In an IT context, KVM stands for keyboard, video and mouse. A KVM switch is basic electronic switch that provides a quick and easy way to use a single keyboard, video and mouse to control multiple devices.
KVM switches are commonly used by those who want to switch between one or more devices/systems set up at their home or office and don’t want to deal with the cables and clutter of a second keyboard, monitor and mouse. Another common application for KVM switches is at datacenters and server farms where it is necessary to periodically access each server individually for maintenance and upgrades.
KVM can also stand for kernel-based virtual machine. The Kernel-based Virtual Machine is free, open source virtualization software for Linux based on the Intel VT-X and AMD-V hardware virtualization extensions and a custom version of QEMU. KVM is instantiated as kvm.ko, a loadable kernel module that provides the core virtualization infrastructure and processor-specific modules that permit full hardware emulation in order to boot most PC operating systems without modifications.
The major advantage of KVM is that you can have multiple virtual machines that are running unmodified Linux or Windows or Mac OS X images. Furthermore, each virtual machine has private virtualized hardware including a network card, disk drive, graphics adapter and so forth.
The kernel of KVM is included in mainline Linux in all versions above 2.6.20.