Webmaster II Webmaster Review - Fort Collins, CO Copyright © XTR Systems, LLC Review of Webmaster I...

Webmaster IIWebmaster Review - Fort Collins, CO

Copyright © XTR Systems, LLC

Reviewof

Webmaster I

Instructor: Joseph DiVerdi, Ph.D., MBA



Website Purposes

• Individuals, Organizations, Businesses• Rely on Web Pages

– Provide and Collect Information– Manage Processes– Interact With Communities and Customers

• Reliable, Informative, & Responsive Web Site– Creates a Positive Image– Increases Visibility– Manages Cost



Webmaster Mission

• Webmasters Make Sure That:– The Information on a Site Is Accessible – The Information on a Site Is Usable– The Site Is Always Available– The Performance Is Good– Users Can Get Needed Information– The Site Can Collect the Information It Needs

• Whatever It Takes to Accomplish These Goals– Legally, Ethically, & Morally



Potential Webmasters

• Content Providers • Work on the Data Itself, Creating or Editing HTML Documents,

Incorporating Images & Forms, & Maintaining the Integrity of the Links

• Designers• Create the Images & Also Define the “Look” of the Site

• Programmers• Write CGI, Perl, Java, JavaScript, & Other Programs for

Incorporation Into the Site

• Administrators• Make Sure That the Server Runs Properly & Efficiently at All

Times, They Might Also Be for Writing New Scripts & Maintaining Document and Site Security



Evolution of Webmaster

• “Webmaster” Is Now Too Big for One Person• It Is Supplemented by Other Titles

– Internet Strategist • Develops, Executes, & Manages Strategy for Use of

Internet Technologies in Support of Corporate Initiatives

– Electronic Commerce Manager • Develops, Drives, Executes, & Manages Internet

Commerce for a Business Unit

– Internet Strategy Director • Develops & Implements a Wide Range of Internet

Strategies to Meet Company Business Objectives



Webmaster vs. Developer

• Webmasters' Responsibilities Are Broader Than Web Developers'– Webmasters Are Expected to Understand the Web

to a Greater Technical Degree Than Are Web Developers

– Web Developers Often Are Expected to Understand Content to a Greater Degree

• Webmasters Often Perform Web Development• Webmasters Often Are "Jacks of All Trades"



How the Internet Works

• The Internet Is a Communications Medium Through Which Information Is Transferred Between Computers– Many Different Services Use the Internet for

Transferring Information

• They Most Often Use TCP/IP to Transfer Data– Transmission Control Protocol/internet Protocol

• The Telephone Network Is Also a Communications Medium but With Very Different Characteristics




• The Internet Is a Packet Switched Network– When Data Leaves the Source Computer It Is

Broken up Into Packets• Small Chunks of Data

– Transmitted Through Larger and Larger Networks• Usually 1-1,500 Bytes Long

• Packets Are Routed Through Many Networks• When the Packets Arrive at the Destination

Computer – They Are Reassembled Into the Original Message




• Breaking the Data up Into Small Packets– Increases the Efficiency of the Whole Network– Exact Path Taken From the Same Source to the

Same Destination Is Often Different

• Path Depends on the Instantaneous Load– On Each of the Routers & Networks

• Packet Data Is Identified by the Internet Addresses– Of the Source & Destination Computers



Network Analogies

• US Postal Service Is a Packet Switched Network– No User Receives a Dedicated Piece of the Network

• Routers Are Equivalent to Postal Substations– Mail Sent From Milford, CT to Loveland, CO Does Not

Use a Reserved Plane or Truck• It Is Pooled at a Substation & Sent to a Series of Substations

• Efficient Utilization of Network Resources



Network Analogies

• Telephone Network Is a Circuit Switched Network– When a Telephone Call Is Made a Piece of the

Network Is Dedicated to That Call

• Even If That Piece Isn't Being Used– Being on Hold– That Piece of the Network Is Unavailable for Use by

Others

• Inefficient Utilization of Network Resources



Internet Addresses

• An IP Address Uniquely Identifies a Computer• IP Addresses Follow Dotted Decimal Notation

– Four Decimal Numbers – Each Ranging From 0 to 255– Each Number Separated by a Period– The Following Are Unique IP Addresses and

Corresponding to Unique Computers:• 206.168.235.2• 192.122.36.5• 128.174.5.6

• IP Addresses Are Registered & Allocated



Domain Name System

• A Host Name Is Assigned to Each Computer Only for the Convenience of Human Users– Computers Refer to Each Other by IP Addresses

• Host Names Use a Hierarchical Domain Structure– Right-to-left <–> Most-to-least Significant– Each Domain Is Separated by a Period

• Host Names Are Registered & Allocated– By a Central Authority



Domain Name Lookup

• Convert a Domain Name Into an IP Address• Use DNS Servers

– Computers Whose Sole Purpose Is to Maintain Lists of IP Addresses and Domain Names

• Local DNS Servers Know Local Addresses– DNS Servers Cache Recently Requested Addresses

• Local DNS Servers Also Know Addresses of More-Significant Domain Name Servers



Host & Domain Names

• The Following Are Unique Host Names Corresponding to Unique Computers:– woody.xtrsystems.com– lamar.colostate.edu– holly.colostate.edu– nic.ddn.mil– whitehouse.gov– uxc.cso.uiuc.edu– linus.ulltra.com

