Shortcut Keys

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Short-cut keys Functions
Commonly Used Short-cut Keys
F1	Universal help (for any sort of program).
Alt + F	File menu options in current program.
Alt + E	Edits options in current program.
Ctrl + A	Selects all text.
Ctrl + X	Cuts the selected item.
Ctrl + C	Copies the selected item.
Ctrl + V	Pastes copied item.
Home	Takes the user to the beginning of the current line.
End	Takes the user to the end of the current line.
Ctrl + Home	Takes the user to the beginning of the document.
Ctrl + End	Takes the user to the end of the document.
Shift + Home	Highlights from the current place to the beginning of line.
Shift + End	Highlights from the current place to the end of line.
Microsoft Windows Shortcut Keys
Ctrl + F4	Closes window in program.
Alt + F4	Closes current open program.
F2	Renames the selected icon.
F3	Start find from desktop.
F4	Opens the drive selection when browsing.
F5	Refreshes contents.
Alt + Tab	Switches from one open application to another open application.
Alt + Shift + Tab	Switches backwards between open applications.
Alt + Print Screen	Creates screen shot for current program.
Ctrl + Alt + Del.	Opens windows task manager/reboot.
Ctrl + Esc	Brings up start menu.
Alt + Esc	Switches between applications on taskbar.
Ctrl + Plus (+) Key	Automatically adjusts widths of all columns in Windows Explorer.
Alt + Enter	Opens properties window of selected icon or program.
Shift + F10	Simulates right-click on selected item.
Shift + Del	Deletes selected programs/files permanently.
Holding Shift During Boot-up	Enables boot safe mode or bypass system files.
Ctrl + N	Starts a new note.
Ctrl + O	Opens a recently used note.
Ctrl + S	Saves changes to a note.
Ctrl + P	Prints a note.
Alt + F4	Closes a note and its Journal window.
Ctrl + Z	Helps Undo a change.
Ctrl + Y	Helps Redo a change.
Ctrl + A	Selects all items on a page.
Ctrl + X	Cuts a selection.
Ctrl + C	Copies a selection to the Clipboard.
Ctrl + V	Pastes a selection from the Clipboard.
Esc	Cancels a selection.
Ctrl + F	Start a search tool.
Ctrl + Shift + C	Display a shortcut menu for column headings in a note list.
Microsoft Word Shortcut Keys
Ctrl + N	Creates a new document.
Ctrl + O	Opens an existing document.
Ctrl + S	Saves changes to a document.
F12	Saves the document as a new file.
Ctrl + P	Prints a document.
Ctrl + Z	Helps Undo a change.
Ctrl + Y	Helps Redo a change.
Ctrl + A	Selects the whole document.
Ctrl + X	Helps cut a selection
Ctrl + C	Copies a selection to the Clipboard.
Ctrl + V	Pastes a selection from the Clipboard.
Ctrl + B	Makes selected text bold.
Ctrl + I	Italicizes selected text.
Ctrl + U	Underlines selected texts.
Ctrl + L	Aligns text left.
Ctrl + R	Aligns text right.
Ctrl + E	Aligns text center.
Ctrl + J	Helps justify text.
Ctrl + 1	Sets single line spacing.
Ctrl + 2	Sets double line spacing.
Ctrl + 5	Sets line spacing to 1.5.
Ctrl + Shift + A	Changes characters to all capitals.
Ctrl + D	Inserts a Microsoft Paint drawing.
Ctrl + F	Finds text
Ctrl + Home	Moves to the beginning of the document.
Ctrl + End	Moves to the end of the document.

Development

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In this chapter, we will discuss the development in Computer Science chronologically.

The following table lists down the development −

Year	Development
1959	Transistors: IBM 7090; IBM 1401
1962	NPN transistor
1963	Mouse; CMOS patented
1964	CDC 6600; IBM Data Cell Drive
1966	Integrated circuits: HP 2116A
1966	Apollo Guidance Computer
1969	Honeywell 316
1971	8" floppy disk; ILLIAC IV
1973	Micral first microprocessor PC
1980	Sinclair ZX80, Seagate hard disk drive
1981	IBM PC, Acorn BBC Micro
1983	Apple Lisa; 3.5" floppy
1984	Apple Mac; Apple Lisa 2
1988	Dell
1989	NeXT
1991	Apple Switches to PowerPC
1992	HP 95LX; Palmtop PC
1995	IBM Deep Blue chess computer
1996	USB 1.0
1997	Compaq buys Tandem; CD-RW
1998	iMac
2000	USB 2
2001	Apple iPod
2005	Mac Mini
2006	Apple transition to Intel
2007	iPhone 1
2008	USB 3.0
2010	Apple iPad
2012	IBM zEnterprise System

Abbreviations

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In this chapter, we will discuss the different abbreviations in Computer Science. The following table lists down those abbreviations −

