MD : To make directory or subdirectory on a specified disk/drive.

CD / CHDIR : Change DOS current working directory to specified directory on specified disk or to check for the current directory on the specified or default drive.

RMDIR / RD : Removes a specified sub-directory only when it is empty. This command cannot remove root directory (C:\) or current working directory.

TREE : Displays all of the directory paths found on the specified drive.

PATH : Sets a sequential search path for the executables files, if the same are not available in the current directory.

SUBST : Substitutes a string alias for the pathname and creates a virtual drive.

File Management Commands :

COPY : Copies one or more files from source disk/drive to the specified disk/drive.

XCOPY: Copies files and directories, including lower-level directories if they exists.

DEL : Removes specified files from specified disk/drive.

REN : Changes the name of a file(Renaming).

ATTRIB : Sets or shows file attributes (read, write, hidden, Archive).

BACKUP : Stores or back up one or more files/directories from source disk/drive to other destination disk/drive.

RESTORE:  Restores files that were backed up using BACKUP command.

EDIT :  Provides a full screen editor to create or edit a text file.

FORMAT : Formats a disk/drive for data storage and use.

The Right Mouse Button : If you move the mouse to almost anywhere or anything on the desktop or in a Window and click the right mouse button, Windows 98 displays a menu with common commands for the object. To close the menu, click the left mouse button anywhere else on the desktop or press the keyboard's Esc key.

Icons on the Desktop : The upper left corner contain four icons. Those icons provides access to your files and documents. Four icons are: My computer, Network Neighbourhood, Recycle bin and Briefcase.

My Computer : The "My Computer" icon on the desktops opens a view into the resources of the local computer. The contents of the My computer Window depend on the disk drives on your PC and the network support that is installed.

Network Neighbourhood : This icon displays the computers and shared printers connected on the windows network.

Recycle Bin : This icon receives all deleted objects like files, folders, documents, applications etc. These deleted objects can be restored back they can be permanently deleted from the disk by choosing EMPTY RECYCLE BIN selection on the file menu.

Briefcase : The commonly used personal documents can be put or stored in the briefcase. This briefcase can be moved to a disk or copied across a network.

Folders : Folders on the desktop can contain other folders, documents, applications and shortcuts to devices such as printer. To add a folder to the desktop, move the mouse cursor to an empty spot on the desktop and press the right mouse button. Click the Folder command. A folder icon labelled "New Folder" appears on the desktop

Document : The references to the current documents are stored in the documents object. The documents list includes Word processing documents, spreadsheets, database files, graphics file etc.

Computer Organization : Digital computers are electronic machines capable of performing high speed arithmetic/logical operations and data processing. It has two major parts i) computer hardware and ii) computer software. Computer hardware consists physical entities like electronics circuit, transistors, capacitors etc. Computer software is basically set of instruction code which instructs the computer to perform a task requested by user. Computer software consists of programs which monitor and coordinates all internal operations and provides easy interface between computer and user.

Computer hardware, a physical entities like electronic circuit, transistors, capacitors has four major parts i) Central processing unit (CPU); ii) Input unit; iii) Output unit and iv) Memory. The CPU in computer is similar to brain in human. It performs all the calculations, it execute all the instruction received from user. It also control activity of computer. Input devices provides the means to input to computer. Following computer devices are commonly used by users i) Keyboard: consists array of key switches; ii) Mouse: it is a pointing device usually contain two or three button; iii) Joysticks: used to play games etc. Output devices are the means by which computer present its result in human readable form. Following computer output devices are commonly used by users i) Monitor/screen: displays data as text or in graphics ii) Printers: allow to print the data; iii) Plotters: used to plot the graphs. Storage devices are used to store and retrieve data in computers. Broadly, it can be classified in two categories i) primary storage and ii) secondary storage. Primary storage are semiconductor memories used access data quickly and randomly (e.g. RAM, ROM). Secondary storage also called Magnetic storage devices. These storage devices are cheaper and reliable (e.g. Floppy disk, Hard disk, Optical disk)

Characteristics of Computers :

