 So, in this module, I will describe what WEB is, WEB basically is a short for the World Wide WEB or WWW. So, we can safely say that WEB was invented by Sir Tim Berners-Lee in early 90s at CERN Switzerland and he as a matter of fact wrote the first browser which was first used at CERN then it was made public. Internet has been around before WEB was there. Internet has been around since the 70s, I will talk more about in the subsequent modules. But the WEB as we know it with the browser, that is attributed to Tim Berners-Lee. So, the World Wide WEB works on the TCP IP protocol and it uses the URLs, the universal resource locators based upon which we can locate the choice, the website of our choice, we can type that and go there or we can search for something click and go where we want to go. So, the WEB has been around for you can count the number of years how long it has been around and it has a tremendous impact on our lives and on the businesses and how we work and how we are going to work in the foreseeable future. So, what is WEB? There are certain fundamental attributes of the WEB based upon which we can define what a WEB is. First of all WEB is distributed, I will go into more details. Distributed means that there are something which we called which I discussed before as the WEB hosting service providers and then there are the central repository where all the addresses are kept and different countries and different organizations have their servers and their repositories which are connected together and the address of website I am typing that may be in the same city I am or it may be across the continent. So, the WEB is distributed that is for sure that is the fact WEB is dynamic I will go into more details actually when I go to the challenges over here WEB is dynamic. Dynamic means that the WEB is changing, changing means that I am not considering the full stops or the commas or the certain text being added or removed as long as it does not changes the semantics of the WEB page. I will go into more details WEB is massive, there are billions of WEB pages and continuously WEB pages are being added and there are so many WEB pages that search engine it just comes sits on its knees if and when it has to index all of those pages and WEB is open open means that there are no licenses there are no patents I will go into more details there are tools and softwares there are protocols which can be used for free and so on I will go into more details so when the WEB is distributed as I have briefly mentioned in the previous slide then what are the challenges first challenge is the vocabulary different vocabularies now since there is no central governing authority over the WEB so one word can have different meanings or one meaning can have different words I think you get my point so the different vocabularies reliability of content since there is no central governing authority so anybody almost literally can put anything over the web okay and there are no challenges because my internet service provider my web hosting service provider just like the telephone they are not judging the contents they are just placing it over the internet for me so there is hardly a difficult unless it is a website of a credible newspaper which you are sure has not been hacked very difficult to ensure the credibility of the contents of the web conflicting information now there are conflicts on the web based upon politics difference in politics difference in religion differences of countries differences of neighboring countries a lot of conflicts on the web these are the challenges of the web web is dynamic variable rate of change okay content can be removed at any time content can be added at any time the amount of content removed or added there are no limits defined so it is changing all the time then change in vocabularies now this is this vocabulary over here this vocabulary is different from the from the vocabulary I talked about in the last slide is different this is different meaning that as the time passes okay since the web is dynamic so the meaning of things change the the meaning of things change new words new concepts are introduced so so the the vocabulary changes you cannot say with a surety that this is what it means the meaning has been changed web is massive 5.7 billion indexed pages as of August 2020 it's almost impossible for a search engine to go and get a smartly intelligently what I'm looking for because of the humongous size and if you look at the items items per page the volume further increases web is open what is the meaning publish content and applications okay without paying to anybody you can publish using HTML using PNG format using JPEG using webm for the movies you don't have to pay a royalty to anybody that is one you're open to publish code and implement you can do the coding okay you don't have to pay anything to anybody there is hardly any patents you have to worry about there are licenses which are freely used licenses of course if somebody or some company or organization has placed something in public domain you are not supposed to are not allowed to use that public domain material for commercial benefit you can access the content you can use the content which is available freely on the web without paying any license fee without paying any royalty so this is what is meant by the web being open okay and certain operational attributes of the web now what I have shown in the bracket over here if you recall these are very similar to the attributes of a database the these two highlighted in bold attributes web pages contain metadata the difference because the database which I am accessing that only contains the data which has been stored in it but in a web page there may be a lot of metadata okay there may be a lot of tags which are not visible to me but which are there so that's one difference of the web from a database and web pages shared across time and space okay the web pages are distributed by default is distributed a database is not by definition distributed but a web by definition is distributed and it is distributed across the space okay the whatever I am accessing that can be anywhere in the world and it's distributed in time also okay in time also so time and space so this is all I have to say about defining the web in this module thank you for your time