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.