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Chapter 4: File Management, Virus Protection, and Backup
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Chapter 4: File Management, Virus Protection, and Backup

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  1. Chapter 4: File Management, Virus Protection, and Backup Chapter 1: Computer, Internet, Web, and E-Mail Basics Chapter 2: Computer Hardware 1 1 1 1

  2. Chapter 2 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 Chapter 2: Computer Hardware

  3. Chapter 2 Preview After this chapter, you should be able to: • Explain the factors that might help a shopper decide whether to purchase a CRT, LCD, or plasma monitor • Compare and contrast the technologies and applications for printers • Describe computer’s expansion bus • Explain hardware compatibility considerations Chapter 2: Computer Hardware

  4. Chapter 2 Outline • Section A • Data Representation and Digital Electronics • Section B • Microprocessors and Memory • Section C • Storage Devices • Section D • Input and Output Devices Chapter 2: Computer Hardware

  5. Chapter 2Computer Hardware Section A: Data Representation and Digital Electronics Computer Concepts 8th EditionParsons/Oja

  6. Data Representation: How do computers represent data digitally? • Data representation makes it possible to convert letters, sounds, and images into a form computers can use for processing • A digital device works with discrete data, such as the digits 1 and 0 • An analog device works with continuous data Page 60 Chapter 2: Computer Hardware

  7. Data Representation: How do computers represent data digitally? • Computers are digital • Just as a standard light switch is a simpler technology than a dimmer, so is digital when compared to analog digital analog Page 60 Chapter 2: Computer Hardware

  8. How does a computer represent numbers? • The binary number system (base 2) uses only two digits 0, and 1 • The following table lists some decimal numbers and their binary equivalent: Page 60 Chapter 2: Computer Hardware

  9. How can a computer represent words and letters using bits? • Character data is composed of letters, symbols, and numerals that are not used in arithmetic operations • ASCII requires only 7 bits for each character • Extended ASCII uses 8 bits to represent each character Page 61 Chapter 2: Computer Hardware

  10. How can a computer represent words and letters using bits? • EBCDIC is an alternative 8-bit used by older IBM systems • Unicode uses 16 bits and provides codes for 65,000 characters • Used for foreign language support Page 61 Chapter 2: Computer Hardware

  11. 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 Page 62 Chapter 2: Computer Hardware

  12. Quantifying Bits and Bytes: How can I tell the difference between bits and bytes? • A bit is one binary digit (b) • 0 • A byte is 8 bits (B) • 0010 0100 Page 63 Chapter 2: Computer Hardware

  13. 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 Page 63 Chapter 2: Computer Hardware

  14. How does a computer store and transport all these bits? • Bits take the form of electrical pulses that can travel over circuits • This is almost the same way as electricity flows over a wire when you turn on a light switch Page 64 Chapter 2: Computer Hardware

  15. What’s inside the system unit? • Desktop units are designed with expectation that the home user may add or update the equipment • Small desktop and notebook computers are not designed for users to access all areas Page 64 Chapter 2: Computer Hardware

  16. What’s inside the system unit? Page 64 Chapter 2: Computer Hardware

  17. What’s a computer chip? • Most electronic components inside a computer are integrated circuits • Thin slices of silicon crystal packed with microscopic circuit elements Page 64 Chapter 2: Computer Hardware

  18. What’s a computer chip? • Semiconducting materials are used to fabricate a chip • Types of chips: • DIPs • DIMMs • PGAs • SEC cartridge Page 65 Chapter 2: Computer Hardware

  19. What’s a computer chip? Page 65 Chapter 2: Computer Hardware

  20. How do chips fit together to make a computer? • The system boardhouses all essential chips and provides connecting circuitry between them Page 65 Chapter 2: Computer Hardware

  21. How do chips fit together to make a computer? Page 66 Chapter 2: Computer Hardware

  22. Chapter 2Computer Hardware Section B: Microprocessors and Memory Computer Concepts 8th EditionParsons/Oja

  23. An integrated circuit designed to process instructions CPU on a chip Microprocessor Basics:What exactly is a microprocessor? Page 68 Chapter 2: Computer Hardware

  24. 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 unitdirects and coordinates processing Page 68 Chapter 2: Computer Hardware

  25. 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 Page 71 Chapter 2: Computer Hardware

