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Title: INFS205


1
  • INFS205
  • Spring 2004

Computer Concepts 6th EditionParsons/Oja Course
Technologies
2
Computer Hardware
Data Representation and Digital Electronics
Section A
CHAPTER 2
PARSONS/OJA
Page 58
3
Computer Hardware
Chapter 2
Chapter PREVIEW
  • When you complete 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 computers expansion bus
  • Explain hardware compatibility considerations
  • Compare and contrast technologies for peripherals

Page 57
4
Data Representation and Digital Electronics
Section A
Chapter 2
Digital Data Representation Why are computers
digital?
  • Data representation
  • Digital electronics
  • digital device
  • analog device

Page 58
5
Data Representation and Digital Electronics
Section A
Chapter 2
How can a computer represent numbers using bits?
  • A computer uses a bit (binary digit) as the
    building block for more complex data
    representations
  • Unlike the decimal system, the binary number
    system (base 2) uses only two digits 0, and 1.

Page 59
6
Data Representation and Digital Electronics
Section A
Chapter 2
How can a computer represent words and letters
using bits?
  • Character data
  • not be used in arithmetic operations
  • ASCII
  • (American Standard Code for Information
    Interchange)
  • EBCDIC
  • (Extended Binary-Coded Decimal Interchange Code)
    is an alternative 8-bit used by older IBM systems
  • Unicode
  • uses 16 bits and provide codes for 65,000
    characters

Page 59-60
7
Data Representation and Digital Electronics
Section A
Chapter 2
How can a computer represent words and letters
using bits?
extended ASCII table
Page 60
8
Data Representation and Digital Electronics
Section A
Chapter 2
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
  • A nibble is 4 bits
  • 0011
  • Kilo- means a 1000, Mega- means million, Giga
    -means billion, Tera- means trillion, and Exa-
    means quintillion
  • Kilobit (Kb)
  • Kilobyte (KB)
  • Megabyte (MB)
  • How many characters (average) can be stored in 1
    MB

Page 61
9
Data Representation and Digital Electronics
Section A
Chapter 2
Does a typical computer owner need to mess
around inside the system unit?
Page 62
10
Data Representation and Digital Electronics
Section A
Chapter 2
Whats 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
  • resistors

Page 62
11
Data Representation and Digital Electronics
Section A
Chapter 2
Whats a computer chip?
Page 63
12
Data Representation and Digital Electronics
Section A
Chapter 2
The motherboard houses all essential chips and
provides connecting circuitry between them
Page 64
13
Computer Hardware
Microprocessors and Memory
Section B
CHAPTER 2
PARSONS/OJA
Page 66
14
Microprocessors and Memory
Section B
Chapter 2
Microprocessor Basics Exactly what is a
microprocessor?
  • A microprocessor is an integrated circuit
    designed to process instructions
  • CPU on a chip

Page 66
15
Microprocessors and Memory
Section B
Chapter 2
What does it look like?
  • The CPU has two parts
  • ALU (arithmetic logic unit)
  • performs arithmetic operations
  • performs logical operations
  • uses registers to hold data being processed
  • control unit directs and coordinates processing.
  • The list of instructions that a microprocessor
    can perform is called its instruction set

Page 67
16
Microprocessors and Memory
Section B
Chapter 2
Microprocessor Performance Factors What makes
one microprocessor perform better than another?
  • CPU speed is influenced by several factors
  • clock speed Megahertz, Gigahertz
  • word size
  • Cache Level 1, Level 2 caches
  • instruction set size
  • Testing laboratories run a series of tests
    (benchmarks) to gauge the overall speed of a
    microprocessor

Page 67-68
17
Microprocessors and Memory
Section B
Chapter 2
Whats the difference between CISC and RISC?
  • Computers based on a CPU with a complex
    instruction set known as CISC (complex
    instruction set computer) microprocessor
  • Intel
  • A RISC (reduced instruction set computer) has
    limited set of instructions that it can perform
    quickly
  • AMD

Page 68
18
Microprocessors and Memory
Section B
Chapter 2
Can a microprocessor execute more than one
instruction at a time?
  • Computers with a single processor execute
    instructions serially (one at a time)
  • Pipelining - technology in which the processor
    can begin executing next the instruction before
    it completes the previous instruction
  • A computer with more than one processor can
    execute multiple instructions simultaneously,
    referred to as parallel processing
  • Supercomputers

