French developer Fabrice Bellard has built a JavaScript-based x86 PC emulator capable of running Linux inside a web browser.
If you’d like to try it out, point Firefox 4 or Chrome 11 to the demo page. Keep in mind that this is just Linux, no X Window or other graphical interface, just the command line, a small C compiler and QEmacs, Bellard’s emacs clone. Still, it’s really Linux, really running in your web browser, really using JavaScript to emulate hardware.
For more info on how Bellard did it, as well as what the hardware emulator supports, see Bellard’s technical notes.
Because the hardware emulation is built around the Typed Array spec, Bellard’s Linux experiment only works in those browsers that support JavaScript typed arrays, namely Firefox 4+ and Chrome 11+ (though a bug in Chrome 12 prevents it from working in the latest version of Chrome ).
Bellard is probably best known for founding the FFMPEG project, but unlike that very useful project, Bellard says his JavaScript-based Linux experiment has no real goals. “I did it for fun,” writes Bellard, “just because newer Javascript Engines are fast enough to do complicated things.”
That said, Bellard does have a few possible uses in mind, including serving as a benchmark for JavaScript performance (how fast can your JavaScript engine boot Linux?), client-side processing and perhaps, with a few improvements, running old DOS games and other software in the browser.
this is surprisingly fast. check out the demo here. alas, the only network adapter was lo. i really wanted to view a webpage, in a vm, on a webpage.
this is even better than the crazy nested VMs folks were doing with VMware and Virtualbox.