ElectrEm is an emulator of the Acorn Electron, an 8bit microcomputer first launched in 1983 that was once the fourth best selling in the UK market. Although sold as compatible with the BBC Micro, the only shared component is the 6502 CPU. All other compatibility is achieved through a well documented firmware interface to graphics mode setting, sound generation and keyboard/joystick input.
Although the number of programs that directly use the Electron hardware sufficiently to be incompatible with the BBC is small, the Electron is subject to a variable bus speed that makes most Electron software work at the wrong speed on the BBC and makes the implementation of an emulation based on an existing BBC emulator or almost any other 6502 emulation code impractical if not impossible.
ElectrEm strives for first class ease of use. On the whole it is enough to point the emulator towards a tape or disc image and it will automatically configure the emulated hardware into a compatible form and then launch the program contained in the image.
The first phase of significant work on ElectrEm occurred between 2000 and 2002. That codebase is now known as "ElectrEm Classic" and was ported to Windows, DOS and Linux supporting a wide array of graphics output libraries including Allegro, SVGALib, GGI, SDL and DirectX. For personal reasons a break in development occurred.
By 2002 several problems with the architectural design of the emulator had become apparent. So a brand new codebase, currently named "ElectrEm Future", was begun. It is effectively a reimplementation so lacks a lot of the testing and still lacks some of the functionality of the older code. Nevertheless it offers better OS integration than the previous version, better modularity of code and so is pushing towards a more accurate emulation which is easier to optimise.
There is a mailing list attached to a Yahoo! Group for Electron and ElectrEm related chat - i.e. bugs, bug fixes, announcements of new releases, which games work, which don't, where to get them, etc, etc.
It's also the easiest way to know when a new beta becomes available. See this page on Yahoo! for details.
The 8 Bit Acorn Webring