a consumer's guide to computer systems what do you need to know when buying a computer? chapter...

A Consumer's Guide to Computer Systems

What Do You Need to Know When Buying a Computer?

Chapter 5

McGraw-Hill/Irwin

Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved.

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Objectives

1. Describe the purpose and characteristics of the system unit components.

2. Identify the various options available for input and output devices and the advantages and disadvantages of each.

3. Describe the possibilities and limitations of adding peripheral devices to a notebook.

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Objectives cont.

4. Understand that a computer is a very flexible tool and, to make the most of its capabilities, you have to make specific choices.

5. Describe some of the many options you have for computer gaming and photography.

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A:// Inside the Box

• System unit– Case or box where

motherboard and system units are housed

• Motherboard– Large circuit board

inside the system unit – Holds the CPU,

memory, and other electronic components

– Also called the mainboard or system board

McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved.

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Motherboard

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The Basic System

• CPU & memory largely determine the power level or speed of your computer

• To run multimedia software, you will need a more powerful computer

• To get a more powerful computer, you pay a higher price

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The Central Processing Unit

• A chip that carries out instructions it receives from system & application software

• Called CPU, microprocessor, processor, or chip

• Comes in various types or speed– Speeds quoted in megahertz or gigahertz -

# of cycles per second

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Memory

• Called RAM ( random access memory)• Temporary memory that holds

– Software instructions– Information for the CPU

• Shortage of memory will slow down processing time

• The more complex the software, the more memory you’ll need


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Computer Memory

System 1 System 2 System 3

128 MB SDRAM 2 GB DDR RAM 4 GB DDR RAM

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Capacity and Type of RAM

• A kilobyte (KB or K) is about 1,000 bytes – A kilobyte is exactly 1,024 bytes

• A megabyte (MB or M or Meg) is roughly 1 million bytes

• A gigabyte (GB or Gig) is about 1 billion bytes• A terabyte (TB) is approximately 1 trillion bytes

How big is a petabyte? Exabyte?

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RAM and Virtual Memory

• RAM – Temporary storage– Holds software instructions

• Virtual memory – Space on the hard disk– Used by your computer when there is not

enough memory in disk• Holds less used software instructions if there’s

no room on in RAM


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RAM & Virtual Memory

Excel

Windows 2000

Word

RAM

Operating System

Word

Virtual Memory

Hard Disk


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I•SeriesEthics, Security & Privacy

• A spy inside your computer– Pentium III CPUs had an

internal serial number (PSN)– Put there by Intel to provide

security– PSN was seen as an invasion

of privacy– PSN was discontinued as of

April 2000

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Bays For Storage Units

• A place in the system unit reserved for storage

• Types– Internal

• For hard disks• Have a least one

– External• Floppy disk drives• CD-ROMs & DVDs• Zip drives

Three 5.25 "

external bays

One 3.25” drive

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Magnetic and Optical Storage

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Hard Disk Drives

• Magnetic storage media

• One or more thin platters that store information

• Read/write heads access the information on surface– Heads read information while copying it

from disk to RAM– Heads write information when copying it

from RAM to disk

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Hard Drives

• Long term storage for the operating system and application software

• Operating system and application software are copied from the hard disk to memory

• Capacity measured in gigabytes

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Removable Storage

• Two varieties– Magnetic – Optical

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Removable Magnetic Storage

• Floppy Mylar disk– Housed inside a hard plastic casing– Thin, flexible plastic disk

• 3.5 inch floppy disks– also called floppies, diskettes, floppy disks

• High-capacity disks– Zip® disk

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Removable Magnetic Storagecont.

• Metal platter disk– Called removable hard disks– Provide a higher storage capacity than

Mylar disks• Example - Jaz® disk with capacity of up to

2 GB

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Optical Storage

• CDs

• DVDs

• Both are optical storage and have three formats:– Read only– Write once– Rewrite

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Optical Storage

• Read-Only CD-ROM DVD-ROM

• One-Time Writable CD-R DVD-R

• Fully Read-and-Write CD-RW DVD-RW or

DVD+RW or

DVD-RAM

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Practically SpeakingAre Deleted Files Gone?

• Files on removable media– Name of the file removed from directory– Space is available– File not physically gone

• Files on hard disk– Files can go into the recycle bin

• Files on server– Copies of e-mail may still be at ISP

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Making the GradeSection A: //

1. The brain of your computer is the ___________.

2. __________ is temporary storage that holds software instructions and information for the CPU.

3. A terabyte is one ________________ bytes.

4. Zip disk drives are an example of removable ____________ storage.

5. You can write information to a CD-R ________ time(s).

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B:// Outside the Box

• Basic output devices– Monitors– Printers

• Basic input devices– Keyboard – Mouse

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Point-and-Click Devices

• Touchpad

• Mouse– Standard mouse– Trackball– Optical mouse– Wireless mouse

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I•BuySaving Your Neck - All the Rest of

You

• Computer work can lead to physical problems

• Ergonomics – deals with reducing discomfort

• Should sit up straight at your computer

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Monitors

• CRTs

• Flat-panel displays– Gas plasma– LCD (liquid crystal display)

• Passive matrix• Active matrix

– Called TFT (thin film transistor)– Separate transistor for every pixel

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Evaluating Monitors

• Screen size– Measured from corner to opposite corner– In a CRT, picture does not fill the screen

• Resolution– Number of pixels– Pixel (picture element) – dots that make up

the image on the screen

• Dot Pitch – distance between the centers of a pair of like-colored pixels

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Printers

• Inkjet – most popular– Make images by forcing droplets through

nozzles– Top speed is 20 pages per minute

• Laser – Forms images using an electronic process– Prints between 3 and 30 pages per minute

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Printers cont.

