Windows 2000 is a multi user operating system. a multi user operating system allows multiple users to use the same computer at the same time and/or different times.
In multiprocessing, multiple programs are executed on different processors at the same time. Some operating systems have features of multiprocessing and to control these type of tasks. In multiprocessing, operating system divides a task between different processors.
Multitasking is the capability of an operating system to load multiple programs into memory and to execute them at the same time. For example, a user can print a document on printer, while editing another document and so on.
This event triggers when you press the left mouse button and move the mouse while keeping the left mouse button pressed. This event is used to select more than one item at a time, or to drop an object into another application.
Mouse events are the actions that can be performed by using the mouse following are most common events triggered with a mouse.
Ø Left click.
Ø Right click.
Ø Drag etc.
The control panel is a special folder that contains the administrative tools (system software) used to perform system management tasks such as installing/uninstalling hardware devices, managing system resources, sharing printers, and setting up data and time etc.
Window explorer acts as a directory browser and file manager for windows. It provides an efficient way for locating and managing files on your computer. It also provides the most efficient way to manage the computer resources.
The recycle bin is special folder of windows on the hard disk and has an icon on desktop. It contains files and folders that deleted from the hard disk. Any files and folders you deleted from the hard disk are transferred to the recycle bin. These files or folders can be restored from the recycle bin to their original location if required for use.
The on screen work area on which application windows, icon, menus, and dialog boxes appear is called desktop. It is called desktop because the surface of screen looks like a desk with objects you might have on your own personal desk.
Windows is popular GUI operating system developed by Microsoft Corporation. It widely used in business, educational institutes and research organizations.
A command line operating system provides a command prompt to the user for typing different commands to interact with computer. The commands are given to the computer according to the predefined format. It is not an easy way to interact with computer. The user needs to memorize commands to perform deferent tasks. Examples of command line operating system are DOS (disk operating system).
A GUI operating system provides a graphical user interface to communicate the user with computer. It provides graphical objects such as icons, menus, windows, buttons etc. to the use to perform different tasks. Examples of GUI operating system are windows, Linux, and Solaris etc.
Software is like any other property. Software copyright is the right to use on the computer. The software company who develops the software keeps copy right with it and distributes by cost. When you purchase commercial software, you are paying for a license to use the software.
The special programs that are used to detect and remove the viruses from the computer are called anti virus programs. A large number of anti virus programs are available. The MacAfee and Norton are examples of most popular anti virus programs.
A secret word or code assigned to documents and programs, or computers system to prevent unauthorized access is called password. You have to type the correct password to open the system.
The principal law governing software piracy is the copyright act 1976. some amendments were made in this law in 1983 and now software piracy is believed to be a punishable crime. It may involve huge amounts of penalties.
Privacy is the act of limiting the access of information (or computer resources) from unauthorized users. It is the right of a person to keep his personal information away from other people. An individual has a right to see the data about him.
It is virus, which is the part of some computer game programs. When game program is installed in the computer and run, this virus is activated. An example of Trojan horse is format C.
Logic bomb is a virus, which is activated on the basis of a logical condition. Examples of conditions that can be used as triggers for a logic bomb are the presence or absence of certain files, a particular day of the date etc. one this virus is triggered, the important data stored into a computer may be deleted or corrupted.
The famous chernobal virus deletes all the Microsoft Office files and also the partition information from the disk one the partition of the disk is deleted, the important data on the disk cannot be acceded.
The software, which is installed into your computer without license is referred to as pirated software.
A small program that gets into your computer and distribute the normal functions of the computer and destroys the important data stored in the computer is called computer virus. The computer virus cannot damage hardware, only data or software is corrupted.
Security is a system of safeguard designed to protect a computer system and data from damage or access by unauthorized persons.
Computer has the following main characteristics:
Computer based training (CBT) or presentation is also called computer aided instruction (CAI). In this method, computer is used as an aid to teach the students in the classroom. The instructions of particular subject are received from the computer and are taught to the students.
