Bochs is a portable x86 PC emulation software package that emulates enough of the x86 CPU, related AT hardware, and BIOS to run Windows, Linux, *BSD, Minix, and other OS's, all on your workstation.

Bochs is a highly portable open source IA-32 (x86) PC emulator written in C++, that runs on most popular platforms.

Bochs includes emulation of the Intel x86 CPU, a custom BIOS and common I/O devices. Currently, Bochs can be compiled to emulate a 386, 486, Pentium/PentiumII/PentiumIII/Pentium4 or x86-64 CPU including optional SSEx, MMX, and 3DNow! instructions.

Bochs is capable of running most Operating Systems inside the emulation including Linux, Windows 95, DOS, and Windows NT 4. Bochs was written by Kevin Lawton and is currently maintained by this project.

Bochs can be compiled and used in a variety of modes, some which are still in development. The 'typical' use of Bochs is to provide complete x86 PC emulation, including the x86 processor, hardware devices, and memory.

This allows you to run OSes and software within the emulator on your workstation, much like you have a machine inside of a machine. For instance, let's say your workstation is a Unix/X11 workstation, but you want to run Win95 applications.

Bochs will allow you to run Win 95 and associated software on your Unix/X11 workstation, displaying a window on your workstation, simulating a monitor on a PC.

What's New in This Release: [ read full changelog ]

CPU and internal debugger:
· VMX: Implemented TPR shadow VMEXIT
· Bugfixes for CPU emulation correctness (mostly for VMX support).
· Bugfixes and updates for Bochs internal debugger
· On SMP system stepN command now affects only current processor

Memory:
· Bugfixes for > 32-bit physical address space.
· Allow to emulate more physical memory than host actually could or would like to allocate. For more details look for new .bochsrc 'memory' option.

Cleanup configure options:
· All paging related options now will be automatically determined according to --enable-cpu-level option. Related configure options
· --enable-global-pages, --enable-large-pages,
· --enable-pae, --enable-mtrr
· are deprecated now. Only 1G paging option still remaining unchanged.
· Deprecate --enable-daz configure option. Denormals-are-zeros MXCSR control will be enabled automatically iff SSE2 is supported (like in hardware).
· Deprecate --enable-vme configure option, now it will be supported iff CPU_LEVEL >= 5 (like in hardware).

I/O Devices:
· Bugfixes for 8254 PIT, VGA, Cirrus-Logic SVGA, USB UCHI

SF patches applied:
· [2817840] Make old_callback static by Mark Marshall
· [2874004] fix for VMWRITE instruction by Roberto Paleari
· [2873999] fix CS segment type during fast syscall invocation by Roberto Paleari
· [2864389] Debugger gui maximize on startup by Thomas Nilsen
· [2817868] Rework loops in the memory code by Mark Marshall
· [2812948] PIT bug by Derek
· these S.F. bugs were closed/fixed
· [2833504] GUI debugger bug-about GDT display
· [2872244] BIOS writes not allowed value to MTRR MSR causing #GP
· [2885383] SDL GUI memory leak
· [2872290] compilation in AIX5.3 ML10 failes
· [2867904] crash with cirrus bx_vga_c::mem_write
· [2851495] BIOS PCI returns with INT flag = 0
· [2860333] vista 64 guest STOP 109 (GDT modification)
· [2849745] disassembler bug for 3DNow and SSE opcodes
· [1066748] Wrong registers values after #RESET, #INIT
· [2836893] Regression: Windows XP installer unable to format harddrive
· [2812239] VMX: VM-Exit: Incorrect instruction length on software int
· [2814130] bx_debug lex/yacc files incorrectly generated
· [2813199] MP Tables Missing From BIOS
· [2824093] VMX exception bug
· [2811909] VMX : CS Access-rights Type.Accessed stays 0
· [2810571] Compile Errors on OSX
· [2823749] GCC regression or VM_EXIT RDMSR/WRMSR bug
· [2815929] Vista/XP64 unnecessary panic
· [2803519] Wrong example in man page bochsrc
· these S.F. feature requests were closed/implemented
· [422766] Large Memory configurations
· [1311287] Idea for a better GUI
· [455971] USB support
· [615363] debugger shortcut for repeat last cmd