1. Calculates at very high speed.

2. Takes in Information & Stores for further retrieval.

3. Takes in & Stores the program (set of instructions written in the language of computers).

4. Obeys a sequence of instructions/programs.

5. Uses simple logical rules to make decisions for their own internal control or for the role of some external  activity

6. Communicates with other systems

7. Exploits a complex internal structure of micro electronic circuits in a variety of ways

8. Privacy

9. Security

10. Individuality

Applications of Computers :

1. Main mode of procuring offline and online information available from databases

2. Disease-Diagnosis, Drugs, Vaccines, Pathogenesis, Treatment, Rehabilitation updates

3. Patient care information

4. Medical Directories

5. Machines are computer based

6. Thesis, Research articles

7. Scientific Research

8. Communications

9. Desktop Applications

10. Business Applications

11. Word Processing

12. Banking

13. Industrial Applications

14. Space Technology

15. Transportation

16. Browsing relevant websites for updates

Software:

1. Not seen (in computer word) by naked eyes i.e. not present physically but co-ordinates hardware.

2. Logic/intelligence which run your computer

3. Set of the instruction (program) which carries out the job/work provided by the user.

System Software (Mostly operating systems)

1. Machinery with no intelligence but tremendous capacity for hard work.

2. Shell-OS-interpreter-interprets human (English) & computer (Binary) language

3. OS commands are necessary to learn

4. OS understand the command and converts the computer language, perform work intended and come out with the result

5. OS converts these results (computer language) back into 'Human Readable Format' and display on monitor

6. Pry Jobs- Machine Maintenance/Machine/Administration/Allocation of Resources

7. Single user Single Task ----DOS

8. Single user Multiple task- Window

9. Multiple user Multiple task-UNIX

10. Networking-NetWare/Windows/UNIX/LINUX

Application software :

1. Does jobs like text processing, calculation, drawing a picture, accounting etc.

2. Graphics: Allows to draw/view/edit pictures

3. Multimedia: Allows to hear/see/watch presentation

4. Text processing: Standard text processing jobs like spell check, tabulation etc.

5. Database: Allows to store/Retrieve/Analyze/Present Information of particular task

6. Accounting: Maintains accounting information.

`7. Games: Allows to play interactive Videogame may contains text, visual and audio Browser

8. Development Tools: Allows developing software.

INTERNET & E-MAIL: Internet is a huge source of enjoyable, important and up-to-the-minute information, which can be accessed and shared by millions of people across the world. Every resource offered by Internet is there because some person or group of people, somewhere in the world, had an idea, developed it and then most important, made it available to the entire world using internet or the 'NET', as it is commonly called.

Internet is a collection of computer network that connects millions of computers around the world for exchanging information. Basically internet is a product of military undertaking. The Pentagon's Advanced Research Project Agency (ARPA) funded the creation of internet in 1969 as ARPnet. The initial intention was to develop a geographical dispersed reliable communication network for military use that would not be disrupted in case of partial destruction from a nuclear attack. The procedure developed for interconnecting ARPnet computer and communicating the data was called TCP/IP (Transmission Control Protocol/Internet Protocol). ARPnet allowed engineers and scientists working on military contracts all over America Online share computers and computer resources. Later on scientist developed a new procedure to exchange messages through a communication network link called E-mail.

The number of computers connected to internet has been growing exponentially. In 1983 there were less than 500 host computers mostly in the Government laboratories and computer science departments. By 1987 there were about 30,000 host computers at different universities and research laboratories. By 1998 this number had increased to more than 5 million hosts.

Historical overview : Internet evolved from a small computer network set up in 1969. Way back then an American defence department agency the Defence Advance Research Projects Agency, realized that they needed to develop an easy way to exchange military information between scientists and researchers based at different geographical locations. A simple network of four computers, know as DARPANET, was therefore established.

The system caught on, although the name was soon changed to ARPAnet, and by 1972 had grown to include 37 computers. At the same time, the way in which the network was being used was changing. As well as just using the system to exchange important, but boring, military information, ARPAnet users started to send e-mail sometimes trivial, sometimes important to each other by means of private mail boxes. They might not have realized it at the time, but this quickly growing group of US defence workers had started something big. Internet had begun and the era of free information exchange was in. Tim Berners-Lee propose World Wide Web, in 1989 and later wrote the first Web browser and server in 1990. The well-known web browsers like Netscape Navigator and Microsoft Internet Explorer were developed, which are used by the vast majority today. More than 36 million computers and 200 million users are on Internet (survey of June 1998).

