CONCEPTS OF INFORMATION TECHNOLOGY

MODULE-I

What is Information Technology

Information Technology(I.T.) is known as all the products and activities of the computing and telecommunications industry.

TYPES OF COMPUTERSThe types of computers range from the Hybrid to the Analog types. The computers you come across in the daily course of your day range from laptops, palmtops and towers, to desktop computers, to name a few. But the very word “computers” reminds one of the desktop computers used in offices or homes. Different categories of computes have been devised in keeping with our varied needs.The Types Of Computers: Analog and Hybrid (classification based on operational principle)Analog Computers: The analog computer is almost an extinct type of computer these days. It is different from a digital computer in respect that it can perform numerous mathematical operations simultaneously. Hybrid computers: These types of computers are, as the name suggests, a combination of both Analog and Digital computers. The Digital computers which work on the principle of binary digit system of “0” and “1” can give very precise results

Apart from this, computers are also categorized on the basis of physical structures and the purpose of their use. Based on Capacity, speed and reliability they can be divided into three categories of computers:

1. The Mainframe Computer – These are computers used by large organizations like meteorological surveys and statistical institutes for performing bulk mathematical computations. They are core computers which are used for desktop functions of over one hundred people simultaneously.

2. The Microcomputer – These are the most frequently used computers better known by the name of “Personal computers”. This is the type of computer meant for public use. Other than Desktop Computer the choice ranges as follows: Personal Digital Computer Tablet PC Towers Work Stations Laptops Hand Held Computer 3.The Mini computer – Mini computers like the mainframe computers are used by business organization. The difference being that it can support the simultaneous working of up to 100 users and is usually maintained in business organizations for the maintenance of accounts and finances.

Yet another category of computer is the Super Computers. It is somewhat similar to mainframe computers and is used in economic forecasts and engineering designs. Today life without computers is inconceivable. Usage of different types of computers has made life both smooth and fast paced.

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Computer system main components

Central Processing Unit(CPU)

Central processing unit is the main part of computer . The CPU controls the over all operation of computer . It works with control of DATA and also controlling logical functionality A CPU that is constructed on a single chip is called as MICROPRECESSOR. CPU process the information very fast this can be measured by CLOCK SPEED and the unit which is used are Megahertz(MHz),Gigahertz(GHz)

Above diagram showing flow of data in CPU

FLOW DIAGRAM

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Main Part Of PC

Monitor

Keyboard

CPU

Mouse

Monitor is that part of the computer hardware which is used as an output device. It is also known as a computer display monitor

A keyboard is the principal input device of the computer also forming an important part of the computer hardware

A mouse is a computer hardware component which is used for controlling the way in which a pointer or cursor moves on the display screen of a monitor .

Central processing units or CPUs are components of computer hardware which act like the computer's brain. They are the most important part which read the various instructions given by the computer programs and then process the data.

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Hardware concepts

• Smart terminals.• Dump terminals.• Peripherals.

What is an Output Device?

An output device is any peripheral device to which the computer gives the result after processing.

Examples of Output Devices

LCD monitor Speakers

Inkjet Printer Headphones

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Memory

• Volatile & Nonvolatile.• RAM & ROM.

Random Access Memory

Read Only Memory

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When you speak about the amount of memory a computer has, you refer to the RAM. The units of

measurement of computer memory are shown in the displayed figure.

• Bit• Byte• Kilobyte (KB)• Megabyte (MB)• Gigabyte (GB)• Terabyte (TB)

0 or 1 8 bits1024 byte1024 KB1024 MB1024 GB

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Computer storage units

STORAGE DEVICES:

There are two types of storage devices - Primary and Secondary storage devices. The

primary storage device for a computer is the Random Access Memory (RAM). It is a volatile storage device meaning that when the computer is switched off, data stored in the RAM is lost.

RAM (Random Access Memory)

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Storage Areas:

You have seen the various storage devices available to computer users. Now you will see how to recognize these areas on your computer. To open the “Computer” window, click on the “Start” button and select “Computer”. You can see the various storage areas on your computer.

