Information Technology

“ICT”

Def:-

          “The combination of computer and telecommunication devices used to collect, store, transform retrieve and disseminate the information is called information technology.”

“Computer”

Def:-

          “Computer is an arithmetic and logical machine which gets data as an input, process that data, store it, can communicate with other devices and can produce as a result of output.”

“DATA”

Def:-

          “The collection of raw facts and figures is called data.”

For example:-

                          Ali, roll no 23. Etc.

Types of data

·         Alphabetic data: - It consist letters from A-Z capital and a-z small. E.g. Abid and Peshawar etc.

·         Numeric Data: - It consists of digit from 0-9. E.g. 123,222 etc.

·         Alphanumeric Data:-It consist alphabetic as well as numeric digit. E.g. Street no A/10 etc.

·         Graphic Data: - It consist tables, charts, graphics and statements.

·         Audio Data: - It consist only sounds. E.g. Music and radio news etc.

·         Video Data: - I consists photos, image and moving picture. Such as TV news.

·         Miscellaneous Data:- It consist more than one type of data. E.g. Combination of audio and video.

“Information”

Def:-

         “The processed form of data is called information.”

For example:-

                          Ali is from Haipur Hazara.

“Difference between Data and information”

DATA	INFORMATION
Data is a set of raw facts.	Information is processed form of data.
Data is used as input.	Information is the output.
Data is not meaningful.	Information is meaningful.
Data is asset of organization and is not available to the people.	Information is normally available for sale.
Data is not used in decision making.	Information is used in decision making.
Data is used rarely.	Information is used frequently.
Data is an independent entity.	Information depends on data.

“Hardware”

Def:-

          “The electrical, electronic or mechanical components that make up the computer are called hardware.”

Or

“The touchable parts of computer are called hardware.”

“Software”

Def:-

           “Set of instructions which tell the computer what to do is called software.”

Types of software

1.      System software.

·   Operating system.

·   Translators.

·   Utility.

2.      Application software.

·   General purpose.

·   Special purpose.

1.     System software:-

                                           ”The software which controls the hardware is called system software.”

Types

Operation system:-

                                     “The software which controls the computer system is called operating system.”

Such as DOS, Windows (XP, 7 &8) and LINUX etc

Translators:-

                        Translators convert computer languages such as Low level, high level and assembly.

Types

Compiler:-

                     It converts high level languages to low level languages. (It converts whole program).

Interpreter:-

                        It converts high level to l

Assembler:-

2.     Application software:-

                                                    “The software which fulfils the specific needs of end user is called application software”

Types

General purpose:-

                                  The software which we use in our daily routine or which can easily be used is general purpose software. Such as MS Office etc

Special purpose:-

                               The software which is designed for special purpose or for specific users is special purpose software. Such as Peach Tree and Quick book etc

“Storage Devices”

There are two types of storage device.

1.      Primary Storage/temporary.

a.      RAM

·         Static Ram

·         Dynamic Ram

                                      i.      SDR

                                    ii.      DDR

b.      ROM

2.      Secondary Storage.

“Input Devices”

Def:-     

          “The devices which are used to input or inter the data into the computer are called input devices.”

Following are Input Devices.

1.     Keyboard.

2.     Mouse.

3.     Microphone.

4.     Pen.

5.     Scanner.

6.     Joystick.

7.     Digital Camera.

“Keyboard”

Most commonly used input device that helps in keying in the required information into the Computer. Keyboard is just like a typewriter in shape but enhanced than that. We can input data and can provide instructions to the computer.

Working:-

                    When we press keyboard’s button, an electrical signal generates. The device ADC (Analog to Digital Converter) converts these signals and sends these instructions to operating system (CPU & Memory).

Layout

Standard QWERTY:-

                                                 It is a standard keyboard. It has 104 keys and following groups.

Group of keys in keyboard.

1.      Alphanumeric keys.

2.      Function keys.

3.      Numeric keypad.

4.      Modifier keys.

5.      Arrow keys.

6.      Special keys.

Alphanumeric:-

                             It has all of the letters and numbers on the keyboard. A-Z and 0-9.

Function keys:-

                             Special keys labeled F1 to F12. These keys have different meaning depending on which program is running

Numeric Keypad:-

                                  It is on the right side of the keyboard. The numeric keypad features digits 0 to 9, addition (+), subtraction (-), multiplication (*) and division (/) symbols, a decimal point (.) and Num Lock and Enter keys.

Modifier keys:-

                             In computing, a modifier key is a special key (or combination) on a computer keyboard that temporarily modifies the normal action of another key when pressed together. These keys are Shift, Ctrl, Alt, Windows logo and Fn key etc

Arrow keys:-

                         Cursor movement keys or arrow keys are buttons that are either programmed ore designed to move the cursor in a specified direction.

Special keys:-

                          These keys are Home, Page up/down, insert and Delete etc that have different functions.

“Mouse”

Mouse is a pointing device, used to point and open the programs into the computer. It is moved on a flat surface to control the movement of the cursor on the screen. Mouse has three buttons. Right click, left click and wheel.

Types

1.       Mechanical Mouse.

2.       Optical Mouse.

3.       Wireless Mouse.

Mechanical mouse.

It is an old mouse. It has three buttons and a ball which rotates to change the direction of pointer.

Working:-

  It has a ball and sensor around it. Electrically signals produced. ADC converter these signals and sends it to the operating system.

