Instruction set virtualization emulates the instruction set of one processor type by hardware, firmware and/or software running on a different processor type. It can apply emulation to individual programs or on entire virtual machines. A user who owns software developed to run on one chip type would be able to use it on a server with incompatible chips. The second type emulates the entire system, allowing an OS built for the emulated chip type to boot up and run software as if it were running on a physical machine of the emulated architecture.