Abbreviation	Full-name
A/D	Analog-to-Digital
ABC	Atanasoff Berry Computer
ACM	Association for Computing Machinery
AI	Artificial Intelligence
ALGOL	Algorithic Language
ALU	Arithmetic Logic Unit
AMD	Advanced Micro Devices
APRANET	Advanced Research Project Agency Network
ASCII	American Standard Code for Information Interchange
BASIC	Beginners All-purpose Symbolic Instruction Code
BCD	Binary Coded Decimal
BIOS	Basic Inpute Output System
BIPS	Billions of Instructions Per Second
BPI	Bytes Per Inch
CAD	Computer Aided Design
CAE	Computer Aided Engineering
CAN	Campus Area Network
CASE	Computer Aided Software Engineering
CD	Compact Disk
CDC	Control Data Corporation
CD-R	CD-Recordable
CD-ROM	Compact Disk Read Only Memory
CD-RW	CD Read/Write
CL	Command Language
CLI	Command Line Interface
COBOL	Common Business Oriented
CODASYL	Conference On Data Systems
CPU	Central Processing Unit
CRT	Cathode Ray Tube
D/A	Digital-to-Analog
DAT	Digital Audio Tape
DBMS	Data Base Management System
DBS	Demand Based Switching
DDL	Data Definition Language
DDS	Digital Data Storage
DEC	Digital Equipment Corporation
DMA	Direct Memory Access
DNA	Digital Network Architecture
DPI	Dots Per Inch
DRAM	Dynamic RAM
DSN	Distributed Systems Network
DTS	Digital Theater System
DVD	Digital Video/Versatile Disk
EBCDIC	Extended Binary Coded Decimal Interchange Code
EDSAC	Electronic Delay Storage Automatic Calculator
EDVAC	Electronic Discrete Variable Automatic Calculator
EFM	Eight-to-Fourteen Modulation
ENIAC	Electronic Numerical Integrator And Calculator
EPG	Electronic Programming Guide
EPIC	Explicitly Parallel Instruction Computing
EPROM	Erasable Programmable Read-Only Memory
FAT	File Allocation Table
FDM	Frequency Division Multiplexing
FEP	Front End Processor
FLOPS	Floating Point Operations Per Second
FM	Frequency Modulation
FMS	File Management System
FORTRAN	FORmula TRANslation
FSK	Frequency Shift Keying
FTP	File Transfer Protocol
GB	Giga Bytes
GFLOPS	Giga FLOPS
GHz	Giga Hertz
GNU	Gnu Not Unix
GPRS	General Packet Radio Service
GSM	Global System for Mobile communication
GUI	Graphical User Interface
HP	Hewlett Packard
HSS	Hierarchical Storage System
HTML	HyperText Markup Language
HTTP	HyperText Transport Protocol
IBM	International Business Machine
IC	Integrated Circuit
IDN	Integrated Digital Networks
IP	Internet Protocol
IrDA	Infrared Data Association
ISDN	Integrated Services Digital Network
ISP	Internet Service Provider
JPEG	Joint Photographic Experts Group
JRE	Java Runtime Engine
JSP	Java Server Pages
KB	Kilo Bytes
KHz	Kilo Hertz
LAN	Local Area Network
LCD	Liquid Crystal Display
LED	Light Emitting Diode
LPM	Line Per Minute
LSI	Large Scael Integration
MAN	Metropolitan Area Network
MAR	Memory Address Register
MB	Mega Bytes
MBR	Memory Buffer Register
MHz	Mega Hertz
MIDI	Musical Instrument Digital Interface
MIPS	Millions of Instructions Per Second
MNP	Microcom Network Protocol
MPEG	Moving Pictures Experts Group
MS-DOS	MicroSoft Disk Operating System
MVT	Multiprogramming with Variable Tasks
NIC	Network Interface Card
NICNET	National Informatics Center NETwork
NOS	Network Operating System
OCR	Optical Character Recognition
OMR	Optical Mark Reader
OS	Operating System
OSI	Open System Interconnection
OSS	Open Source Software
PAN	Personal Area Network
PC	Personal Computer
PDF	Portable Document Format
PDL	Program Design Language
PDP	Program Data Processor
PIP	Peripheral Interchange Program
PROM	Programmable Read-Only Memory
QoS	Quality of Service
RAM	Random Access Memory
ROM	Read Only Memory
SDLC	Software Development Life Cycle
SEQUEL	Structured English QUEry Language
SGML	Syntax for Generalized Markup Language
SIMM	Single In-line Memory Module
SNA	Systems Network Architecture
SNOBOL	StriNg Oriented and symBOlic Language
SQL	Structured Query Language
SRAM	Static RAM
SSI	Small Scale Integration
TB	Tera Bytes
TCP	Transport Control Protocol
TDM	Time Division Multiplexing
UDP	User Datagram Protocol
ULSI	Ultra Large Scale Integration
UPC	Universal Product Code
URL	Uniform Resource Locator
USB	Universal Serial Bus
UTF	Unicode Transformation Format
VAN	Value Added Network
VCR	Video Cassette Recorder
VDT	Video Display Terminal
VGA	Video Graphics Array
VOD	Video-On-Demand
VoIP	Voice over Internet Protocol
VSAT	Very Small Aperture Terminal
WAN	Wide Area Network
WAP	Wireless Application Protocol
WiMAX	Worldwide Interoperability for Microwave Access
WLAN	Wireless Local Area Network
WLL	Wireless Local Loop
WORM	Write Once Read Many
WWW	World Wide Web
XHTML	eXtensible HyperText Markup Language
XML	eXtensible Markup Language
X.400	Electronic Mail Protocol
X.500	Directory Server Protocol

