A variety of technologies for managing computer resources by providing a software interface, known as an "abstraction layer," between the software (operating system and applications) and the hardware. Virtualization turns "physical" RAM and storage into "logical" resources. Following are the ways virtualization is used. See logical vs. physical.Hardware VirtualizationHardware virtualization is what most computer people are referring to when they talk about virtualization. It partitions the computer's RAM into separate and isolated "virtual machines" (VMs) simulating multiple computers within one physical computer. Hardware virtualization enables multiple copies of the same or different operating systems to run in the computer and prevents the OS and its applications in one VM from interfering with the OS and applications in another VM. See virtual machine and OS virtualization.Network and Storage VirtualizationIn a network, virtualization consolidates multiple devices into a logical view so they can be managed from a single console (see network virtualization). Virtualization also enables multiple storage devices to be accessed the same way no matter their type or location (see storage virtualization).Application VirtualizationNumerous technologies fall under the umbrella of "application virtualization," some of which have been around for decades, while others are at the forefront. See application virtualization.OS VirtualizationUnder the control of one operating system, a server is split into "containers" that each handle an application. See OS virtualization.