Emularity (also called "The Emularity") is a loader designed to be used with a family of in-browser emulation systems. It is meant to ease the use of in-browser-based javascript emulation by handling housekeeping functions, making it easy to embed emulators in your website, blogs, intranet or local filesystem. The components of each aspect of the software being emulated (including the .js emulator, the program files, and operating system) can be pulled from local filesystems or through URLs.

Emularity downloads the files you specify (with a Progress screen that shows both emulator logos and what is being loaded), arranges them to form a filesystem, constructs the necessary arguments for the emulator, and handles transitions to and from full-screen mode.

The Emularity system has been used by millions of users at the Internet Archive.

The Emulators

Currently works with two emulators:

JSMESS

JSMESS is a port of the Multi Emulator Super System (MESS) and the Multiple Arcade Machine Emulator (MAME) projects to Javascript. MESS and MAME support hundreds of different machines; producing a single javascript file which supports all of them turns out to be infeasible. Instead the JSMESS developers have split each machine out into a separate js file.

EM-DOSBox

EM-DOSBox is a port of DosBox to Javascript. DOSBox emulates an IBM PC compatible running DOS. There are two versions of this emulator, dosbox.js and dosbox-sync.js. Use the former by default, and the latter if you need the emulator to support console input, batch files, or programs that run other programs.

Known Bugs

documentation is quite poor
splash screen doesn't always fit inside the canvas
need to improve the download progress indicators
browser feature detection for volume/mute/full-screen
handling of aspect ratios, and their interaction with full-screen mode
finish API for volume/mute/full-screen requests