Internet in India

History and Status

Before the appearance of VSNL's GIAS, Internet had been in India for many years in the form of ERNET. However, it was not possible for many people to get access to it, as it was meant for only the educational and research communities. This followed the policy laid down by the American Internet Manager NSF, at the time.

Educational Research Network (ERNET): Internet in India was established almost 10 years ago, as ERNET. It was a joint undertaking of the Department of Electronic (DOE ) of the Government of India, and the United Nations Development Programme(UNDP), which provides technical assistance to developing nations. ERNET is one of the most successful operations that UNDP has funded. It established for India the idea that we can participate in the Internet. Current ERNET operates many nodes and has a 64 Kbps link to USA via Mumbai. All major nodes of ERNET are connected to each other using 9600 bps leased lines. These lines are being ungraded to 64 Kbps links. Over 200 academic and R & D groups exchange e.mail with each other using ERNET. Over 8000 scientists and technologists have access to ERNET facilities. International access is provided over a 64 Kbps leased line, from NCST, Mumbai to USA Plans for ERNET include the creation of a satellite communication system to enable ERNET to reach locations, which do not have good data communication links.

Gate Internet Access Service (GIAS): Videsh Sanchar Nigam Limited (VSNL) India's international trunk carrier and Gateway to the World launched the Gateway Internet Access Service (GIAS) on August 15th 1995 for the first time on commercial basis in the country. VSNL has set up 6 Internet nodes that were established at Mumbai, Delhi, Chennai, Calcutta, Bangalore and Pune. Each GIAS internet node is connected to internet via high speed circuits from one of the following service providers: MCI (USA), KDD (Japan), Telecom Italia and TELEGLOBE. A total approximately 40 Mbps bandwidth is available for internet data transmission in and out of India. VSNL has got other access nodes at Ernakulam, Cochin, Ahmedabad, Dehradun and Arvi. VSNL in coordination with DOT has also launched Internet service at Lucknow, Hyderabad, Kanpur, Chandigarh, Jaipur, Patana, Aurangabad, Gwalior, GOA, Pondichery, Trivendrum, Keonics (Mysore) and Guwahati. Users in remote areas of India can reach GIAS via I-NET. The Department of Telecommunication (DOT) has a widespread network in India called I-Net, which has direct connectivity to each GIAS node You can access GIAS from 99 cities in India by this means.

GIAS Network Topology: The GIAS network uses dual hub and spoke topology. There are six gateways, which forms the backbone for the network. (Mumbai, Delhi, Chennai, Calcutta, Bangalore and Pune) Mumbai is the central node. Each node is connected to Mumbai with multiple high speed uplinks to Internet via different carriers. The total uplink is more than 40 Mbps. Dynamic routing protocol ensures that the shortest path to the destination is always chosen. Load balancing automatically occurs if more than one equal cost path to the destination exists. The best backup path is chosen when the primary path goes down. VSNL's GIAS network is multihomed to MCI, Telecom Italia and Teleglobe via the International connections of the nodes, to ensure proper backup and redundancy at the carrier level also.

Working of Internet : All the content of Internet is held by computers known as the "Servers" which are owned by organizations and companies, eg. University of Kansas, Microsoft etc. who want to distribute the information. When request is made of these servers for the information, they bundle the requested information is small packets, with address as to where it is to be sent, and send them down to the nearest connection to the internet. When they arrive at the internet, the packets are read by the router, which is nothing more than a traffic cop, and sent down in the same general direction as the address. A similar thing happens at the next junction on the Internet. This goes on till the packet is delivered to the right address, where it is put together again with other packets, to make up the original information. Says for example you are sending a message from Mumbai to Lao Alto, California, to a server named svpal.org. The message will be broken up into packets of approximately 1500 bytes, and some may travel from VSNL here to the MCI router in the US some may travel to Madras and then to the MCI router, and so forth. There is no predetermined path and even individual packets of the same message may follow different paths. It all depends on the traffic at the node, at the movement in time. As packets reach svpal.org, they are all put together as in the original message and delivered to the given address.  In order to accomplish the task massaging across a network, computers use a networking protocol. Taking the analogy of diplomacy, the relations and interactions between the representatives of different countries follow a set of rules laid down by tradition and treaty, which is called diplomatic protocol. Similarly, all computers wanting to talk to each other have a conform to a standard set of rules defined in the networking protocol. This enables different type of computers running different types of operating system to communicate efficiently. The de-facto standard today to TCP/IP. All this is accomplished by dedicated but fast computers known as routes that work in unison. Every organization has its own network and every individual user, his own system and set up. What kind does not matter as long as they talk the same protocol to the external world.

