Nuts and Bolts of Networks and Computers How Do Computers and Networks Work? Chapter 6.

Nuts and Bolts of Networks and Computers

How Do Computers and Networks Work?

Chapter 6

McGraw-Hill/Irwin

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

6 -2

Objectives

1. Understand how information is represented and stored in a computer

2. Comprehend how instructions, both system and application, are processed by the CPU.

3. Realize the basic features of networks, small and large.

4. Understand how large and small networks differ.

5. Identify the various means of Internet access available on the market.

McGraw-Hill/Irwin


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A:// What's Going On Inside Your Computer

• Computer components function base on whether electricity is present or not

• Two states - on or off– 1 and 0 correspond to the computer's on

and off states– Each 1 and 0 called a bit (binary digit)– All information is in the form of 1s and 0s

McGraw-Hill/Irwin


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Representing Information Inside a Computer

• A group of 8 bits represents a byte

• A byte is any natural language character

• By combining bits into groups of 8, we can represent letters, symbols, and numbers, like the word "cool"

01000011 01001111 01001111 01001100

C O O L

McGraw-Hill/Irwin


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ASCII, EBCIDIC, and Unicode

• Standard methods of converting human communication symbols into binary– Need for software & information to be transferable

from computer to computer

• ASCII - used by most PCs; uses 8 bits

• EBCDIC – used by IBM mainframes

• Unicode – uses 16 bits instead of 8

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

6 - 6ASCII & EBCDIC Binary Representations

YOUR CHARACTERS

ASCII EBCDIC

(space) 00100000 01000000

! 00100001 01011010

# 00100011 01111011

$ 00100100 01011011

& 00100110 01010000

0 00110000 11110000

1 00110001 11110001

2 00110010 11110010

3 00110011 11110011

4 00110100 11110100

5 00110101 11110101

6 00110110 11110110

7 00110111 11110111

8 00111000 11111000

9 00111001 11111001

McGraw-Hill/Irwin


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The CPU

• Called microprocessor or processor– A chip that carries out the instructions it

receives from both system and application software

– CPU’s role is analogous to that of your brain

• Processor is seated on the motherboard


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Motherboard

McGraw-Hill/Irwin


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How the CPU Carries Out Instructions

• CPU performs machine cycles repeatedly

• Machine or CPU cycle consists of…– Retrieving an instruction

– Decoding the instruction

– Executing the instruction

– Storing the results in RAM

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CPU Speed

• Also referred to as clock speed

• Every CPU has its own CPU clock– Keeps computer's operations synchronized

– Each beat is one clock cycle; equivalent to a CPU or machine cycle

– Used to keep instructions and information marching through CPU at a fixed rate

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How a CPU Works

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Buses

• Data buses– Carries information in the form of bits

around the motherboard– Two types: system and expansion

• System bus – Electrical pathways which move

information between RAM and CPU– The more bits that can travel together at

one time, the faster the bus

McGraw-Hill/Irwin


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Expansion Bus

• Moves information coming from and going to devices outside the motherboard

• Types of expansion buses– ISA (industry standard architecture)

– PCI (peripheral component interconnect)

– AGP (accelerated graphics port)


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Expansion Slots on the Motherboard

PCI Slots

AGP Slot

ISA Slot

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I•SeriesEthics, Security & Privacy

Big Brother in England: A Network of Cameras

• Cameras monitor street activity

• Store images of events

• Identify wanted people

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Wireless Devices

• Need a wireless port on notebook or desktop

• IrDA wireless connections– Use infrared waves– Suitable for short-range communication – Generally used for printers and mice on

notebook computers

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Making the GradeSection A: //

1. A ______ is a 1 or a 0.

2. A group of 8 bits is called a ___________.

3. The coding system that most personal computers and minicomputers use is ___________.

4. The ____________ bus forms the highway system that moves information between the CPU and devices like printers.

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B:// Small Networks

• Computer network– Two or more computers connected– Communicate with each other– Share

• Information• Hardware• Software

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Network Principles

• What you need – Network card

• Located on expansion card or integrated into motherboard

– Hub or router– Communications medium

• Cables• Waves

– Network operating system

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Home & Dorm Networks

• Peer-to-peer network– Network where a few computers share

hardware and information

• Typical small network– Ethernet network interface card– Hub or home router– Cable link to the computers– Windows 95 (or newer)

McGraw-Hill/Irwin


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What’s Needed for a Small Network

• Network interface card (NIC) Expansion or PC card Connects your computer

to a network• Ethernet is most common • Ethernet is available for

ISA or PCI expansion slots

Cat 5 cable with RJ-45 connectors

• Network hub/router Hub - connects multiple

computers Router – smart hub

separates your network from other networks

Network operating system

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Network Hardware & SoftwareWhat is what?

NIC

Cable and connector

Hub

Network Operating System

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Making the GradeSection B: //

1. A(n) ____ is an expansion card that connects your computer to a network and allows information to flow between your computer and the rest of the network.

2. A(n) ______ is a smart hub.

3. The operating system that runs a network is called a(n) ____.

4. The most common type of NIC is a(n) ________ card.

McGraw-Hill/Irwin


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C:// Large Networks

• LAN – local area network Client/server network – one or more

computers are servers and provide services to other computers (clients)

• Cheaper and more efficient than peer-to-peer

• Control of software and information easier


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Business Network

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Using a Large Network

• Must log onto a network computer

• Network administrator is in charge of the network

• Software is on server– Copied to the RAM in your

computer– Usually processed by the

CPU in your computer

McGraw-Hill/Irwin


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Wireless Network Connections on Notebooks

• Wireless adapter

• Wireless access point on computer - device that allows computers to access a wired network using radio waves– Sends information by changing the

electrical pulses into waves– Receives waves by transforming them into

electrical pulses

McGraw-Hill/Irwin


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Radio Wave Transmission Types

• WiFi– Formerly known as IEEE 802.11b– Often used for notebooks

• Bluetooth– Named for the Viking king, Bluetooth– Used for short-range wireless connections– Provides entirely wireless connections for

all kinds of communications devices

McGraw-Hill/Irwin


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Making the GradeSection C: //

1. The person in charge of a network is the _____ administrator.

2. __________technology provides entirely wireless connections for all kinds of communication devices.

