There are two possible definitions of Virtual Desktop:
- In the case of a single PC, Virtual Desktop indicates the possibility for the user to have more desktops at his disposal (intended as workspace displayed on the monitor), from which he can access different configurations based on the desktop. Examples: Virtual Desktops could be organized in order to work with different typologies of applications (graphics, music, video, office, etc.); single Virtual Desktops on the PC could be also used to better organize one’s resources like files.
- In the case of Virtual Desktop Infrastructures (VDI) we indicate a single ‘host’ or virtual ‘machine’ hosted in the Virtualization Infrastructure.
The second case is the one we are interested in and it is generally known as ‘Virtual Machine’.
A Virtual Machine in essentially an emulation of a physical machine (so it is virtual, then, not real) whose virtual computational resources (typically virtual CPU, virtual memory, virtual disk and virtual net) are emulated by a software layer that is run only on a real hardware, which is typically a set of computational, storage and net resources (in the easier case these features are all included in one single physical machine as, in example, a server or a powerful workstation).
In the above image we see how real hardware components, like servers, storages and networks are used by the Virtualization Infrastructure (typically a software) which enables the following creation and management of multiple Virtual Machines. They are, then, provided with an operating system and a set of applications that will be used from the system users.
Operating systems installed on Virtual Machines can be ‘Server’ type, or ‘Desktop’ type, allowing the access to one or more users. It is common to talk about Virtual Desktop in the case of type ‘Desktop’ system operators.
Not being Virtual Machines physical machines, it is not possible to connect classical input-output peripheral devices like mouses, keyboards and monitors. These are usually connected to the so called Endpoint which, through connection protocols, allows the user (and also input/output peripheral devices) to interact with the Virtual Machine often in an indistinguishable way, so the user is convinced he is using a normal PC.