The cloud computing can be divided into three levels depending on the services offered by providers. From the innermost level to the outermost Cloud hosting services include: Infrastructure as a Service, Platform as a Service and Software as a Service. A brief description of each of these levels:
Infrastructure as a Service (IaaS – Infrastructure as a Service)
“Infrastructure as a Service is a provision model in which an organization placed ‘outside’ the equipment used to support operations, this includes information storage, hardware, servers and networking components. Service provider. IaaS is sometimes also referred to as Hardware as a Service or HaaS “
The most obvious advantage of using a IaaS, is to transfer to the supplier management problems related to computer equipment. Another attractive advantage is the reduction of costs, as generally in the technologies associated with cloud computing, to pay only for what is consumed. Infrastructure as a Service also allows scalability virtually automatic and transparent to the consumer, leaving the responsibility to service providers.
Other features are: providing Internet connectivity, policy-based services and the provision of a virtual desktop.
Platform as a Service (PaaS – Platform as a Service)
Cloud computing and its rapid growth has required “include platforms for building and running custom applications, this concept is known as PaaS. PaaS applications are also known as on-demand Web-based or SaaS solutions.
The provider, in addition to solving problems in the hardware infrastructure, the software also handles. The client uses this kind of solutions do not need to install, configure or maintain operating systems, databases and application servers as this is provided under this platform.
A platform as a service (PaaS) solves more problems when compared to a solution that only provides an infrastructure as a service (IaaS), as it has many limitations related to the runtime environment. Among these are the type of system, the programming language (in some cases they may use libraries), the database manager.
Companies like eBay, Google, iTunes, bodhost and YouTube are among those using this model and enable new capabilities and access to new markets through the Web browser, the PaaS offering a more rapid and cost-benefit advantage application development and delivery “.
Software as a Service (SaaS – Software as a Service)
“It is the best known of the levels of cloud computing. SaaS is a software distribution model that provides customers access to it through the network (usually the Internet). Thus, they do not have to worry about the configuration, deployment and maintenance of applications, because all these tasks become the responsibility of the vendor. Distributed applications through a Software as a Service model can reach any company regardless of size or geographic location. “
This model aims to end customers using the software to meet your organization’s processes. The Software as a Service (SaaS) can be described as that application consumed over the Internet, usually through the browser, which payment is conditioned to use it and where the application logic and data reside on the platform of supplier. Examples of SaaS is Google App etc.
This technology, as usually has a gradual growth. While it is true that cloud computing is a technology that is already used for some years, yet to be fully absorbed as a central tendency in organizations.
The level of acceptance among organizations vary with the size of these. The medium and small businesses and start implementing solutions based on cloud computing, while large organizations do according to particular needs.
On the other side of the coin, there are the end users, to whom the cloud computing has changed the way they carry out their activities, improving in most cases, and allowing them to collaborate in a different way with other users on different places, access to applications that require from your web browser from virtually any computer, even from mobile devices.