices. That is, they have

continuous states rather than discrete numbered states. An analog computer

can represent fractional values exactly, with no round off. Analog

computers are almost never used outside of experimental settings. They

handle or process information, which is of physical nature.

Electronic analog computers generally in chemical plants monitoring

temperatures, pressures, voltage, etc.

Now these days, we rarely came across of analog computers in routine life.

TYPES OF COMPUTER-2

Digital Computer

Digital computer is a programmable-clocked sequential state machine. A digital computer uses discrete states. A binary digital computer uses two discrete states, such as positive/negative, high/low, on/off, used to represent the binary digits zero and one. They process data, which is essentially in a binary state.

In other word digital computer refer to a computer, which represent, the data, whether numbers, letter, or symbols, in binary form and they work with numbers in the form of separate discrete digits.

TYPES OF COMPUTER-3

Hybrid Computer

It refers to computer that contain both digital and analog circuit.

EXAMPLE

A digital thermometer employs a mechanism which converts the

temperature into digital form observed in analog signals using to analog-to-

digital conversion

CLASSIFICATION OF COMPUTERS

• Since the advent of the first computer different types and sizes

of computers are offering different services. Computers can

be as big as occupying a large building and as small as a laptop

or a microcontroller in mobile & embedded systems.

• The classification are as follows

– Super computer

– Mainframe Computer

– Minicomputer

– Microcomputer

SUPER COMPUTER

• The most powerful computers in terms of performance and data processing are the supercomputers.

• These are specialized and task specific computers used by large organizations.

• These computers are used for research and exploration purposes, like NASA uses supercomputers for launching space shuttles, controlling them and for space exploration purpose.

• The supercomputers are very expensive and very large in size. It can be accommodated in large air-conditioned rooms; some super computers can span an entire building.

USES OF SUPER COMPUTER

In Pakistan and other countries Supercomputers are used by Educational Institutes like NUST (Pakistan) for research purposes. Pakistan Atomic Energy commission & Heavy Industry Taxila uses supercomputers for Research purposes.

• Space Exploration

Supercomputers are used to study the origin of the universe, the dark-matters. For these studies scientist use IBM’s powerful supercomputer “Roadrunner” at National Laboratory Los Alamos.

• Earthquake studies

Supercomputers are used to study the Earthquakes phenomenon. Besides that supercomputers are used for natural resources exploration, like natural gas, petroleum, coal, etc.

• Weather Forecasting

Supercomputers are used for weather forecasting, and to study the nature and extent of Hurricanes, Rainfalls, windstorms, etc.

• Nuclear weapons testing

Supercomputers are used to run weapon simulation that can test the Range, accuracy & impact of Nuclear weapons.

POPULAR SUPER COMPUTERS

• IBM’s Sequoia, in United

States

• Fujitsu’s K Computer in Japan

• IBM’s Mira in United States

• IBM’s SuperMUC in

Germany

• NUDT Tianhe-1A in China

MAIN FRAME COMPUTER

• Although Mainframes are not as powerful as supercomputers, but certainly they are quite expensive nonetheless, and many large firms & government organizations uses Mainframes to run their business operations.

• The Mainframe computers can be accommodated in large air-conditioned rooms because of its size. Super-computers are the fastest computers with large data storage capacity,

• Mainframes can also process & store large amount of data. Banks educational institutions & insurance companies use mainframe computers to store data about their customers, students & insurance policy holders.

• Popular Mainframe computers

• Fujitsu’s ICL VME

• Hitachi’s Z800

MINI COMPUTER

• Minicomputers are used by small businesses & firms. Minicomputers are also

called as “Midrange Computers”. These are small machines and can be

accommodated on a disk with not as processing and data storage capabilities as

super-computers & Mainframes.

• These computers are not designed for a single user. Individual departments of a

large company or organizations use Mini-computers for specific purposes. For

example, a production department can use Mini-computers for monitoring certain

production process.

• Popular Minicomputers

• K-202

• Texas Instrument TI-990

• SDS-92

• IBM Midrange computers

MICRO COMPUTER

• Desktop computers, laptops, personal digital assistant (PDA), tablets & smartphones are all types of microcomputers.

• The micro-computers are widely used & the fastest growing computers. These computers are the cheapest among the other three types of computers.

• The Micro-computers are specially designed for general usage like entertainment, education and work purposes. Well known manufacturers of Micro-computer are Dell, Apple, Samsung, Sony & Toshiba.

• Desktop computers, Gaming consoles, Sound & Navigation system of a car, Net books, Notebooks, PDA’s, Tablet PC’s, Smart phones, Calculators are all type of Microcomputers.