Computer aided learning (
A computer simulation is a special type of computer model which provides the behavior of a system that might exist outside the computer (i.e in the real life). Simulations are often used to train people or students when:
Ø It is impossible to build system due to economical problems.
Ø Direct experimentation is impossible in real life due to dangerous of the system.
Ø System is yet available.
Computer aided manufacture is a software which used digital design output generated by CAD system and controls all the parts of a manufacturing process.
Computers are also used for the design of products. The computer aided design (CAD) software is used to design the samples, or models of the products.
One of the most popular used of e-commerce is electronic banking. An electronic banking is also known as cyber banking. It includes various banking activities conducted from home, a business, or on the road instead of a physical bank location. Usually the people pay their utility bills through their bank accounts using this facility.
Many businesses now have website that allow internet users to but goods or services. Shopping can take place using a computer at home, or at a cyber café. The e-shop can anywhere in the world and it remain open 24 hours a day.
A videoconference is a meeting between two or more people residing at various places. They can watch and talk with each other. They use a network (i.e. internet). Video conferencing provides a normal meeting environment. It enables both parties to see, hear and present material, just as if they are in the same room.
Office automation (OA) refer to the process of automating office tasks. In an office workers perform different tasks using computer. Many offices use the computer technology to perform various tasks.
Business, industry, medical, airline system, education, weather forecasting, home.
These are discussion groups or forums that provide the services to exchange messages on the internet (not on the web, which is only one area of the internet) about a particular subject. Newsgroups are classified by subject and do not necessarily deal with journalism or new. Health, hobbies, celebrities, and cultural events are subjects or many newsgroups.
Search engines are the special websites that provide facility to internet users to search information on the internet. Search engines maintain a list of billions of web pages containing information on variety of topics.
URL stands for Uniform Resources Locator. Every page has a unique address on world wide web. This called uniform resource locator (URL). If you want to access a web page on the world wide web, you will have to specify the URL of the required page in the web browser.
A web browser or simply a browser is software that allows the internet users to find, retrieves, view, and send information over the internet. Many web browsers are available but the most commonly used web browsers are Microsoft internet explorer and Netscape navigator.
Searching information on the World Wide Web is referred to as web browsing. A software known as web browser is used to search a view web pages.
DNS stands domain name system. the human readable name assigned to the computer server on the internet is called the domain name. it is a common and unique text name and is alternative to an IP address. The domain name system (DNS) stores the information about domain names and their corresponding IP addresses. For this purpose DNS server is used, which translates the domain name into its IP address.
IP stands for internet proctocl. It is a unique identifier for a host or node on the internet. It is numerical address with four numbers separated with dots. A typical IP address looks like this 216.27.61.137.
Gopher id an internet service that organized resources into multilevel menus to make finding information easier on the internet. Before gopher, it was difficult to find information on the internet.
FTP stands for file transfer proctocl. It is a way for transferring files from one computer to another. The process of transferring a file from a network computer to your local computer is called downloading. The process of transferring a file from your own computer to the server on the internet is called uploading.
e-mail stands for electronic mail. It is the most popular services or facility provided by the internet through which we can electrically send and receive message anywhere in the world.
The World Wide Web is simply referred to as web. It consists of a world wide collection of electronic documents stored on the special servers known as web servers. These documents are known as web pages. The web pages are accessible on the internet. So we can easily access the information available on the internet.
ISP stands for internet services provider. It is a company that provides the internet connections to the users. There are many ISP companies in each big city of each country of the world. You have to get an internet connection form any ISP company of your local city to connect to the internet.
TCP/IP stands for transmission control protocol/ internet protocol. It is a real communication protocol that drives the internet. Every computer to access the internet must be installed TCP/IP. This protocol provides connectivity between browsers and servers on the internet for data communication.
An extranet is a network of multiple intranets. It means that intranets of different companies are connected together for the collaboration among the companies.
An organization network through which the files and messages can exchanges among the users of the organization only is called the intranet.
The internet is the network of networks around the world. It is made up of thousand of smaller, national, regional, governmental, academic and commercial networks. It is global network.
