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Internet and WWW

Information Literacy I – EN(IL1) Course

Internet

Computer networks and Internet

The global system of interconnected networks is commonly called “Internet” (https://en.wikipedia.org/wiki/Internet).Historically, this word was used for several computer networks, connected together “a network of networks”, which eventually grew to the global scale.

Internet

IP address: 103.102.166.224Domain name: DNS, host, whois(en.wikipedia.org → 103.102.166.224)Hostname: The unique name of a device, the domain namecommand "hostname" gives the hostname in terminal.("ifconfig -a" – for Mac/Linux, "ipconfig /all“– for Windows)Protocols (TCP, UDP, HTTP, IMAP, SMTP,...)

IP addressIt is combined of 4 values in the range 0-255 and divided by the period.IP address is used to identify devices connected to the Internet,for the purpose of information transmission.

Example: Addresses starting with 131.112 (Tokyo Tech network)

Server Name IP address

Tokyo Tech Portal 131.112.12.20

Tokyo Tech Mailserver (Receiving) 131.112.12.17

Tokyo Tech Mailserver (Sending) 131.112.12.18

Library Website 133.130.93.107

Domain NameAn identifier for networks and devices connected to them. It consists of alphanumerical symbols divided by periods. It may be used instead of an IP address, which may be hard to remember.

Example: Domain names and corresponding IP addresses

Server Name Hostname IP Address

Tokyo Tech Portal portal.titech.ac.jp 131.112.12.20

Tokyo Tech Mailserver (Receiving) mailv3.m.titech.ac.jp 131.112.12.17

Tokyo Tech Mailserver (Sending) smtpv3.m.titech.ac.jp 131.112.12.18

Library Website www.libra.titech.ac.jp 133.130.93.107

Domain Structure

Organizations

Domain name Organization

.biz Business

.com Commercial

.edu US educational institution

.gov US government

.info Any

.mil US military

.net Network technology

.org (Non-profit) organizations

CountriesDomain name Organization

.cn China

.de Germany.fr France.jp Japan.kr South Korea.es Spain.th Thailand.uk United Kingdom.vn Vietnam.us United States

Top-level domain names

Domain Structure (cont)

Other domain names have the form: 〜.top-level-nameac.jp / co.jp / go.jp / or.jp / ne.jp – Main second-level domains in Japanwww.libra.titech.ac.jp – This name reads as follows:A web server (www) of library (libra) of Tokyo Tech (titech) within academia (ac) in Japan (jp).

Domain Structure (cont)

XX: Top-level domain nameYY: Domain YY within XXYY.XX is a part of the bigger domain XX

ZZ: Domain ZZ within YY.XXZZ.YY.XX is a part of the bigger domain YY.XX

Example：www.libra.titech.ac.jp… .ZZ.YY.XX

Reading e-mail addresses

tokodai.h.ab@m.titech.ac.jp is read as follows:• m.titech.ac.jp the domain of mail service

The mail service (m) of Tokyo Tech (titech) within academia (ac)in Japan (jp).

Knowing the structure of domain names,it is easy to see why this message is suspicious!

DNS (Domain Name System) – Resolving Domain Names

DNS is a system that translates domain namesinto IP addresses

On Linux or Mac, run the terminal:host mailv3.m.titech.ac.jpOn Windows, run cmd.exe:nslookup mailv3.m.titech.ac.jp

Web

WWW (World Wide Web)

One of the Internet services – the global hypertext systemHypertext: A document containing hyperlinks,

which allow instant access to other documents (or resources)

Basic technologies constituting WWW:Conceptual level: Web servers, content, browsersImplementation level: URI, HTTP, HTML, JavaScript

Web servers, content, browsers

Web server

Web contents

A view of this course’s webpage in the Web browser

URI / HTTP / HTML

Uniform Resource Identifier (URI): A name that uniquely identifies a web documentExample: https://titechcomp.github.io/y18-bonnet/slides/il1en-3.pdf

HyperText Transfer Protocol (HTTP): A protocol for transferring web documents between servers and browsers

HyperText Markup Language (HTML): A format for representation of web documents

Web servers, content, browsersA view of this course’s webpage in the

Web browser

Web server

Webcontents

/y18-bonnet/index.html

/y18-bonnet/slides/il1en-1.pdf

Entering URI in the address bar= Requesting the document specified by it

titechcomp.github.io

Web contents

/y18-bonnet/index.html

/y18-bonnet/slides/il1en-1.pdf

Dear titechcomp.github.io, please send me /y18-bonnet/index.html

HTTP: Protocol for transferringWeb documents

titechcomp.github.io

Web contents

/y18-bonnet/index.html

/y18-bonnet/slides/il1en-1.pdf

Dear titechcomp.github.io, please send me /y18-bonnet/index.html

Ok, here you go!

