Firefox 15 beta for Windows (download), Mac (download), and Linux (download), brings the memory management improvements developed in Mozilla's MemShrink project one step closer to the stable version of the browser, this time focusing on long browser sessions and how add-ons affect Firefox. Nicholas Nethercote, a developer at Mozilla, wrote on his blog that Firefox 15 beta is likely to be "drastically" faster than Firefox 14, in some cases.
The changes in the beta focus on memory leaks, which Nethercote describes as occurring when a program allocates some of your computer's memory to use, but then fails to release it when finished with its task. He wrote back in January 2012 that memory leaks in add-ons, from the most popular Firefox add-ons to the simplest ones to those developed by corporations, all contribute to instability in the browser. While many of those add-ons have been fixed since then, he points out that the browser must be able to handle add-ons that still leak.
"We have confirmed, via in-house testing and from real-world telemetry data, that [Firefox 15 changes from the MemShrink research] prevents the vast majority of leaks that occur in existing add-ons," he wrote.
The blog post announcing the new beta said that Firefox 15 beta also introduces people to built-in PDF support, a feature that Google Chrome has had for a while; support for version 3 of Google's SPDY networking protocol; and native support for the Opus audio codec, an open source format which offers better compression than MP3, Ogg, or AAC.
People running Firefox for Android 15 beta (download) on tablets will see a dramatic shift, as the new tablet interface for the browser debuts on the beta channel. It's been available in Firefox for Android Aurora for a few weeks, and features a design similar to the new Firefox for Android.
The installer for Firefox for Android will detect if you're using a phone or tablet, and install the proper interface without any additional input required.
The Android beta also gets the ability to switch to a site's desktop view from the Menu; swipe to close tabs; and search in-page. You can now pause, resume, cancel, or retry a download from the Download Manager; toggle which data to clear from Settings; and import your bookmarks and history from the default Android browser.
Firefox for Android beta continues to support many of the under-the-hood features of the desktop version, including the new Opus and SPDY v3.