2. 1B-2
Parts of the Computer System
• Computer systems have four parts
– Hardware
– Software
– Data
– User
3. 1B-3
Parts of the Computer System
• Hardware
– Mechanical devices in the computer
– Anything that can be touched
• Software
– Tell the computer what to do
– Also called a program
– Thousands of programs exist
4. 1B-4
Parts of the Computer System
• Data
– Pieces of information
– Computer organize and present data
• Users
– People operating the computer
– Most important part
– Tell the computer what to do
7. 1B-7
Essential Computer Hardware
• Processing devices
– Brains of the computer
– Carries out instructions from the program
– Manipulate the data
– Most computers have several processors
– Central Processing Unit (CPU)
– Secondary processors: motherboard, RAM,
chip set
– Processors made of silicon and copper
8. 1B-8
Essential Computer Hardware
• Memory devices
– Stores data or programs
– Random Access Memory (RAM)
• Volatile
• Stores current data and programs
• More RAM results in a faster system
– Read Only Memory (ROM)
• Permanent storage of programs
• Holds the computer boot directions
9. 1B-9
Essential Computer Hardware
• Input and output devices
– Allows the user to interact
– Input devices accept data
• Keyboard, mouse
– Output devices deliver data
• Monitor, printer, speaker
– Some devices are input and output
• Touch screens
10. 1B-10
Essential Computer Hardware
• Storage devices
– Hold data and programs permanently
– Different from RAM
– Magnetic storage
• Floppy and hard drive, Audio & Video cassettes,
tape
• Uses a magnet to access data
– Optical storage
• CD and DVD drives
• Uses a laser to access data
11. 1B-11
Software Runs The Machine
• Tells the computer what to do
• Reason people purchase computers
• Two types
– System software
– Application software
12. 1B-12
Software Runs The Machine
• System software: is a type of computer
program that is designed to run a
computer’s hardware and application
programs
– Most important software
– Operating system
• Windows XP
– Network operating system (OS)
• Windows Server 2003
– Utility
• Symantec AntiVirus
13. 1B-13
Software Runs The Machine
• Application software
– Accomplishes a specific task
– Most common type of software
• MS Word
– Covers most common uses of computers
14. 1B-14
Computer data
• Fact with no meaning on its own
• Stored using the binary number system
• Data can be organized into files
15. 1B-15
Computer users
• Role depends on ability
– Setup the system
– Install software
– Mange files
– Maintain the system
• “Userless” computers
– Run with no user input
– Automated systems
19. 3A-19
The Keyboard
• The most common input device
• Also called primary input device for
entering text and numbers. A standard
keyboard includes about 100 keys, each
key sends a different signal to the CPU.
– Must be proficient with keyboard
– The Skill of typing is called keyboarding
means the ability to enter text and numbers
with skill and accuracy.
20. 3A-20
The Keyboard
• How keyboard works
– Keyboard controller detects a key press
– Controller sends a code to the CPU
• Code represents the key pressed
– Controller notifies the operating system
– Operating system responds
– Controller repeats the letter if held/said
21. 3A-21
The Mouse
• All modern computers have a pointing
device as standard equipment.
• Allows users to select objects
– Pointer moved by the mouse
• Mechanical mouse
– Rubber ball determines direction and speed
– The ball often requires cleaning
– Inside the mouse rollers and sensors send
signals to the computer, telling it the
distance, direction, and speed of the ball’s
motions.
22. 3A-22
The Mouse
• Optical mouse
- Non mechanical
– Light shown onto mouse pad
– Reflection determines speed and direction
– Requires little maintenance
23. 3A-23
The Mouse
• Interacting with a 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
24. 3A-24
The Mouse
• Benefits
– Pointer positioning is fast
– Menu interaction is easy
– Users can draw electronically
25. 3A-25
The Mouse
• Mouse button configuration
– Configured for a right-handed user
• Can be reconfigured
– Between 1 and 6 buttons
– Extra buttons are configurable
26. 3A-26
Variants of the Mouse
• Trackballs
– Upside down mouse
– Hand rests on the ball
– User moves the ball
– Uses little desk space
27. 3A-27
Variants of the Mouse
• Track pads
– Stationary pointing
device
– Small plastic
rectangle
– Finger moves across
the pad
– Pointer moves with
the pointer
– Popular on laptops
28. 3A-28
Variants of the Mouse
• Track point
– Little joystick on the keyboard
– Move pointer by moving the joystick
29. 3A-29
Ergonomics and Input Devices
• Ergonomics
– Study of human and tool interaction
– Concerned with physical interaction
– Attempts to improve safety and comfort
– Ergonomics is the process of designing or
arranging workplaces, products and
systems so that they fit the people who use
them.
