Perhaps no innovation in information technology history, more technology than ever before. Hardware is available at the same time, maximizing the capacity of whatever hardware is available-virtualization has changed the way information technology is deployed at both the enterprise and the consumer level. 

Without the scaling capabilities of virtualization, many of the cloud-based services we take for granted today, it would be impossible, or at least cost prohibitive, to achieve. Without virtualization, there might not be an Amazon, Google, Dropbox, OneDrive, or Spotify. I know it is important to know and understand the terminology and technology behind virtualization, if for no other reason than to know how information technology is implemented and deployed in today's world. Here are 20 virtualization terms and concepts elaborating the technology's fundamental concepts and how it works.

Application virtualization 

Software technology that allows an application to run in a virtualized environment separate from the underlying operating system. Applications on virtual machine can be from the rest of the system. From the application's perspective, it is running as if it's installed on the actual operating system.

Desktop virtualization

Refers to a virtual machine that is running a desktop operating system, like Windows, Mac OS, or a version of Linux.

Failover

In virtualization terms, failover allows the virtual machine to continue operation if the host fails. The virtual machine continues to be from the last-known coherent state, rather than the current state.

Guest operating system

The operating system installed on a virtual machine. While this is the operating system, you can use the virtual machine.

Nested virtualization 

Refers to a situation where one virtual machine is hosting another virtual machine. 

Physical to virtual (P2V) 

The migration of physical hardware to a virtual machine. The migration can be server to virtual server or desktop to virtual desktop.server to virtual server or desktop to virtual desktop. 

Snapshot 

A specific image of the state of a virtual machine at a specific point in time. With the image captured, a user can return to that state whenever it is needed. 

Thin client 

A device with a minimal and lean installation of an operating system. The operating system on a server is typically hosted by a server. 

Virtual appliance 

A prebuilt, easily implemented virtual machine running preinstalled software and applications. Generally, a virtual appliance can be installed in the way of configuration by the customer. 

Virtual disk 

A virtual storage device that looks like a virtual machine or even a physical device as a piece of storage hardware, such as a hard drive or NAS device. 

Host machine 

The hardware, or potentially another virtual machine, running the operating system that supports the primary virtual machine.

Hypervisor

The thin layer of operational software that provides the supporting infrastructure for virtualization. This software allows the virtual machine to communicate with the host hardware and any connected peripherals, such as printers, storage devices, and networks.

Infrastructure as a service (IaaS)

A service that provides the infrastructure for virtual machines and virtual servers. Because it is a service, the underlying hardware and virtualization software.

Virtual machine 

Software that is designed to emulate a piece of hardware, including servers, desktops, hard drives, printers, and networks. 

Virtual machine template 

A specific virtual machine that can be replicated when necessary for deployment to users. It's a snapshot of a virtual machine before a user interacts with it. 

Virtual server 

A virtual machine designed to emulate a server system. Several virtual servers can be on one physical server, saving costs and maximizing hardware usage. 

Virtual software emulation 

A virtual machine designed to emulate specific software, including an operating system, desktop environment, or application. 

Virtualization 

The general concept of emulating physical hardware with software, which can save the cost of acquiring additional hardware. 

Zero client 

A device that is even leaner than a thin client. Typically, zero client runs an embedded, proprietary operating system without access to local storage. It is used to connect to remote virtual desktops.

Virtual hardware emulation 

A virtual machine that emulates a specific piece of physical hardware, including equipment like printers, hard drives, and network adapters. To other devices and virtual machines, the emulation appears and reacts just as the physical hardware would.