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• Normally, when an error screen is displayed, you are provided with options to exit the program. Appropriate warnings related to loss of data or other consequences of exit are displayed when you opt to exit.

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Problem Solving• Sometime problems can occur due to

hardware or software. In many cases you will be alerted to a problem by an on-screen message or prompt which may give instructions on how to deal with the problem.

• Sometimes an application may encounter a problem and have to close down.

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System Software• System software is software that

basically allows the user to work. Without the system software the computer cannot do any work.

Examples:

Operating System• An Operating System is a system software

that manages all the computer operations and the computer devices.

• It does storage management and device management.

Examples of Operating System :• Microsoft Windows XP, Vista,2000.• Macintosh.• Unix.• Linux.

More Examples..

Application Software• Software that allows you to do things

like create text documents, play games, listen to music, or surf the web is called application software.

Examples of Application Software:• Microsoft Word, • Microsoft Excel, • Microsoft PowerPoint, • Internet Explorer etc.

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Windows

• Created in 1991 by Finnish student Linus Torvalds

• Linux= Linus + Unix

Solaris

Linux

Mac OS

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Floppy Disk CD DVD

HardDisk Tap-Drive

Flash CD-Drive

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Processor

Megahertz

MHz

Or

Gigahertz

GHz

Processor inside motherboard

What affects computer speed?

Highest to lowest

“Computer Performance” refers to the amount of useful work accomplished by a computer system compared to the time and resources used. You can judge performance according to how quickly tasks are performed. The overall operating speed of a PC depends on various factors which are as follows.

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Case- chassis- system unit

Motherboard

Input & Output ports

Touch screen

Multi-function printer

ADSL modem/ Wi-Fi router

Internal modem

Network card- Ethernet card

USB Wi-Fi card

PCMCIA Wi-Fi card

Wi-Fi card with antenna

Ethernet switch

UPS (Uninterrupted Power Supply)

Examples of Input Devices

What is an Input Device?

An input device is any peripheral device used to provide data to the computer.

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Keyboard Scanner

Joystick Microphone

Types of Memory RAM: This is the memory that a computer uses for storing programs and their

data while working on them. For example, you may use a word processor application to draft a letter. While you are entering the contents, they are stored in the RAM. When you save your letter, it is moved from the RAM and stored onto your hard disk. Later, you may retrieve your letter and make some changes. It is then again copied into the RAM. Thus the RAM functions as a scratch pad and is sometimes called the “scratchpad” memory.

The two main characteristics of the RAM are:1) The data in the RAM can be read or modified. Hence it is called read/write

memory.2) The data in the RAM is lost after the program is terminated or the computer is

switched off.

ROM: The ROM contains permanently recorded instructions that are vital for starting up a computer. The programs in the ROM perform the most basic control and supervisory operations. They check whether all the input and output devices are connected properly to the system unit.

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Software

System Software Application Software

Applications• Programs used for different purposes other than programming software or

system software.• For example:• Word Processing: (Note Pad, Word Pad, MS Word, Writer, Word

Perfect, Adobe Acrobat). • Spread Sheets: (MS Excel).• Databases: (MS Access).• Presentations: (MS Power Point).• E-mail client: (MS Outlook, Outlook Express, Eudora, Incredimail,

The Bat).• 2D graphics creation and editing: (MS Paint, Adobe Photo shop,

Coral Draw, Paint Shop Pro, The Gimp).• 3D graphics creation and editing: (3D Max, Maya, Softimage).• Web Browsers: (Internet Explore- IE, Netscape Navigator, Opera,

Fire Fox).• Media Players: (Windows Media Player, Real Player, WinAmp).• Instant Messengers: (AOL Messenger, MSN Messenger, Yahoo

Messengers, ICQ).

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Operating System (OS)

• A special computer program that manages the relationship between application software, the wide variety of hardware that makes up a computer system, and the user of the system.

