1. Computer Concepts
7 t h E d i t i o n
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2. Chapter 2 Computer Hardware
Section A: Data Representation and Digital Electronics
Computer Concepts 7th Edition Parsons/Oja

3. Chapter Preview After this chapter, you should be able to:
Explain why most computers are digital
Describe the role of the ALU
List factors that affect performance
Explain RAM
Compare storage technologies
Describe computer’s expansion bus
Explain hardware compatibility considerations
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4. Data Representation: How do computers represent data digitally?
Data representation makes it possible to convert letters, sounds, and images into electrical signals
Digital electronics makes it possible for computer to manipulate simple “on” and “off” signals to perform complex tasks
A digital device works with discrete data or digits, such as 1 and 0
An analog device works with continuous data such as sound waves
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5. Data Representation: How do computers represent data digitally?
Computers are digital primarily because digital technology is simple, dependable, and adaptable
Just as a standard light switch is a simpler technology than a dimmer, so is digital when compared to analog
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6. How can a computer represent numbers?
Unlike the decimal system, the binary number system (base 2) uses only two digits 0, and 1
The following table lists some decimal numbers and their binary equivalent:
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7. How can a computer represent words and letters using bits?
Character data is composed of letters, symbols, and numerals that will not be used in arithmetic operations
ASCII (American Standard Code for Information Interchange) requires only 7 bits for each character
Extended ASCII uses eight bits for each character
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8. How can a computer represent words and letters using bits?
EBCDIC (Extended Binary-Coded Decimal Interchange Code) is an alternative 8-bit used by older IBM systems
Unicode uses 16 bits and provides codes for 65,000 characters – a bonus for representing alphabets of multiple languages
Used for foreign language support
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9. How does a computer convert sounds and pictures into codes?
Sounds and pictures must be transformed into a format the computer can understand
A computer must digitize colors, notes, and instrument sounds into 1s and 0s
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10. Quantifying Bits and bytes: How can I tell the difference between bits and bytes?
A bit is one binary digit (b)
A byte is 8 bits (B)
A nibble is 4 bits
0011
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11. Quantifying Bits and bytes: How can I tell the difference between bits and bytes?
Kilo- means a 1000, Mega- means million, Giga -means billion
Kilobit (Kb) is 1,024 bits
Kilobyte (KB) is 1, 024 bytes
Megabyte (MB) is 1,048,576 bytes
Gigabyte (GB) is 1,073,741,824 bytes
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12. Does a typical computer owner need to mess around inside the system unit?
Desktop units are designed with expectation that the home user may add or update the equipment
Notebook computers are not designed for users to access all areas. Although users can update certain components
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13. Does a typical computer owner need to mess around inside the system unit?
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14. What’s a computer chip?
Most electronic components inside a computer are integrated circuits - thin slices of silicon crystal packed with microscopic circuit elements
Wires
Transistors
Capacitors
Logic gates
Resistors
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15. What’s a computer chip?
Semiconducting materials are used to fabricate a chip
Types of chips
DIPs
DIMMs
PGAs
SEC cartridge
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16. What’s a computer chip?
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17. How do chips fit together to make a computer?
The motherboard houses all essential chips and provides connecting circuitry between them
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18. How do chips fit together to make a computer?
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19. Chapter 2 Computer Hardware
Section B: Microprocessors and Memory
Computer Concepts 7th Edition Parsons/Oja

20. Microprocessor Basics: What exactly is a microprocessor?
A microprocessor is an integrated circuit designed to process instructions
CPU on a chip
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21. How does a microprocessor work?
The CPU has two parts
ALU (arithmetic logic unit)
Performs arithmetic operations
Performs logical operations
Uses registers to hold data being processed
The CPU’s control unit directs and coordinates processing
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22. Can I replace my computer’s microprocessor with a faster one?
Technically yes, but most computer owners rarely do
Reasons not to upgrade
Cost
Technical factors – speed
Do research before you upgrade your microprocessor
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23. Random Access Memory: What is RAM?
RAM (random access memory) - an area of the computer that temporarily holds data before and after it is processed
As you type, characters are held in RAM
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24. How much RAM does my computer need?
RAM is primary storage (main memory)
Measured in megabytes (MB) or gigabytes (GB)
Today’s computers have between 128 MB and 2 GB of RAM
Depends on software you use
You can purchase additional RAM
A computer can use disk storage to simulate RAM. This is called virtual memory
Not as fast as RAM
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25. Do all computers use the same type of RAM?