Domain Name System (DNS): The domain name system was developed to solve this problem. DNS is a distributed database. This allows local control of the overall databases, and yet the data in each small segment is available across the entire network. Other than the distributed nature. This allows responsibility for maintaining a domain to be distributed and also allows for the information of the hosts tore side to different computers. Since Internet was conceived and developed in the USA, Americans defined the top level domains. Initially these were designated as follows.

Domain Organization 

Com - For commercial organization (ie business)

Edu - Educational organization (Universities, schools)

Gov - Government organization (non military)

Mil- Military (army, navy etc)

Net - Network resources eg Internet Service Provider

Org - Other organization

These national domain names follow an existing international official standard of two letter abbreviations for every country in the world. An example of other countries represented with domain include

Au - Australia

CA - Canada

Fr - France

UK - The United Kingdom

In - India

How to get connected: Basically there are four steps to getting connected to the Internet. The first step is to get an account with VSNL. The second step is to get a modem for your computer which is approved by DOT for use on telephone lines, and computer hardware suppliers familiar with the internet can guide you with that. The third step is to ensure that your computer hardware is adequate for the type of account you have chosen, and the forth and last step is to verify that you already have suitable communications software stored on your hard disk, and if not to obtain and install the required software package.

Types of accounts available and their cost: There are basically two types of accounts available the terminal account and the TCP/IP account. There are also two types of connections to GIAS-dial-up and leased line. Depending on your status for example, student, professional or commercial organization your costs will vary.

Where to go and what to do: The procedure involved in getting either the Terminal account or a TCP/IP account is the same. Contact the VSNL customer relations section in your city and get an application form and brochure. Fill up the application attached the required Demand Draft taken in favour of VSNL and send it to the customer relations section. Within a short time you will be informed of your login name and password.

Terminal Account :

i) Hardware Requirements: The minimum requirement for accessing the Terminal account is either a VT 100/VT 220 type of terminal or a DOS machine. A 80386 processor machine with an adequate hard disk and 14.4 Kbps error correcting modem will serve you well. The minimum requirement for accessing a TCP/IP account is a 80486 processor machine with 8MB RAM or having similar processing power such as the Apple MAC At least a 14.4 kbps modem is needed, and 28.8, 33.3 & 56.6kbps are also preferred if your line are noise free. For an IBM compatible machine either windows 3.1 or windows95/98/2000 operating system is required for the TCP/IP.

ii) Software requirements : With a DOS, a DOS based terminal emulation programme is needed. There are many of tese programmes available, either as shareware or commercially eg. Telix and Procomm Plus.If you are using windows 3.1 or 3.11 system software, appropriate 16 bit TCP/IP stack software will be required. Windows 95/98/2000 has built in TCP/IP stack software supplied with it, which has to be installed and enabled. For Eudora you will need to supply your POP3 account name, which for VSNL accounts is your e-mail address.

Programs for accessing the Internet : 

FTP : "File-transfer protocol" i.e. accessing files that are stored on remote computer system called sites.

TELNET : Helps communicate with computer using Telnet protocol.

Lynx : World-Wide Web information resource without graphics.

Netscape, Mosaic & Microsoft Internet Explorer : Powerful web browser for accessing the Web server with the graphics.

RCP : The RCP command allow to copy file from remote to local or between two remote hosts.

Internet Access by Email : Different sites on internet allow to access resources via email. Others include FTP by e-mail, Archie by e-mail, Gopher by e-mail, WWW documents by e-mail using an Agora WWW-mail server.

