1_Intro to web Technology, www, web 2.0.ppt

Introduction to Web Technology What is Internet?  Is a massive network of networks, a networking infrastructure.  It connects millions of computers together globally, forming a network in which any computer can communicate with any other computer as long as they are both connected to th...

Introduction to Web Technology What is Internet?  Is a massive network of networks, a networking infrastructure.  It connects millions of computers together globally, forming a network in which any computer can communicate with any other computer as long as they are both connected to the Internet.  Information that travels over the Internet does so via a variety of languages known as protocols. Internet [Cont..]  The Internet is decentralized by design. Each Internet computer, called a host, is independent.  Its operators can choose which Internet services to use and which local services to make available to the global Internet community.  There are a variety of ways to get an access to the Internet.  One can Gain access through a commercial Internet Service Provider (ISP) or any other online services What is Web?  The World Wide Web, or simply Web, is a way of accessing information over the medium of the Internet.  It is an information-sharing model that is built on top of the Internet. The Web uses the HTTP protocol, only one of the languages spoken over the Internet, to transmit data. Web services, which use HTTP to allow applications to communicate in order to exchange business logic, use the Web to share information.  The Web also utilizes browsers, such as Internet Explorer or Firefox, to access Web documents called Web pages that are linked to each other via hyperlinks. Web documents also contain graphics, sounds, text and video. Web [Cont..]  System of Internet servers that support specially formatted documents.  The documents are formatted in a markup language called HTML (HyperText Markup Language) that supports links to other documents, as well as graphics, audio, and video files.  This means you can jump from one document to another simply by clicking on hot spots. [Not all Internet servers are part of the World Wide Web.] Today‘s Users…… expectation????  Application with rich graphical user interfaces, employ multimedia capabilities….  Want App’s that can run on the internet & web and communicate with other applications.  Want to apply database tech for storing & manipulating their business & personal data.  They desire App’s that are just not limited to the desktop or even to some local computer n/w, But that can integrate Internet & web components & remote databases. Programmers Expectation???  Want to use all these capabilities in a truly portable manner so that app’s will run without modification on a variety of platforms History of the Internet & WWW  Late 1960’s ARPA(Advanced research projects agency of the department of defense) rolled out blueprints for networking the main computer systems of about dozen ARPA funded universities & research institutions.  Connected with communication lines operating at stunning 56kbps  ARPA proceeded to implement the ARPANET which eventually evolved into today's Internet  ARPANET goals was to allow multiple users to send & receive information simultaneously over same communication paths. N/w operated on a technique called packet switching(n/w’s were designed to operate without centralized control) Protocols  For communicating over the ARPANET became known as TCP  TCP Ensured that MSG’s were properly routed from sender to receiver and that they arrived intact  As the Internet evolved. Organizations worldwide were implementing their own n/w’s for both intraorganisation & interorganisation communications  Challenge now was to get these different n/w’s to communicate….. Used Internet protocol (IP)  Creating n/w’s of n/w’s  current architecture of the internet  Now its called the TCP/IP  Commercial evolution of the internet  Earlier was limited to universities & research institutions, then military started using it.  Eventually the government decided to allow access to internet for commercial purposes.  But there was resentment concerned that response times would become poor as “the Net” became saturated with users  Businesses rapidly realized that they could tune their operations & offer new and better services to their clients. so they started spending vast amounts of money to develop & enhance the internet.  Resulted in fierce competition among communication carriers, h/w & s/w suppliers to meet this demand  resulting in greater bandwidth( info carrying capacity)  World Wide Web (www)  Allows computer users to locate and view multimedia-based doc’s on almost any subject over the internet.  Though internet was developed decades ago, the web is a relatively recent creation.  In 1989, Tim Berners-Lee of CERN( Eur org for Nuclear Research), began to develop a tech for sharing information via hyperlinked text documents.  HTML  He also wrote communication protocols to form the backbone of his new information system, which he called the WWW.  In particularly he wrote the HTTP – ( protocol to send information over the web)  Web server  A computer program that waits for request from remote clients( ie browsers) for documents stored on the server computer, retrieves them & sends these back to the clients.  Browser  1993 web use exploded with the availability of the MOSAIC Browser, featuring user friendly GUI.  Marc Andreessen, whose team at NCSA developed Mosaic went on to found Netscape WWW Consortium (w3C)  In Oct 94 , Tim Berner-Lee founded an organization “W3C”- devoted to developing nonproprietary, interoperable technologies for the WWW.  One of the W3C’s goals is to make the web universally accessible- regardless of the availability, language or culture.  www.w3.org provides extensive resources on internet and web technologies.  W3C is also a standardization organization. Web technologies standardized by the W3c are called Recommendations. Which include XHTML,CSS,HTML,XML  Web 2.0  Coined by Dale Dougherty of O’Reilly Media 2003  Web 2.0 describes a trend where in companies use the web as a platform to create collaborative, community-based sites (e.g social n/w sites, blogs, wikis, etc)  Web 2.0 involves the user- not only is the content often created by the users, but users help organise it, share it,remix it, critique it, update it, etc.  Embrasses an ‘Architecture of participation’ Web 1.0  The state of web through the 1990s and early 2000s; and was focused on relatively small number of companies and advertisers producing content for users to access. Also known as ‘Brochure web’. Rich Internet App’s (RIAs)  Are developed using technologies that have the look and feel of desktop software.  Enhancing a users overall experience. Software as a Service (SaaS)  S/W that runs on server instead of a local computer has gained prominence because of sophisticated new techs & increased broadband internet access. Search Engines  Have become essential in sorting through the massive amount of content on the web (finding & locating is more effectively done) Web Services  Have emerged and , in the process, have inspired the creation of many web 2.0 businesses.  They allow one to incorporate functionality from existing applications & websites into your own web applications quickly and easily. Personal, Distributed & CS computing  Personal computing was done by standalone system  Distributed computing the load was distributed among various pc’s interconnected.  Client-Server computing where in a client could draw services from remote pc. Programming Languages  Procedural  Object oriented  Fortran  C++  COBOL  JAVA  Pascal  C#  BASIC  JavaScript  C  PHP  Ruby on Rails  Not particularly re-usable  Using reusable componentary, have classes Thank You!