Mac OS

• Created in 1984.• By Apple Company.• The only OS that is 100%

compatible with its hardware.

• One of the best OS.

http://en.wikipedia.org/wiki/Mac_OS

Programming languages• Python.• Fortran.• COBOL.• Perl.• C• C++.• C#.• Visual Basic.• Java.• Java Script.

Software designing phases

System Development

The development of computer based systems includes four main steps which are: analysis, programming, testing and documentation. There may be some variations to this procedure depending upon the size, complexity and nature of the application.

Analysis:

Once the need for computerization has been identified, the basic objectives to be achieved are known. Then more structured methodologies need to be followed. This is where a “Systems Analyst” comes in. Systems Analysis involves the creation of program specifications, anticipating hardware requirements and making estimates of the final system size. A systems analyst’s tasks include meeting key staff members to get a clear picture of the actual manual procedures involved in the activity to be computerized. As a result of the analysis, a “design” for the proposed system is generated.

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Programming:

Sometimes the objectives of a system can be achieved by an available ready-to-use computer package. If not, special programs need to written for specific purposes. This is where “Programmers” come in. The computer language that is used for the programs depends on the nature of the task and integration with existing systems, if any.

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Testing:

The system needs to be tested at all stages of its development to ensure that all objectives are achieved. It is very important to remove all programming errors or “bugs” which may result in problems at later stages. Testing of a system is done by programmers at the programming stage and by the staff of the organization after it is ready. Various testing techniques may be adopted. “Beta testing” is the last stage of testing, and normally involves sending the product to select outside users for real-world exposure.

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• Documentation: After the system has been tested, its details need to be documented. Documentation of two types is normally done. One type includes technical details to enable future maintenance and the other one contains operational instructions for end users of the system.

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HARDWARE/SOFTWARE

Hardware: The hardware consists of all devices of the computer that you can see and touch. These include input, processing and output devices.

Software: The software of a computer system refers to the organized sets of instructions that control the working of the computer’s operations. These instructions are stored as programs. Some programs are used by the computer to control its own tasks and devices.

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Managing the System

Sometimes, you may face a problem with the hardware of your system. To check the functioning of each of the hardware devices you may access the “Device Manager”. You will then be able to monitor and fix any problem you have encountered. Click on the “Start” button and select “Control Panel”. Now select “System and Maintenance → Device Manager”. Click “Continue” in the window displayed.

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Types of networks

• By coverage: LAN WAN

• By User type: Intranet Extranet

• By transfer medium: Wired Wireless

• By Topology: Bus Ring Star Mesh

LAN - Local Area Network

A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. In TCP/IP(Transfer Control Protocol/Internet Protocol) networking, a LAN is often but not always implemented as a single IP subnet.

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WAN - Wide Area Network

• As the term implies, a WAN spans a large physical distance. The Internet is the largest WAN, spanning the Earth. A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address.

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The Telephone Network• The public switched telephone network (PSTN) is

the network of the world's public circuit-switched telephone networks, in much the same way that the Internet is the network of the world's public IP-based packet-switched networks.

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Internet:

The word “Internet” is derived from the word inter-networking which means connecting different networks together. Thus the Internet can be termed as a Network of Networks.

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Intranets and Extranets

• An "intranet" is the generic term for a collection of private computer networks within an organization. An "extranet" is a computer network that allows controlled access from the outside for specific business or educational purposes.

• Intranets and extranets are communication tools designed to enable easy information sharing within workgroups.

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How Intranet Works

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What is Electronic mail

Electronic mail, often abbreviated as email or e-mail, is a method of exchanging digital messages, designed primarily for human use. E-mail systems are based on a store-and-forward model in which e-mail computer server systems accept, forward, deliver and store messages on behalf of users.

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Computers at Work..

You must understand the impact of computers in the world today. Computers are affecting our lives is some way or the other. Airline and railway reservations, telephone and electricity bills, banking, medical diagnoses, weather forecasts… the list of services using computers is almost endless.

