The next major step for Internet is the "cloud computing" technology that allows individuals, corporate companies and even governments to store and process information and data at data centers through remote access. Cloud computing is an appealing computing application providing affordable access to advanced technology and allowing end users to use and process their IT infrastructure, platforms and software on a host system over a communication network. In the upcoming period, it is necessary to briefly review the general framework of cloud computing solutions and service models that frequently appear in business and social life.


Cloud Computing service is provided under four different categories. These four types of infrastructures are;

Public Cloud

In Public Cloud infrastructure, storage and other sources are offered to the public/general users by a service provider. In this model, data processing applications are run over sources on an infrastructure set up by a service provider and leased by users. This solution is suitable especially for individual use/clients. It can be claimed that this type of cloud is a low security structure compared to other cloud infrastructures. Public Cloud infrastructure provides relatively low cost solutions and is usually priced on a pay-per-use basis. It can even be offered to individual users/clients free of charge.

Private Cloud

Private Cloud infrastructure is set up and operated solely for a single institution/organization; public/third party access is not allowed. In this infrastructure architecture, the infrastructure is either stored internally in the organization or by a third party on behalf of the organization. Private Cloud infrastructure is mostly preferred by corporate/large companies and institutions that prioritize data security. Although it is costlier compared to public cloud infrastructure, it provides appealing advantages in terms of data processing investments and expenses.

Hybrid Cloud

Hybrid Cloud infrastructure is a composition of two or more of private, community or public clouds. Relatively sensitive, secret data and critical applications are stored in the private cloud within the Hybrid Cloud while applications that require less security are stored in the public cloud.

Community Cloud

Community Cloud can be defined as sharing the cloud infrastructure between several organizations from a specific community with a common purpose and common security and compliance requirements. Community Cloud can be designed as a public or private cloud.


Software as a Service, SaaS

In SaaS, multiple users are provided access to the application software hosted on the server by the service provider. Users can access and interact with the cloud applications via the Internet, using interfaces such as web browsers, without the need to install any applications on their own systems. In Saas, software is provided as a service via the Internet and the service is priced on a pay-per-use basis. In Saas model, users do not manage or monitor the infrastructure components such as network, platform, operating system and storage devices. Users are only authorized to change configuration/structure settings specific to the application provided as a service.

Platform as a Service, PaaS

The service provider delivers the users a computing platform where they can develop and run their own applications using programming languages, software databases, services and tools provided by the service provider and also provides supplementary services. In PaaS model, users are not authorized to control or manage the servers, operating systems, storage spaces and other components that make up the platform infrastructure. Users' authority is limited to adjustments related to the software transferred to the cloud and configuration settings of the platform the software runs on.

Infrastructure as a Service, IaaS

In IaaS model, users can configure processing, storage, networks and other fundamental computing resources required for running applications and install the operating system and applications required. Users are not fully authorized to manage and control the physical infrastructure. However, users can control the system at the level of storage and operating system and manage specific network components. IaaS model is referred to as"Hardware as a service, HaaS" in some sources.

Cloud computing infrastructure and business models are categorized based on being shared or specific to a single organization, being stored internally or externally, clients' authority to interact with the architectural infrastructure of the service and capacity of customization to clients' needs. These business models are assessed by users in terms of characteristics such as cost, level of user control on the system and scalability. Cloud computing should certainly be considered as a revolutionary innovation in terms of internet use, but as in all new systems, it contains challenges and disadvantages besides its advantages. Upon reviewing the infrastructure and service models briefly explained above, it can be claimed that the major problem in cloud computing is "data security". It is a matter of concern for an organization or an individual to store their information and data in a third party service provider's system. Therefore, the security risks arising out of these sharing and remotely accessed systems should be considered cautiously. In this way, each organization/individual can determine the most appropriate cloud infrastructure and service model for them and reconfigure their computing system affordably to comply with technology.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.