Virus

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A virus is a computer code or program, which is capable of affecting your computer data badly by corrupting or destroying them.

Computer virus has the tendency to make its duplicate copies at a swift pace, and also spread it across every folder and damage the data of your computer system.

A computer virus is actually a malicious software program or "malware" that, when infecting your system, replicates itself by modifying other computer programs and inserting its own code.

Infected computer programs may include data files, or even the "boot" sector of the hard drive.

Types of Virus

Following are the major types of computer virus −

Worms

This is a computer program that replicates itself at a swift pace. Unlike a computer virus, it is self-contained and hence does not need to be part of another program to propagate itself.

Trojan Horse

A Trojan Horse is also a sort of destructive program that remains disguised in a normal software program. It is not exactly a virus, as it cannot replicate itself. However, there is possibility that virus program may remain concealed in the Trojan Horse.

Bombs

It is similar to Trojan Horse, but Logic bombs have some specialty; these include a timing device and hence it will go off only at a particular date and time.

How Does Virus Affect?

Let us discuss in what ways a virus can affect your computer system. The ways are mentioned below −

• By downloading files from the Internet.
• During the removable of media or drives.
• Through pen drive.
• Through e-mail attachments.
• Through unpatched software & services.
• Through unprotected or poor administrator passwords.

Impact of Virus

Let us now see the impact of virus on your computer system −

• Disrupts the normal functionality of respective computer system.
• Disrupts system network use.
• Modifies configuration setting of the system.
• Destructs data.
• Disrupts computer network resources.
• Destructs of confidential data.

Virus Detection

The most fundamental method of detection of virus is to check the functionality of your computer system; a virus affected computer does not take command properly.

However, if there is antivirus software in your computer system, then it can easily check programs and files on a system for virus signatures.

Virus Preventive Measures

Let us now see the different virus preventive measures. A computer system can be protected from virus through the following −

• Installation of an effective antivirus software.
• Patching up the operating system.
• Patching up the client software.
• Putting highly secured Passwords.
• Use of Firewalls.

Most Effective Antivirus

Following are the most popular and effective antivirus from which you can choose one for your personal computer −

• McAfee Antivirus Plus
• Symantec Norton Antivirus
• Avast Pro Antivirus
• Bitdefender Antivirus Plus
• Kaspersky Anti-Virus
• Avira Antivirus
• Webroot Secure Anywhere Antivirus
• Emsisoft Anti-Malware
• Quick Heal Antivirus
• ESET NOD32 Antivirus

Threat

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Threat in a computer system is a possible danger that might put your data security on stake. The damage is at times irreparable.

Definition

As defined by the National Information Assurance Glossary −

• “Any circumstance or event with the potential to adversely impact an IS through unauthorized access, destruction, disclosure, modification of data, and/or denial of service.”

• A computer threat can be "intentional" such as hacking or "accidental" such as malfunctioning of or physical damage.

Types of Threat

Following are the most common types of computer threats −

• Physical damage − It includes fire, water, pollution, etc.

• Natural events − It includes climatic, earthquake, volcanic activity, etc.

• Loss of services − It includes electrical power, air conditioning, telecommunication, etc.

• Technical failures − It includes problems in equipment, software, capacity saturation, etc.

• Deliberate type − It includes spying, illegal processing of data, etc.

Some other threats include error in use, abuse of rights, denial of actions, eavesdropping, theft of media, retrieval of discarded materials, etc.

Sources of Threat

The possible sources of a computer threat may be −

• Internal − It includes employees, partners, contractors (and vendors).

• External − It includes cyber-criminals (professional hackers), spies, non-professional hackers, activists, malware (virus/worm/etc.), etc.

Common Terms

Following are the common terms frequently used to define computer threat −

Virus Threats

A computer virus is a program designed to disrupt the normal functioning of the computer without the permission of the user.

Spyware Threats

Spyware is a computer program that monitors user’s online activities or installs programs without user’s consent for profit or theft of personal information.

Hackers

Hackers are programmers who put others on threats for their personal gain by breaking into computer systems with the purpose to steal, change or destroy information.

Phishing Threats

It is an illegal activity through which phishers attempt to steal sensitive financial or personal data by means of fraudulent email or instant messages.

How to Secure Your Computer System from Threats?

