Cloud Computing

Introduction

Cloud computing, in computer science is a model for ubiquitous and convenient on-demand network access to a common pool of configurable computing resources (e.g., data networks , servers, storage devices, applications and services - both together and separately), which can be efficiently provided and released with minimal operating costs and / or appeals to the ISP (Androutsellis-Theotokis & Spinellis, 2004).

The term Cloud computing is inspired from the cloud symbols that we use in flowcharts and diagrams for representing Internet. Users all around the world maintain a number of data including personal details, bookmarks, music files, pictures and many more on servers that are accessible using network. The whole system of Cloud Computing is powered through virtualization technology. This technology was used in 1967, and was only limited to mainframe computers. The essence of this system was that it created a host computer known as hypervisor, which created number of virtual machines which simulates physical computers which can run software of any nature, whether they are operating systems or end-user applications. Hardware devices are installed independent of geographical location and they are responsible for data processing and storage needs. The layers of software, virtualization and management smoothens the management flow of servers (di Costanzo et al., 2009).

Consumers of cloud computing can significantly reduce the cost of information technology infrastructure (in the short and medium term) and to respond flexibly to changing computing needs, using the properties of computer elasticity cloud services (Androutsellis-Theotokis & Spinellis, 2004). According to IDC the market of public cloud computing in 2009 totaled $ 17 billion - about 5% of the total market of information technologies.



Beginning

The emergence of English-language term beginning actively pursued in 2008 in one of the thematic web conferencing. As a result of the discussion put forward a different version, one of which the term was first used cloud head of Google's Eric Schmidt in a statement and became widespread in the media (di Costanzo et al., 2009). Another popular version suggests that the term cloud computing has become a widely consumed in the U.S. since 2005 after the launch by Amazon.com Elastic Compute Cloud Project (Amazon EC2) and widely spread in the business, including information technology providers and research environment. The term “cloud” is used as a metaphor , an image based on the Internet in the diagram of computer network, or as an image of a complex infrastructure, which is hidden behind all the technical details (Weiss, 2007).

Discussion

Cloud computing is a topic that has captured the minds of IT professionals worldwide. At this point, you can find many interpretations of the term. Every major research agency has its own definitions, which are often complex, ambiguous and confusing. Let us for simplicity consider the definition proposed by the National Institute of Standards and Technology USA.

Cloud systems are called systems, characterized by (Koomey, 2007):

Dynamic allocation of resources to meet the needs of users in the computing resources and services

Emulation of the endless pool of virtual resources that are available upon request

Elasticity, namely the ...