SEARCH ENGINES : These engines allow to search the web pages by keywords, phrases, or question by displaying the list of web pages. Few popular search engines are : www.yahoo.com, www.lycos.com, www.infoseek.com,www.excite.com, www.netscape.com, www.altavista.digital.com, www.webcrawler.com etc.

Applications :

1. To communicate in various ways

2. To share resources

3. Find things that interest for user and

4. Exchange information and files.

5. To send and receive e-mails with people all over the world. Almost as fast as the telephone, there is never a busy signal, and you never play phone tag.

6. Allows to join discussion groups about a common subject

7. To access the information available on remote computer using mail servers.

8. To get or exchange software and files with the File Transfer Protocol (FTP).

10. It allow to connect to thousands of different computers using gopher menu systems

11. To explore the World Wide Web (WWW), which can use all of the above, and adds easy links to other resources and adds multimedia--graphics, sound, and video capabilities.

12. To talk by keyboard with Internet Relay Chat (IRC), which lets small groups of users meet in conference to "talk" to each other by typing on their keyboards.

13. An effective media for business communications.

14. To enjoy fun & games.

15. To have personal development.

Future for Internet :

1. International connections

2. Commercialization

3. Privatization

ELECTRONIC MAIL (E-MAIL)

The post office of the future : E-mail, is a simple tool for exchanging brief text messages between individuals or among a larger audience. E-mail is almost certainly the most widely used application on internet and unsurprisingly so. The advantages are numerous, the most obvious being speed. One of your e-mail letters can arrive at its destination on the other side of the planet within seconds of you hitting the Enter key on your keyboard. There are other advantages, besides raw speed, too. You can send sound, images, video-even computer software. E-mail has its disadvantages, of course. You can't send something physically. Each e-mail is made up of two parts, a heading and the message. The heading is made up of the senders e-mail address and the receiver's e-mail address. An e-mail address serves a similar purpose to an address on an envelop- the electronic postman needs to know where to send the letter and to whom it's intended. E-mail address can seem complex at first glance, but they really are quite straightforward and logical once you look at them more carefully.

Working with E-Mail : 

1. Send mail

2. Read incoming mail

3. Reply to mail

4. Delete mail

5. Exit the mail program

1. Sending mail: All mail programs have a New Message or Compose E-mail command, located on a message menu, and they usually have a keyboard shortcut for the command as well, such as Ctrl+N for New Message. When you start a new message, your program will open a new window.

Type the address of the person to whom you wish to send the mail. The person's address must be of the form username@address.domain

Username is the person's identifier (the name they log in with). Address is the identifier of the person's network or machine on the network. Domain is the short code at the end indicating whether the address is a business (.com). A non profit(.org), A university (.edu), A branch of the government (.gov), A part of the military (.mil) and so on. If you are sending mail to someone on your own network (or another member of your online service or a subscriber of your own network you only have to specify the username, not any of the Internet information.  

Sending mail to people on other network: If you want to send mail to someone on another network, you will need to know their identifier on the network address appears in internet form. Here an example of the most common internet address.

Network- Internet Address

Nagpur.dot.net.in -  jbtdrc_wda@sancharnet.in

Creation of an e-mail message: After entering the recipient's address in the address box, press tab and then type a subject in the subject box(keep it shortly) this will be the first thing. If you want to send a copy of the e-mail message to more than one recipient, you can either: 

Type multiple addresses in either the To: or Cc: line, separating each address by a comma. In some e-mail programs, the addresses may appear on separate lines.

Press tab until the insertion point jumps into the blank message area:  When you are done, send the message or add it to a queue, a list of outgoing messages to be sent all at once. Press the send button.

If the message continues beyond the bottom of the window, use the scroll bar to see the To view the contents of a mail message, highlight it in the Inbox window and press Enter (or double-click it). The message will appear in its own window.

If the message continues beyond the bottom of the window use the scroll bar to see the next screenful. After reading the message, you can close or reply to the message

Replying to Mail:

Add other recipients if necessary or tab your way into the message area to type your reply, and then choose the Send command when you are done.

Deleting Mail: To delete a message, you typically highlight it and press Delete.

Exiting an E-mail Program: When you are finished sending, reading, and replying to mail, you can quit your program or leave it running to check your mail at regular intervals.

You can quit most mail programs by selecting File » Exit or File » Quit.

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