The physical layer of OSI model is the bottom most layer. This layer is related to the transmission media for data transmission. This layer controls and co-ordinates the transmission of data in the form bit stream over a physical medium such as coaxial cable, optic fiber cable etc. it also defines the rules by which the bit are passed from one node (computer) in the network the next.
This layer of OSI model is responsible for carrying a packet of data from one computer (or router) to the next. It is also responsible for the reliability of the physical link established at physical layer. This layer provides for the error free transfer of data from one computer another. It checks whether the data has arrived properly and safely at the destination.
This layer of OSI model ensures the delivery of data packet from source to destination. It means that this layer is responsible for carrying data packets from one computer to another or from node to node.
This layer of OSI provides a mechanism for the exchange of data between source and destinations. It breaks large message from the session layer into segments to be sent to the destinations computers. At the destination computer, it reassembles the data segments and presents the data to the session layer. Transport layer also sends an acknowledgement of receiving of data of to the sender.
This layer of OSI model establishes maintains and manages connections between communicating systems or devices, so that they can talk to each other. These connections called sessions.
This layer of OSI model performs data transformations to provide a common interface for user applications. It means that data is translated between the formats the network requires and format the computers of the end users expect.
The application layer is the topmost layer of OSI of model. It provides services directly to the application programs, to access the network. It provides user interface to send and receive information by the user.
OSI stands for open system interconnection. OSI model is also known as OSI reference model. It is used for networking. It was created by the international standard organization (ISO) to provide a logical framework for how data communication processes should take place across networks.
A software is used for workgroup computing. This software known as groupware. It allows many users or researchers to work on their projects by sharing the same domain of information online. A groupware also permits the individuals to collaborate (work together) with their colleagues inside the organization by means of linked commuter (computer network).
In a computer network people can work together as a group even when they are thousands of miles away from each other. This concept of working together is called workgroups.
What is group computing or collaborative computing?
The phenomenon of sharing information among various members of workgroup through computer network is called working computing. The workgroup computing is also known as collaborative computing.
In mesh network each nose is directly connected to all node on the network. This type if network involves the concept of routes. In this type of network, each node may send message to destination through multiple paths.
In tree network, the nodes are connected to each other in such a way that forms a tree line structure. Typically to form a tree network, multiple star topologies are combined together onto a bus. In this simplest form, only Hub devices connect directly to the tee bus. Each hub functions as the root of tree of devices.
In a star network, each node or device is directly connected to a central connection point known as “Hub”. The central connection may be an actual Hub or a switch. Typically, the nodes or devices are connected to the Hub with unshielded twisted pair (UTP)
In a ring network, each node is connected to two adjacent nodes or neighbors for communication purpose and forms a closed ring or loop. In this way the last node connects to the first node to complete the ring. In this network, all messages travel through a ring in one direction (clockwise or anti clockwise from node to node.
In bus network, all nodes (or devices) are connected to a common communication medium or central single cable. This single cable is called bus. The devices or nodes are attached with the central (or bus) through interface connector.
In networking, the term topology is the way of connecting nodes (or devices) on a network. In other works, a topology represents the shape of network.
The hybrid network had combined features of both client/server and peer to peer networks (or arrangements). It has a server and the users can share the data and software. Similarly, each node can store its own files, programs, and had its own peripheral devices.
In peer to peer arrangement, all nodes (or computers) on the network have equal status. No one has control over others. It means that there is no central computer to control other computers. Each computer stores files on its own storage devices and has its own peripheral devices. The users can share each other’s data and devices (or resources) as and when needed.
In client/server network (or arrangement), the clients are all computers or nodes on the network and sever is a central computer that controls the network. In addition to control the network, the server also provides a centralized storage area for programs and data. It has hard disks that hold the shard data file or database.
De jure means according to law or regulations. These standards have been properly approved by the networks governing body.
Write the names of some networks governing bodies.
The names of most popular networks governing bodies are:
Ø American National Standard Institute (ANSI).
Ø The Institute of Electrical and Electronics Engineers (IEEE).
