Types of Services Provided by Cloud Computing

Based upon the services offered, clouds are classified in the following ways:

1. Infrastructure as a service (IaaS):

Involves offering hardware related services using the principles of cloud computing. These could include some kind of storage services (database or disk storage) or virtual servers. Leading vendors that provide Infrastructure as a service are 

Ex: Amazon EC2, Amazon S3, Rackspace Cloud Servers and Flexiscale.

2. Platform as a Service (PaaS):

Involves offering a development platform on the cloud. Platforms provided by different vendors are typically not compatible. Typical players in PaaS are 

Ex: GoogleApplicationEngine, Microsoft’s Azure, Salesforce.com force.com .

3. Software as a service (SaaS):

Includes a complete software offering on the cloud. Users can access a software application hosted by the cloud vendor on pay-per-use basis. This is a well-established sector. The pioneer in this field has been Salesforce.com offering in the online Customer Relationship Management (CRM) space.

Ex: Salesforce CRM, Google’s Gmail, Google docs, Microsoft’s Hot mail and Microsoft’s online version of office called BPOS (Business Productivity Online Standard Suite)

Types of Cloud Computing?

Cloud computing is typically classified into three ways:

1. Public Cloud

2. Private Cloud

3. Hybrid Cloud

• Public cloud: 

In Public cloud the computing infrastructure is hosted by the cloud vendor at the vendor's premises. The customer has no visibility and control over where the computing infrastructure is hosted. The computing infrastructure is shared between any organizations.

• Private cloud: 

The computing infrastructure is dedicated to a particular organization and not shared with other organizations. Some experts consider that private clouds are not real examples of cloud computing. Private clouds are more expensive and more secure when compared to public clouds.

• Hybrid cloud: 

Organizations may host critical applications on private clouds and applications with relatively less security concerns on the public cloud. The usage of both private and public clouds together is called hybrid cloud.