3. A network of computers that are contained within a small area like a room or a building or campus is called a ___________.

4. A ________ is the operating system that runs a network.

McGraw-Hill/Irwin


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D:// A Super-Sized Network

• Internet is the largest network in the world– Internet is a WAN– Wide Area Network

(WAN) extends over a large geographical area

• Can connect to the Internet with:– Telephone or dial-up

modem– DSL (Digital Subscriber

Line)– Cable modem– Satellite modem– Wireless connection

McGraw-Hill/Irwin


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Telephone Modem

• A telephone for your computer

• A device that connects your computer through a phone line to a network

• Changes the digital computer signal to an analog phone-line signal

• To access the Internet…– Telephone modem– Phone line– Internet Service Provider– Connectivity software

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Telephone Modems

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More on Telephone Modems

• Usually built into the motherboard or is an expansion card

• Generally has two RJ-11 telephone jacks• Slowest type of Internet connection

– Fastest speed is 56Kps (bits per second)

• To get a faster connection use DSL, a cable or satellite modem, or wireless

McGraw-Hill/Irwin


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Digital Subscriber Line (DSL)

• A high-speed Internet connection using the phone line

• Can talk on the phone while surfing the Internet

• Types of DSL systems– ADSL– SDSL– HDSL

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DSL Modems

• 100 times faster than a phone modem• “Always on”• Can use the same phone line for voice

connections• If you have a home network with a router,

can use the same DSL connection for multiple computers

• Must live within range of phone company

McGraw-Hill/Irwin


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Cable Modem

• Use cable TV wiring

• Both cable TV and Internet connection travel on one wire– Splitter in home router directs signal – Cable modem attaches to Ethernet card or USB

port

• Between 20 and 100 times faster than a telephone modem

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DSL & Cable

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I•Buy"Always-On" Internet

• Up side – instant access to the Internet

• Down side – open to attacks by hackers

• Protection– Long password– Firewall

• Software like ZoneAlarm• Hardware like router

McGraw-Hill/Irwin


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Satellite Modem

• Modem that allows you to get Internet access using a satellite dish (antenna)– Some satellite dishes can give

both Internet access and TV reception

• Satellite modem usually uses a USB port

• Software comes with the satellite modem

McGraw-Hill/Irwin


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Wireless Internet Connection

• Need wireless PC card• Need a wireless Internet service

provider• Can use a PDA

– Palms/ Handspring type– PocketPC type

What is the difference between these two PDAs?

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Disadvantages of Hand-Held Wireless Web Access

• Access is very slow

• Access is not very reliable

• Won’t get the readability on the small screen

• Not all Web features are available

McGraw-Hill/Irwin


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Making the GradeSection D: //

1. A ____________ modem is a device that connects your computer to your phone line

2. A _________ modem is a device that uses your TV cable to deliver an Internet connection.

3. A ___________ does the same job as the standard ISPs except you don’t need a wired connection for access.

4. PocketPCs use the operating system________.

McGraw-Hill/Irwin


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E:// “Key” Key Terms

• ASCII (American Standard Code for Information Interchange) (p. 6.3)

• bit (binary digit) (p. 6.2)

• byte (p. 6.3)• cable modem

(p. 6.21)

• cache (p. 6.8)• central processing

unit (CPU) microprocessor, processor) (p. 6.4)

• EBCDIC (p. 6.3)• Ethernet card

(p. 6.12)

McGraw-Hill/Irwin


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Key Terms cont.

• expansion bus (p. 6.8)

• machine cycle (p. 6.7)

• network interface card (NIC) (p. 6.12)

• router (p. 6.13)• telephone modem

(modem) (p. 6.19)• Unicode (p. 6.3)• wide area network

(WAN) (p. 6.18)

McGraw-Hill/Irwin


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Frequently Asked Questions

• What is the difference between a bit and a byte?

• Help! I can't decided between DSL and cable?

• How does memory work with the CPU?

• I was told to save my resume as an ASCII file. What does that mean?

McGraw-Hill/Irwin


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FAQs cont.

• I don't understand how cache works.

• How does a system bus differ from an

expansion bus?

• I was told to buy a NIC card. What’s

that?

McGraw-Hill/Irwin


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Hands On ProjectsE-Commerce

• Make a comparison of buying clothes at

a store versus buying clothes over the

Internet.

• Design a virtual vacation that could be

booked "on" the Internet. What would

be included? What would you charge?

McGraw-Hill/Irwin


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Hands On ProjectsOn the Web

• Find computer ads that mention cache. How do you know how much cache you will need for your computer?

• Find out about satellite Internet access. What are its advantages? Is it affordable?

McGraw-Hill/Irwin


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Hands On ProjectsEthics, Security & Privacy

• Discuss how some companies are using the segmenting of customers in the following businesses/organizations:– Food stores– Banks– Medical facilities/health insurance– Toy stores– Motor vehicle departments

McGraw-Hill/Irwin


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Hands On ProjectsGroup Activities

• You need to create a short film clip for your class. Meet with your group and decide what hardware and software is needed.

• Does your school have a firewall? How about an intranet? What happens when a virus strikes the campus? Are any precautions taken?

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Nuts and Bolts of Networks and Computers How Do Computers and Networks Work? Chapter 6.

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