What is Email? Write its Advantages and Disadvantages

Electronic Mail:
With an e-mail anyone can send messages to other users of the internet and to many network connected to the internet through gateways. Most email programs also per miles users to attach data files and program files to messages. An internet electronic mail address has two parts, the user name and the domain name. The user name identifies the person who originates or receiver the mail; the domain name identifies the computer system on which the users had an account.

Advantage of Email: 
 Compared to the postal services, electric mail has many advantages.

1. It's fact-Most systems can deliver your message to the recipient in a matter seconds almost instantaneous. Many systems let you check to see whether the recipient has accessed you message. 
2. Its easy when you contact the service, you see a list of the messages you have received. You read the first message and then decide how to respond. You can reply to the message if you like, or just delete it if it requires no reply. You can save it or print it, you can even forward the message to others. 
3. It's available the email services is available round the clock and round the globe. 
4. It's fun International electronic mail systems enable you to find friends all over the world. 
5. It's cheap Worldwide electronic mail access is available through services such as gmail, outlook, hotmail, these services are free to certain level of service and  charge less than you expect to pay for monthly telephone service for some advance services. 
6. It's flexible you  can send a message to more than one person if you like. 

Disadvantages of Email:
Following are some disadvantages of email.

1. It is still not generally available to all. 
2. It has created an information overload, people are swapped by junk mails and finding what is relevant and need to read from the handled of mails. 
3. It is possible that any of the email contains virus, which may affect your computer system. 
4. Any email sent to wrong address can not be recalled back after 28seconds only in gmail. 
5. It is not completely private or confidential due to hacking. 
6. As email is free, so some one may send email for trouble so that you may feel uneasy to deal with. 

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Mechanism of a Hard Disk

In a disk drive a floppy diskette rotates at speeds of 300-400 RPM(revolutions per minute). Typically, hard disks rotate 7200 RMP. In a disk pack, all disks rotate at the same time, although only one disk is being read or written on at any one time. In the same way,  the high-density 3 1/2 inch floppy disk can  store 1.44 MB of data. Today, hard disks with the capacity range of giga-bytes (GB) are very common. With a hard disk, most people can store all their programs and files in one location. Still hard disk do not eliminate the need for a floppy disk drive. It serves as a transfer device to get software, purchased on floppies, in to hard disk. Some hard disk mechanisms for large system use moving head. in this design, all the read/write heads in a stack of disks are attached to a single access mechanism that moves directly to a specific address. This method is relatively slow, because all the access arms must move together.

A faster technology is that of fixed-head disks. These devices have fixed access arms with separate disk, read/write mechanisms for each track of the disks. The disk, rather than the head, whirls to bring the correct sector to the arm; the read/write mechanism for the depending on the application. Other disk devices combine the technologies of both moving  and fixed head access to produce a high capacity, rapid access device. With a brand new hard disk, the computer will try to place the data in clusters that are contiguous-that, is that are adjacent(next to one another). Thus, data world be stored on track 1 in sectors 1,2,3,4 and so on However as data files are updated and the disk fills up, the operating system stores data in whatever free space is available. Thus files become fragmented. Fragmentation means that a data file becomes spread out across the hard disk in many non-contiguous clusters. 

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Secondary Memory and three its three types

Secondary Memory:

Secondary memory or storage can store a ruler of information permanently and lies outside the CPU. It provides computer the means of storing and processing large quantities of data for longer periods of time and that is not currently being passed. Secondary storage is also call Auxiliary storage or external memory. It is non volutile.

Purpose of Secondary storage:

Auxiliary storage is used to store.
Input data and programs.
Output results of processing.
Auxiliary storage is where us put last years results of ur school, addresses for old students, programs you may or may not each use, data you entered yesterday everything that is not being used right now.
Secondary memory(or Secondary Storage) is the slowest and cheapest form of memory.
It can not be processed directly by the CPU. It must first be copied in to primary storage (RAM).
Types of Secondary Storage Devices:
Secondary memory devices includes magnetic storage devices like floppy disks, hard disks and magnetic tapes(the first forms of secondary memory) and optical disks such as CDs and CD-ROMS.
Magnetic Storage Devices: 
Magnetic storage devices are designed in such a way that their surfaces are coted with millions of thing from particles. So that data can be stored on them each of these particles can act as a magnet in magnetic field when subjected to an electromagnet. A read/write head is use to access data from these devices.
Storing Data in Magnetic Storage Devices:
The read write head of a hard disk device, floppy disk device and tap device contain electromagnets. Which generate magnetic field in the from on the storage medium as the head posses owr the disk or tape. The read write head record strings of is and of by alterneting the direction of current in the electro-magnets.
    There are following magnetic storage devices.
(1)Floppy Disk   (2)Hard Disk    (3)Magnetic Tape
Optical Storage Devices:
Optical storage techniques make use of the user beams to write and read data which can consist of the graphics, audio clips, or video image at magnetic disk. a single optical disk of the type called CD-ROM can hold up to about too megabytes of data. This works out to about 269,000 pages of test, or more than 7500 photos or graphics or 20 hours of speech or 77 minutes of video. Although some disks are used strictly for data storage many combine, visuals and sound. In the principal type of optical disk technology a high power loser beam is used to represent data by burning tiny pits into the surface of a hard plastic disk. To read the data, a now powers loser light scans the disk surface: pillet area are not reflected and are interpreted as 0 bits: Smooth areas, called land are reflected and are interpreted as 1 bits. Because the pits are very tiny much more data can be represented than is possible in the same amount of space on a magnetic disk whether flexible or hard.
Many types of optical disks are available for computer users. Among them the commonly available optical disks are:

1. CD-ROM DISKS
2. CD-R DISKS
3. CD-RW DISKS 
4. DVD-ROM DISKS

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Define Star topology with diagram

Star Network: 

In a star network topology each device is connected to a central unit. Any communication between one device and another goes through the central unit. The image shows a typical configuration using central server and peripherals. Each device is directly connected to the central server, which is a computer containing the interface cards and software ;to manage all data communication in this network. If a user at workstation 2 wants to print out a page, workstation 2 sends that request to the central server. This central server notifies workstation 2 when that task is complete.

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Diferentiate b/w Soft Copy and Hard Copy

HArD COpy:

1. Paper output is known as hard copy. 
2. Hard copy is tangible and permanent. 
3. Hard copy produced by a printed on paper. 
4. The principal hard copy output devices are printers plotters, and microfilm output devices. 
5. Soft copy is best for information that needs to be viewed only occasionally or a few moments. 
6. Example of hard copy output is news papers, books magazines etc. 

SOft Copy:

1. Screen output is known as soft copy. 
2. Soft copy is intangible and temporary. 
3. Soft copy produced by a monitor on screen. 
4. The principal soft copy output devices are monitors and sound of voice output devices. 
5. Hard copy output is bets for information that may be used later or that may have greater value over time. 
6. Examples of soft copy output's are ATM Machine, air lines departure and arrivals display. 

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What is information technology? Describe any three fields of it?

                                                                                Information Technology:

We can define the term information technology as information technology is the merger of of computer and technology means the use of hardware. Or Information technology means the use of hardware, software, services and supporting infrastructure to manage and deliver information using voice data and video.
.
Fields of Information Technology: 
Art:
Artists are using personal computers to generate and manipulate experimental images, sculptures for example can use personal computers to create models and experiment with variations before committing to an actual physical piece.
Energy:
Energy companies use computers to locate oil, coal, natural gas and uranium.
Agriculture: 
Computers have penetrated to farms. Farmers now use small computers purchased for less than the price of a tractor to help with billing, crop information, cost per acre feed combination and market price checks.

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Types of Modem

There are three types of modems.

DIRECT CONNECT: 
Which are linked to the computer by cable and the Rs.232 point and plus in to a standard telephone socket.
INTERNAL: 
Which are built in to the computer and have backup capabilities.
Sales of micro-computers which contain internal, board-mounted modems are increasing rapidly. Alternatively, there are add-on modem cards that can be fitted inside the computer.
ACOUSTIC COUPLER: 
A cheap, low-speed modem where the user places the telephone handset in to the cradle of the coupler.

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Differentiate b/w compiler and interpreter

Compiler:

1. It translates the whole program at once and give an errors list to be removed.
2. Computer is not  necessary for repeated execution of a program.
3. Compiler is a complex program.
4. Compiler analyses each statement, it uncovers certain types of errors referred to as diagnostic errors .
5. A computed machine language programs runs much faster than an interpreted program .

Interpreter:

1. In interpreter is a program that translates a high level programming language in to machine language during the actual step by step execution of program.
2. In case of the interpreter when cover an instructions are used, it must once again be interpreted and translated into machines language.
3. Interpreter are easy to write and they do not require large memory space in the  computer.
4. An interpreter provides a fast response to engages in the source program.
5. The interpreter is a time consuming translation method.

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Define OSI model?

The OSI Model:

One communication standard created by ISO is called the open system inter connections (OSI) model that simulates the communications processing using seven layers, each with its own set of protocols. The purpose of the OSI model is to enable any vendor’s computer system to share data with any other vendor’s computer system in an open networking environment.

