Mr. Balvant TandelM.Com, MLISc, UGC-NET
Asst. ProfessorDept. of Library and Information Science
Anand Institute of P G Studies in Arts
An electronic machine that is used for storing, organizing,and finding words, numbers, and pictures, for doing calculations, andfor controlling other machines.
- British English Dictionary
Present Computing Technologies
10 things you have to know to computer literate!
Components of a computer system
What is Operating System
Various Dos Commands
CLS is an internal command.The CLS command clears your computers screen and moves the system prompt to the top of the screen.Example:To clear the screen, type the following command:CLS [Enter]
CHDIR(sp)\WP [Enter]The command can be abbreviated to CD:CD(sp)\WP [Enter]After executing this command, you will be in the WP directory. To go back to the main directory, type the following command:CHDIR(sp).. [Enter] or CHDIR\ [Enter] -or- CD(sp).. [Enter] or CD\ [Enter]Commands given while in a sub-directory act on that directory only.
COPYCOPY is an internal command.
The principal use of the COPY command is to copy files from one disk or directory to another. Its use is very simple.Example:To copy the file LETTER.DOC from drive A: to drive B:, enter the following command:COPY(sp)A:LETTER.DOC(sp)B: [Enter]To copy LETTER.DOC to Drive B: and change its name on drive B: to LETTER1.DOC, type the following:COPY(sp)A:LETTER.DOC(sp)B:LETTER1.DOC [Enter]To copy LETTER.DOC from the WP sub-directory on drive C: to drive B:, use this format:COPY(sp)C:\WP\LETTER.DOC(sp)B: [Enter]
DIR is an internal command.The DIR command allows you to see a list of the files stored on any disk. Along with the filenames, it also provides other information about the files.Example:To see a list of files on drive A:DIR(sp)A: [Enter]You will see a list of files, along with the size of each file in bytes, and the date and time that data was last entered in that file. In addition, the amount of space left on the disk will be displayed.Sometimes, a disk will have more files than can be displayed on the screen. Using the DIR command will cause the files to scroll off the top of the screen faster than you can read them. To avoid this, add the parameter /P. Here is an example:DIR(sp)B:/P [Enter]DOS will fill the screen with file information, then print at the bottom of the screen:Press a key to continue:After you press ANY key, another screen full of data will be displayed. This continues until the entire directory has been presented. There is another option with DIR. To see a list of files on disk A:, arranged in multiple columns, but without file size and other information:DIR(sp)A:/W [Enter]NOTE: Use the DIR command frequently to check on the files on your disks and to keep track of the amount of disk space available.
MKDIR is an internal commandThe MKDIR command allows you to create new sub-directories.Example:To create a new subdirectory, called CHAPTER1 on drive C:MKDIR(sp)C:\CHAPTER1 [Enter]To create a subdirectory within a subdirectory, for example to create the subdirectory CHAPTER1 in the directory NOVEL on drive C:MKDIR(sp)C:\NOVEL\CHAPTER1 [Enter]If you are already in the directory in which you want to place a subdirectory, you do not need the \ character. For example, If you had used the CHDIR or CD command to move to the NOVEL subdirectory, create the CHAPTER1 subdirectory like this:MKDIR(sp)CHAPTER1 [Enter]Note: You can abbreviate the MKDIR command to MD.Example:MD(sp)CHAPTER1 [Enter]CAUTION: Be certain you know which directory you are in before using the simplified form of this command. Otherwise you may create a subdirectory in an unwanted place. To avoid confusion, use the full format, including drive name, as in the first and second examples.
RMDIR is an internal command.RMDIR, or its abbreviated form RD, removes a subdirectory from a disk. Before removing the directory, however, all files in that directory must be deleted with the DEL or ERASE commands.Example:To remove the \WP directory from your hard disk, enter the following series of commands:CD(sp)\WP [Enter]DEL(sp)*.* [Enter]CD(sp).. [Enter]RMDIR(sp)\WP [Enter]CAUTION: Be certain that you really want to delete all the files in that directory. If there are files you wish to save, COPY them to another directory, or to a floppy disk before deleting them.
Introduction of Windows
My computer Icon
What is a Computer Network?
Collection of autonomous computers interconnected by a single technology is called computer network.
Two computers are set to be interconnected if they are able to exchange information.
Connection can be through a copper wire, fiber optics, microwaves, infrared or satellite.
CATEGORIES OF NETWORKS
A Local Area Network (LAN) is a collection of networking equipment located geographically close together. E.g. Single room, campus etc.
Data transferred in High speed which ranges from 100 Mbps to gigabit for system development and have a low implementation cost.
Upper limit: 10 km ; Lower limit: 1 km
Twisted pair cable or Co-axial cable connects the plug in cards to form a network.
Designed to share resources between PCs and workstation such as hardware or data.
A work to internet connections would most likely require broadcast network (LAN) with a connection to
the internet (packet switched network)
Cost reductions through sharing of information and databases, resources and network services.
Increased information exchange between different departments inan organization, or between individuals.
The trend to automate communication and manufacturing process.
Special security measuresare needed to stop users from using programs and data that they should not have access to; Networks are difficult to set up and need to be maintained by skilled technicians. If the file server develops a serious fault, all the users are affected, rather than just one user in the case of a stand-alone machine.
There are three topologies of LAN Network
The metropolitan area network (MAN) is designed to extend over an entire city.
It may be a single network such as cable television networkavailable in many cities.
A MAN uses distributed queue dual bus.
Range: Within 100 km (a city).Bus A
It provides a good back bone for a large network and provides greater access to WANs.
The dual bus used in MAN helpsthe transmission of data in both direction simultaneously.
A Man usually encompasses several blocks of a city or an entire city.
More cable required for a MAN connection from one place to another.
It is difficult to make the system secure from hackers and industrial espionage (spying) graphical regions.
Network that provides long distance transmission of data, voice, image and video information over large geographical areasthat may comprise a country, a continent.
Range: Beyond 100 km.
Covers a large geographical area so long distance businesses can connect on the one network.Shares software and resources with connecting workstations.Messages can be sent very quickly to anyone else on the network. These messages can have pictures, sounds, or data included with them (called attachments).Expensive things (such as printers or phone lines to the internet) can be shared by all the computers on the networkwithout having to buy a different peripheral for each computer. Everyone on the network can use the same data. This avoids problems where some users may have older informationthan others.
Need a good firewall to restrict outsidersfrom entering and disrupting the networkSetting up a network can be an expensive, slow and complicated. The bigger the network the more expensive it is. Once set up, maintaining a network is a full-time job which requires network supervisors and technicians to be employed. Security is a real issue when many different people have the ability to use information from other computers.Protection against hackers and viruses adds more complexity and expense.
ISDN ( Integrated service digital network) 2 types
Basic rate interfacePrimary rate interfaceFrame relaySwitched multimegabit data service (SMDS)Synchronous optical network (SONET)High data link controlled (HDLC)Synchronous Data Link Control (SDLC)
BASIS LAN MAN WAN
Full Form Local Area Network Metropolitan Area Network Wide Area Network
Range A communication network
linking a number of stations in
same local area. Range is 1 to
This network shares the
characteristics of packet
Range is100 km
A communication network
distinguished from a Local Area
Network. Range is Beyond 100
Media Used Uses guided media Uses guided as well as
Uses unguided media
Speed A high speed i.e. 100kbps to
Optimized for a large
geographical area than LAN.
communications, which may or
may not be provided by public
Cost cheaper costly expensive
NIC, switch and hub Modem a