Following are the significant tips through which you can protect your system from different types of threat −

• Install, use, and keep updated Anti-Virus in your system.
• Install, use, and keep updated a Firewall Program.
• Always take backups of your important Files and Folders.
• Use Strong and Typical Passwords.
• Take precaution especially when Downloading and Installing Programs.
• Install, use, and keep updated a File Encryption Program.
• Take precaution especially when Reading Email with Attachments.
• Keep your Children aware of Internet threats and safe browsing.

Security

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Advancement of computer technology has radically changed the world; resultantly, most of the works whether it is matter of nation’s security system or buying a shoe online everything depends on computer.

Such increased dependency also raises the issue of security, as most of the data is now stored in the computer system.

Your computer systems store various sorts of data and hence if it is not secured, then you might be in for a big trouble.

Why Do We Computer Security?

Let us now see why do we need Computer security. It is required for the following major reasons −

• To prevent damage of the hardware.

• To prevent theft or damage of the installed software.

• To prevent theft or damage of stored data and information.

• To prevent the disruption of service.

• Likewise, security system keeps the computer system safe by protecting the installed software and the stored data (information).

Protection of Data and Information

Following are the important steps to protect data −

• Make backup of all your important files.
• Keep your system virus by using anti-virus software.
• Keep updating your computer system.
• Run disk defragmenter and disk cleanup on certain interval of time.
• Use a firewall.
• Use anti-spyware software.

Further, if you use internet, then you need to take greater precaution. Consider the following points to understand the precautions that need to be taken −

• Do not click on any link that you don’t know (as it may be dangerous for your computer - virus attack).

• Do not open unauthorized an unlawful website (it may damage your computer system).

• Do not download unsolicited data from unknown website.

What is Defragmentation?

Frequent saving and deleting of file (data) from the hard disk creates problems in performance and also reduce the space; therefore, defragmentation again clean-up the drive and restore the system to run smoothly.

Following are the simple steps of defragmentation −

Disk Cleanup

While browsing websites (on internet), many of the files get stored in the hard disk automatically (actually these stored files later help to reopen the website faster); besides some other cookies also get stored in the hard disk. All these stored files create problem along with eating space.

So, disk cleanup process cleans all these files and releases the space occupied by these unwanted files.

Following are the simple steps of disk cleanup −

Multimedia

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In this chapter, we will discuss how the Computer Multimedia works. If a system presents, some information through more than two media, it is known as multimedia. For example, TV presents audio and video; book presents text, image, and graphs, computer, etc.

The information presented through multimedia has better quality and capability, as it can be understood easily.

The advanced computer system is a great example of modern multimedia.

Literal Meaning of Multimedia

In this section, we will understand the literal meaning of multimedia.

• Multi − it means more than one

• Medium − it is singular and it means intermediary or mean

• Media − it is plural and it means conveying the information

Likewise, Multimedia is the field of Computer Science that integrates different forms of information and represents in the form of audio, video, and animation along with the traditional media, i.e., text, graphics/drawings, images, etc.

Multimedia Computer System

Multimedia computer system has high capacity to integrate different media including text, image, graphics, audio, and video.

The multimedia computer system stores, represents, processes, manipulates, and makes available to users.

Significant Features of Multimedia Computer System

Following are the major features multimedia computer system −

• Its Central Processing Unit (CPU) is very fast, as it needs to process large amount of data.

• It has huge storage capacity.

• It has huge memory power that helps in running heavy data programs.

• It has high capacity graphic card that helps in displaying graphics, animation, video, etc.

• The sound system makes it easy to listen to audio.

• With all these features (discussed above), a computer system is known as high end multimedia computer system.

• However, all the features listed above are not essentially required for every multimedia computer system, but rather the features of a multimedia computer system are configured as per the need of respective user.

Multimedia Components

Following are the major components of a multimedia computer system −

Text

It contains alphanumeric and some other special characters. Keyboard is usually used for input of text; however, there are some internal (inbuilt) features to include such text.

Graphics

It is technology to generate, represent, process, manipulate, and display pictures. It is one of the most important components of multimedia application. The development of graphics is supported by a different software.

Animation

Computer animation is a modern technology, which helps in creating, developing, sequencing, and displaying a set of images (technically known as ‘frames’). Animation gives visual effects or motion very similar to that of a video file (see image given below).

Audio

This technology records, synthesizes, and plays audio (sound). There are many learning courses and different instructions that can be delivered through this medium appropriately.

Video

This technology records, synthesizes, and displays images (known as frames) in such sequences (at a fixed speed) that makes the creation appear as moving; this is how we see a completely developed video. In order to watch a video without any interruption, video device must display 25 to 30 frames/second.

Multimedia Application

Let us now see the different fields where multimedia is applied. The fields are described in brief below −

Presentation

With the help of multimedia, presentation can be made effective.

E-books

Today, books are digitized and easily available on the Internet.

Digital Library

The need to be physically present at a library is no more necessary. Libraries can be accessed from the Internet also. Digitization has helped libraries to come to this level of development.