Ø The International Standards Organization (ISO)
Ø The International Telecommunications Union Telecommunication Standards Sector (ITU-T, formally CCITT.
Ø The Electronic Industries Association (EIA).
De facto means by tradition or by facts. These standards were developed without any formal plan and came to existence because of historical developments. These standards are most commonly used by the organizations worldwide.
The standards are the precise documents containing technical and physical specifications about the network being designed. Normally those standards are taken into consideration and are worldwide acceptable.
A metropolitan area network (MAN) is communication network system that covers a geographical area of a single city. Usually, MAN connects more then one LANs in a city or twon and covers a smaller geographical area than a Wan. Mobile phones (cellular) system are often MANs.
A wide area network is a network system that covers a large (or wide geographical area such as different cities of country or different countries of the world.
ARCnet stands for attached resource computer network. It is LAN protocol. It uses either twisted pair wire or coaxial cable, and the star topology with hub attached the network.
The method of controlling access to the shared network cable is called token passing.
A computer network in which each node is connected to two adjacent nodes or neighbors from a closed ring or loop is called ring network topology. The token ring protocol is used in thid type of network. The token ring is closely associated with IBM, which works on the concept of a ring network and a token.
A token is a special electronic signal. It consists of a series of bits, which functions like a ticket. The computer with the token can transmit data over the network. Only one token exists per network.
Before transmitting the data a node must find out if the cable is in use. If so the node must wait. When the cable is free, the node must begin transmitting immediately. This process is also known as CSMA/CD (carrier sense multiple access with collision detection)
The recycle bin is special folder of windows on the hard disk and has an icon on desktop. It contains files and folders that deleted from the hard disk. Any files and folders you deleted from the hard disk are transferred to the recycle bin. These files or folders can be restored from the recycle bin to their original location if required for use.
Ethernet is the most commonly used protocol in LAN. It uses a high speed network cable and bus topology , so it is relatively simple and cheaper.
The rules to send and receive data through computer network are called network protocols. These rules are defined in the network software.
Router is a communication device that connects two or more networks (different or similar) and transmits data to its corrects destination using the available path on the network, is called router. It stores the routing information of each node or computer on the network. It used this information to transfer data between nodes.
Router is a communication device that connects two or more networks (different or similar) and transmits data to its corrects destination using the available path on the network, is called router. It stores the routing information of each node or computer on the network. It used this information to transfer data between nodes.
A gateway is also an electronic device or system (collection of hardware and software resources) that connects two different types of networks and translates information from one to other. It enables computer or node to communicate with a computer on another different types of network.
A bridge is an electronic device that connects two similar networks and controls the data flow between them. A bridge looks at the information in each packet header and forwards data that is traveling from one network to another to its destination.
A network interface card (NIC) is used to connect a computer to other computers in the local area network. It is a circuit board that is installed inside the computer’s internal expansion slots. The NIC has a socket where the network cable is connected. The most popular network interface card is Ethernet card used to connect computers in local area network.
A local area network (LAN) is a type of computer network in which computers are interconnected in limited geographical area, such as network of computers in college computer laboratory or network of computers in office building etc.
A network (or computer network) is a way to connect computers together so that they can communicate with each other and share information.
Information networks are the computer networks that communicate with public telecommunication networks. In information networks, two important technologies: computing and telecommunication work together.
A translator program that translates the program written in assembly language into machine code is called assembler.
A translator program that translates each instruction of source program into machine code and execute it immediately before to translate the next instruction is called interpreter.
The language processor that translates the complete source code (written in high level language) as a whole into machine code before execution is called complier.
The source code written in high level language must be translated into machine code so that the CPU can understand it. Therefore, the source code translated into machine code is called object code.
The programming languages that are closed to human languages (e.g like English language) are called high level languages.
The programming languages that are very close to machine code (0s and 1s) are called low level languages? The examples of low level programming languages are machine language and assembly language.
