OSv (stylized OS) is a cloud computing focused computer operating system released on September 16, 2013. It is a special-purpose operating system built to run as a guest on top of a virtual machine, thus it does not include drivers for bare-metal hardware. It is a slim, bare bones unikernel including just the functionality necessary to run Java or POSIX applications. For this reason, it does not support a notion of users (it's not a multiuser system) or processes - everything runs in the kernel address space. Using a single address space removes some of the time-consuming operations associated with context switching. It uses large amounts of code from the FreeBSD operating system, in particular the network stack and the ZFS file system. OSv can be managed using a REST Management API and an optional command line interface written in Lua.