bochs: The Open Source IA-32 Emulation Project (Home Page)
Bochs is a highly portable open source IA-32 (x86) PC emulator written in C , that runs on most popular platforms. It includes emulation of the Intel x86 CPU, common I/O devices, and a custom BIOS. Currently, bochs can be compiled to emulate a 386, 486 or Pentium CPU. Bochs is capable of running most Operating Systems inside the emulation including Linux, Windows® 95, DOS, and recently Windows® NT 4.