E-learning

Today, most of the institutions (public as well as private both) are using such technology to education people.

Movie making

Most of the special effects that we see in any movie, is only because of multimedia technology.

Video games

Video games are one of the most interesting creations of multimedia technology. Video games fascinate not only the children but adults too.

Animated films

Along with video games, animated film is another great source of entertainment for children.

Multimedia conferencing

People can arrange personal as well as business meetings online with the help of multimedia conferencing technology.

E-shopping

Multimedia technology has created a virtual arena for the e-commerce.

Windows Desktop Elements

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Once you are logged in a window computer system, you will get dozens of applications, so you can choose an option of your requirement.

Many of the options have shortcut icon readily available on your computer screen; however, in some computers, you may not find any such option on the screen; in such a case, you can take the help of menu button (as shown in the image given below) −

As you can see in the above image, in the left bottom, there is a window symbol (i.e., menu button); once you click on it, the given menu option will appear and from here you can choose your option.

Start Menu Options

The following table lists down the options that appear after clicking on the Start menu −

Sr.No.	Option & Description
1	All programs It displays all those programs, which are installed in your system.
2	Document It displays a list of folders used by the user.
3	Recent file It displays the recently used file.
4	My picture It displays a list of pictures.
5	My music It displays a list of music/song, etc.
6	My computer It displays the drives of computer where user keeps his/her work, file, folder, song, video, picture, e-book, etc.
7	Control panel It displays all the installed computer programs (software).
8	Printer It displays the installed printers (if printer is installed in the system, user can take print easily).
9	Help (support) It helps users to know how to do a particular task.
10	Search It helps a user to find a file in computer.
11	Run It helps to start an application program or execute a DOS command.
12	Setting It has different options that help to manage different settings of the computer, software as well as hardware.
13	Log Off It helps a user to log off the currently logged in user of the system.
14	Sleep It makes the system non-functional; however, puts the ongoing work and settings in memory and also keeps drawing small amount of power.
15	Hibernation Hibernation puts the open documents and programs on hard disk and then turns off your computer; in comparison to ‘sleep’, it uses very low power.
16	Restart Its function is to shut down and again start (log on) computer; it is done normally to refresh computer especially when computer is hanged.
17	Shut down It simply shuts down the system.

Note − Depending on the version of your window, the menu option may vary in terms of appearance and number of menu options; however, there would not be any change in basics.

Recycle Bin

Recycle Bin is a trash location where deleted files remain stored. Once you delete any sort of file, it gets stored (automatically) into recycle bin; therefore, if you mistakenly deleted some important file, don’t panic, go to recycle bin and restore it. However, if you deleted file from recycle bin as well, then it is very difficult to restore that permanently deleted file.

Internet Option

The option (i.e., short-cut key) of the Internet browser may be available on the main screen or at the bottom menu bar (as shown in the image given below). However, if do not find it at both these places, go to the menu, as all programs are listed there.

Mobile

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Mobile computers are the systems, which are physically not remain connected to specific place rather these are mobile in nature, as one can carry anywhere anytime.

The mobile computer technology carries battery back; therefore, it does not require consistent electric power.

Mobile computers can be connected with Internet through wire or the connection can be wireless as well through Wi-Fi or Bluetooth technology. Likewise, it is portable, self-powered (because of inbuilt battery), and infused with wireless technology computing device.

Types of Mobile Computing Device

Following are the popular mobile computing devices −

Laptop

A laptop is a portable version of desktop computer. It is equally competent to do any computing work.

Notebook

It is a light weight portable personal computer.

Tablet

It is comparatively handier slate-shaped mobile computer.

Smart Phone

A smart phone is a fully equipped cell phone with most of the computing features.

Personal Digital Assistant (PDA)

It is a computer device more popular as pocket computer. It is largely used in calculation, accessing the Internet, sending and receiving E-mails, scanning bar codes, use as a radio or stereo, playing computer games, video recording, typewriting and word processing, use as an address book, making and writing on spreadsheets, Global Positioning System (GPS), as a clock and calendar, etc.

Portable Data Terminal (PDT)

It is a computer device, which is largely used to enter or retrieve data through wireless transmission (i.e., WLAN or WWAN).

Mobile Data Terminal(MDT)

It is a computer device, which is used in police cars, taxi-cabs, military logistics, service trucks, commercial trucking fleets, courier vehicles, fishing fleets, etc.

Ultra-mobile Personal Computer (UMPC)

It is small form of tablet PC.

Extranet

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An extranet is a sort of personalized service, which is controlled and regulated by private network.

This personalized and controlled technology provides access only to partners, vendors, and suppliers; sometimes, not essentially, but also to some specific customers.

An extranet is a private network organization, which is actually the part of respective company’s intranet and its services are extended to users outside the company. Sometimes, it is also considered as a specialized technique to practice business with other companies and selling products to the customers.

