What is Cloud Computing
Cloud computing means providing computer related technologies through the internet as a service.
It is like your home electrical system. You use it when you want and only pay for what you used. It is same in the cloud you only pay for the resources you consumed and you do not pay for the resources you don’t use, which called pay as you go in cloud computing.
Consumer access the cloud service using a simple web browser and there is hardly need of special software to access services. Which Mean you can access the cloud from anywhere and any device with any platform.
Different Types of Clouds and What They Mean
Cloud can be categorized to different types depends on the purpose and the Ownership.
In a private cloud model, the cloud is owned by the organization itself and they act as both the provider and the consumer. Typically Organization uses it for their own ICT Requirements. Cloud platforms such as vCloud, Openstack and Apache Cloudstack allows organizations to build their own private cloud.
Public Cloud is owned by the cloud service provider. Open to the general public and not limited to a single organization. Anyone can get the services from the public cloud even a single person.
Examples - Amazon Web Services, Microsoft Azure, Rackspace Cloud, Google Cloud Platform.
A combination of two or more cloud types, called as hybrid cloud. For example organization which owns a private cloud may provide some of the services to the other organization and the general public.
Cloud Services are provided based on three categories. Software as Service(SAAS), Platform as a Service(PAAS) and Infrastructure as service(IAAS)
Software as a Service (on-demand software)
Software as a service is Delivering Application Softwares through the internet instead of installing on local computers. Users can access the Applications From Various client Devices by using a Web browser or software interface provided by the service provider. Also Called as on-demand software.
Good Example for this is Microsoft Office 365. With Office 365 you can use microsoft office software through the internet without having to install on your local computer. This way you don't have to spend money on buying office suite at one time, instead you use office software through the cloud and only pay for when you uses.
Examples for SAAS - Microsoft Office 365, Google Drive, Gmail, Salesforce.
Platform as service
Platform as service or PAAS Provides Software platform for the developers to run their applications. Platform may refer to Operating System, Web Servers, Software runtime environment and so on.
Example for PAAS - Google App Engine
Infrastructure as a Service
Infrastructure as services refer to Running Organization's IT Infrastructure at service provider's premises. This includes Servers, Computer hardwares, Network Routers, Firewalls and etc.
Examples for IAAS - Amazon Web Services(AWS), Microsoft Azure, Rackspace Cloud.
What is Cloud computing? Other Definitions.
The truth is there is no single definition to explain what is cloud computing is. Some even say no “one really don’t know what exactly the cloud is”. Having said that below is some other definitions on what is cloud computing?
"Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. This cloud model is composed of five essential characteristics, three service models, and four deployment models."
NIST definition of cloud computing
Services provided by the internet network, which is used by customers for running their Information Technologies (IT).
International Journal of Cloud Applications and Computing, By Hong Cai, Shadi Aljawarneh