Virtualization is where we have computers that appear to be real physical computers, however are actually just a computer that as been created inside another computer. Essentially it is an imaginary machine inside a real machine, but for almost all purposes is just as real as the real.
Today you will hear a lot about servers being virtual servers; however desktop machines could be virtual computers also.
When you have virtual machines (servers or desktops, you will have one main physical machine, although you may not be able to actually see the machine if it is on the cloud through services like AWS or Azure. Then on that machine you will use a virtualization program to create a virtual machine or machines. The three most common virtualization programs are VMware, Virtual Box and Hyper-V.
Once the virtual machine is created it will have a CPU and memory that are actually using part of the real machine’s CPU and memory. The same for a hard drive which is the virtual drive is actually a drive on the physical machine’s hard drive.
You will find many organizations now having moved many of their servers to being virtual servers on a larger single machine. One advantage is that you can keep everything working as it was before on one machine without having to reconfigure lots of programs as they appear still as on separate machines. Secondly machines have gotten much larger in capabilities and having one physical machine reduces the investment in equipment and also in the costs of the required environment such as A/C costs, amount of square footage required for a secured room for them, etc. If you put them on the cloud the first one applies as it still appears as if local machine and cloud costs if managed correctly should be cheaper, and the cloud provider does not need separate physical machines for each user. If ion the cloud the environment costs are just part of your subscription fee.
Desktops can be virtualized also. These are sometimes called network PCs or similar. You don’t need to but all the equipment just a limited box that has a processor to start from and limited memory and ability to work from network. The processing, memory and disk space is kept on a virtual server that can have numerous virtual desktops using it. Works just like a normal desktop for the user, except if the network is down they can do nothing. It preserves everything just like their desktop used to, the screen looks the same and it works the same. If more memory or disk space is needed the IT administrator just increases what is assigned to that desktop on the server. It will use less space that the old traditional desk top did. From the IT administrator view point it means most things just need administered from one physical location and easier to make sure all machines backed up regularly.
Using virtual machines whether locally at your location or through the cloud is the future we are entering now.