6. Choosing a Computer
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Transcript 6. Choosing a Computer
B.A. (Mahayana Studies)
000-209 Introduction to Computer Science
November 2005 - March 2006
6. Choosing a Computer
Considering the hardware
choices involved in choosing a
computer.
Overview
1. How to Choose a Computer
2. The Processor
3. The Hard Disk
4. External Data Storage
5. Keyboard / Mouse
6. The Monitor
7. The Sound Card
continued
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8. Room for Expansion
9. Laptop Battery Life
10. The Printer
11. A Computer's Life
12. The Software
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1. How to Choose a Computer
Decide how much to spend, and stick to it.
How will you use the computer?
what
software will you need?
Hardware issues
desktop
or laptop?
processor, hard disk external storage, keyboard,
mouse, monitor, sound card, printers, etc.
when to buy?
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Windows XP
Minimum hardware for Windows XP:
Pentium
500 MHz processor, or higher
256 MB of RAM or more
more memory is the best way to improve XP's speed
4
GB hard drive (1.5 GB for XP)
a Super VGA monitor with (800x600) resolution
try 1024x768 or higher with 24-bit colour
CD-ROM
or DVD-drive
keyboard and mouse
sound card and speakers
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1.1. Lotus, July 2005
and 3 others
cover, mouse pad, adapter,
microphone, speakers
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Free Items:
printer, ink, table,
chair, fax modem,
50 hours on Internet,
speakers, cover,
mouse pad, adapter,
microphone,
10 CD disks,
monitor frame
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Some Buzzwords
Others Later
DDR: Double Data Rate SDRAM; faster RAM
HDD: Hard Disk Drive
FDD: Floppy Disk Drive
CD-RW 52-32-52:
the CD drive can write data at 52x speed, it can rewrite data at
32x speed, and it can read data at 52x speed
USB: Universal Serial Bus
a plug-and-play interface between a PC and devices such as hard
drives, audio players, scanners, and printers
continued
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AGP: Accelerated Graphics Port; speeds up 3D
many companies sell AGP-compatible graphics cards
10/100 LAN: Local Area Network
dual speed 10/100 Mbps (bits/sec) with auto-sensing
HT: hyper threading; multiple threads of execution
VIA: VIA Technologies, Taiwan; makes motherboards
FSB: Front Side Bus; links motherboard to the CPU
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2. The Processor
Chip makers assign model numbers or names
to processors.
the
chip model indicates the processor’s
architecture
Each new model is faster, with other
enhancements.
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Intel Chips
Pentium 4 with hyper-threading
3.00
to 3.80 GHz
model numbers include 670, 660, 650, 640, 630
571, 570J, 561, 560J, 560, 551, 550J, 550, 541, 540J,
540, 531, 530J, 530, 521, 520J, 520
Celeron
can
do the same operations as the Pentium
less expensive, but slower
950 MHz to 2.80 GHz
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Intel Chip History
1982: Intel 286
134,000
1985: Intel 386
275,000
transistors, 33 MHz
1989: Intel 486
1.2
transistors, 12.5 MHz clock speed
million transistors, 50 MHz
1995: Pentium Pro
5.5
million transistors, 200 MHz
continued
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1999: Pentium 3
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million transistors, 733 MHz
2000: Pentium 4
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million transistors, 1.5 GHz (1500 MHz)
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Part of Intel's Range in 2005
Desktop
PentiumExtreme Edition, Pentium D,
Pentium 4 supporting Hyper-Threading,
Pentium 4, Celeron D, Celeron
Notebook
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Pentium M, Mobile Pentium 4 supporting Hyper-Threading,
Mobile Pentium 4, Mobile Pentium 4 Processor-M,
Celeron M, Mobile Celeron Processor
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Factors Affecting Price
Clock speed
indicates
how many instructions can be processed
per second
Level 1 cache - cache built into the processor
Level 2 cache - the cache is on a separate chip
faster
than level 1 cache
Benchmark tests
a
set of standard processing tasks that measure the
performance of hardware or software
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Processor Overall Performance
July 2005 from
http://www.cpuscorecard.com/
:
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2.1. How much RAM?
