What is Cloud Computig...?

What is Cloud Computig...?

Cloud computing is Internet-based computing, whereby shared resources, software and
Information is provided to computers and other devices on-demand, like electricity.

The idea of cloud computing is based on a very fundamental principal of „reusability of IT capabilities'. The difference that cloud computing brings compared to traditional concepts of “grid computing”, “distributed computing”, “utility computing”, or “autonomic computing” is to broaden horizons across organizational boundaries.

Conceptual view of cloud computing

Cloud Model

Cloud Model

Cloud Computing Model :


Cloud Providers offer services that can be grouped into three categories.

1. Software as a Service (SaaS): In this model, a complete application is offered to the customer, as a service on demand. A single instance of the service runs on the cloud & multiple end users are serviced. On the customers‟ side, there is no need for upfront investment in servers or software licenses, while for the provider, the costs are lowered, since only a single application needs to be hosted & maintained. Today SaaS is offered by companies such as Google, Salesforce, Microsoft, Zoho, etc.

2. Platform as a Service (Paas): Here, a layer of software, or development environment is encapsulated & offered as a service, upon which other higher levels of service can be built. The customer has the freedom to build his own applications, which run on the provider‟s infrastructure. To meet manageability and scalability requirements of the applications, PaaS providers offer a predefined combination of OS and application servers, such as LAMP platform (Linux, Apache, MySql and PHP), restricted J2EE, Ruby etc. Google‟s App Engine, Force.com, etc are some of the popular PaaS examples.

3. Infrastructure as a Service (Iaas): IaaS provides basic storage and computing capabilities as standardized services over the network. Servers, storage systems, networking equipment, data centre space etc. are pooled and made available to handle workloads. The customer would typically deploy his own software on the infrastructure. Some common examples are Amazon, GoGrid, 3 Tera, etc.

Service Model Architetecture

Service Model Architetecture

Cloud Computing

Cloud Computing Challenging:

1. Data Protection :

2. Data Recovery and Availability :

3. Management Capabilities

4. Regulatory and Compliance Restrictions
Characteristics
The fundamental concept of cloud computing is that the computing is "in the cloud" i.e. the processing (and the related data) is not in a specified, known or static place(s). This is in opposition to where the processing takes place in one or more specific servers that are known. All the other concepts mentioned are supplementary or complementary to this concept..


Advantages

Rapid reconstitution of services
Enables availability
Provision in multiple data centers / multiple instances
Advanced honey