“Wireless mouse”

It works without wire. Bluetooth is used to operate this mouse. Its range is 15-20 meters.

“Use of Mouse”

Every mouse has two main buttons and a wheel.

1.                  Primary Button:-

                                                    It is used to open the folder/file.

2.                  Secondary Button:-

                                                         It is used to open various options. Such as Open, cut and copy etc.

3.                  Scroll Button/wheel:-

                                         It is used to scroll up and down.

“Track Ball & Touchpad”

Trackball has same functionality as mechanical mouse while touchpad has sensors which sans human fingers.

“Pen”

The pen based devices use to photoelectric circuitry to enter data into the computer through a video screen. A user can write on the video display, the light sensitive pen sends information to the computer when user touches the pen on certain areas of a special design screen.

“Scanner”

Scanner is an optical reader input device that is used to enter a printed page into the computer. It provides a method of direct of input the data from sources documents into a computer system.

Working:-

                    Beam of light emits through scanner. It reflects onto the paper and bounce back to the light sensing diodes and then light signals are converted into the electrical and digital singles. The ADC converter converts it and sends these signals to the operating system.

“Types of Scanner”

1.      Flatbed Scanner.

2.      Sheet fed Scanner.

3.      Pen Scanner.

·         Flatbed Scanner:-

                                               In this type of scanner we insert the pages one by one to scan.

·         Sheet Fed Scanner:-

                                                  It inserts pages automatic which we want to scan.

·         Pen Scanner:-

                                       It is used for data collectors. Simple as barcode reader is used to scan and recognize the printed page. The documents we scan are recognized by OCR (Optical character Recognition). This converts printed page into text.

”Barcode Reader”

It is an input device like scanner. It scans the image. It has light sensing diodes that convert into electrical signal.

“Joy Stick”

It is an input device specially designed for computer games like racing and flying games. Joystick has base, stick and buttons. It can control movement of game.

“Micro Phone”

It is an input sound device that is used to input sound into the computer. It converts sound signals into electrical.

Working:-

                    When we talk our sound struck with diaphragm then it vibrates and sends these vibrations to the coil & Magnet then electrical signals generates, it transfers these signals to ADC which converts it into digital signals.

Condenser Microphones

It has two Plates, front and back plate. When sound hit to one plate then it pushes to the back plate. The distance creates between them and electrical signal generates.

”Digital Camera”

Digital camera is an input device. It captures still image electronically. Light reflects on image and it bounces back to the light sensing diodes and then electrical signals produced and these signals are converted into digital.

Output Devices

Def:-

            “The devices through which we can see the data are called output devices.”

Output Devices

1.      Printer

2.      Monitor

3.      Speaker

4.      Plotter

Printer:-

                Most commonly used output device that prints character, symbols and graphics on paper. The printed page is called hard copy. Print resolution is commonly measured in dots per inch (DPI).

Types

1.     Impact printer.

·   Dot-Matrix Printer.

·   Daisy-Wheel Printer.

2.     Non impact printer.

·   Laser Printer

·   Ink-Jet Printer

Impact printer:-

                              Impact printer works like a typewriter. It prints character or images by striking a print hammer or wheel against an inked ribbon. Following are impact printers.

a.      Dot-Matrix Printer:-

                                       Dot Matrix printer produces printed images when tiny pins on a print head strikes an inked ribbon. When the ribbon presses against the paper, it creates dots that form characters and graphics. The dot matrix printer head contain nine to 24 pins. Dot matrix output measured in CPS (character per second).

b.      Daisy-Wheel:-

                                        Daisy wheel printer is similar to type-writer. They produce rather excellent letter quality printout as compared the dot-matrix printer. They work just like type-writer and use a hammer and a wheel to print something on paper.

Non-Impact Printer:-

                                         Non-impact printer produces character without striking devices on paper. They are much quieter than impact printer. The following are the non-impact printers.

a.      Laser Printer:-

                        A Laser printer works on the principles of a photo copier. A metal drum called TONER is filled with special ink which, just sprinkle ink onto the paper and thus prints the character. They are very fast and use multiple fonts for text and graphics.

b.      Ink jet printer:-

                           It prints character and graphics by spraying tiny drops of liquid ink on paper. These printers can produce and graphics in both black and white and color. Inkjet printer is slower than laser printers. They can print 1-6 pages per minute. Its print quality Is higher than laser printer.

“Plotter”

A plotter is an output device that is used to produce image quality graphics in a variety of colors. Plotters work by drawings on paper using pins and held in a mechanical arm. They are mostly used for engineering and maps drawing purposes.

“Monitor”

Most commonly used TV like device that is used by the computer for displaying the information to the outside world is called as CRT or VDU or Monitor.

Types

1.     Monochrome.

2.     Gray Scale.

3.     Color.

·   CRT

·   LCD

Monochrome Monitor:-

                            It is type of Monitor that can display only one color.

Gray Scale Monitor:-

                                       It is type of Monitor that can display more than one color.

Color Monitor:-

                                Further it has two types.

1.     CRT:-

                       CRT Stands for Cathode Ray Tube. Electron gun is used in this monitor. E.gun bombards the electrons. These electrons strike on a phosphorous it glows and produce a picture. These monitors are costly cheap but consume high electricity.

2.     LCD:-

                        LCD stands for Liquid Crystal Display. It is also called a flat panel monitor. In this monitor liquid and diodes are used to display the data. These monitors are costly but consume less electricity.