In order to do business with other business partners, extranet technology facilitates the intranet from one location to other and also provides security to data flow.

An extranet service requires firewall server management in order to provide security and privacy.

Features of Extranet Services

Following are the significant features of extranet services −

• Extranet is an extended Internet service to the private business network.

• The services extend outside the corporate firewall.

• Sometimes, it can be referred to an Intranet, as it can be (partially) accessible to some outsiders (with permission).

• The technique of extranet links two (or more) business organizations who share common business goals.

Application of Extranet

Extranet can be applied for the following services −

• It facilitates collaborative business between two (or more) companies

• By using this technology, a joint training program (with other company) is conducted

• By using electronic data interchange, large volumes of data are shared swiftly

• It is used to share product catalogs especially with wholesalers

• Extranet service is also used in providing customer support

• It is used to share business news with partner companies

Advantages of Extranet

The advantages of Extranet services are as follows −

• It makes business (services) swift and faster.
• It helps greatly in improving the business communication.
• It helps in reducing the cost (especially in terms of stationery stuff).
• It helps in improving the efficiency and confidence of the employees.
• It reduces some big physical barriers (especially the geographical distance).

Major Fields Using Extranet

Following are some of the major fields that are using Extranet service on a large scale −

• Corporate houses
• Government offices
• Education centers

Intranet is more localized, as only internal employees have the accessibility. In contrast, Extranet covers a wider area, as outsiders (such as partner, vendor, or even customer) have the authorized accessibility.

Algorithm Flowchart

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A flowchart is a blueprint that pictorially represents the algorithm and its steps. The steps of a flowchart do not have a specific size and shape rather it is designed in different shapes and sizes (see the image given below).

As shown in the above image, the boxes in different shapes and interconnected with arrows, are logically making a flow chart. A flow-chart represents the general steps in a process.

Benefits of Flowchart

Let us now discuss the benefits of a flowchart.

Simplify the Logic

As it provides the pictorial representation of the steps; therefore, it simplifies the logic and subsequent steps.

Makes Communication Better

Because of having easily understandable pictorial logic and steps, it is a better and simple way of representation.

Effective Analysis

Once the flow-chart is prepared, it becomes very simple to analyze the problem in an effective way.

Useful in Coding

The flow-chart also helps in coding process efficiently, as it gives directions on what to do, when to do, and where to do. It makes the work easier.

Proper Testing

Further, flowchart also helps in finding the error (if any) in program

Applicable Documentation

Last but not the least, a flowchart also helps in preparing the proper document (once the codes are written).

Flow-Chart Symbols

The following table illustrates the symbols along with their names (used in a flow-chart) −

Name	Symbol	Name	Symbol
	Flow Line		Magnetic Disk
	Terminal		Communication Link
	Processing		Offline Storage
	Decision		Annotation
	Connector		Flow line
	Document		Off-Page Connector

Sample of Flow Chart

Software Programming

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In order to make a computer functional, a set of instructions need to be programmed, as these programmed languages are carriers to the performance of a task.

Likewise, a computer accepts users’ instructions in the form of computer programming and then carries out the given task.

Features of Software Programming

A computer program, which actually is a set of instructions and helps computer to perform a specific task, has the following basic features −

• It ensures the given instructions are performed successfully.

• It ensures the given instructions are performed in sequential order.

• Explains the input (data) given is correct or insufficient and accordingly gives the result.

• It is written with high level language.

Steps to Development of Program

Development of programming language is entirely dependent on the kind of problem and requirement. However, development of a programming language normally (not essentially, but) includes the following steps −

Defining the Problem

This the first step, wherein the problem has to be defined.

Analysis of Task and Methods

Once the problem is defined, the developer analyzes and develops various solutions in order to solve the problem and finally, the best feasible solution is developed.

Development of Algorithm

Algorithm is a proper technique that illustrates the right solution in logical and feasible steps. Algorithm is normally done in the form of flowcharts and pseudo codes.

Verification of Algorithm

Once the algorithm is developed, it cannot be applied directly rather primarily it needs to be tested specially for the accuracy. If there is any error, it is rectified and solved in the beginning itself. The verification process saves time, money, and energy.

Coding

Once the basic processes and steps are completed successfully, then the actual coding of a program starts in the given programming language.

Testing of Program

Testing of the development of program code is another essential feature, as it is bound with errors; hence, testing makes it error free. The developer keeps testing and correcting the coding until he/she develops it finally.

Documentation

Once the coding and programming is done successfully, it is the job of the developer to document all these features and steps. The documented program instructs users on how to run and operate the respective program.

Implementation

Once the above steps are executed successfully, the developed codes (programming language) are installed in the computer system for the end users. The users are also manuals - explaining how to run the respective programs.

Electronic Commerce

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The advancement of computer technology and internet, domestic as well as international businesses are being fascinated towards these technologies. Today, most of the small or big businesses and domestic or international businesses offer their products and services through Internet.

The business organizations these days have attractive and interactive website through which they promote and market their business.

