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Computer Network Introduction And Its Benefits

Computer Network Introduction And Its Benefits


Computer Network
A collection of computers and other devices that are connected together by communication channels for sharing information and other resources is called computer network. The resources may include printers, scanners, and hard disk. Computer network is also called the information network. The most popular information network is the internet.

In a computer network, two important technologies: computing and telecommunication work together. The computers on a network may be linked through cables, telephone lines, radio waves (Wireless), and satellites.


Uses/Benefits of network
The main beneficts or uses of computer network are :
1- Communication
     Using a network. different people can communicate with each other all over the world. People can communicate at very low cost via e-mail, chatting, telephone, video telephone, video conferencing, groupware, and SMS service.
2- Sharing Resources
In a computer network, resources such as, printers, scanners, fax machine and modems can be shared among different users. Suppose several personal computers and laser printers are connected to network. Each user can acess the printer.
3- Sharing Software
In a Computer network, usually application programs and other software are stored on the central computer. Users connected to a network can access these programs or software
4- Data Sharing
Data or information can be shared among different users. Any Authorized user can access data stored on other computer on the network. For example, on the internet large number of internet users can access same database.
Non-Impact Printers And Its Types

Non-Impact Printers And Its Types

Printers
Printers are the most commonly used output device. They are used to print output on the paper. The output may be in the form of characters, symbols and graphics information printed on paper is called hardcopy

Categories/Types of Printers
Printers are classified into two main categories or types:
       1- Impact Printers
        2- Non-Impact Printers


Non-Impact Printers
The printers that produce output on paper without striking the paper are known as non-impact printers. They Use Electrostatic , inkjet, and thermal technologies for printing.


Non-Impact printers are faster and produce hight quality output than impact printers. They can print up to 24 pages per minute. They produce no noise during printing. These printers are costly than impact printers

The Examples of Non-Impact printers are :
      1- Laser Printer
      2- Inkjet Printer
      3- Thermal Printer

Laser Printer
Laser stands for Light Amplification by Simulated Emission of Radiation. A laser printer is the fastest and hight quality non-impact printer. It works like a photocopier. The laser printer transfers the image of output on paper using LASER technology and toner. Toner is an ink powder. It is used in laser printers and photocopiers also

The laser printer has a special drum inside it. first the image of output is created on the drum, and then it is transferred from drum to paper. The image of output is created on the drum by throwing magnetic ink powder in the form of microscopic dots. These dots can be from 300 dpi to 1200 dpi (dpi means dots per inch and these dots refers to microscopic dots).

The Laser printer can print both text and graphics in very high quality resolution. Laser printer prints one page at a time. The laser printers are, therefore also called page printers. The printing speed of laser printer is about 4 to 32 pages per minute for microcomputer and up to 200 pages per minute for mainframe computers.

Ink Jet Printer
Ink-jet printer is type of non-impact printer. It creates output on paper by spraying tiny drops of liquid ink. Inkjet printer has print-head that can spray very fine drops of ink. It consists of print cartridge filled with liquid ink and has small nozzles in form of matrix. Like dot matrix printer, the combination of nozzles is activated to form the shaper of character or image on the paper by spraying the liquid ink. These printers have resolution ranging from 300 to 720 dpi.

The ink-jet printers have low price than laser printers. They are also slower and have low print quality than laser printer. However, They are faster and have hight print quality than dot matrix printers. The printing speed of ink-jet printer is from 1 to 6 pages per minute.

Thermal Printer
Thermal printer is another type of non-impact printer. It can only print output on a special heat sensitive waxy paper. The image if the output is created on the waxy paper by burning dots on it. For coloured output, coloured waxy sheets are used.

Thermal Printer produces a high quality printout. It is quite expansive as compared to other non-impact printers.

