Cloud Computing is a broad term that describes a broad range of services. As with other significant developments in technology, many vendors have seized the term “Cloud” and are using it for products that sit outside of the common definition.
The generally accepted definition of Cloud Computing comes from the National Institute of Standards and Technology (NIST).1 The NIST definition runs to several hundred words2 but essentially says that:
“Cloud Computing is a model for enabling 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. ”
NIST also offers up several characteristics that it sees as essential for a service to be considered “Cloud.” These characteristics include:
- On-demand self-service. The ability for an end user to sign up and receive services without the long delays that have characterized traditional IT.
- Broad network access. Ability to access the service via standard platforms (desktop, laptop, mobile etc).
- Resource pooling. Resources are pooled across multiple customers.
- Rapid elasticity. Capability can scale to cope with demand peaks.
- Measured service. Billing is metered and delivered as a utility service.
The three categories of Cloud Computing:
- Software as a Service (SaaS) is software that is deployed over the internet. With SaaS, a provider licenses an application to customers either as a service on demand, through a subscription, in a “pay-as-you-go” model, or (increasingly) at no charge when there is opportunity to generate revenue from streams other than the user, such as from advertisement or user list sales.Saas mainly used where appplications where extremely fast processing of real time data is required.
- Platform as a Service (PaaS) brings the benefits that SaaS bought for applications, but over to the software development world. PaaS can be defined as a computing platform that allows the creation of web applications quickly and easily and without the complexity of buying and maintaining the software and infrastructure underneath it
- Infrastructure as a Service (IaaS) is a way of delivering Cloud Computing infrastructure – servers, storage, network and operating systems – as an on demand service. Rather than purchasing servers, software, datacenter space or network equipment, clients instead buy those resources as a fully outsourced service on demand.
Posted from my blog with : https://www.ipragmatech.com/understanding-cloud-computing/