List of Layers of the OSI Model:

The OSI model consists of seven layer.

1. Physical layer
2. Data link layer
3. Network layer transport layer
4. Session layer
5. Fresentation layer
6. Application layer

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Short Note- Uses of Computer

Uses of computer:

computers are tools, they help people perform many different kinds of tasks. One way to gain an appreciation for computers is to see have some people use them in their daily lives.

Information management:

Computers are excellent tools for managing large quantities of information. This includes all use of computers that support the administrative aspects of  an organization, such as airline reservation systems, student registration system, hospital patient billing system and countless others.

Communication:

The telephone and the computer are two of your most useful tools. Combine them and you end up with a powerful communication system.

Science, Research and Engineering:

For decades scientific research has benefits from the high speed, massive compilation capabilities of computers Engineers and scientists routinely use the computer as a tool experimentation design, and development.

Education and Reference:

Computers can interact with students to enhance the learning process. Relatively inexpensive hardware capable of multidimensional communication, (sound, print, graphics and animation) has resulted in the phenomenal growth of the computer as an educational tool in the home in the classroom and in business.

Entertainment and Education:  

Personal computers have reinvented the concept of entertainment, improvement in personal computer graphics and speed have allowed and sophisticated games to be created.

Artists:

Artists are using personal computer to generate an d manipulate experimental images.

Energy:

Energy companies use computers to locate oil, coal, natural gas and uranium.

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Short Note- Word processing

Word Processing

A word processor is just a computerized type writer. You use it to enter, edit, arrange, and print next you can use one to create memos, letters , reports, brochures any printed material. All word processors are designed for producing different kinds of written documents. Some are simple they have features for typing, editing and printing. Some word processing programs are complex they have features for formatting characters and pages, and or incorporating drawings, tables and charts into documents.

You would benefit from using a word processor if you:

1. Spend a lot of time typing and revising documents.
2. Send out mailings.
3. Write documents of any kind. Some features to consider in a word processing package include.
4. Word wrap features that automatically wrap text from the end of one line to the beginning of the next time. If a word processing program has no word wrap, it means you don’t need to press enter at the end of each line unlike a type writer, where you hit return  wherever you get to the end of line. This makes it easy to insert of delete text. The word processing program automatically adjusts the time breaks.
5. Features that enable you to copy and move text from one place in a document to another, or to text easy. Drag and drop editing enables you to accomplish these taks using a mouse you just selected the text and drag it to its new place in the document.

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Short Note- Web Search Engine

Web Search Engine:

A search engine like Alta vista or Hot Bot offers a much more complete database of what is on the web because the database of what is on the web because the database is complied automatically. A search engine uses software agents, sometimes called spiders or software robots, to explore the web retrieve information and send it to the data base. To find information with search engine, you type a query using keyword just you might locate construct complex queries using Boolean logic. A search engine can easily produce a list of hundreds of hits pages that contain requested keywords or match a query. Most search engines attempt to list pages in order from best to worst, but their rankings are not nearly as reliable as those done by the human researchers. Who create directories like yahoo. Still search engines are invaluable research tools especially when, you need to find something that has not been cataloged in your favorite directory.

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Short Note- Modem

Modem:

The simplest form s of data transmission involve the connection of terminals to a computer via a telephone line. But the problem here is that the computer generates data in the form of digital signals where as the telephone lines used for data communication in computer networks are usually meant for carrying analogue signals when digital data are to be sent over an analogue facility. The digital signals must be converted to analogue form the technique by which a digital signal is converted to its analogue form is known as modulation . The reverse process, that is the conversion of analogue signal to its digital form, at a destination device is called demodulation. The process of modulation and demodulation, that is the conversion of digital data to analogue form and vice versa is carried out by a special device called a modem short for modulator demodulator.

Also see:

Types of modem

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Short Note-Uses and abuses of Internet

An international computer network connecting other networks and computers from companies universities and other institution in order to quick exchange of information is called “Internet”.

Internet has its own merits and demerits. The use and abuse of internet depends upon the users. Some important merits or use of internet are being described as following.

1. It gives information about every field of life.
2. You may get information according to your need through internet.
3. You may take advantages from encyclopedias and dictionaries with the help of internet.
4. It gives a coordination with whole world and its interests.
5. It helps to exchange views with person of some mental attitude.
6. Internet  bring the world closer.
7. Current happening incidents can be discovered  by the use of internet.
8. Every kind of related with politics, fashion, science etc can be discovered by the use of internet.

Internet has to many advantages, if it is used positively. Internet is producing false trends especially among the students which easily become a victim of its colorful and charming aspects. Some disadvantages of internet may be described as following.

