Firefox 3.6 due this month; next comes 'Lorentz'

Mozilla hopes to release the final version of Firefox 3.6 later this month and a stability-improving update code-named Lorentz by March as part of a revised updating strategy.

Mike Beltzner, Mozilla's director of Firefox, said Tuesday that he's pleased so far with his scrutiny of test data from the more than 1 million people using the first release candidate of Firefox 3.6, which came out late last week.

"So far we haven't found showstoppers," he said. If no more major issues are uncovered, "we're looking at releasing somewhere in the last two weeks of January," he said.

The most visible change with Firefox 3.6 is Personas, a mechanism to customize the browser's appearance with artwork, sports team logos, movie imagery, and other graphics. It had been available as a plug-in. Another change blocks third-party software from encroaching on Firefox's file system turf to increase stability. Support for a technology called the Web Open Font Format means many non-English browser users should have a faster time loading Web pages with downloadable fonts.

And perhaps most significantly given the competitive threat from Google Chrome, the new version is designed to launch and load pages faster, offer a more responsive user interface, and run Web-based JavaScript programs about 20 percent faster than the current Firefox 3.5, Mozilla said.

Under the hood, Firefox 3.6 gets support for the File interface, which can help with tasks such as uploading multiple photos and is part of the draft HTML5 standard effort. Another deeper change is running scripts asynchronously, which can help load a Web page faster by putting off some work until the high-priority chores are complete. Google and Facebook are among the sites taking advantage of the asynchronous feature, which requires Web developers support but isn't hard to add, Beltzner said.

Browser market on fire
Mozilla had hoped to release Firefox 3.6 in 2009 but gave itself a bit more time for Firefox 3.6 and 4.0. The open-source browser--used by about a quarter of Net surfers worldwide, according to Net Applications--has significantly challenged the dominant browser, Microsoft's Internet Explorer.

However, Google's Chrome is on the rise, edging past Apple's Safari in usage 15 months after its debut. Chrome, it should be noted, comes from a company borne of the Web with many cloud-computing projects such as Gmail and Google Docs, and therefore represents a qualitatively different challenge than IE and Safari, both of which came from operating system companies. Like Mozilla, Chrome is open-source software.

Mozilla has plenty of ideas in the pipeline. Next on Mozilla's agenda is an update to Firefox 3.6 code-named Lorentz, a release that embodies a new attempt to speed up the frequency of Firefox updates.

The big feature of Lorentz, which likely will get the official number of Firefox 3.6.5, is out-of-process plug-ins (OOPP), which isolate execution of Adobe Systems' Flash or Apple's Quicktime into a separate computing process from the main browser process.

The result is that when Flash programs crash--a common cause of problems in Firefox--the user is presented with an error message in a browser tab rather than a browser that completely crashes and restarts, Beltzner said.

"It's something we want to get into users' hands. It's a noninvasive change, and not a change to the interaction of the browser," Beltzner said. "We'd like to ship it as a minor update."

OOPP is a first stage of a project called Electrolysis to split the browser into separate processes. The next phase, Beltzner said, is to separate the processes of content-handling and user interface. After that, Mozilla is examining the possibility of splitting browser tabs into more separate processes, he said.

Mozilla hopes to freeze the code base for Lorentz soon, begin testing work, then potentially release a beta in early February.

"We're hoping to get the out-of-process plug-ins update executed within this quarter--probably later toward the end of this quarter," Beltzner said.

Faster release cycle?
Mozilla has been trying to speed up the frequency of Firefox releases, and Lorentz represents a new tactic in the strategy.

One tricky part of updating the browser is bringing along all the involved parties without breaking anything. That includes not just users who can be irritated or confused by changing software, but also Web developers who don't want their sites to malfunction and third-party programmers who develop browser add-ons.

Right now, Firefox proceeds more cautiously when something significant changes for these groups; new releases from, say, Firefox 3.5.6 to 3.5.7 come when bugs and security holes need fixing.

But starting with Lorentz, Mozilla hopes to release non-intrusive changes as well. The motivation for minor updates will be not just security and stability but also what Beltzner called enablement.

"If we prove the success of this model, it takes some of the pressure off releasing short cycles. We can spend more time on interactive changes and package a bunch of them together" as a major release, he said.

Roadmap update coming
The new approach likely will mean flux for work going on for versions that had been called Firefox 3.7 and 4.0, he said.

"People in their heads have bunch of features tied to those version numbers--some features with 3.7, some with 4.0. This is always a moving target. As we gain confidence we'll finish a feature in a certain timeframe, the shape of the release may change, and the release [date] may change," Beltzner said.

He and Mike Shaver, Mozilla's vice president of engineering, hope to release a new roadmap that reflects the changes, he said. What's currently called Firefox 3.7--with features including the new Jetpack add-on foundation--could arrive in beta form in the second quarter and in final form in the third quarter--but it may have a different version number, including 4.0

It may sound like moving the goalposts, but Mozilla is more concerned with updating the browser smoothly and quickly than with labeling. Ultimately, Beltzner said, the approach might, for example, accelerate the shift that had been planned for Firefox 4.0 to a refreshed user interface that devotes more real estate to content.