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Computers at work

• Computer In Businessa) Airline Bookingb) Banksc) Insurance Companiesd) Claim Processing• Computers in Healthcare• a)To keep patient’s record• b)Ambulance control system• c)Diagnosis• d)Surgical equipments and instruments.• Computers in Governments• a)To keep public records .• b)To keep Social Security Number.• c)Vehicle registration.• d)Census information.

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The Electronic World

Information Superhighway-It is used to describe a situation where information of any kind ,anywhere in the World,would be available to anyone,eho had access to a PC linked to the internet.

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Security, copyright and law

• Program license:EULA.Intellectual property rights.

• Backup:Incremental.Differential.

• Virus/ Antivirus.• Y2K problem.• Privacy & security.• Data Protection Act.

Computer & Health

• Health precautions:Back\neck.Eyes.Wrists.Legs.RSI (Repetitive Strain Injury).

• Computer safety & ergonomics:Ventilation.Chair design.Lighting.

Health and Safety

Health precautions:• Back\neck.• Eyes.• Wrists.• Legs.• RSI (Repetitive Strain Injury).• Computer safety &

ergonomics:• Ventilation.• Chair design.• Lighting.

Ergonomics: The term “ergonomics” refers to the relationship between workers and their working environment. The Health and Safety at Work Act (HASWAW) lays down wide-ranging duties on employers and sets out the basic principles by which Health and Safety at Work is regulated. An employee too must take responsibility for his own safety at the workplace.

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Some of the aspects of the working environment that need to be kept in mind are as follows:

1) There should be adequate lighting and ventilation

2) Computer screens should be appropriately positioned and of good quality.

3) Chairs should be adjustable and comfortable and desks should be stable and spacious.

4) All equipment should be suitably positioned. 5) Frequent breaks away from the computer

should be provided.

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Protecting computer & disks

• No food.• No beverages.• No mobile phones\ electromagnetic devices.• No heat\ direct sun rays.• No humidity.• Shut down properly.• Use UPS.• Regular maintenance (disk cleanup-scandisk-

defrag).• Use protection software (Antivirus-anti spyware-

firewall).• Backup and disk imaging.

Information security

• Information security means protecting information and information systems from unauthorized access, use, disclosure, disruption, modification or destruction

What is a Virus?• A computer virus is a computer program that can copy itself

and infect a computer without the permission or knowledge of the owner. The term "virus" is also commonly but erroneously used to refer to other types of malware, adware, and spyware programs that do not have the reproductive ability. A true virus can only spread from one computer to another (in some form of executable code) when its host is taken to the target computer; for instance because a user sent it over a network or the Internet, or carried it on a removable medium such as a floppy disk, CD, DVD, or USB drive.

• Some of the popular antivirus packages are Norton Antivirus, MacAfee, Dr. Soloman, PcClean and Quick Heal etc.

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• Software copyright legislation: This exists in order to give the developers of software the same legal protection which authors of published, written and musical works have. Software copyright operates in such a way that the individual who buys a computer program does not become the owner of the program. He only purchases the right to use it and gets a “single user license”. This enables him to install one copy of the software on a single computer. The license accompanying the software sets out exactly what he is permitted to do without breaking copyright laws.

• copy prevention and copy restriction, is a technology for preventing the reproduction of copyright ed software, movies, music, and other media..

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The Data Protection Act (1998)

Regulates the use of personal data by all businesses. It aims to protect an individual’s right to privacy by promoting high standards in handling of personal information. This act defines personal data as any data that can be used to identify a living individual, including names, addresses, e-mail addresses etc. Under this act the “data controller” is the person who determines the purposes for which and the manner in which any personal data is to be processed.

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When you press your computer’s power button to startup, the PC needs to get oriented. The computer reads several files and performs a series of tests to make sure all its hardware components are working properly.

We shall see the startup procedure using the operating system Windows VISTA / Windows XP.

STARTING THE COMPUTER

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