30. 3A-30
Ergonomics and Input Devices
• Repetitive Strain Injury (RSI)
– Caused by continuous misuse of the body
– Many professions suffer from RSI
– a painful medical condition that can cause
damage to the hands, wrists, upper arms,
and backs, especially of people who use
computers and other forms of keyboard
• Carpal Tunnel Syndrome
– Carpal tunnel is a passage in the wrist
– Holds nerves and tendons
– Prolonged keyboarding swells tendons
32. 3A-32
Ergonomics and Input Devices
• Office hardware suggestions
– Office chairs should have
• Adjustable armrests and height
• Armrests
• Lower back support
– Desks should have
• Have a keyboard tray
• Keep hands at keyboard height
• Place the monitor at eye level
33. 3A-33
Ergonomics and Input Devices
• Techniques to avoid RSI
– Sit up straight
– Have a padded wrist support
– Keep your arms straight
– Keyboard properly
– Take frequent breaks
Teaching tip
Suggest to your students that the majority of people who purchase computers do so because of software. They want to email, or type letters. Nearly every reason given to purchase a computer is based on software needs.
Teaching tip
A good exercise to relate the importance of making data meaningful is to list some random numbers on the board. Then ask what they mean. Without a title, the numbers have no meaning. Once a title is presented, the numbers make sense.
Teaching tip
It is helpful to walk through a simple program to demonstrate the cycle. I often use a simple arithmetic problem to show this cycle.
Teaching tip
The interaction between a CPU and secondary processors is much like the interaction between a boss and subordinate. The boss tells the subordinate what to do but not necessarily how to accomplish the task. The subordinate only bothers the boss when guidance or more data is needed.
Insider information
Intel, the manufacturer of popular CPUs, originally made RAM for mainframe and minicomputers. Today Kingston is a leading RAM manufacturer.
Chapter 5 discusses ROM and the BIOS. Refer your students to this chapter if they desire more information.
Teaching tip
It is helpful to have examples of input and output devices in class. Stories of obscure input output devices are typically well received by the students.
Insider information
A new CD technology is emerging. A shorter wavelength blue laser beam is being used to burn CD’s. This allows more data to be saved on a disk. The technology is in it’s infancy but should be mature in the near future.
Chapter 11 of the text provides more detail regarding storage devices.
DVD writers are available for purchase. They have not been standardized yet. Several competing formats are vying for acceptance. Of these, the DVD+RW seems to have the strongest support.
Teaching tip
Chapter 5 in the text explores data processing in greater detail.
Figure 1B.5 shows data in binary format.
Teaching tip
Most computer problems are caused by user error. Given this fact, it is fun here to teach the student the acronym PEBKAC the Problem Exists Between Keyboard And Chair. A little humor can break up the lecture monotony.
Teaching tip
Table 5A.3 presents the ASCII code. An exercise that never fails to amuse students is to use the Alt and the number pad to enter letters into an application. As before, open MS Word. Have students hold down the Alt key and type an ASCII value into the number pad. Once they release the Alt, the letter appears. This is a useful skill when the keyboard breaks. Challenge the students to explore numbers above 128.
Insider information
Douglas Englebart patented the first mouse in 1970 as the “X-Y position indicator for a display system.” The name mouse comes from the tail on the device.
Insider information
The term track point is copyrighted by IBM.
Teaching tip
Hairstylists often suffer from carpal tunnel. Bicyclists can suffer from overuse injuries of the knee.
Page 116 of the text has a diagram of the carpal tunnel.