Download Computer Basics

January 15, 2018 | Author: Anonymous | Category: , Science, Physics, Electronics
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Year 1 - Chapter 1/Cisco 1 - Module 1

Computer Basics By Robert M. Cannistra

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Objectives • • • • •

Describe the basic computer hardware components Understand computer software basics Understand the binary numbering system Define networks and networking Define digital bandwidth

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Computer Hardware Components • Electronic Components – Connector, IC, LED, resistor, transistor

• Personal Computer Subsystems – Bus, CD-ROM drive, CPU, disk drives, microprocessor, motherboard, RAM, ROM

• Backplane Components – Mouse port, network card, parallel port

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

All Computers Have a CPU, Memory, Storage, and Interfaces.

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Network Interface Cards • When you select a network card, consider the following three factors: – Type of network – Type of media – Type of system bus

• Installing a NIC in a PC

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Computer Software • Web Browsers – A Web browser acts on behalf of a user by • • • •

Contacting a Web server Requesting information Receiving information Displaying the results on a screen

• Plug-Ins – Flash/Shockwave, QuickTime, Real Audio

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Number Systems • Knowing What Base Someone Refers To – Decimal uses 10 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. – Binary uses 2 digits: 0 and 1.

• Base Conventions – 101 in Base 2 is spoken as one zero one.

• Working with Exponents – 103 = 10 X 10 X 10 = 1000 – 24 = 2 x 2 x 2 x 2 = 16

• Binary Numbers – Use principle of place value just as decimal numbers do

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Base 10 (Decimal) Numbers

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Base 10 Calculations • •

The upper table shows the actual math. The lower table is a simplified version that requires the following: – Start the value row and position row with 1 in the rightmost box. – Each subsequent value is current value times the base (10 in this case) – Value to be calculated is entered in the digit row. – Multiply digit amount times value entry above.

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Base 2 Table

27

26

25

24

23

22

21

20

128

64

32

16

8

4

2

1

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Base 2 (Binary) Numbers

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Base 2 Calculations 8-Bit Values Binary Value: 10101010 Start the value row and position row with 1 in the rightmost box. Each subsequent value is the current value times the base (2 in this case).

Binary Value: 11101001 Copyright 2002

Cisco Press: CCNA Instructor’s Manual

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Binary Number System • Even and Odd – A binary number is a multiple of 2 (even number) if the rightmost digit is a 0. – A binary number is odd if the rightmost digit is 1.

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Converting Decimal to Binary Example: 35 = 32 + 2 + 1 = 00100011

27 128

26 64

25 32

24 16

23 8

22 4

21 2

20 1

0

0

1

0

0

0

1

1

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Converting Decimal to Binary

Start by dividing the decimal by the largest number in the Value row that will go. Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Looking at the Table Relationships The table will work with larger numbers, such as this 12-bit example. For any number in the value row, the sum of all numbers to the right is the current value minus 1 (64 - 1 = 63).

Sometimes its easier to subtract the 0 values from 255 (largest 8-bit value). Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Powers of 2 for Non-Math Majors

Powers of 2 are used extensively in networking. One solution: 1. Start with 2 (which is 21). 2. Double the number to get the next value. 3. If you need 26, continue until you have 6 values. Look over the example to the right. The second column is included only for reference. Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Binary Number System Exercises 1. 2. 3. 4.

Convert the binary number 1010 to Base 10. Convert the Base 2 number 11110000 to decimal notation. Convert the decimal number 1111 to binary notation. Convert the decimal number 198 to binary notation.

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

Network and Networking • Data Networks • Data Networking Solutions – Local-area networks – Wide-area networks

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

LANS Are Designed To: • • • •

Operate within a limited geographic area Allow many users to access high-bandwidth media Provide full-time connectivity to local services Connect physically adjacent devices

Copyright 2002

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LAN Devices

Copyright 2002

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WAN Technologies Include • • • • • • •

Analog modems Integrated Services Digital Network (ISDN) Digital Subscriber Line (DSL) Frame Relay Asynchronous Transfer Mode (ATM) T (US) and E (Europe) Carrier Series: T1, E1, T3, E3 Synchronous Optical Network (SONET)

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

www.ciscopress.com

WAN Devices

Copyright 2002

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Bandwidth Measurements

Copyright 2002

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Digital Bandwidth • Two Analogies That Describe Digital Bandwidth – Width of a pipe – Number of lanes on a highway

• Media Bandwidth Differences – – – –

Category 5 UTP – 100 meters maximum physical distance Multimode (62.5/125um) optical fiber – 2000 meters Modem – 56 Kbps = 0.056 Mbps T1 – 1.544 Mbps

Copyright 2002

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Bandwidth Pipe Analogy

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Bandwidth Highway Analogy

Copyright 2002

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Digital Bandwidth (cont.) • Data Throughput in Relation to Digital Bandwidth – Factors that determine: internetworking devices, type of date being transferred, topology, number of users, user’s computer

• Data Transfer Calculation – Estimated time = size of file / bandwidth

• Why Is Bandwidth Important? – Bandwidth is finite!

Copyright 2002

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Media Bandwidth

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

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Importance of Bandwidth

Copyright 2002

Cisco Press: CCNA Instructor’s Manual

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