Peter Norton, 6th edition

By: Rena Essa

Lesson 3A:Using the Keyboard and Mouse

Most keyboards have keys arranged in five groups:The alphanumeric keysThe modifier KeysThe numeric keypadThe function keysThe cursor-movement KeysSpecial-purpose keys

A standard computer keyboard has about 100 keys.

Most keyboards use the QWERTY layout, named for the first six keys in the top row of letters.

When you press a Key: The keyboard controller detects the keystroke.

The controller places a scan code in the keyboard buffer, indicating which key was pressed.

When the system SW receives the signal , it determines the appropriate response, the SW read the code that is located in the buffer.

The system SW passes that code to the CPU by interrupt request, telling the CPU to accept the keystroke.

The mouse is a pointing device. You use it to move a graphical pointer on the screen.

The mouse can be used to issue commands, draw, and perform other types of input tasks.

Using the mouse involves five techniques: Pointing: Move the mouse to move across the desk, the pointer moves in relation to the mouse. Clicking: Press and release the left mouse button

once. Double-clicking: Press and release the left

mouse button twice.

Dragging: Hold down the left mouse button as you move the pointer. Right-clicking: Press and release the right mouse

button.

Trackballs Trackpads Integrated Pointed Devices

A trackball is like a mouse turned upside-down.

Use your thumb to move the exposed ball and your fingers to press the buttons.

A trackpad is a touch-sensitive pad that provides the same functionality as a mouse.

To use a trackpad, you glide your finger across its surface.

Trackpads provide a set of buttons that function like mouse buttons.

is a small joystick built into the keyboard.

To use it, you move the joystick. These devices provide a set of buttons

that function like mouse buttons.

Lesson 3B: Inputting Data in Other Ways

Pens: Used by tablet computers, also used to point or write on the screen.

Touch screen: accept the input directly on the computer screen.

Game controller: act as mouse, its used to input data to the computer.

Bar code readers. Image Scanners and Optical character

Recognition (OCR).

The most common type is the flatbed model.

Used in the supermarkets, handhold, by the delivery workers.

Converting printed image into electronic form by shining light onto the image and sensing the intensity of the light’s reflection at every point.

Additive colors is (Red, green and Blue). Color scanner used filters to separate the

components of colors into the additive colors.

In the computer used special SW to organize the photos.

OCR SW used to translate the image into text, then can edit.

Creates an image from the page, the page stored in the memory as a bitmap.Bitmap is a grid of dots, each dote

represented by one or more bits.

The OCR SW is translate that array of dots into text that the computer can interpret as letters and numbers.

To translate the bitmaps into text ,The OCR SW look at each character and tries to match it with its own assumptions about how the letter should looks.

Microphones Other types of audio input (MIDI) Video Input (Webcam) Digital cameras