Mozilla has long been planning a browser split into multiple processes. The project promises a few benefits from it: the browser should become more stable, where the possibility of a failed plug-in doesn't bring the whole browser down. Moreover, dividing up the processes makes better use of the newest multicore CPUs and can improve performance. The modified process model also touches security, where some processes can run at a lower priority.

Mozilla was contemplating the solution even before Google's multi-process Chrome browser was announced, according to Mozilla developer Benjamin Smedberg in his blog. Under Smedberg's leadership the project has gotten a name: Electrolysis.

Chris Jones has developed an .ogg video that shows the first results of what will probably be four phases of development. In it, a Firefox process starts and spawns a subsequent process, gecko-iframe, which draws the webpages to the screen. To prove the point, the kill -9 gecko-iframe command (simulating a crash) immediately kills the process, the content disappears, but the browser keeps running.

Because development work has just begun on Electrolysis, don't expect to see the new feature until after Firefox 3.5, which is soon to be released.