Computers: Information Technology in Perspective By Long and Long Copyright 2002 Prentice Hall, Inc. Going Online Chapter Jaana Holvikivi

Quit 7.2 What Is the Internet? The Net is a worldwide collection of interconnected networks.

Quit 7.3 Internet History  ARPANET  Internet  InterNIC  W3C  No person or organization governs the Internet! Internet

Quit 7.4 Submarine cables For a recent image see:

Quit explosion-as-internet-use-soars-can-bottlenecks-be- averted/ May 1, 2012

Quit 7.6 Amazon cloud down; Reddit, Github, other major sites affected major-sites-affected / Google down: Reliance on cloud services

Quit 7.7 How do you get on?  Via dial-up/ ADSL connection to Information Service Gateway Information Service Gateway Telecommunications company Telecommunications company Internet Service Provider (ISP) Internet Service Provider (ISP)  Via direct network connection using a shared high-speed line on LAN or WLAN

Quit 7.8 Internet Terminology   Transmission Control Protocol/ Internet Protocol (TCP/IP)   Packets: transmission is split and packets could take different routes   IP addresses every machine has an address dynamic IP addresses; sub-networks   Extension of address space IPv6 official on 1 June 2012

Quit 7.9 Retrieve/View Internet Information  Client/server programs  Browsers Internet Explorer Internet Explorer Firefox, Safari, Chrome Firefox, Safari, Chrome  The Internet address (URL) Identifies location of server site Identifies location of server site Files are downloaded for viewing Files are downloaded for viewing

Quit 7.10 Uniform Resource Locator DomainName Directory Filename AccessMethodOrProtocol

Quit 7.11 URL: Access Methods Hypertext Transport Protocol ftp:// File Transfer Protocol gopher:// Gopher menu tree secure Hypertext Transport Protocol XMPP chat protocol

Quit 7.12 Affiliation Commercial Education US Businesses Government US International Military US Network Resources Nonprofit Organizations ID.com.edu.firm.gov.int.mil.net.org.info URL: Top-Level Domains (TLDs)

Quit 7.13 Countries Finland Canada UK Russia Tuvalu Germany China South Africa ID.fi.ca.uk.ru.tv.de.cn.za URL: Top-Level Domains (TLDs) Extension could be anything!

A sample HTML document This is a sample HTML document HTML: Basic structure

A sample HTML document HTML document This is a sample HTML document Created by JHH in 2012

Important HTML - elements link: Search engine Search engine Start, close element space attribute="value" image: empty element Space stripped (breaks, tabs, enter)

Quit 7.17Tables<table><tr> cell1 cell1 cell 2 cell 2 </tr><tr> 1 1 </tr></table> Symmetrical structure!!

Quit 7.18 HTML document contents   Every HTML document should contain certain basic information about its origin:   The author of the document, and the person who is formally in charge of the document.   The date of creation of the document, or the date of last update, or both.   The context of the document and its status,   part of official documentation by a company about one of its products,   or part of a private person's information.

Page requests on the Web Internet User workstation Browser: HTML, scripts Database server HTTP request Server HTML pages Program Server CGI HTTP: HTML pages PHP JavaASP SQL Oracle

HTTP requests GET /index.html HTTP/1.1 Host: Accept: www/source Accept: text/html Accept: image/gif User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv: ) Gecko/ Firefox/ a blank line *   The client lists the Multipurpose Internet Mail Extension (MIME) types it will accept in return.   Finally, the client sends a blank line indicating it has completed its request.

HTTP server response HTTP/ OK Date: Mon, 09 Apr :39:22 GMT Server: Apache/ (Unix) (Red-Hat/Linux) Set-Cookie: fe_typo_user=4f74f6c85b; path=/; domain= Last-Modified: Wed, 08 Jan :11:55 GMT Etag: "3f80f-1b6-3e1cb03b" Accept-Ranges: bytes Content-Length: 438 Connection: close Content-Type: text/html; charset=UTF-8

GET and POST methods The difference between these two methods is in the way of sending data to the page:  GET method sends data using URL (size limit),  GET method sends data using URL (size limit), ethod  POST method sends data through a standard entrance

Local disk Windows OS D:\documents Server disk Linux or Unix OS index.html page2.html index.html picture1.jpg logo2.gif Home directory of user x public_html Mail and other data Workstation Local use: editing FTP, SHH Remote use through internet: visiting Web pages Creating and sending home pages

Quit 7.24  or e- mail server  The message  response options  Post Office Protocol  synchronization of mails Telecommuting To CC: and/or BCC:) SubjectMessage Attached file(s) Reply Reply to all Forward

Quit Open and shared information  social media  Blogs  Commercials sites include user ratings and forums (hotel comparison, shops, Amazon)  Google: maps, images, applications  Open Data  use of information 7.25

Quit Cloud  Amazon EC2: server space  Dropbox  SAAS software as service, pay as you use  Youtube, Skype, Twitter  Facebook, Linkedin, Google+  Risks, fast evolving 7.26