• One Computer May Have Several Host Names



Original High-level Domains

Domain Usage

com Commercial Organizations

edu Educational Organizations

gov Non-Military Government Organizations

mil Military Organizations

org Other Organizations

net Network Resources



Country Domains

• The Internet Is a World-Wide Network• Foreign (Relative to the USA) Countries Have

Responsibility for Their Own Names• Country Codes Are a Set of Two Letter

Highest-level Country Domains• About 300 Country Codes Exist

BO - Bolivia BR - Brazil IR - Iran

CA - Canada TD - Chad IQ - Iraq

FR - France DE - Germany UK - UK

US - USA TO - Tonga TW - Taiwan



Country Domains

• THe Following Are Unique Host Names Corresponding to Unique Computers:– hockey.guelph.ca– alpha.psd.k12.co.us– ci.fort-collins.co.us– uxc.urbana.il.us

• Host Names Are Registered & Allocated– By Central Authorities



Telephone Services

• Voice Transmission• Fax Transmission



Internet Services

• World Wide Web - Hypertext Documents– Other Services Which Use the Internet As a

Communications Medium - Nothing to Do With the WWW

• Telnet - Login to Remote Computers• FTP - Inter-computer File Transfer• Email - Jokes for Everyone• Newsgroups - Bulletin Boards• Internet Relay Chat (IRC) - Chat Rooms



How the WWW Works

• The World Wide Web Is an Information Service That Uses the Internet As Its Communication Medium– It Is Based on the Technology Called Hypertext

• Hypertext Is a Method of Presenting Information• Selected Words in a Text Can Be "Expanded"

– To Provide Other Information About the Word– These Words Are Called Links to Other Documents

• Text, Images, Sounds, etc.



Clients and Servers

• The Web Browser on Your Desktop Is a Web Client– Navigator, Explorer, Opera, Mosaic, Etc.

• Most Common Interface to the WWW• To Request a Document With a Browser It

Needs a Universal Resource Locator (URL)• URL Identifies Computer With Information • URL Identifies Path to the Document



Uniform Resource Locators

http://perl.oreilly.com/news/2000_june.html

scheme://host/path

Scheme: the Protocol That Connects to the Site

Host: the Name of the Server to Connect

Path: the Location in the Server’s Directory Tree



Clients & Servers

• Browser Contacts Server (Remote Computer)• Requests Specified Document Using URL• Receives Specified Document• Renders or Displays Document on Browser



Clients and Servers

• A Server Is a Computer Running Server Software– Apache

• A Server – Sits Patiently Running Server Software– Listening to Its Internet Connection– Awaiting Requests

• Uses Hyper Text Transfer Protocol (HTTP)



Clients and Servers

• Upon Receiving a Request– Accepts URL Path– Converts Path Into File Name– Returns Status to Requesting IP Address– Returns File to Requesting IP Address, If Found

• Uses Hyper Text Transfer Protocol (HTTP)



A Very Simple Transaction



Simple Transaction w/ Image



Site Hosting Issues

• Basically Three Options– Your Own Server– Internet Service Provider (ISP)– Presence Provider (PP)



Site Hosting Issues

• Internet Service Provider (ISP)– A Service From a Company That Houses Its Own

Server Computers Which Rents Out Bits of Them on a Monthly Fee Basis

– ISP Supplies Internet Connection & Sys Admin– Sys Admin Maintains Hardware

• You Call & Complain

– You Access Through Your Own Internet Connection

• Which You Must Purchase Through an ISP



Site Hosting Issues

• Presence Provider (PP)– A Service From a Company That Houses Its Own

Server Computers Which Rents Out Bits of Them on a Monthly Fee Basis

– ISP Supplies Internet Connection & Sys Admin– Sys Admin Maintains Hardware

• You Call & Complain

– You Access Through Your Own Internet Connection

• Which You Must Purchase Through an ISP



Site Hosting Issues

• Your Own Server– When You’re Really Big

• Or Tired of Using an ISP

– You Must Supply a Dedicated Internet Connection• DSL, T1, T3, etc.

– You Must Supply One or More Dedicated Computers

– You Must Supply Real System Administrator(s)– You Access Directly



Site Hosting Issues

• In This Class You Will Use “Local Hosting”– Viewing Web Pages Using a Web Client on the

Same Computer Without Any Server

• You Will Also Use "Remote Hosting"– You Will Be Assigned a Linux Account– On a Server Here at Ulltra Technology Corp.– You Can & Will Access Your Account From Any

Computer With an Internet Connection– You Can & Will Develop Your Web Site From Any

Computer With an Internet Connection



Sample Site Configurations

• Low Volume– 1,000 - 10,000 Hits Per Day– 0.01 - 0.1 Hits Per Second - Average– 0.1 - 1.0 Hits Per Second - Peak– Can Be Run Out of The Home (Office)– Good Intel (486, Pentium I) Hardware ($200)

• Or AMD Equivalent (K6, Athlon, etc.)

– Linux Operating System ($0)– Apache Server Software($0)– DSL (0.7 Mbps) (<$100/month)– Flat-file, Perl-hash, or MySQL As Database

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