Command prompt is also referred to as command line user interface. In this typed of user interface, the operating system provides prompt line on the computer screen. The user communicates with the computer (or operating system) by typing commands using a keyboard. The user interface provided by MS DOS operating system is an examples of command prompt.
The main functions performed by the operating system are:
A set of programs running in the background on a computer system and providing an environment in which other programs can be executed and the computer system cab used efficiently.
The instruction of three address format used three address fields. Each address field can specify either a register or a memory address. This type instruction requires too many bits to specify three addresses.
The instruction of three address format used three address field. Each address field can specify either a register or a memory address. This typed of instruction requires too may bits to specify three addresses.
The instruction of two address format used two address field. Each address field can specify either a register or a memory address. Two address instructions are the most common in commercial computers.
The instruction of one address format uses only one address field. This format of instruction used accumulator register for all data manipulations. However, for multiplication and division, there is need for register.
In zero address instruction format, no address is specified. A stack organized computer does not use an address field for instructions like ADD and MUL.
The instructions that used to transfer the execution control from one part of the program to another during program execution are called control transfer instructions. These instructions may be used to execute a set of instructions repeated for a number of times.
The instructions that used to write ad read data and from I/O devices are called I/O instructions. Every CPU provides facility to users to perform operations of reading data from a peripheral device and writing data to peripheral device. For this purpose, the programmer used the input and output instructions.
The instructions that used to transfer data from one unit of computer to another during program execution are called data transfer instructions.
A set of instruction that a CPU can execute to perform different operations on data are known as the instruction set of that CPU. Different types of processors have different instruction set.
A CPU also has general purpose registers that are used along with other registers to perform arithmetic & logical operations and these registers are also used for data movement purpose inside the computer. These registers are called EAX, EBX, ECX and EDX.
The segment or address register holds addresses of the memory locations that are being currently used by the CPU. It is used as base location for program instructions data and the stack. There are four segment registers named as CS, DS, ES and SS. Each has size of 02 bytes.
A stack represents a set of memory blocks; the data is stored in and retrieved from these blocks in an order, i.e first in and last out (FILO). This stack pointer register is used to manage the stacks in memory. This register holds the value of the top of the stack.
MBR stands for memory buffer register. It holds the contents of data or instruction read from, or written in memory. The CPU used this register to store data coming from the memory or going to the memory.
Once an instruction is fetched it is stored in the IR where this instruction decoded.
Program counter (PC) register holds the address of the next instruction to be fetched for execution. After instruction is fetched, the value of PC is incremented by 1. thus this register always points or holds the address of next memory location from which an instruction to be fetched.
I/O unit provided the way to communicate between processor and I/O devices such as keyboard, monitor, printer, disk drives etc. the I/O unit to write and read data directly to and from the main memory without the involvement of CPU. Without DMA, this work is done through CPU.
The computer bus (or parallel lines), which is used by CPU to send different commands (or control signals) form one component to the other is called control bus.
The computer bus, which is used to identity different components of a computer as well as to specify the address of different memory locations is called address bus.
The amount of data that a bus can carry at one time form one component of computer to another is known as width of data bus.
The computer bus which used to transfer data from one component to the other, is called data bus. It consists of 32 or 64 parallel lines. A data bus of 64 lines can transfer 64 bits (or 8 bytes) of data at a time.
The system buses are the part of motherboard and are used to connect main component of the computer such CPU, and main memory. The modern general purpose computers have 70-100 lines system bus.
A byte is a combination of 8 bits. One character takes one byte of memory. ( a character may be a letter, numeral or special character). The capacity of the memory or the storage is expressed in terms of number of bytes it can hold or store. It means amount of data and program size are also measured in bytes.
The binary number 0 and 1 is called a bit (for binary digit), which is basic unit for storing data in the computer memory. Actually the main memory consists of large number of electronic switches. Each switch can have either of two states i.e on or off. The on state represents 1 and off stat represents 0.
CPU stand for central processing unit. It is the most important component of the computer and it is also known as processor. CPU is considered as the brain of the computer. The CPU used in personal computer or small workstation consists of a single chip called microprocessor.
