CENTRAL PROCESSING UNIT

%	Percent
&	Ampersand
^	Exponents
-	Hyphen / Dash / Subtractions
_	Under score
<	Less than
>	Greater than
+	Addition
*	Asterisk / Multiplication

2)         MOUSE: - 

A mouse is hand held pointing device that allows you to control yours computer without having to type in instructions with the keyboard. Now its programmes provide menu options for various commands and a mouse is very useful and easy to choose specific options from the menu. It is used to select an object.  The mouse we can point any where on the screen. Mouse is widely used in GUI (Graphical User Interface) application. Mouse consists of Two or Three buttons.

1. LEFT BUTTON: - This button used more than right button for command (Instructions) to computers, So this button is also called “Primary Button”.
2.  RIGHT BUTTON: - This button is also called “Secondary Button”. And used for to open pop-up (Property Sheet Menu) menu commands purpose.
3. SCROLL BUTTON: This Button is used to move Page Up and Page Down.

3)         SCANNER: - 

       A Scanner is device that acts like a Photocopy Machine. It can transfer an image of a photograph or written information’s to the computer. It can be used to scan typed or hand written text, graphs diagrams and photographs. And also scan physical image or hard image and soft image.

4)         JOY STICK: -

          It is used for playing the media games on computer. There is a very large job of joystick in computer field in a joystick there is a handle or level attached on the tracking ball, which can freely rotate on a fixed base.(In simply words used to play PC games)

5)         LIGHT PEN: - 

         light pen is a small pen like device with the small scores of light pen is a tip. This pen can be used by directly placing the point on the screen when we want.

6)         MIC: This is also input device. With the help of MIC we can load as well as store the sound like songs, voice mail etc.

7)         WEB CAM: 

         It is used for to take photos as well as Video Pictures.

8)         TOUCH SCREEN: - 

           This option also used to give Instruction & Commands to the

Computer (Now a days we follows at ATM machines)

C P U (CENTRAL PROCESSING UNIT)

All major calculations and comparisons are made inside the CPU. The CPU is also responsible for controlling of entire operation of the computer system. The CPU unit is further divided into three sub – units

Memory Unit

            Control Unit

            Arithmetic and Logical Unit

I  MEMORY UNIT: - 

      Data and instruction stored inside the computer before the processing. The main memory of the computer and is logically divided into the following four areas:

1) Input Storage Area: - The area in which input data is held until it is ready to process.

2) Working Storage Area: The area that holds the data being processed and intermediate result.

3) Output Storage Area: This is where finished (output) are held until released to the output devices.

4) Programs Storage Area: While the above areas are data related storage areas, the programs storage area holds the processing instructions

MAIN MEMORY UNIT (MMU) or Memory: - 

Data and instructions are stored as charges in electronic components. Data and instructions are stored in memory in binary form the only computer understands. Data representation, with in the computer is in the form of 0’s and 1’s. These are called BITS; short form of BInary DigiTS.  Combinations of 8 bits are 1 BYTE. Memory capacity is in terms of kilobytes (K.B’s), Mega bytes (M.B’s), etc.

MEMORY MEASUREMENT TABLE AS FOLLOWS:

8 Bits	1 Byte
1024  Bytes	1 Kilo Bytes (KB)