x86 virtualization in JavaScript, running in your browser and NodeJS (mirror)

Join.Gong b81df77801 fix queue selected (#869) 1 week ago
.cargo 853bf477cc minor fixes 2 years ago
.github 7ab26e175e upgrade CI image to ubuntu-22.04 10 months ago
bios 497f618cab Merge branch 'wasm' into master 2 years ago
docs 17a6b3b4e9 docs: how it works, networking with state images and profiling 5 months ago
examples 0c17fea221 Remove serial0-output-line, fix stack overflow in serial debug output (fix #741) 6 months ago
gen 38a103c56b Implement HADDPS instruction so that KolibriOS Raytracing demo can run. (#837) 1 month ago
lib b96665285b Allow sharing files with guest using UI, even with custom profile (#702) 10 months ago
src b81df77801 fix queue selected (#869) 1 week ago
tests d1cf93e2ed Add redox (#301) 6 months ago
tools bbac74d589 Fix Locale Configuration In Debian Dockerfile (#850) 1 month ago
.editorconfig 0766da0fa0 Only use vga color linked list for small changes 5 years ago
.gitattributes 741e09569a Add .gitattributes 2 years ago
.gitignore 497f618cab Merge branch 'wasm' into master 2 years ago
.jshint.json d5c9b29942 Upgrade jshint 2 years ago
.rustfmt.toml 75dbbbc55a Update rustfmt 2 years ago
Cargo.toml 5d72ffa84c cargo: update test profile 1 year ago
LICENSE fe74b8d332 Fix license 2 years ago
Makefile 9ecee545c8 fix spurious make error 6 months ago
Readme.md e5866f6031 Update Readme.md (#838) 1 week ago
debug.html 53098adc5c Delete src/browser/lib.js, move remaining code to lib.js 8 months ago
index.html 00d2b35222 Allow capturing network traffic and loading it in wireshark 10 months ago
v86.css c4843cedbf Update xterm.js 2 years ago


or #v86 on irc.libera.chat

v86 emulates an x86-compatible CPU and hardware. Machine code is translated to WebAssembly modules at runtime in order to achieve decent performance. Here's a list of emulated hardware:

  • An x86-compatible CPU. The instruction set is around Pentium 4 level, including full SSE2 support. Some features are missing, in particular:
    • Task gates, far calls in protected mode
    • Some 16 bit protected mode features
    • Single stepping (trap flag, debug registers)
    • Some exceptions, especially floating point and SSE
    • Multicore
    • 64-bit extensions
  • A floating point unit (FPU). Calculations are done using the Berkeley SoftFloat library and therefore should be precise (but slow). Trigonometric and log functions are emulated using 64-bit floats and may be less precise. Not all FPU exceptions are supported.
  • A floppy disk controller (8272A).
  • An 8042 Keyboard Controller, PS2. With mouse support.
  • An 8254 Programmable Interval Timer (PIT).
  • An 8259 Programmable Interrupt Controller (PIC).
  • Partial APIC support.
  • A CMOS Real Time Clock (RTC).
  • A generic VGA card with SVGA support and Bochs VBE Extensions.
  • A PCI bus. This one is partly incomplete and not used by every device.
  • An IDE disk controller.
  • An NE2000 (8390) PCI network card.
  • A virtio filesystem.
  • A SoundBlaster 16 sound card.


Arch LinuxDamn Small LinuxBuildroot LinuxReactOSWindows 2000Windows 98Windows 95Windows 1.01MS-DOSFreeDOSFreeBSDOpenBSD9frontHaikuOberonKolibriOSQNXAndroid 1.6-r2Android 4.4SkiftOS


How it worksNetworkingArchlinux guest setupWindows 2000/XP guest setup9p filesystemLinux rootfs on 9pProfiling


Here's an overview of the operating systems supported in v86:

  • Linux works pretty well. 64-bit kernels are not supported.
    • Damn Small Linux (2.4 Kernel) works.
    • All tested versions of TinyCore work.
    • Buildroot can be used to build a minimal image. humphd/browser-vm and darin755/browser-buildroot have some useful scripts for building one.
    • SkiffOS (based on Buildroot) can cross-compile a custom image.
    • Archlinux works. See archlinux.md for building an image.
    • Debian works. An image can be built from a Dockerfile, see tools/docker/debian/.
    • Ubuntu works up to the latest version that supported i386 (16.04 LTS or 18.04 LTS for some variants).
    • Alpine Linux works.
  • ReactOS works.
  • FreeDOS, Windows 1.01 and MS-DOS run very well.
  • KolibriOS works.
  • Haiku works.
  • Android x86 1.6-r2 works if one selects VESA mode at the boot prompt. Newer versions may work if compiled without SSE3. See #224.
  • Windows 1, 3.x, 95, 98, ME, NT and 2000 work reasonably well.
    • In Windows 2000 and higher the PC type has to be changed from ACPI PC to Standard PC
    • There are some known boot issues (#250, #433, #507, #555, #620, #645)
  • Windows XP, Vista and 8 work under certain conditions (see #86, #208)
  • Many hobby operating systems work.
  • 9front works.
  • Plan 9 doesn't work.
  • QNX works.
  • OS/2 doesn't work.
  • FreeBSD works.
  • OpenBSD works with a specific boot configuration. At the boot> prompt type boot -c, then at the UKC> prompt disable mpbios and exit.
  • NetBSD works only with a custom kernel, see #350.
  • SerenityOS works.

You can get some infos on the disk images here: https://github.com/copy/images.

How to build, run and embed?

You need:

  • make
  • Rust with the wasm32-unknown-unknown target
  • A version of clang compatible with Rust
  • java (for Closure Compiler, not necessary when using debug.html)
  • nodejs (a recent version is required, v16.11.1 is known to be working)
  • To run tests: nasm, gdb, qemu-system, gcc, libc-i386 and rustfmt

See tools/docker/test-image/Dockerfile for a full setup on Debian or WSL.

  • Run make to build the debug build (at debug.html).
  • Run make all to build the optimized build (at index.html).
  • ROM and disk images are loaded via XHR, so if you want to try out index.html locally, make sure to serve it from a local webserver. You can use make run to serve the files using Python's http module.
  • If you only want to embed v86 in a webpage you can use libv86.js. For usage, check out the examples. You can download it from the release section.

Alternatively, to build using docker

  • If you have docker installed, you can run the whole system inside a container.
  • See tools/docker/exec to find Dockerfile required for this.
  • You can run docker build -f tools/docker/exec/Dockerfile -t v86:alpine-3.14 . from the root directory to generate docker image.
  • Then you can simply run docker run -it -p 8000:8000 v86:alpine-3.14 to start the server.
  • Check localhost:8000 for hosted server.


The disk images for testing are not included in this repository. You can download them directly from the website using:

wget -P images/ https://k.copy.sh/{linux.iso,linux4.iso,buildroot-bzimage.bin,openbsd-floppy.img,kolibri.img,windows101.img,os8.img,freedos722.img}

Run all tests: make jshint rustfmt kvm-unit-test nasmtests nasmtests-force-jit expect-tests jitpagingtests qemutests rust-test tests

See tests/Readme.md for more infos.

API examples

Using v86 for your own purposes is as easy as:

var emulator = new V86Starter({
    screen_container: document.getElementById("screen_container"),
    bios: {
        url: "../../bios/seabios.bin",
    vga_bios: {
        url: "../../bios/vgabios.bin",
    cdrom: {
        url: "../../images/linux.iso",
    autostart: true,

See starter.js.


v86 is distributed under the terms of the Simplified BSD License, see LICENSE. The following third-party dependencies are included in the repository under their own licenses:


More questions?

Shoot me an email to copy@copy.sh. Please report bugs on GitHub.


Fabian Hemmer (https://copy.sh/, copy@copy.sh)