ROLE OF COMPUTERS IN SOCIETY

• Computers play a great role in the society. Whether at home, in school, at the mall or in the office, computers significantly help in the accomplishment of various tasks. Be it at work or at play, computers have undeniably been utilized to perform general or specific activities that enable life to be more convenient and worry-free

• Computers in Business

In the field of business, computers are very useful. They are used in keeping records of daily sales and profits. Computers are also used to prepare materials to promote the products of the Business establishments.

• Computers in Engineering

Engineers use computers to create the design of a complex object using a computer program for Computer-Aided Drafting.

• Computers in the Government

Computers are used to keep records of the people that the government serves. Several government agencies use computers to facilitate the task they are required to give to the people.

ROLE OF COMPUTERS IN SOCIETY

• Computers at Home

Computers are used at home for recreational purposes. You can listen to music, watch movies and play games. Children use their computers at home to do their schoolwork. Parents use computers to assist them in doing their daily tasks. If your computer at home has internet access, then you can explore the amazing features of the Internet in the comfort of your home..

• Computers in Manufacturing

Computers are used in manufacturing to manipulate machine that perform dangerous tasks or tasks that are repeatedly done.

• Computers in School

Computer Education is one subject taught in schools today. Teachers use computers in classroom instruction, in computing grades and in preparing visual aids. Students use computers to study various computer applications. Libraries are connected to the Internet and students access the internet to do research.

• Computers in Science

Computers are used in science to stimulate experiments, which are dangerous to perform in real life. Computers are also used to record data and information derived from experiments.

HARDWARE

• Hardware, in the computer world, refers to the physical components that make up a computer system. There are many different kinds of hardware that can be installed inside, and connected to the outside, of a computer.

• Here are some common individual computer hardware components that you'll often find inside a modern computer case:

• Motherboard

• Central Processing Unit (CPU)

• Random Access Memory (RAM)

• Power Supply

• Video Card

• Hard Drive (HDD)

• Solid-State Drive (SSD)

• Optical Drive (e.g. BD/DVD/CD drive)

• Card Reader (SD/SDHC, CF, etc.)

HARDWARE

SOFTWARE TYPES

• Traditionally, software has been divided into two different categories: systems software and applications software. However, in addition to those, an entire new batch of wares has entered the computer vernacular in recent years.

• What is System Software?

System software sits directly on top of your computer's hardware components (also referred to as its bare metal). It includes the range of software you would install to your system that enables it to function. This includes the operating system, drivers for your hardware devices, linkers and debuggers. Systems software can also be used for managing computer resources. Systems software is designed to be used by the computer system itself, not human users.

• Application Software Defined

Unlike systems software, applications software is designed to be used by end-users. Applications software, in essence, sits on top of system software, as it is unable to run without the operating system and other utilities. Applications software includes things like database programs, word processors and spreadsheets, e-mail applications, computer games, graphics programs and such. Generally, people will refer to applications software as software.

Different Types of Operating

System

Storage Devices -1

Primary storage: is the storage provided by memory in a computer

system

e.g. ROM/RAM.

Secondary storage: is storage provided by peripheral devices other

than memory

Secondary storage: is required in a computer system for three reasons

1. The content of memory is usually volatile, which means that if power is

disconnected the data is lost.

2. The capacity in megabytes of memory is limited.

3. Memory is more expensive than secondary

storage.

Storage Devices -2

Several types of disks may be used for Secondary storage.

• Floppy disks

• Hard disks

• Optical disks (including CD-ROM, writeable CD, DVD

• Backup Storage Devices e.g. tape

Storage Devices -3

Floppy Disk

A floppy disk is a low capacity disk which may be removed from the computer.

There are two types:

Those holding a small amount of data (typically 1.44 Mb )

And ‘Super floppies’ known as ZIP disks (typically 100 Mb )

Data may be written to and read from a floppy. A small notch can be used to make the

disk read-only

Storage Devices -4

Floppy Disk

They are small lightweight and easy to transport.

Ideal for backups of small amounts of data or for transfer of data from one

machine to another.

Floppy Drives are common to most if not all computers.

On the down side, they may be easily misplaced, damaged or stolen.

There is a risk of transferring VIRUSES

Storage Devices -5

Hard Disk

A hard disk is a higher capacity medium, with up to

hundreds of gigabytes.

They are usually non-removable, but removable hard disks are becoming more

common.

They can be both read from and written to, and are the standard medium for

storage on computer systems today.

Storage Devices -6

Hard Disk

Hard disks are manufactured in metal and coated with a magnetisable recording medium,

similar tothe material used in a floppy disk or audio tape.

Depending on the storage capacity of the unit, it may comprise a number of disks each

having its ownread/write head.

Hard disks are much faster than floppy disks and can store much larger amounts of data.

Storage Devices -7

Hard Disk

Storage Devices -8

Optical disks

DVD disks provide high quality playback of films and audio and are increasingly found

as standard on the home PC.

