 So students in this module I will talk about the simple storage service which is also fondly called as S3. Now S3 is very popular and it is one of the first services provided by Amazon Web Services. S3 is used by Dropbox which keeps record of all your storage. Basically S3 is like a filing cabinet of internet. This also uses S3. All the movies of Netflix are available on S3. So S3 is like a poster child for Netflix and of course health services also keep their records on certain health services on S3. So S3 is very popular for a number of reasons. So now we look at the module coverage. You see it's quite comprehensive module coverage. So let's go over all of these modules one by one. So there is a bucket name associated with S3. Now that bucket name has to be unique. That bucket name although it is a flat structure. It is a flat structure. It means that the bucket name has to be unique and it has to be unique across all the regions where the S3 servers are available. And of course the data which is associated with S3 it can be simple it can be complex also. And it has a certain methodology of addressing. It appears to have a directly like structure but the structure of actual S3 storage may not be visible to you. It is under different layers okay. It is under different layers layer 1, layer 2, layer 3 okay. The purpose is to make it accessible in a user friendly manner. The people which are used to it it has to be intuitive also. So S3 objects are not associated by APIs. You are going to directly call the S3 through the APIs. They are different layers as I mentioned in the previous slide. And of course it is a graphical user interface GUI through which the S3 objects are accessed. The purpose is obviously it's simple to make it user friendly to make it more intuitive. And of course S3 updates not allowed. This is the main difference between storing on S3 and storing on your hard disk. On your hard disk I can make changes in my file in my database and those changes are directly made in that database or in the file. But in the case of S3 the storage that is not the case. You cannot modify it okay. You cannot, what you do is that you make versions. You make version V1, make version V2 okay. And you store V1 as V2 and you have multiple versions. And based upon those versions you know which is the latest one, the latest update. So it also supports a very fine grain granularity of security. The data is secure as I mentioned in the beginning of this module that health records, health data is stored on S3 which follows certain standards. And of course a lot of patient privacy involved in it. Now these standards are there therefore S3 is reliable, S3 is secure okay. Now what are the levels, how the access is there? The access is obviously given to the owner of the data. The access is given to specific groups or I as a owner give access, authenticated access to an individual. And of course the access is available all over the internet which is the last one. So in S3 what we do is what Amazon actually works as is do is assign that the right who has the right to do what, what can be done by which person, which group, which individual. So the point I am trying to make over here is that S3 is secure based upon number of levels and high level of granularity of security. Now why S3 is being used by companies because they have digital menus, they have videos okay and that can encompass terabytes of data, terabytes okay. So S3 is there for the companies. Now the other advantage of this is that when you run the application okay I will come back to it again. One of the advantage of this approach is that once the data is on S3 okay. Now there is no traffic load on the company's website. So that there's no congestion over there when the customers then when the visitors they are viewing the manuals or the videos about the company. The traffic is actually taking place okay at the Amazon web services servers not at the website of the company not at the internet of the company. So the response is good. So what is the S3 cycle? The S3 cycle is before you. You can create, you can assign permission, you can access it okay. But you cannot do the changes over there. Versioning is there. So S3 provides encryption and of course you can also do a static web page hosting without a web server which we have been discussing. So it means that if there is static data, tremendous amount of static data, you can use S3. And the S3 scope is that bucket name is unique which I have already mentioned. And there is no network traffic charge because the data is in region 1 and region 2 okay, region 3. This is maybe this is the West Coast, this is the Far East and so on. So if the traffic is within over there, there is no extra charge. But if the traffic goes from there or there or something like this, then there's charging. You have to be careful about it. And of course what you can do is you can duplicate your data across these regions. You can have your data one over here and data one over here also data one over here also. So when you make the changes, you make the changes within the regions. There is no network traffic. Of course there's the extra cost of storage. And finally the costing of S3, of course the costing is based upon the volume of data, the costing is based upon the type of APIs are called. It is put copy or whatever okay. And of course the volume of data which comes, which goes across the regions. The costing is based upon the network traffic also. And finally fewer copies, if you keep fewer copies of your data on S3, the charging is less. And of course in the notes, all the details are given, literally details about the dollars and cents. You can figure out where you stand. That's all I have for this module. Thank you very much.