The 'best' amount of RAM depends on the OS
and applications you plan to use.
at
least 64 - 256 MB to run Windows XP
256 MB or more is better
a very good way of improving performance
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3. The Hard Disk
Storage capacity is measured in gigabytes (GB).
get
at least 40 GB
Hard disk speed is usually measured in
revolutions per minute (RPM)
the
higher the RPM , the less time you'll spend waiting
for your computer to access files
best for desktops: 5400, 7200 RPM
best for laptops: 4200, 5400 RPM
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Hard Drive Controllers
Disk drives are classified by their type of
controller
the
hardware that rotates the hard disk, and moves the
read-write head
Popular drive controllers are:
Ultra
ATA, EIDE, SCSI
Ultra ATA is twice as fast as EIDE
SCSI is slightly faster than EIDE
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4. External Data Storage
Floppy disk drives are on their way out.
Rewritable CDs (CD-RW) are popular.
increasingly
with DVD support
Many computers include USB ports for flash
drives
get
a USB port supporting version 2.0 (potentially 40x
faster than 1.1)
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Flash Drive
Uses flash memory
a
rewritable memory chip that
remembers its content without needing
a power supply (non-volatile)
A flash drive can be added/removed from the PC
while the macine is switched on (hot-swappable).
Storage capacities: 64 - 256 MB
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5. Keyboard/ Mouse
Microsoft’s Natural
Keyboard may help
prevent computer
related injuries.
Wireless
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Mouse Types
Mechanical, optical, laser mice
Cord or cordless?
How many buttons?
Mouse wheel?
Connector type
serial
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port, USB port
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Laptop Input Choices
Track point
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Trackball
Touchpad
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6. The Monitor
CRT (cathode ray tube) monitors use similar
technology to television sets
inexpensive
and dependable
LCD (liquid crystal display) monitors produce
images by manipulating light within a layer of
liquid crystal cells.
compact,
lightweight, easy to read
standard on laptops
flat-panel displays are available for desktops
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Flat Panel Displays
Advantages of LCD
display
clarity
low radiation emission
portable
compact
3x the price of a CRT
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Monitor Sizes
Screen size is the
measurement in inches
from one corner of the
screen diagonally across to
the opposite corner.
The viewable image size
(vis) excludes the screen's
black border from the
calculation.
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A monitor’s viewable image
size is less than the screen size.
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Monitor Resolution
Dot pitch - a measure of image clarity
smaller
dot pitch means a crisper image
Maximum resolution: the maximum number of
pixels a monitor can display
a
typical max. resolution is 1280 x 1024 pixels
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Graphics Cards
Often the graphics card may be a part of the
motherboard
especially
in laptops
the card should have 8 - 64 MB of video memory
The most powerful graphics cards are used for
3D graphics
sometimes
called GPUs (graphics processing units)
continued
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The main 3D graphics card manufacturers are:
ATI
Technologies
cards: Radeon 7/8/9000 Series, Radeon X Series
NVIDIA Corporation
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cards: GeForce including GeForce FX Series, GeForce 6
Series, GeForce 7 Series
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SVGA Graphics Cards
Super Video Graphics Array (Super VGA or
SVGA) is the most popular display type.
SVGA graphics cards have a standard resolution
of 800x600 (480,000 pixels).
They should be able to offer resolutions up to
1280x1024, with 24-bit colour (16 million
colours).
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Laptop Display Screens
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 laptops
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7. Sound Cards
A sound cards improves a computer's sound
quality, and adds other sound capabilities:
makes
it possible to use speakers, a stereo, and a
microphone to record and play sound
some sound cards also include MIDI
Some sound card manufacturers
Turtle
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Beach, Diamond, Creative Labs
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MIDI
Musical Instrument Digital Interface
MIDI enables electronic instruments, such as
synthesizers, samplers, sequencers, and drum
machines, to communicate with one another and
with computers.
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8. Room for Expansion
When you buy a computer, make sure it has
expansion options.
Motherboard expansion slots to add peripheral
drivers.
