Cloud Computing

Cloud computing is the resource availability for computer systems over the internet whenever requested by user called "on demand". Specially data storage and computing or processing power is available in the internet and end user does not need to have hardware/software resources with in the client system like laptop, desktop, tablet or mobile device. What you all need is cloud service and internet. Then you are cloud enabled.

There are bunch of cloud  service providers (SPs) in all over the world including Microsoft as one of pioneer in the information technology industry. Amazon, Google, VMware and many other cloud service providers.

Cloud computing mainly contains three types of services such as,

IaaS  - Infrastructure as a Service

With this, cloud service provider provides the hardware infrastructure to the user as requested. Simply this is providing VMs (Virtual Machines) with OS (Operating System). End user does not need to worry about the OS licensing, upgrades, security patches and no hardware maintenance at all.  But any other software installed in the VM does not include in the IaaS unless there own utility tools. Also user must responsible for EULA of those software. Any time user can upgrade or downgrade the system using a control panel. With this option user can choose the hardware specifications,

• The OS required
• Hard disk space and type with number of partitions
• RAM
• Number of cores in CPU
• etc...

Payment can be done for usage called "Pay as you Go" or one time payment for given period called "Reserved" in Microsoft IaaS cloud services. There will be different payment methods in other SPs.

PaaS - Platform as a Service

Providing a platform to build software of piece of software is called PaaS. Here user does not even worry about the VM or OS. User will be given a development environment to built the component. For e.g. to build a database, you don't need PC and DBMS installed there. You will be given a online DBMS to connect and do your database work using supported client tools. Another example is to build Java/C#.Net code, you don't need Java or DotNet to be installed anymore. PaaS service provide you the platform to do it and deploy where you want. PaaS is very sophisticated to communicate each other. There are many PaaS services provided by cloud service providers for,

• DBMS
• Mobile App Development
• Server-less computing 
• Integration
• Analytics 

In PaaS also payment will be vary based on service and the service provider. Commonly you pay for what you used.

SaaS - Software as a Service

No Infrastructure, No platform. This is a fully completed software deployed in web which can be used as service via internet. So installation not required. There can be facility for custom configuration as user preferences or customization for user requirements. Payments are probably for number of user accounts created in the software. 

Examples for SaaS are,

• Google Apps
• Sales force dot come
• Drop Box
• Etc...