Showing posts with label cloud computing. Show all posts
Showing posts with label cloud computing. Show all posts

What is REST API

Posted by Tushar Bedekar

Basic Description 

The Word REST stands for Representational State Transfer which is nothing but the technology that is generally preferred to more robust simple object access protocol (SOAP) Technology. Robust because it leverages less bandwidth usage and hence more suitable for internet usage.

An API ( Application Programming Interface ) for a website or an app is a code that allows two software programs to communicate with each other. It is the program that requests the hosted services.

An API is required when we want to consume the services that are running or hosted on the other web servers rather than installing the huge redundant hardware devices as per the demand that fulfills our purpose. This can be understood by the following examples:

As we are creating the weather app for the mobile device. Now the app needs to be dynamic, that is the weather needs to change as per the environment. That we need to have some sensors to collect the data for weather. Also, there can be one approach that we install sensors at different locations across the globe for collecting the data. This will be very costly if we go like this. The second approach can be contacting some vendor/service provider that can share the required weather information.

Now as our app is ready that means we have a ready design for use and we just need some data to make the response dynamic. We can get that data from the other hosted servers dedicated for this purpose using communication interfaces such as REST API`s.

Data Format 

Now the data we receive from other serves need to have some specific format that is structured so that it can be easily understood.In case of REST API, this data format can be JSON(JavaScript Object Notation) or XML(Extensible Markup Language).

Communication Using REST API 

In Our Example here we need weather information. That may contain data such as city name, humidity level, temperature etc. Now all this data can be contained within one object or specific to one object ( instance) here that object is "weather object" which is related to whether class. As we know that each and every object has some properties such as state, behavior etc. So if we need weather data we need to first set up a connection to the specific port of the server where a particular service is running and then we need to capture the state of the object weather which is nothing but the representational state. Now, this representational state is being transferred using some communication channel called an API.The state information can be transferred in JSON or XML format.

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Types of Cloud Computing

Posted by Tushar Bedekar
Basically cloud computing is divided into 3 categories.

  • SaaS (software as a service)
  • PaaS (Platform as a service)
  • IaaS (Infrastructure as a service)

Software as a service - SaaS

SaaS s a software that is centrally hosted and managed for the end customer. It is usually based on a multi tenant architecture - a single version of the application is used for all the customers. It can be scaled to a multiple instances to ensure the best performance at all the locations. SaaS Software is typically licensed through a monthly or annual subscription.
Example :- Microsoft Office 365 is a prototypical model of SaaS. Other example are                                    Dropbox,WordPress and Amazon Kindle.

Platform as a Service - PaaS

With PaaS, you deploy your application into an application-hosting environment provided by the cloud service vendor. The developer provides the application, and the PaaS vendor provides the ability to deploy and run it. This frees developers from infrastructure management, allowing them to focus strictly on development.

Infrastructure as a Service - IaaS  

An IaaS cloud vendor runs and manages server farms running virtualization software, enabling you to create VMs (Virtual Machines) that run on the vendor’s infrastructure. Depending on the vendor, you can create a VM running Windows or Linux and install anything you want on it.
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What is Cloud Computing

Posted by Tushar Bedekar

Cloud Computing: Meaning and Implications.

Cloud computing represents a new revolutionary organizing principle for computing. It is new because of its scale and revolutionary because of its consequences. For instance, it liberates individual and institutions from owning a computing device or infrastructure but still make them capable of accessing computing resources. Today an developer can avail and access and meet computational needs from outside by way of cloud computing services and  without building or buying her own computing infrastructure.  

Cloud computing builds resources in large and supply in retail. For example, a user in cyber center is availing a service such as email- Gmail or Hotmail. Cloud computing separates developing computing from its consumption. In doing so it has created an entire spectrum of industries - 
  • Infrastructure as a service-  business of building and supplying basic computational resources such as computing, storage -
  • Platform as a service-  business of providing computing resources and environment for building and operating services

  • Software- as a service - business of developing and offering software

Cloud Computing: Physical Meaning

Cloud computing is new service paradigm. It refers to the provision of computational resources on demand via a network.In its practical and most widely known form this network is the Internet. However cloud can be developed and deployed on network which not necessarily the Internet. When done that way, cloud may resemble a kind of VPN.. The central idea behind cloud computing model is derived and can be can be compared to the supply of electricity and gas, or the provision of telephone, television and postal services. All of these services are presented to the users in a simple way that is easy to understand without the users needing to know how the services are provided. In other words,  benefits are for users and burden is for the provider.  The details workings of a system behind a service always remains a mystery for the end user.

Example: A letter posted in Bangalore will reach its destination say in Gujarat using postal network consisting of many points where it gets bagged( putting into a bag meant for a destination) and debugged ( when a letter is removed from a bag when it has to reach a different destination).  

However, postal service seeker is not concerned with these detail. Her only one objective is to send/receive a letter. The behind the scene mechanism always remains mystery but she is given a simple interface A post office to send her letter. This simplified view is called an abstraction. Similarly, cloud computing offers computer application developers and users an abstract view of services that simplifies and ignores much of the details and inner workings. A provider's offering of abstracted Internet services is often called as Cloud. 

Cloud Computing In a Nutshell:-

Cloud computing is a multi-perspective and multi-dimensional phenomenon.  The answer to the question “What is cloud computing “is depends on who is answering that question. However, the most widely known perspective on cloud computing projects it as a service delivery model that uses the Internet as the common interface to reach its beneficiary. The beneficiary of cloud computing service could be a citizen, consumer or a learner depending on whether it is used by a government, business or university. When applied to business, cloud computing assumes a sharper form and becomes service composition, delivery and consumption model. 

The categories of services that a business can deliver using cloud computing is currently limited to three (although some are on the horizon) and is known as “service models”. The different purposes for which an enterprise can build a cloud computing infrastructure and ways in which it can  determine its scope and access is described in cloud “deployment models” and at,present there are four ways in which this can be done. The cloud computing phenomenon because of its huge scope and deep potential to participate in virtually all human affairs – banking to education to health and others is tackling all important and perpetually concerned issues such as cloud security and trans-border business aspects. In sum cloud computing is a living and affecting lives of many. 

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