Internal bays : mounting
brackets in the computer
case for devices.
continued
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External bays: openings in the case so that
devices can be (temporarily) connected to the
computer.
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Laptop Expansion
PCMCIA expansion slots are found in many
laptops. Classified according to size:
Type
1 - thinnest, for memory expansion
Type 2 - for modems, sound cards, network cards
(most common)
Type 3 - thickest, for hard disk drives
Make sure the laptop has plenty of USB ports (26).
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9. Laptop Battery Life
The length of time a laptop's battery will last
depends on:
the
processor speed
the screen type (e.g. active matrix LCD)
how many peripherals are attached
Hot swap: the ability to swap batteries while the
computer is on.
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10. The Printer
Details to consider when choosing a printer:
Resolution
printer
resolution is measured in dpi (dots per inch), the
number of dots it can print per linear inch
more dpi means the final image will be clearer
Colour capability
can
the printer support colour?
continued
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Print speed
print
speed is measured by pages per minute (ppm) or
characters per second (cps)
colour printing takes longer than black and white
text prints faster than graphics
ten pages per minute is a typical speed
duty cycle: the number of pages that can be printed per
month
Printer cost
from
$100 to $5000
continued
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Per-copy cost
these
are the ongoing costs for the printer, including
ribbons, ink cartridges, and toner
the cost estimate assumes that a page uses an average
amount of text, graphics, and colour
Warranty
how
long does the warranty last for?
does it cover all printer parts?
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Inkjet Printers
The most popular type of
printer
it
produces low-cost colour
and black-and-white
printouts
Colour ink cartridge
Black ink cartridge
continued
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The print head uses a series of nozzles that spray
coloured inks onto the paper
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Laser Printers
The laser in the printer charges an
electrostatically sensitive drum to accept toner
which is then fused to the paper.
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Features
Higher quality output than inkjets
More expensive to buy than inkjets
Less expensive to operate than inkjet
The toner cartridge and drum cost approx. $70
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Dot-matrix Printers?
Dot matrix printers prints by striking groups of
wires or thin rods onto an ink-coated ribbon
against paper.
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Features
Old/reliable technology: introduced in the 1970s
Low quality output
Can print onto multipart carbon forms
Used for “back-office” applications that need low
operating cost and dependability.
A $4 ribbon can print 3 million characters
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11. A Computer's Life
The lifecycle of a computer has five phases:
product
development
product announcement
introduction
maintenance
retirement
Vaporware: computers (and software) that are
announced but never produced.
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Price Drops over Time
Toshiba Satellite
Pentium M, 1.50GHz,
256MB RAM
60 GB Hard Disk
CD RW / DVD
modem
average price
15.4 inch active matrix
display
high price
Weeks up to
July 2005
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low price
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Computer Companies
Top-tier companies
computer business for many
years
Apple, Compaq, IBM
more expensive computers
responsible for many
innovations
Second-tier companies
newer companies
Gateway, Packard Bell, Dell
less expensive computers,
same quality
limited research and
development
continued
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Third-tier companies
smaller startup companies
sell locally
less expensive
may use poorer quality
components
more likely to go out of
business
technical support depends on
the owner
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Build your own
readily available parts
relatively easy assembly
customize to your own
needs
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12. The Software
Software publishers produce software
Alpha test: first phase of testing done in-house
Beta test: conducted by off-site tester
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Software Versioning
The original version (release) of software is
typically version 1.0
a
new version is indicated by a new number (e.g. 2.0)
a new version is usually a major improvement
Revision: a release that fix bugs or makes small
changes
the
revision number is separated from the version
number with a period (e.g. 1.1)
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Software Pricing Issues
Street price: average discounted price
Version upgrade price: discounted price for owners of an
earlier version of the software
must show proof to the vendor
Competitive upgrade: special price for switching to a
competitor’s product
Upgrading software is important
less technical support for older versions
may lose eligibility for special pricing
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Other Software Issues
Compatibility with hardware/OS
Warranty
Technical Support
help-lines,
local user groups, personal service
Web-based technical sites, newsgroups, mailing lists
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