The program bochs is a highly portable open source x86 PC emulator written in C++, and runs on most popular platforms. It includes emulation of the Intel x86 CPU, common IO devices, and a custom BIOS. Currently, bochs can be compiled to emulate a 386, 486, Pentium, Pentium PRO or AMD64 CPU. Bochs is capable of running most operating systems inside the emulation including Linux, NetBSD, Windows 95, DOS, and Windows NT 4.