Mozilla and Google have hit back at Microsoft over what they consider to be restrictive browser settings within the Windows on ARM version of the upcoming Windows 8 OS.
In a Wednesday blog post, Harvey Anderson, Mozilla's general counsel, argued that "Windows on ARM - as currently designed - restricts user choice, reduces competition and chills innovation."
Microsoft will release a version of its OS - dubbed Windows RT - that is optimized for ARM processors. Like the other versions of Windows 8, it will include two environments: the classic Windows interface and the more Windows Phone-esque Metro style option.
According to Mozilla's Anderson, however, "Windows on ARM prohibits any browser except for Internet Explorer from running in the privileged 'Windows Classic' environment."
"In practice, this means that only Internet Explorer will be able to perform many of the advanced computing functions vital to modern browsers in terms of speed, stability, and security to which users have grown accustomed," Anderson wrote. "Given that IE can run in Windows on ARM, there is no technical reason to conclude other browsers can't do the same."
Anderson said the topic is important because while ARM chipsets are currently used primarily in phones and tablets "in the future ARM will be significant on the PC hardware platform as well."
Google did not immediately respond to a request for comment, but in a statement provided to CNET, the company said it shares Mozilla's concerns.
"We've always welcomed innovation in the browser space across all platforms and strongly believe that having great competitors makes us all work harder," Google told CNET. "In the end, consumers and developers benefit the most from robust competition."
Anderson suggested that the move could have antitrust implications.
"If Windows on ARM is simply another version of Windows on new hardware, it also runs afoul of the EC browser choice commitments and seems to represent the very behavior the DOJ-Microsoft settlement sought to prohibit," he wrote.
Back in 2010, Microsoft was required by European officials to roll out a "browser ballot" on its Windows OS, in order to provide users with a choice of browser beyond Internet Explorer. The decision came out of a 2009 complaint that said Microsoft violated European antitrust law by bundling IE with Windows.
Microsoft did not immediately respond to a request for comment.
For more, see Microsoft: All You Need to Know About Windows 8 on ARM as well as Windows on ARM: 3 Big Questions. Also check out PCMag's hands on with the Windows 8 consumer preview and the slideshow below.
For more from Chloe, follow her on Twitter @ChloeAlbanesius.
