This chapter discusses common computer input devices like the keyboard and mouse. It describes the standard QWERTY keyboard layout and the purpose of different types of keys. Mice can be mechanical or optical, and variants include trackballs and touchpads. Proper ergonomics are important to prevent repetitive strain injuries when using input devices extensively. The keyboard and mouse allow users to interact with computers by entering text, numbers, commands and selecting options.

1. McGraw-Hill Technology Education
McGraw-Hill Technology Education
Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.

2. Chapter 2
Interacting With Your
Computer
McGraw-Hill Technology Education
Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.

3. Chapter 2A
Using the Keyboard And
Mouse
McGraw-Hill Technology Education
Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.

4. Overview
• If CPU is a computer’s brain
• Then input devices are its sensory
organs—the eyes, ears, and fingers.
• you interact directly with input devices
and only indirectly with the CPU.
• The most commonly used input devices
are the keyboard and the mouse.
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5. The Keyboard
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• The primary input device for entering
text and numbers
• Standard keyboard includes about 100
keys
• Each key sends a different signal to the
CPU
• Must be proficient with keyboard
• Skill of typing is called keyboarding
• It is the ability to enter text and numbers
with skill and accuracy

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7. The Standard Keyboard Layout
• The IBM Keyboard. It has about 100
keys arranged in five groups
• (The term IBM-compatible computer
refers to any PC based on the first
personal computers, which were made
by IBM. Today, an IBM compatible PC is
any PC other than a Macintosh
computer.)
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8. The Alphanumeric Keys
• The alphanumeric keys: The area of the
keyboard that looks like a typewriter
• Keys are arranged the same way on
almost every keyboard.
• Sometimes this common arrangement is
called the QWERTY (pronounced
KWER-tee) layout because the first six
keys on the top row of letters are Q, W,
E, R, T, and Y.
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9. The Alphanumeric Keys
keys having specific functions
– The Tab key moves you to predefined tab stops in
many application programs (such as word
processors).
– The backspace key erases characters you have
just typed
– Caps lock key lets you "lock* the alphabet keys so
they produce only capital letters.
– The Enter key lets you finalize data entry
• used to choose commands and options in many
programs
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10. The Modifier Keys
• The SHIFT, ALT (Alternate), and CTRL
(Control) keys are called modifier keys
• They modify the input of other keys
• Holding down a modifier key while pressing
another key, changes the second key's input
in some way
• For example, if you press the ―j‖ key, you
input a small letter j.
• But if you hold down the shift key while
pressing the J key, you input a capital J.
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11. The Numeric Keypad
• Located on the right side of the
keyboard
• Looks like a calculator's keypad, with its
10 digits and mathematical operators (+,
-, *, and /)
• The NUM LOCK key, forces the numeric
keys to input numbers
• When NUM LOCK is deactivated, the
numeric keypad's keys perform cursor
movement control and other functions
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12. The Function Keys
• Labeled F1, F2, F3 and so on
• Arranged in a row along the top of the
keyboard.
• Allow to input commands without typing long
strings of characters
• Navigating dialog boxes
• Each function key's purpose depends on the
program being used
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13. The Function Keys
• In most programs, F1 is the help key
• F2 key renames selected files and
folders
• F3 will change the text from uppercase
to lowercase . Vice versa
• Most IBM-compatible keyboards have
12 function keys.
• Along with modifier keys give the
function keys more capabilities.
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14. The Cursor-Movement Keys
• A set of cursor-movement keys
• Let you move around the screen without
using a mouse
• a mark called cursor on the screen
indicates where the characters you type
will be entered.
• the cursor or insertion point, appears on
the screen as a blinking vertical line
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15. Special-Purpose Keys
• Start key,
– features the Windows logo (and is
sometimes called the Windows logo key),
– opens the Windows Start menu.
– same as clicking the Start button on the
Windows taskbar.
• shortcut key,
– features an image of a menu
– opens an on-screen shortcut menu in
application programs.
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16. Special-Purpose Keys
page up and page down keys
• let you ―flip― through a document, screen
by screen
• like turning the pages of a book.
• page up jumps to the previous screen
• press page down jumps to the next.
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17. Special-Purpose Keys
• HOME is pressed to move the cursor to
the beginning of a line.
• END to move to the end of a line.
• The Esc or ESCAPE key is used to
―back up" one level in a multilevel
environment.
• The Print Screen key allows the user to
capture whatever is shown on the
screen as an image
– This key does not work with all programs
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18. Special-Purpose Keys
• Scroll lock causes the cursor to remain
stationary on the screen, and the
document's contents move around It.
– This key doesn't function at all in some
programs.
• Delete removes one character at a time
at the cursor's location
– It erases characters to the right of the
cursor.
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19. Special-Purpose Keys
• The Insert key switches some programs
from Insert mode" (in which text is
inserted into the document at the cursor)
to ―overtype mode (in which new text is
typed over existing text), and vice versa.
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20. Multimedia Keys
• Feature buttons that can perform any number
of tasks
– Use the buttons to launch a Web browser,
– check e-mail,
– start your most frequently used programs.
– Control the computer’s CD-ROM or DVD
drive
– adjust the speaker volume.
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22. How the Computer Accepts Input
from the Keyboard
Input from the keyboard is complex
 When you press a key, a tiny chip called the
―keyboard controller‖ notes that a key has
been pressed.
 It places a code into part of its memory called
the ―keyboard buffer‖, to indicate which key
was pressed.
(A buffer is a temporary storage area that holds
data until it can be processed.)
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 keyboard controller then sends a signal to the
computer's system software, notifying it that
something has happened at the keyboard