Impact Printers And Its Type

Impact Printers And Its Type


Printers
Printers are the most commonly used output device. They are used to print output on the paper. The output may be in the form of characters, symbols and graphics information printed on paper is called hardcopy

Categories/Types of Printers
Printers are classified into two main acategories or types:
    1- Impact Printers
    2- Non-Impact Printers

Impact Printers
The types of printers that produce output on paper by striking the print hammer or wheel against  an inked ribbon are called impact printers. impact printers work like typewriter. They can print characters and graphics on the paper
Impact printers are slower in printing and produce low quality output. The printing speed of these printers is measured  in characters or lines per minute. They also produce more noise during printing. Today they are not commonly used.

The examples of impact printers are :
     1- Dot matrix printer
     2- Daisy Wheel printer
     3- Line printer

Dot Matrix Printers
A dot matrix printers is an impact character printer. It makes a hardcopy by printing one character at a time. Its printing speed is from 200 to 1000 or more characters per minute.

Dot matrix printer contains a print-head with a matrix of small pins arranged in rows and columns. Dot matrix printer produces output on paper by striking pins against an ink ribbon. Usually, a dot matrix printer uses 100 to 300 dots per inch (DPI) to print output on the paper. Print-heads are avialable with 9, 18 or 24 pins. The dot matrix printer with 24-pins provides best quality printout.

Dot matrix printers are usedd with personal computer. They are less expensive. The printout quality of these printers is not bad. They also produce more noise during printing.

Daisy Wheel Printer
Daisy wheel printer is also an impact character printer. It is similar to typewriter. It has a print wheel with a series of petals. This wheel is known as daisy wheel. Each petal of dasiy wheel contains a character at its end. A motor rotates the wheel. When the desired character reaches at the print position on the paper, a hammer strikes a petal against the ribbon. In this way, a character is printed on the paper. This printer is slower than dot-matrix printer. However, its print quality is better than dot matrix printer

Line Printer
Line printer is an impact printer. it is very fast printer. It prints a complete line of characters at a time. The printing speed of line printer is measured in lines per minute (lpm). It is upto 3000 lines per minute.
Line printers are normally used with mainframe and mini computers.

Two types of line printers are ;
    1- Chain Printer
    2- Band Printer

Digitizer or Graphic Tablet

Digitizer or Graphic Tablet



Digitizer or Graphic Tablet
Digitizer is used for drawing new images or tracing old images. Usually. it is used for making maps and engineering drawings. A digitizer is also known as graphic tablet. It consists of a flat, rectangular board (or pad ) and an input device stylus or puck. Each location on the rectangular board points to corresponding positions on the computer screen. The Stylus or puck is connected to the board/pad by a wire.

Stylus looks like a pen. It is used for drawing images on a specially designed graphics screen or digitizer. Puck looks like a mouse. Puck is also called cursor. Usually, it is generally used for tracing old images
Software And Its Types

Software And Its Types



Software
Software tells the computer what to do and how to do. A computer performs different operations according to the instruction of software. Software is developed in a computer programming language.

Types of Software
Software can be classified into following two main categories or types
      1- System Software
      2- Application Software

System Software
A program or set of programs that is especially designed to control different operations of computer system is called system software. It controls the working of different components of the computer. The system also enables the other application programs to excute properly

Operating systems, utility programs, and device drivers are the examples of system software. Operating system is the main and most popular type of system software.

Application Software
A program or set of programs that are especially designed to solve the specific problems of users, are called application software. It is also known as software package

There are Different kinds of application software such as comercial software, scientific software, financial packages, Games, multimedia software.

Categories of Application software
The Application software is divided into two main categories
     1- Custom-built software
     2- Packaged software

Custom-built software
The software that is developed for a particular customer or organization is called custom-built software. It is also known as customized software. For example, software developed to  maintain the records of students of a particular collage is an example of custom-built software

Packaged Software
The software that is developed for sale to the general public is called packaged software. Packaged software is  used to solve some common problem of many people or users

Some examples of packaged software are ;
    1- Word processor such as MS-Word
    2- Spreadsheet such as MS-Excel
    3- Database software such as MS-Access
    4- Graphic software such as Adobe Photoshop and CorelDraw
    5- Communication Softwware such as Internet Explorer