Format of URI

https titechcomp.github.io /y18-bonnet/index.html

Scheme

Method for obtaining

information resources

http(s) – Method for obtaining standard web content

Host Hostname of a web server titechcomp.github.io – Web server of GitHub

PathLocation of a resource

on the server/y18-bonnet/index.html – Name of the specific page

Major SchemesPurpose Example

http Transferring web documents http://www.mizuhobank.co.jp/index.html

https SSL-secured http https://web.ib.mizuhobank.co.jp/servlet/LOGBNK0000000B.do

file A file on the local computer file:///Users/hanako/Documents/report.docx

ftp Remote file transfer ftp://ftp.jaist.ac.jp/pub/CTAN/systems/texlive/

mailto Starting e-mail application for composing a message

mailto://pm@kantei.go.jp

http vs. httpsPurpose Example

http Transferring web documents http://www.mizuhobank.co.jp/index.html

https SSL-secured http https://web.ib.mizuhobank.co.jp/servlet/LOGBNK0000000B.do

file 手元のコンピュータ上のファイル

file:///Users/hanako/Documents/report.docx

ftp 遠隔ファイル転送 ftp://ftp.jaist.ac.jp/pub/CTAN/systems/texlive/

mailto メールメッセージの作成メールアプリが起動する

mailto://pm@kentei.go.jp

http vs. httpsPurpose Example

http Transferring web documents http://www.mizuhobank.co.jp/index.html

https SSL-secured http https://web.ib.mizuhobank.co.jp/servlet/LOGBNK0000000B.do

file 手元のコンピュータ上のファイル

file:///Users/hanako/Documents/report.docx

ftp 遠隔ファイル転送 ftp://ftp.jaist.ac.jp/pub/CTAN/systems/texlive/

mailto メールメッセージの作成メールアプリが起動する

mailto://pm@kentei.go.jp

HTML: Format for Web documentsHTML-formatted document

Hypertext Markup Language

HTML document Its view in the browser<!DOCTYPE html><meta charset="UTF-8"><title>History of the Web</title><h1> History of the Web</h1>

<p>HTML was originally developed by Tim Berners-Lee while at <a href="http://cern.org/">CERN</a>. During the course of the 1990s it has blossomed with the explosive growth of the Web. It depends on Web page authors and vendors sharing the same conventions for HTML. This has motivated joint work on specifications for HTML.</p>

<p>HTML has been developed with the vision that all manner of devices should be able to use information on the Web: PCs with graphics displays of varying resolution and color depths, cellular telephones, hand held devices, devices for speech for output and input, computers with high or low bandwidth, and so on.</p>

<h1>References</h1><ul><li><a href="http://www.w3c.org/">World Wide Web Consortium</a>,International community promoting standards of the Web. </li><li><a href="http://www.w3.org/pub/WWW/History/1989/proposal.html">Information Management: a Proposal</a>, The original proposal by Tim Berners-Lee concerning the World Wide Web.</li></ul>

[Adapted from: https://www.w3.org/TR/WD-html40-970917/intro/intro.html]

Evolution of Web technologies

Static Web (~2003)

Web documents are prepared in advance and uploaded to the web server for display.

Their contents remain unchanged or regularly updated by the authors (i.e., the administrators) but not the readers (i.e., the users)On the contrary, the contents of currently used services are usually edited not only by the administrators, but also by the users (c.f. twitter, facebook, flickr, YouTube,…)

Dynamic Web (Web 2.0: 2004〜2008)

Static Web (Web 1.0) Dynamic / Social Web (Web 2.0)

Static HTML information Contents dynamically created using databases and SNS: facebook, twitter

Passive consumption of information Web contents created by the users: Flickr, Hatena, Vimeo, Wikipedia, YouTube, …

Individual consumption of informationSocial activities: communities/groups, collaborative evaluation (bookmarks, favorites, reviews, comments), tags, recommendations

Individual bookmarking and frequent visiting Search, information aggregation (RSS feed)

Minimally interactive systems (e.g., CGI-based) Interactivity: JavaScript/AJAX, Google Maps, Web-based games

Static Web HTML Dynamic Web (Web 2.0) WYSIWYG

<p>HTML was originally developed by Tim Berners-Lee while at <a href="http://cern.org/">CERN</a>. During the course of the 1990s it has blossomed with the explosive growth of the Web. It depends on Web page authors and vendors sharing the same conventions for HTML. This has motivated joint work on specifications for HTML.</p>

<p>HTML has been developed with the vision that all manner of devices should be able to use information on the Web: PCs with graphics displays of varying resolution and color depths, cellular telephones, hand held devices, devices for speech for output and input, computers with high or low bandwidth, and so on.</p>

Amazon Review – Elements of Social Interaction

Amazon Review – Elements of Social Interaction

Amazon Review – Elements of Social Interaction

Amazon Review – Elements of Social Interaction

Amazon Review – Elements of Social Interaction

Amazon Review – Elements of Social Interaction

Summary of key points

Internet – the global system of interconnected networksIP address identifies devices connected to the networkDomain name – a human-memorable analogue of IP addressDomain name service (DNS) translates domain names into IP addresses

Summary of key points (cont.)

WWW – the global hypertext systemURI uniquely identifies a Web resourceHTTP – the protocol for transferring Web documentsHTML – the format of Web documents

Summary of key points (cont.)

Dynamic Web (Web 2.0)User/customer-generated contentsSocial networking servicesSearch enginesInteractive contents

2nd Test – Internet, Web

Your answers should be submitted via the Google Form:https://forms.gle/TuU89dvaKXDBbpsh8 (link also on the website).

To be completed by June 7, 23:59.

You can submit your answers multiple time, the last submission before the deadline will be considered final.

This test is mandatory – it is a part of your course evaluation.