Page 68
19
Microprocessors and Memory
Section B
Chapter 2
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
  • RAM is a reusable computing source
  • RAM is volatile requires power to hold data

Page 70
20
Microprocessors and Memory
Section B
Chapter 2
Why is RAM so important?
  • It holds the data and the instructions for
    processing the data
  • It even houses OS instructions

Page 70
21
Microprocessors and Memory
Section B
Chapter 2
How much RAM does my computer need?
  • RAM is primary storage (main memory)
  • Measured in megabytes (MB)
  • Use drives amount of RAM
  • A computer can use disk storage to simulate RAM.
    This is called virtual memory
  • Speed is measured in nanoseconds. 1 nanosecond is
    1 billionth of a second
  • It can also be expressed in MHz (millions of
    cycles per second)
  • Most computers use SDRAM (synchronous dynamic RAM)

Page 71
22
Microprocessors and Memory
Section B
Chapter 2
Do all computers use the same type of RAM?
  • RAM is usually configured as a series of DIPs
    soldered onto a small circuit board called a DIMM
    (dual in-line memory module), RIMM (Rambus
    in-line memory module), or SO-RIMM (small outline
    RIMM)
  • DIMMs contain SDRAM, RIMMs and SO-RIMMs contain
    RDRAM

SDRAM chip
Page 72
23
Microprocessors and Memory
Section B
Chapter 2
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
  • Since RAM is empty when a computer is turned on,
    ROM BIOS is used
  • ROM BIOS (basic input/output system) is a set of
    instructions that tells computer how to access
    the disk drives and peripheral devices

Page 72
24
Microprocessors and Memory
Section B
Chapter 2
Where does a computer store its basic hardware
settings?
Page 73
25
Computer Hardware
Storage Devices
Section C
CHAPTER 2
PARSONS/OJA
Page 76
26
Storage Devices
Section C
Chapter 2
Storage Basics What are the basic components
of a data storage system?
  • A storage device, such as a floppy disk drive, a
    hard drive, zip drive, and a CD-ROM drive, is
    used to store the data
  • A storage medium is the disk, tape, CD, DVD,
    paper or other substance that contains data
  • Storing - writing data or saving a file
  • Retrieving reading, loading or opening

Page 76
27
Storage Devices
Section C
Chapter 2
Whats the difference between magnetic and
optical storage technologies?
  • 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
  • Optical storage stores data as microscopic light
    spots (lands) and dark spots (pits) on the disk
    surface
  • Data stored on an optical storage device is less
    susceptible to environmental damage

Page 77
28
Storage Devices
Section C
Chapter 2
Whats the difference between magnetic and
optical storage technologies?
Page 77
29
Storage Devices
Section C
Chapter 2
Whats the difference between magnetic and
optical storage technologies?
CD-ROM PITS
Page 78
30
Storage Devices
Section C
Chapter 2
Can I add storage devices to my computer?
  • Devices can be added into empty drive bays

Click to start
Page 78
31
Storage Devices
Section C
Chapter 2
Which storage technology is best?
  • Speed - measured by access time and data transfer
    rate
  • Access time - average time it takes a computer to
    locate data and read it
  • millisecond one-thousandth of a second
  • Random access - ability of a device to jump
    directly to the track or sector holding the data
  • floppy disk, hard drive, CD, DVD, zip disks
  • Storage capacity - maximum amount of data that
    can be stored on a storage medium

Page 79
32
Storage Devices
Section C
Chapter 2
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

Page 79
33
Storage Devices
Section C
Chapter 2
Whats the capacity of a floppy disk?
  • 3 ½ diskettes have capacity of 1.44 MB
  • Other floppy disk types
  • ZIP disks 100 MB and 250 MB
  • Superdisks 120 MB

Superdisk
ZIP disk
Page 80
34
Storage Devices
Section C
Chapter 2
How can ZIP disks and Superdisks store so much
more data than standard floppy on the same size
disk?
  • Disk density - closeness and size of magnetic
    particles it stores
  • High-density disk - stores more data than
    double-density
  • Double-sided disk - stores twice as much as
    single-sided
  • Zip disks and Superdisks store data at a higher
    density than a standard 3 ½ floppy disk

