Cloud computing (cloud computing), also known as virtual servers, computing is computing model using computer technology and development based on the Internet.
The term "cloud" here is the metaphorical speech only the Internet (based on how the layout of it in computer network diagrams) and as an associate of the complexity of the infrastructure contained in it.
The definition of Cloud Computing
In this computing model, all likely related to information technology are offered in the form of "service", allowing the user to access the services from a supplier somewhere "in the cloud" that do not need to have the knowledge, experience in technology that , nor need attention to the infrastructure that serves it. According to the IEEE Computer Society Organization "It's model in which information is stored in servers on the Internet and will only be stored temporarily in the client computers, including personal computers, entertainment centers, computers in business, means of handheld computers,...". Cloud computing is the overall concept includes concepts such as Web 2.0, software services and other issues appeared recently, featured technology trends, in which the subject matter is primarily based on the Internet for satisfying the computing needs of users. For example, Google AppEngine service offers online business applications usually can access from a web browser, while the software and data are stored on the server.
The term cloud computing launched mid-2007 not to talk about a trend, which is essential to the direction of the information infrastructure, which had been held from those years.  This concept can be interpreted in a simple way: the giant computing resources such as software, the service, and the services will be located on the virtual server (the cloud) on the Internet instead of in the Office and home computers (on the ground) for people to connect and use whenever they need to. With the services available on the Internet, businesses do not have to buy and maintain hundreds, even thousands of computers as well as software. They just need to focus on their own areas of business by another worry of infrastructure and information technology instead of them. Google, by nature, is among the advocates of virtual server computing most actively by their business activities based on the distribution of the cloud (virtual server). The majority of Internet users have approached the cloud services like e-mail, photo albums, and digital maps.
The term cloud appears derived from the application grid computing (grid computing) in the 1980s, followed by the on-demand computing (utility computing) and software services (SaaS).
Grid computing on the move a load of work (workload) to the location of the computing resources needed to use. A grid is a group of servers on which major tasks are broken down into small tasks to run in parallel, was viewed as a virtual server.
With cloud computing resources, such as servers can be shaped or small cut from background hardware infrastructure and become ready to accomplish the mission, support the environment not the grid computing as three-layer Web running traditional applications or Web 2.0 applications.
Summary of characteristics
Mobile computing is often confused with grid computing ("a form of distributed computing in which exist a ' virtual supercomputer ', is the inclusion of a cluster of computer networks, the computer link software, coordinated activities to execute the large tasks"), on-demand computing (utility computing) ("block of the computer resources , such as the processor and memory, as a similar number of monitoring services with the works of traditional infrastructure such as electricity or the phone network "),  and Autonomic Computing (autonomic computing) (" computer systems capable of self-management ").  in fact many of your cloud computing systems today are equipped with mesh systems, autonomous and features have been marketing like the utilities, but cloud computing can be seen as a natural next step from the grid-pattern according to the needs.  many successful cloud architectures have no infrastructure or at least set rules or the marketing system in which peer networks like BitTorrent and Skype and volunteer computing like SETI @ home.
Public infrastructure of cloud computing today is the combination of reliable services delivered through data centers (data center) was built on the server with the different levels of virtualization technologies. These services can be accessed from anywhere in the world, in which the cloud is a single access point for all the computers that have the customer's needs. The commercial services need to meet the quality of service requirements from customers and often given the extent of the service agreement (Service level agreement).  The open standard (Open standard) and open source software (open source software) also contributes to the development of mobile computing.
3. The characteristics
So, to be able to deploy an application (for example a Web page), you must go buy/rent one or more servers (server), then put the server in the data center (data center), the cloud now allows you simplified the process of purchase/rent. You just raised its requirements, the system will automatically pick up the free (free) resources to meet your requirements. Therefore, including a few basic benefits of cloud computing are as follows:
Using computational resources dynamically (Dynamic computing resources): The resources allocated to business what business wants an immediate way. Instead of the business must calculate whether to extend or not, must invest the server business then just ask "Hey, cloud, we need additional resources equivalent to 3.0 GHz CPU, 128 GB RAM..." and the cloud will seek resources to provide for you.
Reduce costs: enterprises will have the ability to cut costs to purchase, sale, installation and maintenance resources. Apparently instead of having to send a specialist to go buy a server, the server settings, server maintenance then you don't need to do anything in addition to determine the exact needs and the resources required. Too convenient!.
Reduce complexity in the structure of the business: businesses produce goods which must have both an IT professionals to operate, the server maintenance is too expensive. If this process were the securities business will only focus on the production of the goods his expertise and reduce the complexity of the structure.
Increased ability to use computational resources: one of the questions the headaches of the investment resources (e.g. servers) is how long it will run out of depreciation, I like the investment with interest whether or not there be outdated about technology or not. When using the resources on the cloud, you don't have to care about this anymore.