Coming Soon to Firefox: Quick Background Updates

It's been predicted for some time now that Google's Chrome browser would catch up with Firefox in market share before year's end, and it looks like that may finally be happening.
As of Thursday, the two browsers were more or less matched in share, with Firefox at 25.41 percent and Chrome at 25.34 percent of the global market, according to StatCounter. On several days over the past few weeks, in fact, Chrome has already pulled ahead a few times, only inching back slightly afterward.
That doesn't appear to be having any kind of a dampening effect on Firefox users, however, who have apparently been upgrading to version 8 of the software with gusto. Less than a week after Firefox 8's Nov. 8 release, in fact, the new version already accounted for a full 35 percent of all Firefox traffic, analytics firm Chitika reported on Wednesday.
Meanwhile, Mozilla's Firefox team is continuing its push with new features for the popular browser. I've already written about the new Firefox 9 beta versions and the browser's current memory “diet”, but just the other day Firefox engineer Ehsan Akhgari described a new effort now under way to make Firefox updates take place in the background.

'This Is Clearly Less Than Ideal'

“The goal of my project is to minimize the amount of time it takes for Firefox to launch after downloading an update,” wrote Akhgari in a blog post on Mozilla's Future of Firefox site.

Currently, Firefox updates are downloaded in the background and then staged in a directory until the next time the software starts up. When that next time comes, Firefox launches an updater program and applies the update on top of the existing installation, with a progress bar to show the user how much time remains.
Only when the update process is finished will the updater program restart Firefox, causing users to have to wait until that's done. “This is clearly less than ideal,” Akhgari wrote.

'Swapping Directories Is Really Fast'

With the new process--explained in detail on the MozillaWiki--it will be much less visible to users.
Specifically, when Firefox finishes downloading an update, it will launch the updater program in the background and apply the update in a brand-new directory that's completely separate from the existing installation directory. There, it will stage an entire updated version of Firefox rather than just the update itself, Akhgari notes.

So, the next time Firefox starts up, the existing installation can then simply be swapped with the new, updated one without any progress bar or interruption for users.
“Swapping the directories, unlike the actual process of applying the update, is really fast,” Akhgari explained. “We are effectively moving the cost of applying the update to right after the update has been downloaded while the browser is running. This leaves only the really fast copy operation to be performed the next time that the browser starts up.”

Time for Testing

The new background updates are still in the testing stages, and Mozilla isn't yet sure in which version they'll make their debut. In the meantime, though, the team welcomes testing help, and has set up a temporary channel called Ash in which the latest builds can be downloaded. Directions for testing are spelled out at the end of Akhgari's blog.