23. system software receives the signal
it determines the appropriate response.
When a keystroke has occurred the
system reads the memory location in the
keyboard buffer that contains the code
of the key that was pressed
The system software then passes that
code to the CPU.
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24. The keyboard buffer can store many
keystrokes at one time.
This capability is necessary because
some time elapses between the
pressing of a key and the computer’s
reading of that key from the keyboard
buffer.
With the keystrokes stored in a buffer,
the program can react to them when it is
convenient
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25. This all happens very quickly.
Unless the computer is very busy
handling multiple tasks,
you notice no delay between pressing
keys and seeing the letters on screen.
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27. The Mouse
• All modern computers have a mouse
today
• Allows users to select objects
– Pointer moved by the mouse
1). Mechanical mouse
– a small rubber ball that protrudes through a
hole in the bottom of the mouse's case
– The ball rolls inside the case when you
move the mouse around on a flat surface
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28. The Mouse
– Inside the mouse, rollers and sensors
send signals to the computer
– telling it the distance, direction, and
speed of the ball's motions
– Rubber ball determines direction and
speed
– The ball often requires cleaning
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29. The Mouse
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31. The Mouse
2). Optical mouse
– Light shown onto mouse pad
– Emits a beam of light from its underside
– Uses the light's reflection to judge the
distance, direction, and speed of its travel
– Reflection determines speed and direction
– Requires little maintenance
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33. The Mouse
• Interacting with a mouse:
– use a mouse to move the pointer to a
location on the screen,
– ―a process called pointing(pushing the
mouse across your desk)‖
– In multi-button mice, one button must be
designated as the ―primary‖ button, referred
to as the mouse button.
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34. The Mouse
Actions involve :
– pointing to an object
– Clicking selects the object
– Clicking and holding drags the object
– Releasing an object is a drop
– Right clicking activates the shortcut menu
– Modern mice include a scroll wheel
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35. The Mouse
• Benefits
– Pointer positioning is fast
– Menu interaction is easy
– Users can draw electronically
• Mouse button configuration
– Configured for a right-handed user
–It Can be reconfigured
– Mostly they have between 1 and 6 buttons
– Extra buttons are configurable
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36. Variants of the Mouse
• The primary goals or these ―mouse
variant’s are to provide ease of use
while taking up less space than a mouse
• Trackballs
– Upside down mouse
– Hand rests on the ball
– User moves the ball with
index finger
– Uses little desk space
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37. Variants of the Mouse
•
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Track pads/ Touchpads
– Stationary pointing
device
– Small plastic rectangle
– Finger moves across
the pad
– Pointer moves with the
pointer
– Popular on laptops

38. Variants of the Mouse
• Track pointer/
Pointing Stick
– Little joystick on the
keyboard
– a pressure-sensitive
pointing device
– shaped like a pencil
eraser
– Move pointer by
moving the joystick
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39. – Typically between the G and H keys
– The pointer on the screen moves in
the direction you push the pointing
stick.
– By pressing buttons below the
keyboard users can click and perform
other mouse-type operations with a
pointing stick
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40. Variants of the Mouse
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41. Ergonomics and Input Devices
• Ergonomics
– A tool or a workplace is designed to work
properly with the human body, and thus
reduces the risk of strain and injuries OR
– Study of human and tool interaction
– Its Concerned with physical interaction
– That attempts to improve safety and
comfort.
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42. Ergonomics and Input Devices
• Repetitive Strain Injury (RSI)
– They are Caused by continuous misuse of
the body
– Many professions suffer from RSI
Carpal Tunnel Syndrome
– Carpal tunnel is a passage in the wrist
which holds nerves and tendons
– Prolonged keyboarding swells tendons
which is called carpel tunnel syndrome.
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44. Ergonomics and Input Devices
• Office hardware suggestions
– Office chairs should have
• Adjustable height
• Adjustable Armrests
• Lower back support
– Desks should have
• Have a keyboard tray
• Keep hands at keyboard height
• Place the monitor at eye level
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45. Ergonomics and Input Devices
• Techniques to avoid RSI
– Sit up straight
– Have a padded wrist support
– Keep your arms & wrists straight
– Keyboard properly
– Take frequent breaks
– Learn to type( don’t ―hunt & peck‖)
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50. Chapter 2A
Presented
By
Waqas Ahmed
McGraw-Hill Technology Education
Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.