DVDs may be read only or read/write. They are sometimes know as DVD-ROM and

DVD-RAM.

DVD or Digital Versatile Disk is a higher capacity version of a CD and DVD drives

have a higher transfer rate.

Storage Devices -9

This section will cover computer programming, including its history and the progression of computer-programming languages.

Computer Programming

A computer program is a set of step-by-step instructions that tell a computer exactly what to do. People who write computer programs are called programmers. When the step-by-step instructions are followed, the results will be those anticipated by the programmer. The computer program will include decision points and actions to be taken depending on the decision made.

Computer Programs

Places Where Computer Programs Are Used

There are computer programs working behind the scenes in many places. Grocery stores use computer programs to scan the labels on

grocery items. Hospitals use computer programs to keep patient records and

scan identification bracelets. Colleges use computer programs to register students for classes

and calculate grades. Gas stations use computer programs to dispense gas and accept

payment. Banks use computer programs to dispense cash and track

account balances.

The content of a computer program is called code. The sample code on the right is written in Python. It first defines fruits, and then it instructs the computer to print the statements with the appropriate fruits.

Example of a Computer Program

Computer Programming

Computer programming is the process of writing the step-by-step instructions a computer can understand. The first step in computer programming

is defining the problem. The next step is creating a logic problem

that can be solved using a computer program.

Writing the actual program is the last step in the process.

Computers read binary machine language made up of 0s and 1s. Because it is difficult for programmers to create a program in machine language, high-level programming languages have been developed.

A compiler or interpreter is then used to translate the high-level programming language into the machine language that the computer can understand.

Computer-Programming Languages Like all forms of language, computer-programming languages enable the communication of information. Programming languages allow programmers to communicate instructions to the computer. Just as there are different languages like English, Spanish, and French, there are different programming languages. These programming languages have their own syntax, which are rules for how the language is used. In the same way that French and Spanish use different words to mean the same thing, different programming languages use different commands to achieve the same result.

Panel switches were used by hand to program computers in the 1940s to enter instructions and data. It was important that the programmers knew the instruction set for each processor. As computers became more advanced, computer programs began to handle some of the entering of the instructions and data. Programmers would handwrite the directions in assembly language programs. Then the Assembly language, a low-level programming language, would translate the instructions into binary machine language for the computer to understand the directions.

1940s: Programming Languages

1950s: Programming Languages

The first high-level programming languages were created in the 1950s. Examples include the following: FORTRAN was the first high-level

programming language and used the first compiler. FORTRAN is an acronym for FORmula TRANslation. It remains a top language in scientific programming.

COBOL was one of the earliest high-level programming languages designed for business applications. COBOL is an acronym for Common Business-Oriented Language.

LISP was developed and used for research in artificial intelligence.

During the 1960s, two important programming languages were developed: C and BASIC. First the B and then the C computer-programming

languages were developed in the 1960s at Bell Laboratories. Later in 1973, Unix was written in C programming language. Can you believe this simple operating system became the inspiration for Linux and Apple OS?

In 1964, the BASIC programming language was developed at Dartmouth College. BASIC is an acronym for Beginner’s All-purpose Symbolic Instruction Code. This language was designed to make it easy for students to write programs at shared terminals while learning programming at the college.

1960s: Programming Languages

1970s: Programming Languages

During the 1970s, Microsoft began to release computer-programming software, and a programming language was developed for use in teaching programming. Pascal programming language was first

defined in 1971, with revisions released in 1973. It was designed to teach programming to college students. Until the 1990s, it was considered the best language for teaching programming.

In 1975, Microsoft announced the release of Altair BASIC, the first programming language for personal computers.

1980s: Programming Languages Many new programming languages were developed and introduced in the 1980s. Ada was published in 1980 as the result of a comprehensive

development project by the US Department of Defense (DoD) to create a standardized programming language to replace the 450 programming languages used across the DoD and in the Army, Navy, and Air Force.

Microsoft developed versions of BASIC, FORTRAN, COBOL, and Pascal for IBM for its personal computer in 1980.

C++ programming language was released by Bjarne Stroustrup in 1985.

Borland’s Turbo Pascal programming language was released. dBASE programming language and database formulae was

developed. Perl programming language was created in 1986. Perl is an

acronym for Practical Extraction and Report Language. Microsoft released Visual BASIC in 1987.

Introduced in the 1960s, object-oriented programming (OOP) grew in influence in the 1980s. With object-oriented programming: a program is divided into parts known as

objects. objects can contain data. objects can contain programs that

perform a specific function.

The “objects” in OOP were important because they allowed programmers to handle increasingly complex programs and collaborate more effectively.

