Organization of Computer

(III) Memory

(IV) Other Component

Input device These hardware parts which is used to input data into the computer. There are two types of Input device.

1. Online Input Devices (Mouse, keyboard, Scanner, Joystick, Light Pen, Touch Screen, and Track ball, Microphone and Webcam)

2. Offline Input Devices ( Camera)

Mouse:- Mouse is an input device. It is also called pointing device because it is generally, used to point the icon, menu item or any portion of the screen. Invented by “Douglas Engelbart” of Stanford Research Center in 1963.

How to Use Your Computer Mouse

1 Click or left click 2 Double Click

3 Right click 4 Drag and Drop

Keyboard: Keyboard is an input device, which is used to feed the instruction to the computer. It is similar to the typewriters key but it has too many extra keys, such as Esc, End, Home, Ctrl, Page up, Page down, Insert, Delete, Function, Alt, etc. Keyboard is dealt in detail later.

The keys on your keyboard can be divided into several groups based on function:

1 Alphabet Keys (A-Z)

2 Numeric Keys (0-9)

3 Function keys (F1-F12)

4 Cursor Control Keys / Navigation keys / Arrow Key

5 Special Purpose Keys (Tab, Caps Lock, Window, Delete, Space and Backspace etc)

FUNCTION OF KEYS

Caps lock: - It is used to make the alphabets capital or small. When it is pressed on it gives capital alphabets and when it is off it gives small alphabets.

Enter: - It is used to break the lines, paragraph or columns.

Shift: - it is used to display capital and small alphabets by holding shift we can bring changes in the character.

Tab: - It is used to give long space between two character and words

Space bar: - It is used to give space between two character and word.

Back space: - It is used to remove character at the back of the cursor.

Delete: - It is used to remove character at the right of the cursor.

End: - It is used to move the cursor at the end of the line.

Home: - It is used to move the cursor at the beginning of the line.

Page up: - It is used to move the cursor one page up.

Page down: - It is used to move the cursor one page down.

Esc: - It is used to cancel any job function.

Num lock: - It is used to lock and unlock the numeric pad.

Alt + ctrl: - For special purposes only

Arrows: - There are 4 arrow keys

Down arrow: - It is used to move the one line down

UP arrow: - it is used to move the one line up

Right: - It is used to move the cursor one character right

Left arrow: - It is used to move the cursor one character left.

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.

Example: Alt, Ctrl, Shift

Types of Keyboard & Mouse

1 Serial

2 PS2 (Personal System 2)

3 USB (Universal Serial Bus)

4 Wirelesses

Microphone: Microphone is an input device used to enter sounds into the computer. We can record sounds in computer with the help of microphone and sound card.

Joystick: Joystick is an input device used to play games on computer.

Touch Screen: In ATM and in latest smart phones, touch screen is used to receive input from the user. The user enters data by the touch of his finger on different menu options or icons present on touch screen.

Scanner: Scanner is an input device. It is used to save pictures or text on paper into computer memory. It converts picture or text on paper in to binary form and saves it in computer memory. With the help of scanner we may save our time to type a lot of text.

There are two types of Scanner:-

1. MICR (Magnetic Ink Character Recognition) MICR technology is used by banks.

2. Optical Scanner

Example: OCR (Optical Character Recognition), OMR (Optical Mark Reader) and OBR (Optical Bar Code Reader)

MICR: MICR is a character recognition technology used primarily by the banking industry to facilitate the processing of Cheque. The human readable characters are printed on documents using a magnetic ink. It stands for Magnetic Ink Character Recognition.

OMR: OMR which stands for Optical Mark Recognition is the process of gathering data with an optical scanner by measuring the reflectively of light at predetermined positions on a surface.

OCR: OCR stands for Optical Character Recognition. OCR is the recognition of printed or written text characters by a computer. It is the application software that allows a computer to recognize printed or written characters, e.g. letters, numbers, punctuation marks, and pictograms using an optical scanner for input. OCR is being used by libraries to digitize and preserve their holdings.

OBR: It stands for Optical Bar Code Reader which is used for reading bar-coded data. It scans a set of vertical bars of different width for specific data and is used to read tags. Bar code reading is done by a light pen or scanner connected to a computer.

Processing Device:

These devices which is used to process data.

Example: - CPU

Output device: The device which is used to give the result or information’s.

Example: Monitor, Printer, Plotter and Speaker.

Monitor:-

The monitor displays the video and graphics information generated by the computer through the video card. Monitors are very similar to televisions but usually display information at a much higher resolution. Monitors are also known as Visual Display Units (VDUs)

Types of Monitor

1 CRT (Cathode Ray Tube)

2 TFT (Thin Film Tube)

3 LCD (Liquid Crystal Display)

4 LED (Light Emitting Diode)

Types of Monitor According To Color Capabilities:

• Monochrome Monitor: (Single Color)

• Gray Scale Monitor

• Color Monitor (RGB)

Video Standard:-

Video Standard Color Time Company No of Pixel

CGA 4 1981 IBM 320x200