Despite constantly downplaying the relevance of Linux and Mac OS X, because of a variety of reasons, from high Total Cost of Ownership (TCO) to security risks and inferior shipment volumes, Microsoft is well aware of the real threat to Windows represented by the open source platform and Apple's operating system. Windows itself, namely Windows XP SP2 and Windows Vista RTM have proved incapable of negatively impacting the continuously increasing adoption of Linux and OS X, but with the advent of SP3 for XP and SP1 for Vista, Microsoft has virtually managed to breathe new life into Windows.

Still, the Redmond company continues to be far away from a turning point from the perspective of what seems to be a perpetually eroding share on the operating system market. But even a certain dose of stability could help Windows, as it is undoubtedly going down from the dominant position on the market. Both Mac OS X and Linux have made consistent inroads into Windows' territory, a trend which only managed to accentuate following the availability of Windows Vista. But, at the end of July 2008, Microsoft got a little space to breathe.

According to statistics published by market analysis firm Net Applications, Windows jumped from a share of 90.89% at the end of June 2008 to 91.02% the past month. During the same period, Mac OS X dropped from 7.94% to 7.76%, while Linux increased its share at the usually modest pace from 0.80% to 0.82%, climbing the position of sixth most used operating system in the world, after XP, Vista, MacIntel, Mac OS and Windows 2000.

The release of Service Pack 3 did little to curb the constant erosion of XP's market share, especially with Microsoft having discontinued the availability of Vista's successor through the retail and OEM channels as of the end of June. XP's market share is down to 70.64% in July 2008 from 71.20% in June, while Vista has climbed to 16.93% the past month from 16.14% a couple of months ago.

The operating system market ballet offers an interesting perspective, because while it can be argued that Mac OS X and Linux are on the same front against Windows, Vista and XP form a dysfunctional pair. The fact is that Vista has no room to grow except in the space occupied by Windows XP, with Microsoft regarding this as the natural evolution of its operating system versions. Still, while applauding over 180 million sold licenses of Vista, 40 million since SP1, the current operating system seems impotent to dislodge XP, now with SP3, until Windows 7 is delivered at the end of 2009, but no later than the end of January 2010.