1. The students waste their precious hours on sitting internet without taking any positive and constructive benefit.
2. Most of the people are using internet to satisfy their sexual desires.
3. Nude pictures and sexual material is easily available through internet which destroy the moral values of young boys  and girls.
4. Computer hacking is very common by the use of internet, some extreme minded people can digest the money through the use of credit card of others.
5. The students waste their time in useless talking with each others.
6. Several hours on internet without any purpose produce wrong effects on a persons health.

The government is trying to take such steps in which the only positive use of internet could make possible however it is totally depended upon the trends and education of the people, if they are aware of their profit and loss they will use internet with their justification.

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Define the terms user interface. Distinguish between a command line interface and a graphical user interface?

User Interface: 
A user interface is combination of hardware and software that you use to communicate with and control the computer. Through the user interface, you are able to make selections the computer, request information from the computer and respond to message displayed the computer. Thus, a user interface provides the means for dialog between you and the computer.

The two broad categories of user interface supported by various operating systems are:

1. Command Line Interface
2. Graphical user interface(GUI)

Command Line Interface

1. In command line interface, the user give instruction to the computer by typing commands. 
2. They use less RAM and secondary storage capacity. 
3. They do not require graphics display. 
4. It execute the command very fast. 
5. Simple task can be performed easily. 

Graphical User Interface

1. Instead of typing command, selection is achieved by moving a pointer with a mouse and clicking a mouse button. 
2. They use more RAM and secondary storage capacity. 
3. They require a more powerful processor and a better graphical display. 
4. They are slower when executing a command because a much more interpretation takes place. 
5. They can be irritating to use for simple task because a greater number of operations is required. 

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What is the copyright law state its advantages?

Copyright: 

Copyright law is used to cover computer software. It is illegal to make or distribute copies of computer programs without authorization. No other copies may be made without specific authorization from the copyright owner. 

Advantage of Copyright Law: 

1. Focus on creating a fair and competitive environment.
2. Give networks operators the freedom to built their own back bone and local access. 
3. Facilitate rapid deployment of infrastructure for promotion of IT services. 
4. To enable a free society to function, minimum amount of instruction will be permitted in terms of monitoring and filtering on all kinds of communication. 

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Server software-GUI-Password-TGP-URL

What is server software? 
The server software is used to manage and  administrate the server side applications. The software is installed on main server system which assigned to handle multiple clients.
What does GUI stands for? 
GUI stands for graphical user interface.
What is password? 
A word or phrase known only to the user when entered, it permits the user to gain access to the system.
What does TGP stands for?
Thumb Nail Graphic Post.
What does URL stands for? 
URL stands for Uniform Resource Locator.

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What are the main functions of spread sheet program

The main functions of spread sheet program are to manipulate data in tabular form.

1. It organize data clearly  into rows and columns. 
2. To sort the data easily. 
3. To make use of predefined, built in functions as formulas. 
4. To format the data easily in the form of graphs and charts.

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Differentiate between switch and router

Switch:

1. The switch can not send data out out to internet, or across a WAN. 
2. Switch can handle only similar type of network or toplogy. 
3. Switch has simple software to handle network activities. 
4. The switch learns the MAC address of each computer. 
5. Switch just used in LANs. 

Router:

1. The router is a device which is smart enough to route data from the LAN to the internet, or to your ISP, or to your WAN or even to another LAN. 
2. Router can manage several network or topologies. 
3. A router has additional smart software with security features. 
4. Router concerned with IP address instead of MAC address. 
5. High speed routers can serve as a part of internet of back bon.

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Define a bus. Describe the function of the address bus, control bus and data bus

Bus: 

A bus is a communication path way connecting two or more devices. A key characteristics of a bus is that it is a shared transmission medium. Thus a bus is a wire through which electrical signals can be transmitted. 

There are three types of buses called:

Address bus

Data bus

Control bus

Address Bus: 

The address bus is used by micro processor to transmit the address of the memory location which it wants to access for reading or writing purposes. An address bus is undirectional i.e.electric signals are transmitted in one direction only from micro processor to other devices by this bus. 

Data Bus: 

The data bus is used to transmit data from the memory to micro processor and vice versa. It may be used to transmit data to other devices such as output units. The data bus is bi-directional because data has to pass from microprocessor to memory as well as from memory to the micro processor.

Control Bus: 

The control bus supervises the reading or writing of data. It transmits signals to all the devices at the proper time. In fact, it informs the micro processor that p particular unit has completed its job. 

                  The picture above shows the bus system of a micro computer. 

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