Drum plotter works like a flatbed plotter. It consists of a drum or roller on which paper is placed. The drawing pens are also mounted on the drum. The drum rotates back and forth to draw (or print) the graph on the paper. Drum plotter is used to produce continuous output such as to track earthquake readings.
The laser printer has special drum inside it. The laser printer produces an image of the output on a drum with laser beam and magnetically charged powered ink, called toner, and then transfers the image from drum on the paper.
Thermal printer is non impact printer. It can only print output on a special heat sensitive waxy paper. The image of the output is created on the waxy paper by burning dots on it.
Daisy wheel printer is also an impact character printer. It has a print wheel with series of petals. This wheel is known as daisy wheel.
An impact printer prints characters and graphics on the paper with the strikes of hammer or wheel against an inked ribbon. Dot Matrix, Daisy Wheel and Line printers are examples of impact printers.
A computer must have a video display adapter to display output in the form of graphics. Video display adapter is also known as video graphics card that determines the resolution, number of colors, and speed with which images appear on the display screen.
The output printed on the paper is called hardcopy. The printers and plotters devices are used for this purpose.
The output received on the display screen or in the audio or video forms, is called softcopy output. This kind of output is not tangible and it cannot be touched.
Video input is used to record film and video images. For this purpose, there must be a special circuit board known as video capture card inside your computer. The video capture card converts the video signals into digital signals that a computer can use.
To enter sound signals inside the computer, a computer must have a sound card. It is a special circuit board also known as audio board.
Video input device is used to record films and video images. VCR and video camera are examples of video input devices. For this purpose, there must be a special circuit board known as video capture card inside your computer.
Dedicated fax machine is an independent normal fax machine, which can send receive information to and from the other fax machine.
A magnetic stripe card has stripe of magnetically encoded information on its back. Usually, the magnetic strip cards used for personal identification during driving, in the departmental stores, at public places etc.
Bar code is a unique identification code in the form of light and dark vertical lines (or vertical zebra-stripped marks) or bars with spaces between them of different widths. It is printed on most of the manufactured products. Actually, the name of products, its price and other descriptions are coded as bar codes. There are several bar coding schemes or systems. The most popular and commonly used bar code is UPC (Universal Product Code).
Touch pad is a pointing input device. Touch pad is also known as track pad. It is also stationary device like trackball but it has no moving parts. It is a small flat surface (or sensitive pad) over which we slide our fingertip to move the pointer on the flat surface of touch pad, the pointer (or cursor) moves on the screen.
A trackball is also a pointing input device. It performs functions like a mouse but it is a stationary device with a moveable ball on its top. The ball is rotated or rolled with finger (or plam of the hand).
A pointing device is an input device that is used to control the movement of the pointer or cursor on the screen and to send command signals to the computer. Usually, the pointing device is used to select items on the screen, to select commands from commands menu, to draw graphs etc.
The devices that are used to enter data and instructions into the computer are input devices. The input device is hardware component. It accepts input (data & programs) in a form that the computer can use, and then sends to the processing unit.
Data is defined as collection of raw facts and figures which is collected for specific purpose. The data may be in the form of text, numbers, sounds, images, video clips.
When raw facts and figures are arranged in such a suitable manner that they give the clear & proper meanings then they are called information.
Information technology is a technology that combines computing with high speed communication links for carrying data from on place to another, all over the world (i.e over this village)
The devices that are used to enter data and instructions into the computer are input devices. The input device is hardware component. It accepts input (data and programs) in a form that the computer can use, and them send to the processing uint.
A program or set of programs that is specially designed to control different operations of computer system is called system software. The system software also enables the other application program to execute properly. Operating system, utility programs and device drivers are examples of system software.
A set of instructions given to the computer to perform a specific task, is called software. It tells the computer what to do and how to do.
The physical components of a computer is called hardware. You can touch, see and feel hardware. The input/output devices, CPU, memory unit etc are examples of hardware.
A computer is an electronic machine that can be programmed to accept data (input) , process it into useful information A(output), and store it in a secondary storage device for later use.