Page 80
35
Storage Devices
Section C
Chapter 2
Can I protect the data on a floppy disk?
  • The write-protect window allows you to protect
    data by making it read-only when it is open, but
    to modify the storage data, it must be closed

Page 81
36
Storage Devices
Section C
Chapter 2
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

Page 81
37
Storage Devices
Section C
Chapter 2
How does a hard disk work?
Click to start
Page 82
38
Storage Devices
Section C
Chapter 2
Whats all this business about Ultra ATA, EIDE,
SCSI, and DMA?
  • A hard drive mechanism includes a circuit board
    called a controller that positions the disk and
    read-write heads to locate data
  • Popular drives
  • Ultra ATA (AT attachment)
  • EIDE (enhanced integrated drive electronics)
  • SCSI (small computer system interface)
  • 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

Page 82
39
Storage Devices
Section C
Chapter 2
Can I use a second hard disk drive as a backup?
  • Removable hard disk - hard disks that can be
    inserted and removed from drive
  • increase storage capacity
  • provides security for data
  • RAID - (redundant array of independent disks)
  • type of hard disk storage
  • found on mainframe and microcomputer
    installations
  • contains many disk platters
  • provides redundancy
  • faster data access

Page 83
40
Storage Devices
Section C
Chapter 2
Tape Storage Whats the purpose of a tape
drive?
  • Tape
  • most popular form of storage in 1960s
  • Requires sequential access
  • Inconvenient and slow
  • Data is arranged as essentially a long sequence
    of bits that begin at one end of the tape and
    stretches to the other
  • Tape backup - copy of data on hard disk stored on
    magnetic tape.

Page 83
41
Storage Devices
Section C
Chapter 2
Is it easy to install a tape drive?
  • Yes. Tape drives are available in either internal
    or external models

Page 84
42
Storage Devices
Section C
Chapter 2
CD technology Why would I want a CD-ROM drive
in addition to a hard disk drive?
  • CD-ROM
  • stands for Compact Disc Read-Only Memory
  • data stamped on when manufactured
  • coated with clear plastic, durable
  • estimated life exceeds 500 years
  • inexpensive to manufacture
  • ideal for distribution of large files

Page 84
43
Storage Devices
Section C
Chapter 2
Whats the capacity and speed of a CD?
  • A single CD-ROM holds up to 650 MB
  • Original CD-ROM had speeds of 150 KB per second
  • Today, speeds of 24x or higher (24 x 150 KB
    per/sec) )

Page 85
44
Storage Devices
Section C
Chapter 2
Whats the difference between CD-ROM and ROM
BIOS?
  • They are different technologies
  • ROM-BIOS (chip on the motherboard) is magnetic
  • CD-ROM (optical storage device) is optical

Page 85
45
Storage Devices
Section C
Chapter 2
Whats the difference between CD-ROM and ROM
BIOS?
Page 85
46
Storage Devices
Section C
Chapter 2
Can I create my own CDs?
  • CD DVD
  • R stands for compact disc-recordable
  • RW Rewritable allows you to create your own CDs
  • DVD ROM
  • Rewritable requires Phase change technology -
    alters the crystal structure on the disk surface

Page 85
47
Storage Devices
Section C
Chapter 2
Are CDs and DVDs interchangeable?
  • CD-ROM drives can not play DVDs
  • DVDs can play CD-ROM, most CD-R and most CD-RW
    disks
  • Both DVDRW and DVD-RAM can be read on DVD-ROM
    drives

Page 87
48
Computer Hardware
Input and Output Devices
Section D
CHAPTER 2
PARSONS/OJA
Page 88
49
Input and Output Devices
Section D
Chapter 2
Expansion slots, cards and ports How does a
computer get data from RAM to a peripheral device?
  • Data Bus carries data from one component to
    another
  • I/O (computer jargon for input/output) refers to
    collecting data and transporting results.
  • Expansion bus - the segment of the data bus that
    transports data between RAM and peripheral devices

Page 88
50
Input and Output Devices
Section D
Chapter 2
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 microcomputers have 4 - 8 expansion slots