No. RAM components vary in speed, technology, and configuration
Speed is measured in nanoseconds. 1 nanosecond (ns) is 1 billionth of a second
It can also be expressed in MHz (millions of cycles per second)
SDRAM (Synchronous Dynamic RAM)
RDRAM (Rambus Dynamic RAM)
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26. Read-Only Memory: How is ROM different from RAM?
ROM (read-only memory) is one or more chips containing instructions that help a computer prepare to process tasks
ROM is permanent and non-volatile
Only way to change the instructions on a ROM chip is to replace the chip
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27. CMOS memory: Where does a computer store its basic hardware settings?
A computer needs a semi-permanent way of keeping boot data, such as the number of hard disk sectors and cylinders
CMOS memory - holds data but requires very little power to retain its contents
Retains important computer settings after you turn the power off
Can run by a battery on the motherboard
Housed within the same chip carrier as ROM BIOS
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28. Where does a computer store its basic hardware settings?
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29. Chapter 2 Computer Hardware
Section C: Storage Devices
Computer Concepts 7th Edition Parsons/Oja

30. Storage Basics: What are the basic components of a data storage system?
A storage medium is the disk, tape, CD, DVD, paper or other substance that contains data
A storage device, such as a floppy disk drive, a hard drive, zip drive, CD drive, and a DVD drive, is used to store the data
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31. How does magnetic storage work?
Magnetic storage - stores data by magnetizing microscopic particles on the disk or tape surface
Read-write head - mechanism in the disk drive that reads and writes magnetized particles that represent data
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32. How does magnetic storage work?
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33. How does optical storage work?
Optical storage stores data as microscopic light spots (lands) and dark spots (pits) on the disk surface
Data recorded on optical media is generally considered to be less susceptible to environmental damage than data recorded on magnetic media
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34. How does optical storage work?
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35. Can I add storage devices to my computer?
Devices can be added into empty drive bays
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36. Floppy disk Technology: Why is it called a “floppy disk”?
A floppy disk is a round piece of flexible mylar plastic covered with a thin layer of magnetic oxide and sealed inside a protective casing
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37. How much data can a floppy disk hold?
3 ½ diskettes have capacity of 1.44 MB
Other floppy disk types
ZIP disks – 100 MB, 250 MB, and 750 MB
Superdisks – 120 MB or 240 MB
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38. Disk density - closeness and size of magnetic particles it stores
How can ZIP disks and Superdisks store more data than standard floppy disk?
Disk density - closeness and size of magnetic particles it stores
Zip disks and Superdisks store data at a higher density than a standard 3 ½ floppy disk
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39. What are the advantages and disadvantages of floppy disk technology?
Major advantage – portability
Major disadvantage – not a particularly speedy device and limited storage capacity
Today most software vendors use CD-ROM or DVD-ROM disks instead
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40. How does a hard disk work?
Hard disk platter - a flat, rigid disk made of aluminum or glass and coated with magnetic oxide
Density far exceeds floppy disk
Hard disk - one or more platters and their associated read-write heads.
Preferred type of main storage
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41. How does a hard disk work?
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42. What’s the downside of hard disk storage?
Head crash - when a read-write head runs into a dust particle or other contaminant on the disk
Head crash damages some data on disk
Triggered by jarring the hard disk while in use
Not limited to hard disks
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43. Tape Storage: What’s the purpose of a tape drive?
Tape backup - copy of data on hard disk stored on magnetic tape
Relatively inexpensive
Not suitable for everyday storage tasks
Sequential-access storage medium
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44. CD and DVD technology: Is there a difference between CD and DVD technology?
Holds up to 80 minutes of music or 700 MB of data
DVD
Holds about 4.7 GB of data
Upcoming DVD standards will further increase the storage capacity
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45. How do CD and DVD drives work?
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46. How do CD and DVD drives work?
Recordable technology uses a laser to change the color in a dye layer sandwiched beneath the clear plastic disk surface
Rewritable technology uses “phase change” technology to alter a crystal structure on the disk surface
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47. Can I use a single drive to work with any CD or DVD media?
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48. Are rewritable CD or DVD drives an replacement for a hard disk?
It is slower than hard disk access; therefore not a suitable replacement yet
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49. Most movie DVDs are encoded in MPEG-2 data coding format
Is my computer DVD drive the same as the one connected to my television set?
Not exactly. Movie files are still very large. Television DVD drives include MPEG decoding circuitry
Most movie DVDs are encoded in MPEG-2 data coding format
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50. Solid State Storage: When would I use solid state storage?
