Cloud Computing

Cloud computing is also called on demand computing. Cloud computing enables companies to consume resources just like electricity. No need to build it in house just consume and pay for that.
What is 5-3-2 Rule?

#5:

There are five characteristic of cloud computing

1. On-Demand and Self Service. 2. Ubiquitous Network access (Exist everywhere). 3. Location transparent resource pooling. 4. Rapid Elasticity (Companies can increase or decrease use of resources as per demand). 5. Measured Service with pay per use. These characteristic were introduced by National Institute of Standards and Technology (NIST).

#3:

Three services of cloud computing are three delivery methods. 1. Software as a Service. 2. Platform as a Service 3. Infrastructure as a Service.

2#:

Two Deployment models are Private and Public Deployment model. While NIST lists down four deployment method but other two are derivation from first two, main deployment models are only two. As name indicate public computing means for public use and private computing means for private use.


5-3-2 is easily understandable, easy to use in common conversation.

What do you mean by SaaS?

SaaS stands for Software as a Service. Means no hardware required, no installation headach, you need only internet to use a software, you just login and use it. Gmail is the best example. Software will be hosted on internet, so user no need to buy or pay for maintenance.

Suppose you are going to start your own business for that you need an email. If start from scratch you need to develop or buy a software for mailing while the other way is you can use already build software gmail. For your mailing server you need to buy a server and need maintain that software and configure that too.

How SaaS Works?

SaaS works on the base of subscriptions you need to pay according to time and space if you are using for 1 hour daily and you have bought 1 GB space than you have to pay for that only if you use extra space or beyond your time limit than you have to pay more for that.

Example of SaaS:

Gmail, Salesforce, Bank, WebEx, Drop Box, Google Docs

What do you mean by PaaS?

Platform as a Service. PaaS means user can use platform as a service to develop his applications. He no need to worry about hardware required for that platform on which he wants to develop application. Google App Engine is the best example of PaaS?

Target Audience:

Developers

Benefits:

You no need to worry about hardware, maintenance of server, operating system and runtime to build the application. All the Services will provide by platform provider.

How PaaS Works?

Suppose you want to write a code but don’t want to take tension of IDE hardware required for that IDE so you go to a PaaS vendor.

Example:

Google App Engine,Heroku, IBM Bluemix, Red Hat’s OpenShift.

What do you mean by IaaS?

The lowest level of Cloud services is Iaas. You no need to worry to buy or maintain server infrastructure. You can get server from IaaS vendor. User can choose his own OS,own runtime and application code.

Example of IaaS : 

Amazon Web Services.

Target Audience: 

IT Admins

Benefits:

IaaS saves your time and headache that maintaining hardware infrastructure. You can get the servers from IaaS vendor.

How IaaS works?

IaaS works using virtual environments. IaaS vendor have data centers which have multiple servers. And every server have multiple virtual machine running which is allotted to customers. User can decide his OS and runtime. Although his is working on a virtual machine but he will never know that he is working on virtual machine.

Example:

AWS, HPCloud, CloudSigma

Graphical representation of SAAS, PAAS, IAAS.