Importance of Object-Oriented Programming

Web-based programming, also known as browser-based programming, is a significant innovation of the 1990s through present time. Web-based programming enables your web browser to access a server maintained by a large company or other organization. For example, an online merchant uses a server that you can access using your web browser so you can buy products from their website. Java programming language was developed at Sun Microsystems and released in 1995. Sun Microsystems has since merged with Oracle, which oversees the continued development of the language

1990s through Present time: Programming Innovation

NETWORKS

Arguably, the greatest advancement in technology and

communication over the past 20 years has been the development

and advancement of the computer network. From emailing a

friend to on-line bill paying to downloading data off the Internet to

e-commerce, networking has made our world much smaller and

changed the way we communicate forever.

THE COMPUTER NETWORK

net·work: [net-wurk] – noun, a system containing any

combination of computers, computer terminals, printers,

audio or visual display devices, or telephones

interconnected by telecommunication equipment or

cables: used to transmit or receive information.

WHAT IS A COMPUTER NETWORK?

The Internet

Other LANS

Firewall

Router

Fiber Optic Network Cable

Server

PC

Wireless Network

Wired Network

Switch

NETWORK DIAGRAM

PEER TO PEER

WIDE AREA LOCAL AREA

THREE TYPES OF NETWORK

• A Wide Area Network exist over a large area

• Data travels through telephone or cable lines

• Usually requires a Modem

• The world’s largest Wide Area Network in the

Internet

WIDE AREA NETWORK

• A Local Area Network spans a relatively small

area

• LAN are usually confined to one building or a

group of buildings

• Data travel between network devices via

network cables.

• The most common type of Local Area Network

is called Ethernet

LOCAL AREA NETWORK

• Usually very small networks

• Each workstation has equivalent capabilities

and responsibilities

• Does not require a switch or a hub.

• These types of networks do not perform well

under heavy data loads.

PEER TO PEER NETWORK

• Reduces interference in the network

• Transmit data faster than copper network cable

• Allows for more bandwidth

• Smaller and more fragile than copper cable

Standard

Network

Copper Cable

FIBER OPTIC CABLE

• Data travels faster through switches because data is not

sequenced as it is in a hub

• The information is more secure when it passes through

a switch as opposed to a hub.

• Information travels more efficiently through a switch

because travels directly to it’s destination as opposed

to being broadcast to all PC’s on the network hub.

Network Switches Network Hubs

SWITCHES AND HUBS

VIRUS Introduction

• Computer viruses are a type of software program that, like a biological

virus, reproduces and spreads itself

• Some virus may display only a message on the screen, others may slow

down the Pc

• They can also erase files or even format your floppy or hard disk and crash

the system

Symptoms

• Letters looks like they are falling to the bottom of the screen.

• The computer system becomes slow.

• The size of available free memory reduces.

• The hard disk runs out of space.

• The computer does not boot.

How does it spread

• Computer viruses spread by attaching themselves to other computer

program files

• When you exchange a file or pen drive with a virus, the virus spreads from

one computer to the another

• Viruses also spreads when a Computer Engineer comes to repair your

system and puts his/her diagnostics disks in your PC

Types of computer viruses

• Boot viruses:- The boot virus copies the virus

code in the boot sector

• Polymorphic viruses:- They are coded in such

a way that they infect a system and change their

signature

• Macro viruses:- Macros are blocks of code

written to automate frequently performed tasks

and embedded in a program file

• Worms:- Worms are program that replicate and

spread to other system

• Trojans:- A Trojan is a program file that claims

Preservation and cure

• Install an Antivirus software

• Regularly update the program

• Open email attachment files only if you are

expecting the attached files, or the sender is

known and has confirmed sending the file

• Try to avoid downloading and installing software

from the Internet

• Install only registered copies of software on the

system

Antivirus Software

• Norton Anti-Virus

• MaCfee

• Avast

• Quick Heal

• Panda

Hacking

• Hobby/profession of working with computers.

• Breaking into computers

• Gaining access

Types of Hacking

• Website Hacking

• Email Hacking

• Network Hacking

• Password Hacking

• Online banking Hacking

• Computer Hacking

Website Hacking

• Main focus- Vulnerable loopholes

• Collapses the information

• Make changes in the information

Email Hacking

• Can Emails Be Hacked?

• Store business data, private

information

• Serious precautions are not taken

Computer Hacking

• Steals information from pc

• Remote desktop connection technique

• Accessing other person’s files

Online banking Hacking

• Online banking disadvantages

• Hackers create fake websites

• Using proper website address

Ethical Hacking

• Computer or network expert

• Seeking vulnerabilities

• Victims – Official & Private

websites

What do ethical hackers do?

An ethical hacker’s evaluation of a system security seeks answers to these

basic question:

What can an intruder see on the target systems?

What are you trying to protect ?

What can an intruder do with that information ?

• Thousands of dollars in fines

• Imprisonment

• Seizure of your computer

Consequences

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