Desktop/Server Virtualization
What is "Virtualization"?
Virtualization is technology that allows you to run multiple Operating Systems with one PC or Server.
This can be done through the use of a "Hypervisor" which functions in-between the device hardware and an operating system(s).
An example of this would be: You want a new Server for your Office, you want to use it as a File Server, Database Server such as SQL, and you also wand to host your own Website directly from your location. Virtualization allows you to use one really good Server to install all 3 servers totally independent from each other. They don't even need to be the same OS, as one could be Windows Server 2016 for the File Server, Ubuntu Linux Server for SQL Database, and perhaps Red Hat Linux to run Apache Webserver.
Virtualization can also be used within an existing Operating System running like any other program.
For example, you may have an Apple Mac Laptop or PC and realize that you need a Microsoft Windows 7/8/10 Operating System to install a Windows based Program/App that is not ported for Mac. Instead of purchasing a totally separate PC with Windows on it, you run a Virtual Windows OS directly on your Mac. (This scenario actually happens a lot since the business world mostly uses PC's not Mac's)
Another example would be to run a Linux Virtual Machine within your Windows 10 OS for the purpose of having a simple PC just for a more secure web browsing experience.