Standard Methods of Input
• The Keyboard
• The Mouse
• Variants of the Mouse
• If the CPU is the brain of the computer, then the
input devices are its eyes and ears.
• The keyboard was one of the first peripherals to be
used with computers, and it is stil the primary
• The Standard Keyboard Layout
• Ergonomic Keyboards
• How a Keyboard Works
The Keyboard – Standard Keyboard Layout
• A standard computer keyboard has about 100 keys.
• Most keyboards use the QWERTY layout, named for
thefirst six keys in thetop row of leters.
Most keyboards have keys arranged in five groups:
1. Alphanumeric keys
2. Numeric keypad
3. Function keys
4. Modifier keys
5. Cursor-movement keys
The Keyboard – Ergonomic Keyboards
• Long periods of keyboard use can cause injuries.
• An ergonomicaly correct keyboard can help you
• You also can avoid injuries by adopting correct
The Keyboard – How a Keyboard Works
When you pres a key:
•The keyboard controler detects the keystroke.
•The controler places a scan code in the keyboard
bufer, indicating which key was pressed.
•The keyboard sends the computer an interrupt
request, teling the CPU to accept the keystroke.
•An interrupt is a signal; it notifies a program that an
event has occurred.
• What is a Mouse?
• Mouse Techniques
The Mouse – What is a Mouse?
•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.
The Mouse – Mouse Techniques
Using the mouse involves five techniques:
1. Pointing; Move the mouse to move the on-screen
2. Clicking; Pres and release the left mouse buton
3. Double-clicking; Press and release the left mouse
4. Dragging; Hold down the left mouse buton as you
move the pointer.
5. Right-clicking; Press and release the right mouse buton.
Variants of the Mouse
• Integrated Pointed Devices
Variants of the Mouse – Trackbals
• A trackbal is like a mouse turnedupside-down.
• Use your thumb to move the exposed bal and your
fingers to pres the butons.
Variants of the Mouse – Trackpads
•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
•Trackpads provide a set of butons that function like
Variants of the Mouse- Integrated Pointing Devices
•An integrated pointing device is a smal joystick built
into the keyboard.
•To use an integrated pointing device, you move the
•These devices provide a set of butons that function