Cloud Computing Primer: Cloud computing is not equal to distributed computing

Cloud computing is a very popular concept nowadays. What kind of thing is it? The following Gartner definitions have become classic and are heavily referenced: Cloud computing is "a style of computing where massively scalable it-related capabilities are Provided ' as a service ' across the Internet to ListBox external customers using Internet technologies. " That is, cloud computing is the use of Internet technology to integrate information technology capabilities into a vastly scalable way to provide services to multiple external customers as a way of computing. It's too much to say. Cloud computing is a way of computing the leasing services of users (due to the use of Internet technology) Users should be able to get services anywhere, and the rents should be very cheap (because they can be extended on a large scale).

But is there anything new about using Internet technology to connect a large number of servers to provide rental computing services? In other words: A large distributed computing network is equipped with a front-end billing server (see below), so that distributed computing becomes cloud computing? Of course not! Or else I would have painted a cloud in the diagram below that represents distributed computing.

Cloud computing has an extensible computing resource integration approach. So we can also think of cloud computing as customizing a virtual computer for users. When it comes to virtual computers, we usually think of the virtual machine model that the following diagram illustrates. The Virtual machine Monitor (VMM) is an important part of virtualization technology. The main function of VMM is to turn hardware resources into virtual resources. There are many benefits to turning hardware resources into virtual resources, and I will not elaborate on them here. Just one: sometimes virtual resources are even better than real hardware resources, as we all know that virtual memory can do much more than the amount of memory the hardware can provide. However, the virtual machines that are joined in the following diagram are still unable to integrate the cloud computing A virtual machine that is tailored to the needs of the user. The key is that the usual virtualization approach takes into account only virtual individual hardware resources. If you are just connecting a separate, individual virtual, distributed computing environment, there is still no idea of the distributed computations shown above.

The virtualization technology required for cloud computing must be virtual architecture technology. To put it simply, the connection should be considered at the level of the VMM cluster. As a result, the virtualization of hardware resources does not have to be limited to a single individual hardware resource. Figure (Source: VMware founder Dr Mendel Rosenblum) The schematic of virtual architecture is given. On such a virtual architecture, a request for hardware resources (usually a hardware interrupt, interrupt) for an application software Can not be limited to the same physical hardware resource. The virtual machines that are integrated with the virtual architecture technology can be truly tailored to the user.