At the end of last week, the Mozilla Foundation publicly voiced its concerns about certain restrictions that Microsoft is imposing on its new Windows RT operating system – the version of Windows 8 designed and optimised for ARM-based devices. Microsoft’s plan is for Internet Explorer 10 to be the only browser on Windows RT that can operate in both the new Metro and ‘classic’ Desktop environments.

Mozilla’s complaints have not gone unnoticed outside of the tech community. GigaLaw.com picked up news from The Hill that US Senate Judiciary Committee staffers intend to review the allegations made by Mozilla – and also by Google – that Microsoft’s browser policy for these devices is anti-competitive. An aide to the Chair of the Antitrust Subcommittee, Senator Herb Kohl, confirmed the Committee's plans to look into the concerns, although there are no indications as yet that anything resembling a full antitrust investigation will be launched against Microsoft.

There may well be incredulity at the idea that Microsoft - which effectively has zero share of the tablet market, alongside Apple's dominant iPad, and even the range of slow-selling Android tablets out there - could be held accountable for antitrust violations in this context. But remember that antitrust legislation is in place to prevent anti-competitive behaviour; there is no pre-requisite for a monopoly of any kind to exist for antitrust violations to be demonstrable.

Lawyers acting for Mozilla and Google would likely contend that Microsoft's tablet market share is irrelevant here in any case - the issue relates specifically to browser market share, and they would probably assert that in restricting the capabilities of third-party browsers on Windows RT, Microsoft is seeking to unfairly promote Internet Explorer on RT systems, as a means to safeguard its browser usage on those devices, in reaction to the downward trend of its global share of the browser market.

Windows RT focuses its user experience almost exclusively on the Metro environment, with only a few selected programs - including ARM-optimised versions of Office - able to run on the Desktop. While browsers such as Mozilla’s Firefox and Google Chrome will be available within the default Metro user experience on Windows RT, Metro apps have some restrictions that do not exist on Desktop programs – plug-ins such as Flash won’t be available in Metro web browsers, for example.

Mozilla’s position – shared by Google – is that this gives Internet Explorer an unfair advantage on Windows RT devices. In their own words, this state of affairs “restricts user choice, reduces competition and chills innovation”, and they believe that Microsoft is “allowing only IE to perform the advanced functions of a modern Web browser” on such devices.

Microsoft does not plan any such browser limitations for other versions of its new operating system. Windows 8 and Windows 8 Pro devices, running on non-ARM systems, will include the Metro user experience and its associated apps, but will also be able to run other software – including legacy Windows applications – without restrictions via the Desktop environment.



Image via Mozilla