The facility of computer based technology and Internet collectively integrates the fragmented markets by offering them a common arena. Technology has further helped organizations in cost cutting and has also helped reduce the cost of products and services.

Technology facilitates customers in buying products or services of their requirement by sitting at home or any place.

What is Electronic Commerce?

Electronic commerce or simply ecommerce is normally a process that involves facilitating the availability of products and services online. The users can search, choose, sell, buy from a wide range of options through Internet.

The major activities of ecommerce are as follows −

• Selling products and services online (through internet)
• Buying products and services online
• Paying and accepting payment online
• Transaction of businesses and other services online

Features of E-Commerce

Following are the important features of ecommerce −

• It efficiently increases the business capability.
• It substantially reduces the cost.
• It perceptively increases the delivery services.
• It unbreakable solution of quick business transactions and office automation.
• It potentially increases the intra-business functionality.
• It competently increases the business communication.

Types of E-Commerce

Following are the major types of e-commerce businesses −

Business-to-Business (B2B)

It is conducted between two business firms.

Business-to-Consumer (B2C)

It is conducted between the business firm and the consumer.

Consumer-to-Consumer (C2C)

Consumer-to-consumer business deals happen between two consumers; there are certain websites that facilitate a common platform to both the consumers - one who wants to buy and one who wants to sell.

Benefits of E-Commerce

Let us now discuss the benefits of e-commerce −

• It facilitates free market.

• It is available 24×7.

• Its presence is global (there is no constrain of political boundary as such).

• Set up cost is substantially low.

• It provides user-friendly technology.

• It offers multiple opportunity parallel and simultaneously.

• It provides frugal facilities to promote and market businesses.

• It has features to offer market research facility.

• It makes customer relations management easier.

• It facilitates the provision of 24×7 customer care services.

• It provides fund transfer facility domestically as well as internationally with simple steps.

Computer Related Jobs

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The fast computerization of every work and gradual dependency on computer based work has exponentially opened a new arena of Information technology for employment.

However, the IT field requires qualified and trained employees who can design and develop a new information system.

Information technology has also helped in research and development and has further developed new technologies. The IT employees emphasize on planning, designing, developing, managing the work, and providing technical support to various users.

Types of Computer Related Jobs

In recent times, a number of jobs have come up that are done with the assistance of computer. We will discuss the different job titles performing computer related jobs −

Programmer

A person who is qualified enough to write a creative code for the computer program is known as Programmer.

The codes written by programmer are the instructions given to the computer over what to do, how to do, when to do, etc.

There are dozens of languages, which are written by the different programmers. E.g. Java, C, C++, python, Ajax, etc.

System Analyst

The job of a system analyst is highly classified and also very crucial.

A system analyst fundamentally designs, develops, and implements new systems or adds some additional features in the existing system to give instructions to perform additional tasks.

System analyst also specializes in fields such as engineering, science & technology, finance, business, accounting, etc.

Database Administrator

A database administrator or simply DBA is a trained person who is accountable for the storage of and management of the database system.

Network Administrator

Computer networking is another specialized field where a qualified person is required.

A network administrator specializes in installing, configuring, and supporting computer network system. Likewise, he manages the local area network, wide area network, the Internet system or the segment of a network system in the respective organization.

The job of a network administrator is a very crucial one as almost every network in an organization requires at least one network administrator.

Web Designers

A web designer is an architect who designs an effective and communicative website.

He places the images, contents, and other such information on right places to make the website interactive and user friendly.

Information Security Analysts

This is one of the most significant jobs under which an Information Security Analyst designs, implements, and supports the security system of a computer or whole network.

Networking

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A computer networking is a process of connecting two more than two computers with the purpose to share data, provide technical support, and to communicate (especially for the business purpose.

Internet is the technology that is used to connect different computer systems (located in different geographic location). Networking technology has revolutionized the world and created a new arena for the overall development of every nation.

Advantages of Networking

Let us now discuss the advantages of networking. The advantages are described below −

Facility of Technical Support

Because of having computer networking, a person sitting in the United States of America provides technical support to a person sitting in a remote part of India.

Easy Sharing of Data

With the help of networking, it is very simple to share all formats of digital data from one computer system to another (irrespective of their geographic location).

Easy Sharing of Hardware Resource

With the help of networking, it has now become very simple to share the expensive resources including storage space, processor, fax, etc.

Easy Sharing Software

Through the networking system, it is easy to share and install the software from one computer system to another computer system.

Easy to Decentralize Data Processing

Through the networking system, it is very simple to decentralize the data processing system. It ultimately helps to control, secure, and manage the important data.

Easy to Communicate

With the help of networking, the communication system has now become highly efficient, frugal, and fast. The different modes of communication are text chatting, video chatting, emails, etc.

Types of Network

In this section, we will discuss the different types of network. The types are described below −

• Local Area Network (LAN)
• Metropolitan Area Network (MAN)
• Wide Area Network (WAN)

Local Area Network

Local Area Network or simply LAN is the technique of interconnecting a few computers located in a given premise. It is normally used for a single business office or a residential apartment.

