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.

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


8. Room for Expansion 9. Laptop Battery Life 10. The Printer 11. A Computer's Life 12. The Software


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


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


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


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


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


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


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


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


1999: Pentium 3 28 million transistors, 733 MHz

2000: Pentium 4 42 million transistors, 1.5 GHz (1500 MHz)


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


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


Processor Overall Performance

:

July 2005 fromhttp://www.cpuscorecard.com/


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?


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


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


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


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


Microsoft’s NaturalKeyboard may helpprevent computerrelated injuries.

5. Keyboard/ Mouse

Wireless


Mouse Types

Mechanical, optical, laser mice Cord or cordless? How many buttons? Mouse wheel? Connector type

serial port, USB port


Track point Trackball Touchpad

Laptop Input Choices


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


Advantages of LCD display clarity low radiation emission portable compact

3x the price of a CRT

Flat Panel Displays


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


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


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


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


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).


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


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


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.


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


External bays: openings in the case so that devices can be (temporarily) connected to the computer.


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


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


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


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


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?


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


The print head uses a series of nozzles that spray coloured inks onto the paper


The laser in the printer charges an electrostatically sensitive drum to accept toner which is then fused to the paper.

Laser Printers


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


Dot matrix printers prints by striking groups of wires or thin rods onto an ink-coated ribbon against paper.

Dot-matrix Printers?


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


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


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


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


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


Software publishers produce software

Alpha test: first phase of testing done in-house Beta test: conducted by off-site tester

12. The Software


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


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


Other Software Issues

Compatibility with hardware/OS Warranty Technical Support

help-lines, local user groups, personal service Web-based technical sites, newsgroups, mailing lists

Documents

6. Choosing a Computer