Cloud computing refers of using the computer resources whether hardware or software that are made available as a service over internet (or any other network). The term got its name from the fact that a cloud like symbol is used for representing the complex infrastructure it is made up of in the system diagrams. The remote services are entrusted by the cloud computing and may involve the data, computation and software of the end users.
There are a number of types of cloud computing available for public sector namely:
1. IaaS (infrastructure as a service)
2. PaaS (platform as a service)
3. SaaS (software as a service)
4. NaaS (network as a service)
5. STaaS (storage as a service)
6. SECaaS (security as a service)
7. DaaS (data as a service)
8. DBaaS (database as a service)
9. TEaaS (test environment as a service)
10.APIaaS (API as a service)
11.BaaS (backend as a service)
– In a business, the software is used as a service through which the access to the application and its data bases is provided to the users.
– The infrastructure as well as the platform on which the application executes is managed by the cloud providers.
– The third type of the cloud computing i.e., SaaS in some cases is called as the on–demand software.
– The cost of this is decided on the basis of pay–per–use.
– SaaS applications are priced through a subscription fees by the SaaS providers.
– The cloud – based applications can be accessed by the users through a web browser or some mobile application.
– The data of the users and business software are stored appropriately on various remote servers.
– It has been claimed by the proponents that with cloud computing lets the enterprises run their web applications at a much faster speed with improved ability of managing the application and reduced need of maintenance.
– Cloud computing achieves economies of scale and coherence by the sharing of the resources.
– Two broad concepts lie at the foundation of cloud computing namely:
1. Shared services and
2. Converged infrastructure
– Cloud computing has similarities with the following systems:
1. Autonomic computing
2. Grid computing
3. Client – server model
4. Mainframe computer
5. Utility computing
6. Peer – to – peer
7. Cloud gaming
Characteristics of Cloud Computing
Below mentioned are the characteristics of the cloud computing:
1. Agility: The ability of the user by virtue of which the technological infrastructure process can be re–provisioned is improved.
2. API or application programming interface: REST–based APIs are commonly used by the cloud computing systems. This makes the interaction between the machines and the cloud software feasible.
3. Cost: Cloud computing reduces the cost by a huge margin. Actually what happens is that in public cloud computing model the capital expenditure gets converted in to what is called the operational expenditure. A third – party provides the infrastructure for the whole system and thus there is no need of purchasing for infrequent tasks.
4. Device: The users can access the cloud applications via a web browser.
5. Location independence: The users can access the applications from anywhere.
6. Virtualization: This technology lets the storage devices and servers to be share-able and increase their utilization. This also makes it easy for the applications to migrate from one server to another.
7. Multitenancy: This characteristic lets the resources and costs to be shared across a large number of users. This in turn affects the following:
– Peak load capacity
– Utilization and efficiency
8. Reliability: It is improved because of the usage of the multiple redundant sites.
9. Scalability and elasticity: On demand provisioning.
Apart from these, 5 essential characteristics have been defined by the NIST:
1. On demand self service
2. Broad network access
3. Resource pooling
4. Rapid elasticity
5. Measured service