• Multifunction printers

– Will scan, copy, fax, and print

– Cheaper than buying all individual units

– Can be inkjet or laser

– Take up less desk space than

separate devices

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Connecting Devices to the System Unit

• USB (universal serial bus) connector– allows hot-swap Plug and Play

• Firewire – faster than USB• Serial connector

– some have 9 holes– some have 25 holes

• Parallel connector – – has 25 pins– generally used to connect printers

• IrDA (infrared data association) – for wireless devices


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Types of Connectors

Parallel Connector used

with printers, CD drives, Zip

drives.

Serial connector

used with a modem or a

mouse

USB connector used with modems,

keyboards, scanners, and a variety of other

devices

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Ports

• Connectors plug into ports

• Ports correspond to connectors

– USB ports fit USB connectors

– Serial ports have 9 or 25 pins

– Parallel ports have 25 holes

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Examples of Ports

Serial ports

USB ports

Parallel port

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Making the GradeSection B: //

1. A(n) _________ mouse senses movement with red light and moves the cursor accordingly.

2. The ___of your screen is the number of pixels it has.

3. _______ printers make images by forcing ink droplets through nozzles.

4. The kind of connector you might find on a keyboard or flat panel display would be a __________ connector.

5. An IrDA port is for _________ devices.

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C:// Notebook Computers

• Small, light weight, and portable

• Can run on a battery

• Monitor or screen is usually an LCD screen

• Pointing devices are usually touchpads or trackballs built into the keyboard

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Adding Peripheral Devices to Notebooks

• PC Card slots• PC Card

– Expansion card used to add devices– Hot-swap

• Can change, or swap out cards without shutting down your computer

– Docking station• Small platform for notebook• Plug peripherals into docking station

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Making the GradeSection C: //

1. A notebook computer can run when plugged into a wall outlet or off a __________.

2. The main advantage of a notebook is its _____.

3. The pointing device on a notebook is usually a trackball or _________.

4. An expansion card for a notebook is called a _________ Card.

5. The term _________ means you can change or swap out devices without turning off the computer.

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D:// Consumer Issues

• Gaming enthusiast– Joystick– Speakers– Speed for processing

• Photography enthusiasts– Digital cameras for input– Printers– Speed for processing

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Question and Answers

• Do I need a docking station for my notebook computer?

• Do I need to buy a video card?

• Do I automatically get sound with my system?

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Making the GradeSection D://

1. A joystick is a(n) ___________ device.

2. Both video and ________ cards are usually installed on the motherboard or integrated into it when you buy your computer system.

3. The resolution of digital camera images is measured in __________.

4. Video cards often have their own CPU and ____.

5. A small platform into which you can plug your whole notebook computer is called a _____station.

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E:// "Key" Key Terms

• bay (p. 5.8)• CD-R (compact disc –

recordable) (p. 5.13)• CD-ROM (compact

disc read-only memory) (p. 5.13)

• CD-RW (compact disc – rewritable) (p. 5.15)

• central processing unit (CPU, processor) (p. 5.3)

• computer system (p. 5.2)

• CRT (p. 5.17)

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"Key" Key Terms cont.

• DVD-R (DVD – recordable) (p. 5.13)

• DVD-ROM (p. 5.13)• DVD-RW (DVD-

RAM, DVD+RW)• ergonomics (p. 5.15)• Firewire (p.000)• flat-panel display (p.

5.21)

• LCD (liquid crystal display) (p. 5.17)

• motherboard (main board, system board) (p. 5.2)

• RAM (random access memory) (p. 5.5)

• USB (universal serial bus) (p. 5.21)

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Frequently Asked Questions

• I just increased the speed of my computer's CPU and even though my games run faster, I don't notice a difference when I create a document in Word. Is something wrong?

• What's the difference between the CPU and memory?

• I have a Pentium II computer. Is this an older computer?

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FAQs cont.

• I saw advertisement in the paper for a computer with 64MB of memory? Is this a good deal?

• Someone sent me a zipped file. Do I read this on a Zip disk drive – like a Jaz drive?

• I am confused. What's the difference between DVDs and CDs?

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FAQs cont.

• What 's the advantage of having a flat screen monitor?

• Is Firewire some kind of wire or cable?

• If I want to add a printer to my notebook computer, do I need a docking station?

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Hands On ProjectsE-Commerce

• You want to build your own computer. Find Web sites that will tell you what parts you need and how to put one together.

• Many companies accept resumes over the Internet. Find sites that will help you create a resume. Are the rules the same for sending a resume over the Net versus through the mail?

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Hands On ProjectsOn the Web

• If you could afford the best computer, what would you get? Go to a Web site and price a computer that is "loaded" with everything you want. Find the same computer at other sites and compare the price.

• You want to send pictures over the Internet. Go to the Internet and price a variety of digital cameras.

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Hands On ProjectsEthics, Security & Privacy

• Computer theft, especially of notebooks, happens often. What can be done to protect computer equipment and keep it out of the hands of thieves?

• What security measures are in place in your school's computer lab? Visit the different labs and make recommendations.

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Hands On ProjectsGroup Activities

• List all of the CPUs that you come in contact with during the course of one day. Compare your list with others.

• Why is temporary storage on a computer called memory or RAM? Do research and find out why developers chose these titles.

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