 Dear students, in this module, I will talk about the Amazon Web Services, I will give an overview with reference to the databases and with reference to the API's application programming interface. Now you would be wondering that Amazon has been around for quite a while and it has been selling books online, electronic devices, gadgetry, movies, you make the list. So how does the web or the cloud come into existence, the web services. So as I'll talk about, it is just a logical extension of what Amazon has been doing. And one thing is for sure that Amazon is a leader in this area. There are the products and services by Microsoft also, Azure. But Amazon has been the leader and it was a logical extension. So I'll talk about the databases with reference to the storage because that was the key facility and the feature that Amazon offered and then about the application programming interfaces. So traditionally, or after the standard databases, the approach was to have a distributed architecture, distributed databases. Now using the traditional infrastructure, creating such distributed databases was a challenge and it has certain issues also. So the issue was resolved and the option was the cloud. So what is a cloud? A cloud is a network based access to the computing resources, to the data resources and I'll talk more about it. So what are the benefits of the cloud? Remember, people adopt technology not for the sake of technology, but the technology has certain benefits. That is why people and the companies and the businesses adopt technology. So the benefit of cloud is that there's no upfront capital expense because as a user, you don't have to set up an infrastructure. It is already there and whatever you consume, whatever you use in terms of CPU cycles, in terms of the bandwidth, in terms of the storage, you only pay for it and it costs low. The quality is there, but the cost is less and it's a self-service infrastructure. So these are the benefits and of course, it improves the business agility. What is the meaning of business agility? It means that if the business has to do certain things or it has to move into certain area, it does not take months and weeks to get the equipment, to put it into action, to make it operational and then use it. You just have to open your account and you can just go ahead. So there's the business agility. So these are the benefits of the characteristics of the cloud. So what is a cloud? The word cloud over here means that there is no well-defined structure. It is hidden from you. It is transparent to the end user. So there are the computing resources which may be anywhere in the world. And they actually distribute setup. And those resources are accessible to the end user over a network. So that is a cloud. So there is a certain functionality associated with the cloud. And there is abbreviation AAS as a service. So with the cloud structure, you have the infrastructure as a service, platform as a service, software as a service. So for example, if you have to run a certain software, you don't have to install that software on your servers and maintain them and put the patch on them and so on. That software is running somewhere in the cloud. And you just pay the fee for accessing and running that software. So that's the concept over here. So what are the essential characteristics of a cloud? As you can see on your screen, they are listed over there. So it is on-demand service, resource pooling and so on. Now if you look at resource pooling, then it is just like car pooling. So when number of people are using a certain transport facility, then the cost is amortized across those users. In the context of the cloud, that is the case over there also. So there was a very smart consultant, Juan Liu, who basically looked at the IP addresses of the Amazon servers. And this is a list. This is kind of an old list, but it gives an idea because Amazon lumps everything together into others, which includes the web services also. So you can see that it's a very large number of servers. And of course, then it's the depth and breadth of the services which are offered by the Amazon web services. So it's a very, very rich ecosystem. So there are developers and there are users. And of course, the Amazon is also there. So the point I'm trying to make over here is that instead of going or spending money or waiting to get the money to use large data sets to store data, to process data, use the Amazon web services. And finally, how do you access the Amazon web services? There's something called as an API application programming interface. And you cannot directly access the Amazon web services resources. So there are the Amazon web services APIs. There are people, there are programmers who also write the APIs. And you don't have to worry about those APIs because there is the management console. And every user accesses the Amazon web services through that management console. And that management console itself is running those APIs, application programming interfaces. So there's a request from one program with certain things which goes to the second program. And that program responds, that service, that hardware responds to it and the things is completed. And then there is the API gateway of Amazon web services where the API is reside. And you can use those APIs to your benefit and do wonderful things using the Amazon web services. Thank you very much.