Page 88-89
51
Input and Output Devices
Section D
Chapter 2
What is an expansion slot?
Click to start
Page 88
52
Input and Output Devices
Section D
Chapter 2
What are the major types of expansion slots?
  • The microcomputer motherboard typically has up to
    three types of expansion slots
  • ISA - older technology, modems and slow devices
  • PCI - for graphics, sound, video, modem or
    network cards
  • AGP - for graphics cards
  • Expansion cards are built for only one type of
    slot

Page 89
53
Input and Output Devices
Section D
Chapter 2
What are the major types of expansion slots?
Page 89
54
Input and Output Devices
Section D
Chapter 2
Do notebook computers also contain expansion
slots?
  • 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)

Page 90
55
Input and Output Devices
Section D
Chapter 2
What is an expansion port?
Expansion port - any connector that passes data
in and out of a computer or peripheral device
Page 90
56
Input and Output Devices
Section D
Chapter 2
What are the major types of expansion cables?
Page 90-91
57
Input and Output Devices
Section D
Chapter 2
Why do some peripheral devices include a disk
or CD?
  • Adding and device
  • Software device driver manually add
  • Plug and Play (PnP) automatically takes care of
    these technical details
  • A Graphics card takes signals from the processor
    and uses them to paint images on the screen

Page 92
58
Input and Output Devices
Section D
Chapter 2
Whats the difference between a CRT and an LCD?
  • 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

Page 92
59
Input and Output Devices
Section D
Chapter 2
Which display device produces the best image?
  • Screen size is the measurement in inches from one
    corner of the screen diagonally across to the
    opposite corner.
  • Viewable image size (vis) - black border that
    makes image size smaller than size specified
  • Dot pitch - a measure of image clarity
  • smaller dot pitch means a crisper image
  • Resolution - number of pixels a monitor can
    display

Page 93
60
Input and Output Devices
Section D
Chapter 2
Which display device produces the best image?
Two different resolutions
Page 93
61
Input and Output Devices
Section D
Chapter 2
Which display device produces the best image?
  • Color depth - number of colors that can be
    displayed at one time
  • Passive matrix screen - relies on timing to make
    sure the liquid crystal cells are illuminated
  • Active matrix screen - updates rapidly
  • essential for crisp display of animation, video
  • found on newer notebooks
  • SVGA - (super video graphics array) 800x600
  • XGA - (extended graphics array) 1024x768

Page 94
62
Input and Output Devices
Section D
Chapter 2
What features should I look for in a printer?
Lexmark Printer
Page 95
63
Input and Output Devices
Section D
Chapter 2
What features should I look for in a printer?
  • Print speed (typical 10 ppm)
  • measured either by pages per minute (ppm) or
    characters per second (cps)
  • color vs BW
  • Duty Cycle - indication of the number of pages a
    printer can be expected to print per month
  • Per-copy cost
  • printers require ongoing costs including
  • per copy cost is the cost of printing a page with
    an average amount of text, graphics, and color
  • Warranty
  • cover mechanical problems

Page 94
64
Input and Output Devices
Section D
Chapter 2
Whats the difference between an ink jet
printer and a solid ink printer?
  • An ink jet printer is todays most popular
    printing technology.
  • print head consists of a series of nozzles that
    sprays ink onto paper
  • On special paper can produce photographic quality
  • 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

Page 95
65
Input and Output Devices
Section D
Chapter 2
Is a laser better than an ink jet?
LaserJet
Click to start
Page 96
66
Input and Output Devices
Section D
Chapter 2
Is a laser better than an ink jet?
  • Laser printers use their own printer language to
    construct a page before printing it.
  • Printer Control Language (PCL) - most widely used
  • PostScript language - preferred by publishing
    professionals
  • printer languages require 2MB - 8MB memory

Page 96
67
Input and Output Devices
Section D
Chapter 2
Is it easy to install a printer?
  • Uses a cable to connect to one of your computers
    ports
  • USB
  • Parallel most common
  • Serial
  • Many come packaged with device driver software
    that you install following manufacturers
    direction
  • Can be set to default printer using windows
    software

Page 97
68
Computer Hardware
Chapter 2
Chapter REVIEW
  • You should be able to
  • Describe the role of the ALU
  • List factors that affect computer performance
  • Explain RAM
  • Compare storage technologies
  • Describe computers expansion bus
  • Explain hardware compatibility considerations

Page 57
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