1. Introduction to cloud computingCloud computing refers to applications delivered as services over the Internet hardware and software and systems in data centers that provide these services both. The hardware and software data center is what we call a cloud. Cloud computing is a relatively new concept and has become popular recently. Cloud leverages virtualization technology and the essence of cloud computing is a logical separation between different nodes, each node appears as a separate physical machine for the user. Unlike grid computing, distributed for several computers connected together to form one large logical equipment that can handle large amounts of data and computing. If Cloud computing virtualization technology enables each node appears as separate from the physical machine that allows the user to load custom software and the operating system on each node and configure custom rules for each node.
The idea of cloud computing has evolved parallel processing, distributed computing and grid computing. There is a little similarity between them, but they work differently. Although cloud computing is an emerging field of computing, the idea has been around for a few years. It is called cloud computing because there are data and applications in the "cloud" web servers. To simplify the concept, cloud computing can be simply defined as the distribution and use of applications and resources in a network environment to do their work without having to worry about the ownership and management of resources and applications network. According to the scale, cloud computing, computer resources to perform the work and its data are no longer stored in the personal computer itself, but are housed elsewhere to be accessible anywhere and anytime.
2. Comparison of technology related
2.1. Grid computing A form of distributed computing and parallel computing, in which a "super and virtual computer 'is composed of a set of networked, loosely coupled computers acting in concert to perform very large tasks
2.2. Utility computing The packaging of computer, such as computation and storage, as a measure similar to a traditional public service such as electricity service resources.
2.3. autonomic computing
Computer systems capable of self-management.
3. General mechanism
Cloud computing using information technology as a service on the network. The concept encompasses general Infrastructure as a Service (IaaS), Platform as a hardware service (PaaS) as a service (Haas) and software as a service (SaaS). It may be the possibility of renting a server or servers and run a geophysical modeling application available anywhere. It may be the ability of (S Rupley, 2009) rent a virtual server, load software on it, turn it on and off at will, or clone to meet a sudden demand workload. It can be store and protect large amounts of data that are accessible only by authorized applications and users. It can be supported by a cloud provider that sets up a platform with the ability to automatically scale in response to changes in workloads. You may be using a cloud storage to contain application, business, and personal data. And it may be the ability to use a handful of Web services to integrate photos, maps and GPS information to create a cover on client Web browsers.
In a system of cloud computing, there is a major change workload. local teams no longer have to run applications. The network of computers that make up the cloud handles them instead. In this situation demand hardware and software is reduced by the user side. Let the cloud take care of it. The only thing that local computers should be aware of is the software interface that the application will run. Today, a web browser like Mozilla Firefox and Internet Explorer 8 is widely used as an interface software in the computer system in the cloud.
The truth is that Internet users and some type of computer used in the cloud. If you have an email account with an email service based on the Web as Hotmail, Yahoo Mail or Gmail, then they had some experience with cloud computing. Instead of running a mail program on a local computer, the user can connect to a Web e-mail account remotely. The software and storage of the account does not exist on the local computer that is included in the computer service in the cloud.
4. key feature of Cloud Computing
Currently, there is no standard definition or specification for cloud computing. It may take some time to define the key characteristics of cloud computing based on practices in the field.Based on practices in the areas of service delivery and design of the solution, the following two key technologies could play a vital role in this revolutionary phase of cloud computing:
4.1. Virtualization technology
Virtualization technology works to manage how the image of the operating system, middleware, and application procreated and assigned to a physical machine or part of the server stack away. Virtualization technology can also help reuse licenses operating systems, middleware or applications software, once a subscriber service releases its cloud computing platform.
4.2. Service-oriented architecture (SOA).
A service-oriented architecture is essentially a collection of services. These services communicate with each other. Communication can imply either data or simple step could involve two or more services coordinating some activity. some means of connecting services to each other is needed. The evolution of a system or software architecture is now moving towards services-oriented, unlike several decades ago most of the application is self-cleaning and purpose of individual use. Recently, the huge growth in the availability of Internet users and Internet technology using software can now be rented. giant company like Google, Microsoft, Sun or even Amazon has this capability provides software services rather than selling the software directly to the user. SOA is a software or system architecture to address componentization, reuse, extensibility and flexibility. These all feature fundamentals is a need for companionship that are looking to reduce costs and choose to rent instead of buying.