COMPUTER SYSTEM (1)

 COMPUTER SYSTEM (1)

1. What is a computer?

A computer is an electronic machine. It follows our instructions, accepts data, processes it, gives results, and stores them for future use.

2. The Four Main Functions of a Computer

·      Input: The computer receives data or instructions.

·      Storage: The computer saves data.

·      Processing: The computer works on the data.

·      Output: The computer shows the results.

Remember: Data is raw facts. Information is data that has been organised and made useful.

3. How Does a Computer Work?

We enter data using input devices, such as a keyboard, mouse or scanner. The computer stores and processes the data in the Central Processing Unit (CPU). It then gives information through output devices, such as a monitor or printer.

4. Input and Output Devices

·      Input devices enter data into the computer: keyboard, mouse and scanner.

·      Output devices show or produce results: monitor, printer and speakers.

·      The processing unit processes data. The storage unit saves data.

5. The Keyboard

A keyboard is an input device. We press its keys to type letters, numbers and instructions.

·      Alphabet keys: Type letters.

·      Number keys and numeric keypad: Type numbers.

·      Spacebar: Leaves a blank space.

·      Enter key: Starts a new line or carries out a task.

·      Backspace key: Removes the character to the left of the cursor.

·      Delete key: Removes selected objects or characters.

·      Caps Lock and Shift: Help us type capital letters.

·      Arrow keys: Move the cursor around the screen.

·      Function keys: Help us perform special tasks.

·      Esc key: Helps us leave or stop a task.

·      Ctrl and Alt keys: Work with other keys to perform special tasks.

·      Windows key: Opens the Start menu.

·      Application key: Opens a shortcut menu.

6. Hardware

Hardware means the parts of a computer that we can touch and feel.

The computer system (2)

Mouse, Mouse Substitutes, Scanner and Storage

Mouse

·      A mouse is an input device and a pointing device.

·      It is used to draw and select objects on the computer screen.

·      A mouse has two buttons and a scroll wheel.

Mouse Pointer

The mouse pointer moves on the screen when we move the mouse.

Mouse Actions:

·      Click: Press and release the left mouse button once.

·      Double-click: Press the left mouse button twice quickly.

·      Right-click: Press and release the right mouse button.

·      Dragging: Move the mouse while holding the left button.

Mouse Substitutes

These devices can perform the same function as a mouse.

·      Touch Screen: Allows us to point and click using our fingers.

·      Digital Pen: Used to write notes and draw on a computer.

·      Light Pen: Used to point and select items on the screen.

·      Track Ball: Used to move the pointer by rotating a ball.

Scanner

·      A scanner is an input device.

·      It is used to send pictures and text into the computer.

Storage

·      Storage means saving data and information in a computer.

·      It helps us keep information for future use.

Types of Storage Devices:

·      Hard Disk Drive: Stores programs and information.

·      CD/DVD Drive: Reads and stores information on CDs and DVDs.

·      Floppy Disk Drive: Used to read and store data on floppy disks.