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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.
000-209 Intro to CS. 6/Choosing 2
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
000-209 Intro to CS. 6/Choosing 3
8. Room for Expansion 9. Laptop Battery Life 10. The Printer 11. A Computer's Life 12. The Software
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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?
1. How to Choose a Computer
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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
Free Items:printer, ink, table,chair, fax modem,50 hours on Internet, speakers, cover,mouse pad, adapter,microphone,10 CD disks,monitor frame
and 3 others
cover, mouse pad, adapter,microphone, speakers
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Some Buzzwords
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 s
peed, 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 driv
es, audio players, scanners, and printers
continued
Others Later
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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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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.
2. The Processor
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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
Intel Chips
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Intel Chip History
1982: Intel 286 134,000 transistors, 12.5 MHz clock speed
1985: Intel 386 275,000 transistors, 33 MHz
1989: Intel 486 1.2 million transistors, 50 MHz
1995: Pentium Pro 5.5 million transistors, 200 MHz
continued
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1999: Pentium 3 28 million transistors, 733 MHz
2000: Pentium 4 42 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 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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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
Factors Affecting Price
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Processor Overall Performance
:
July 2005 fromhttp://www.cpuscorecard.com/
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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
2.1. How much RAM?
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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
3. The Hard Disk
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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
Hard Drive Controllers
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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)
4. External Data Storage
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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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Microsoft’s NaturalKeyboard may helpprevent computerrelated injuries.
5. Keyboard/ Mouse
Wireless
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Mouse Types
Mechanical, optical, laser mice Cord or cordless? How many buttons? Mouse wheel? Connector type
serial port, USB port
000-209 Intro to CS. 6/Choosing 23
Track point Trackball Touchpad
Laptop Input Choices
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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
6. The Monitor
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Advantages of LCD display clarity low radiation emission portable compact
3x the price of a CRT
Flat Panel Displays
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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.
A monitor’s viewable image size is less than the screen size.
Monitor Sizes
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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
Monitor Resolution
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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)
Graphics Cards
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 cards: GeForce including GeForce FX Series, GeForce 6 Seri
es, 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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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
Laptop Display Screens
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A sound cards improves a computer's sound quality, and adds other sound capabilities: makes it possible to use speakers, a stereo, and a m
icrophone to record and play sound some sound cards also include MIDI
Some sound card manufacturers Turtle Beach, Diamond, Creative Labs
7. Sound Cards
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MIDI
Musical Instrument Digital Interface MIDI enables electronic instruments, such as syn
thesizers, samplers, sequencers, and drum machines, to communicate with one another and with computers.
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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.
8. Room for Expansion
continued
000-209 Intro to CS. 6/Choosing 35
External bays: openings in the case so that devices can be (temporarily) connected to the computer.
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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 (2-6).
Laptop Expansion
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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.
9. Laptop Battery Life
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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?
10. The Printer
continued
000-209 Intro to CS. 6/Choosing 39
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
000-209 Intro to CS. 6/Choosing 40
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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The most popular type of printer it produces low-cost colour
and black-and-white printouts
Black ink cartridge
Inkjet Printers
Colour 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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The laser in the printer charges an electrostatically sensitive drum to accept toner which is then fused to the paper.
Laser Printers
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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 prints by striking groups of wires or thin rods onto an ink-coated ribbon against paper.
Dot-matrix Printers?
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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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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.
11. A Computer's Life
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Toshiba Satellite Pentium M, 1.50GHz, 256M
B RAM 60 GB Hard Disk CD RW / DVD modem 15.4 inch active matrix displ
ay
high price
low price
average price
Weeks up toJuly 2005
Price Drops over Time
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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
000-209 Intro to CS. 6/Choosing 50
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
Build your own readily available parts relatively easy assembly customize to your own
needs
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Software publishers produce software
Alpha test: first phase of testing done in-house Beta test: conducted by off-site tester
12. The Software
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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)
Software Versioning
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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
Software Pricing Issues
000-209 Intro to CS. 6/Choosing 54
Other Software Issues
Compatibility with hardware/OS Warranty Technical Support
help-lines, local user groups, personal service Web-based technical sites, newsgroups, mailing lists