  26. Random Access Memory: What is RAM? • A temporary holding area for data, application program instructions, and the operating system • As you type, characters are held in RAM Page 72 Chapter 2: Computer Hardware

  27. 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 Page 73 Chapter 2: Computer Hardware

  28. 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) Page 74 Chapter 2: Computer Hardware

  29. Read-Only Memory: How is ROM different from RAM? • Type of memory circuitry that holds the computer’s startup routine • Permanent and non-volatile • Only way to change the instructions on a ROM chip is to replace the chip Page 74 Chapter 2: Computer Hardware

  30. CMOS Memory: Where does a computer store its basic hardware settings? • A computer needs a semi-permanent way of keeping boot data • CMOSmemory 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 system board Page 75 Chapter 2: Computer Hardware

  31. Where does a computer store its basic hardware settings? Page 75 Chapter 2: Computer Hardware

  32. How do I get the best computer for my money? • Different buyers have different needs • Assess your budget and think about how you plan to use your computer • Look at ads and visit online computer stores Page 76 Chapter 2: Computer Hardware

  33. Chapter 2Computer Hardware Section C: Storage Devices Computer Concepts 8th EditionParsons/Oja

  34. 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 is the mechanical apparatus that records and retrieves data from a storage medium Page 78 Chapter 2: Computer Hardware

  35. How does magnetic storage work? • Stores data by magnetizing microscopic particles on the disk or tape surface • Read-writehead - mechanism in the disk drive that reads and writes magnetized particles that represent data Page 79 Chapter 2: Computer Hardware

  36. How does magnetic storage work? Page 79 Chapter 2: Computer Hardware

  37. How does optical storage work? • Stores data as microscopic light spots (lands) and dark spots (pits) on the disk surface • Less susceptible to environmental damage than data recorded on magnetic media Page 79 Chapter 2: Computer Hardware

  38. How does optical storage work? Page 79 Chapter 2: Computer Hardware

  39. How does solid state storage work? • Stores data in a non-volatile, erasable, low-power chip • Some solid state storage requires a device called a card reader to transfer data to or from a computer • Provides faster access to data than magnetic or optical storage technology because it includes no moving parts Page 80 Chapter 2: Computer Hardware

  40. Can I add storage devices to my computer? • Devices can be added into empty drivebays Page 80 Chapter 2: Computer Hardware

  41. What is floppy disk technology? • 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 Page 81 Chapter 2: Computer Hardware

  42. How much data can a HD DS disk and a Zip disk hold? • HD DS 3½” diskettes have capacity of 1.44 MB • Zip disks come in 100 MB, 250 MB, and 750 MB versions Page 82 Chapter 2: Computer Hardware

  43. What are the advantages and disadvantages of HD DS floppy disks? • Major advantage – portability • Major disadvantage – not a particularly speedy device and limited storage capacity • Slowly being replaced by solid state technology • Today most software vendors use CD-ROM or DVD-ROM disks instead Page 82 Chapter 2: Computer Hardware

  44. How can ZIP disks store more data than standard floppy disk? • Diskdensity - closeness and size of magnetic particles on the disk’s surface • Zip disks store data at a higher density than a standard 3½” floppy disk Page 82 Chapter 2: Computer Hardware

  45. How does a hard disk work? • Hard disk platter- a flat, rigid disk made of aluminum or glass and coated with magnetic iron oxide particles • Density far exceeds floppy disk • Harddisk - one or more platters and their associated read-write heads • Preferred type of main storage • Miniature hard drives store 20 to 40 GB Page 83 Chapter 2: Computer Hardware

  46. How does a hard disk work? Page 83 Chapter 2: Computer Hardware

  47. What’s the downside of hard disk storage? • Headcrash - 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 Page 84 Chapter 2: Computer Hardware

  48. Tape Storage: What’s the purpose of a tape drive? • Tapebackup - copy of data on hard disk stored on magnetic tape • Relatively inexpensive • Primarily used on business computers • Not suitable for everyday storage tasks • Sequential-access storage medium Page 85 Chapter 2: Computer Hardware

  49. CD and DVD technology: Is there a difference between CD and DVD technology? • CD • Holds up to 80 minutes of music or 700 MB of data • DVD • Holds about 4.7 GB of data • A double layer DVD has two recordable layers on the same side and can store 8.5 GB of data Page 86 Chapter 2: Computer Hardware

  50. How do CD and DVD drives work? Page 86 Chapter 2: Computer Hardware