List several cloud computing companies, talk about what cloud services they provide, and give one or two cases to illustrate the application of cloud computing.

1, the industry likes to compare hydropower to cloud computing, that is to say, there is no need to buy power generation equipment and water intake equipment, as long as the lines and pipelines are laid and used as much as possible at any time.

2. Many anti-virus software can be called cloud computing. When installing, some virus libraries and Trojan libraries will be downloaded locally, but if there is suspicious code, you can submit it, and it will have more virus libraries to help you find it in the cloud, and finally return the results.

3. Many emails can also be called cloud computing projects. It can be used for free, paid and paid. You don't need to know where the server is, and you don't need to set too many settings.

4. Some vendors provide online document editing and saving, which is also a kind of cloud computing.

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Features:

1, virtualization technology. Virtualization breaks the boundaries between time and space and is the most important feature of cloud computing. Virtualization technology includes application virtualization and resource virtualization.

2. Dynamic scalability. Cloud computing has efficient computing power. Adding cloud computing function to the original server can quickly improve the computing speed, and finally realize the dynamic expansion of virtualization level and achieve the purpose of application expansion.

3. High flexibility. At present, most IT resources, software and hardware in the market support virtualization, such as storage network, operating system and software and hardware development features.