Firefox 4 debuts: The last kitchen sink release

By Cade Metz in San Francisco • Get more from this author

Posted in Applications, 22nd March 2011 18:06 GMT

Mozilla has officially released Firefox 4, the latest version of its popular open-source browser, after nearly a year of development.

Available for download on Windows, Linux, and Mac, Firefox 4 offers added JavaScript performance through a new extension to Mozilla's SpiderMonkey engine, hardware acceleration on all platforms, new tools for organizing and navigating browser tabs, a service for syncing browser settings across multiple machines, and a revamped interface. "We focused a lot on speed," Mozilla vice presidents of products Jay Sullivan tells The Register.

"But beyond raw speed, we're speeding up the way users flow through the internet. We're speeding up your real online life, improving startup time, tab switching, and scrolling – stuff beyond the benchmarks."

Sullivan also emphasizes that unlike Microsoft's Internet Explorer 9, which made its official debut last week, Firefox 4 runs on Windows XP. "This is really important for so many people," he says, citing studies indicating that between 40 and 50 per cent of the web users are still on this aging Microsoft OS. "We need to provide updates to security, privacy, and innovations to those folks as well."

Microsoft is (overly) quick to provide a counter argument. On Monday evening, in anticipation of the release of Firefox 4, Redmond sent a canned statement to journalists defending it decision to offer Internet Explorer 9 only on Windows Vista and Windows 7. "The developer community has been vocal that they want to push the web forward," the statement read.

"The browser is only as good as the operating system it runs on and a browser running on a ten year old operating system tethers the web to the past. The time has come to stop focusing on lowest common denominator, and to really push what’s possible with innovations like full hardware acceleration. Customers can tell the difference when they see it.”

Firefox 4 does offer hardware acceleration on Windows XP, but it's limited. Compositing is accelerated through Direct3D, but web content is not accelerated. On Windows Vista and Windows 7, Firefox 4 accelerates content through Direct2D. It should also be pointed out that unlike IE, Firefox 4 supports WebGL, which provides hardware accelerated 3D inside the browser, mapping JavaScript to the OpenGL desktop graphics interface.

Mozilla also provides hardware acceleration on Linux and Mac. Content acceleration is handled through XRender on Linux and through Quartz on Mac, while compositing is handled via OpenGL on both platforms. Mozilla acknowledges that Quartz uses the CPU rather than the GPU. QuartzGL, which provides GPU acceleration through Quartz 2D API, is not supported). But Quzrtz GL isn't supported by any browser, and no, you can't get IE9 on a Mac. Or Linux.

On Monday, Mozilla also unfurled a release candidate for an Android incarnation of Firefox 4. And Sullivan says this version is slated to officially arrive "in the next couple of weeks". Like the desktop incarnations of the browser, Firefox 4 for Android offers the Mozilla's Firefox Sync service, which lets you synchronize your browser setting across multiple devices.

Originally known as Firefox Weave, Sync has long been available as a Firefox plug-in, and it's the basis for Firefox Home, the Mozilla iPhone application that lets you access your Firefox data on Apple's holy handheld (which will run Firefox itself). On Firefox 4, it lets you synchronize bookmarks, history, "Awesome Bar" data, passwords, form-fill data, and open tabs.

On the desktop, Mozilla's new browser also offers Panorama, a means of better organizing your browser tabs. letting you sort tabs like playing cards on a table. And it includes what Mozilla calls "App Tabs", letting you create compact icons on the browser toolbar for frequently used web applications, such as Twitter or Gmail.

At the heart of the browser, Mozilla offers a new extension to its JavaScript engine known as JaegerMonkey (aka JagerMonkey). This operates in tandem with the TraceMonkey extension that debuted with Firefox 3.5 in June 2009. TraceMonkey speeds JavaScript performance by detecting code loops and converting them to assembly language. With Firefox 4, TraceMonkey still looks to convert loops, but when it can't, JaegerMonkey converts entire methods into assembly. This new method JIT (just in time) compiler uses the Nitro assembler from Apple’s open source WebKit project.

Mozilla is claiming better performance than its competitors – including IE9, Chrome, and Safari – on its own Kracken benchmark (naturally) as well as Facebook's JSGameBench.

Firefox went through 12 betas and two release candidates, and this is the last incarnation of the popular open source browser to receive such as an extended development and test period. In response to Google, which now delivers a new version of its Chrome browser every six to eight weeks, Mozilla is moving Firefox to a quarterly release schedule, planning to offer three more new versions of the browser before the end of the year.

"The motivation here is that as we build stuff, we want to get it to people as fast as possible," Sullivan says. "If you look at Firefox 4, all of its tools have been done for a while. But we created this relatively large unit to ship with. Now, when we get stuff done, we need to get it in people's hands."

It's yet to be seen whether Mozilla can actually deliver new browsers at this pace. Working on a year to two-year release schedule, it has a history of delays, including a roughly three month delay on Firefox 4. But the move to quarterly release schedule is welcome. And Firefox 4 is here.