The major purpose of such interconnectivity is to establish a communication system in order to make the work easier.

However, in such connectivity, some other devices can also be attached such as laser printers, fax machine, etc.

Metropolitan Area Network

Metropolitan Area Network or simply MAN is a system of network that normally covers a large metropolitan area (city part).

It provides high speed Internet services throughout the area covered within the network.

Wide Area Network

Wide Area Network or simply WAN is a system of network that covers a large geographical area across the world.

The services of WAN are provided by public (government) agencies as well as private agencies. The network also provides the facility to access databases located remotely.

The WAN system is highly beneficial for MNCs and other big corporate companies (offering online services).

Data Processing

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Collection, manipulation, and processing collected data for the required use is known as data processing. It is a technique normally performed by a computer; the process includes retrieving, transforming, or classification of information.

However, the processing of data largely depends on the following −

• The volume of data that need to be processed
• The complexity of data processing operations
• Capacity and inbuilt technology of respective computer system
• Technical skills
• Time constraints

Methods of Data Processing

Let us now discuss the different methods of data processing.

• Single user programming
• Multiple programming
• Real-time processing
• On-line processing
• Time sharing processing
• Distributed processing

Single User Programming

It is usually done by a single person for his personal use. This technique is suitable even for small offices.

Multiple Programming

This technique provides facility to store and execute more than one program in the Central Processing Unit (CPU) simultaneously. Further, the multiple programming technique increases the overall working efficiency of the respective computer.

Real-time Processing

This technique facilitates the user to have direct contact with the computer system. This technique eases data processing. This technique is also known as the direct mode or the interactive mode technique and is developed exclusively to perform one task. It is a sort of online processing, which always remains under execution.

On-line Processing

This technique facilitates the entry and execution of data directly; so, it does not store or accumulate first and then process. The technique is developed in such a way that reduces the data entry errors, as it validates data at various points and also ensures that only corrected data is entered. This technique is widely used for online applications.

Time-sharing Processing

This is another form of online data processing that facilitates several users to share the resources of an online computer system. This technique is adopted when results are needed swiftly. Moreover, as the name suggests, this system is time based.

Following are some of the major advantages of time-sharing processing −

• Several users can be served simultaneously
• All the users have almost equal amount of processing time
• There is possibility of interaction with the running programs

Distributed Processing

This is a specialized data processing technique in which various computers (which are located remotely) remain interconnected with a single host computer making a network of computer.

All these computer systems remain interconnected with a high speed communication network. This facilitates in the communication between computers. However, the central computer system maintains the master data base and monitors accordingly.

Generations of Computer

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The development of computer systems is normally discussed as the development over different generations.

With the succession of different generations, came the advancement in computer technology.

Computer Generations

Let us now discuss the development in Computer Technology over the different generations.

First Generation

• The period 1940 to 1956, roughly considered as the First Generation of Computer.

• The first generation computers were developed by using vacuum tube or thermionic valve machine.

• The input of this system was based on punched cards and paper tape; however, the output was displayed on printouts.

• The first generation computers worked on binary-coded concept (i.e., language of 0-1). Examples: ENIAC, EDVAC, etc.

Second Generation

• The period 1956 to 1963 is roughly considered as the period of Second Generation of Computers.

• The second generation computers were developed by using transistor technology.

• In comparison to the first generation, the size of second generation was smaller.

• In comparison to computers of the first generation, the computing time taken by the computers of the second generation was lesser.

Third Generation

• The period 1963 to 1971 is roughly considered as the period of Third Generation of computers.

• The third generation computers were developed by using the Integrated Circuit (IC) technology.

• In comparison to the computers of the second generation, the size of the computers of the third generation was smaller.

• In comparison to the computers of the second generation, the computing time taken by the computers of the third generation was lesser.

• The third generation computer consumed less power and also generated less heat.

• The maintenance cost of the computers in the third generation was also low.

• The computer system of the computers of the third generation was easier for commercial use.

Fourth Generation

• The period 1972 to 2010 is roughly considered as the fourth generation of computers.

• The fourth generation computers were developed by using microprocessor technology.

• By coming to fourth generation, computer became very small in size, it became portable.

• The machine of fourth generation started generating very low amount of heat.

• It is much faster and accuracy became more reliable.

• The production cost reduced to very low in comparison to the previous generation.

• It became available for the common people as well.

Fifth Generation

• The period 2010 to till date and beyond, roughly considered as the period of fifth generation of computers.

• By the time, the computer generation was being categorized on the basis of hardware only, but the fifth generation technology also included software.

• The computers of the fifth generation had high capability and large memory capacity.

• Working with computers of this generation was fast and multiple tasks could be performed simultaneously.

• Some of the popular advanced technologies of the fifth generation include Artificial intelligence, Quantum computation, Nanotechnology, Parallel processing, etc.