Portable, provides fast access to data and uses very little power
Widely used in digital cameras, MP3 music players, notebook computers, PDAs, and cell phones
You can use solid state storage as you would a floppy disk
USB flash drive
CompactFlash card
MMC
SecureDigital
SmartMedia
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51. Chapter 2 Computer Hardware
Section D: Input and Output Devices
Computer Concepts 7th Edition Parsons/Oja

52. Basic Input Devices: What devices can I use to get data into a computer?
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53. What are my options for display devices?
CRT (cathode ray tube) uses gun-like mechanisms to direct beams of electrons toward the screen and activate individual dots of color that form an image
LCD (liquid crystal display) produces an image by manipulating light within a layer of crystal cells
LCDs are clearer, have low radiation emission, are portable, and compact
LCDs are also more expensive than CRTs
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54. What are my options for display devices?
Plasma screen technology creates an on-screen image by illuminating miniature colored fluorescent lights arrayed in a panel-like screen
Lightweight, compact, and more expensive than CRT monitors
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55. How does an ink jet printer work?
Nozzle-like print head that sprays ink onto paper to form characters and graphics
Most ink jet printers use CMYK color
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56. How do laser printers compare to ink jet printers?
A laser printer uses the same technology as a photocopier to paint dots of light on a light-sensitive drum
Higher quality than ink jet
More expensive to buy than ink jet
Less expensive to operate than ink jet
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57. Is a laser better than an ink jet?
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58. What is a dot matrix printer?
Dot matrix printers produce characters and graphics by using a grid of fine wires
Introduced in 1970s
Low quality output
Used for “back-office” applications that demand low operating cost and dependability
Can print multipart carbon forms
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59. Why would anyone want a dot matrix printer?
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60. What other printer technologies are available?
Thermal transfer printer
Uses page-sized ribbons coated with wax
Print head consists of heating elements to melt the wax
Dye sublimation printer
Similar to wax, but page-sized ribbon contains dye
Print heads diffuse the dye
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61. Printers: What features should I look for in a printer?
Resolution
Printer resolution is measured in dpi (dots per inch), the number of dots it can print per linear inch
Come in color or black and white
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62. What features should I look for in a printer?
Print speed
Measured either by pages per minute (ppm) or characters per second (cps)
Color takes longer than black and white
Text prints faster than graphics
Ten pages per minute (black and white) = typical speed for today’s jet and laser printers
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63. What features should I look for in a printer?
Duty cycle - indication of the number of pages a printer can be expected to print per month
Indicates maintenance costs
Operating costs
Printers require ongoing costs including ribbons, ink cartridges, and toner
Per copy cost is the cost of printing a page with an average amount of text, graphics, and color
Memory
A computer sends data for a printout to the printer along with a set of instructions on how to print the data
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64. Installing Peripheral Devices: Is it difficult to install a new peripheral device?
Internal devices
Tools required
Screwdriver
Directions
Before installing
Unplug the computer
Ground yourself
Installing
Follow the directions
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65. What is an expansion slot?
Expansion slot - long, narrow socket on the motherboard into which you can plug an expansion card
Graphics card (for connecting monitor)
Modem (for transmitting data over phone or cable lines)
Sound card (for connecting speakers)
Expansion card - small circuit board that provides computer with ability to control storage, input or output device
Most computers have expansion slots
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66. What is an expansion slot?
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67. What are the major types of expansion slots?
ISA (Industry Standard Architecture)
Used today only for some modems and other relatively slow devices
PCI (Peripheral Component Interconnect)
Offers fast transfer speeds and a 32-bit or 64-bit data bus
AGP (Accelerated Graphics Port)
Provides a high-speed data pathway primarily used for graphics cards
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68. Do notebook computers also contain expansion slots?
Most notebook computers are equipped with a special type of external slot called a PCMCIA slot (personal computer memory card international association)
Typically a notebook only has one slot, but the slot can hold more than one PC card (PCMCIA expansion cards)
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69. What is an expansion port?
To connect a peripheral device to an expansion card, you plug a cable from the device into the expansion port
Expansion port - any connector that passes data in and out of a computer or peripheral device
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70. What is an expansion port?
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71. How do I know which port to use?
Serial DB-9
Parallel DB-25M
USB
SCSI C-50F
IEEE 13394
VGA HDB-15
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72. Conclusion You should now be able to:
Explain why most computers are digital
Describe the role of the ALU
List factors that affect performance
Explain RAM
Compare storage technologies
Describe computer’s expansion bus
Explain hardware compatibility considerations
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