Two years after its official debut, Windows 7 will finally become the leading operating system around the world by the end of 2011, says a report out today from Gartner.

Microsoft

Before the year is over, the current flavor of Windows is expected to show up on 42 percent of all PCs globally. Further, Gartner's latest research shows that 94 percent of all new computers shipped this year will come with Windows 7, leading to almost 635 million new Windows 7 PCs in 2011 alone.

Recent stats from Net Applications found that Windows XP was finally losing some of its dominance but that Windows 7 still currently holds only around 28 percent of the overall OS market.

Many organizations have been slow to migrate to Windows 7. Rollouts are expected to ramp up this year, but not necessarily across the board.

"Steady improvements in IT budgets in 2010 and 2011 are helping to accelerate the deployment of Windows 7 in enterprise markets in the U.S. and Asia/Pacific," Gartner research director Annette Jump said in a statement. "However, the economic uncertainties in Western Europe, political instability in selected Middle East and Africa (MEA) countries, and the economic slowdown in Japan after the earthquake and tsunami in March 2011 will likely lead to slightly late and slow deployment for Windows 7 across those regions."

Windows 7 may be the last Microsoft OS that gets installed directly for all corporate employees via large-scale deployments, Gartner said it believes. Down the road, many companies may instead opt to use virtualization and cloud computing to deliver Windows desktops to their users.

Meanwhile, the Mac OS has inched up in popularity over the past year, notes Gartner. Apple's operating system is expected to ship on 4.5 percent of personal computers this year, up from 4 percent in 2010. By 2015, the Mac OS may hit 5.2 percent of all PCs. Though Apple has a strong hold in North America and Western Europe, the fastest growth is likely to be seen in certain emerging markets.

"The adoption of Mac PCs and Mac OS is a result of Apple's ability to grow well above the market average in the last 12 to 24 months, thanks to its ease of use from the user interface (UI) point of view and ease of integration with other Apple devices, such as the iPhone, iPad, iPod Touch and the existing Apple ecosystem of applications and programs," Jump said.

Eyeing other operating systems, Linux is expected to remain a niche player over the next several years with an overall share of less than 2 percent. Google's Chrome OS and Android and HP's WebOS are also unlikely to cause much of a dent in the PC arena due to application compatibility issues and the huge array of Windows-based software used by the corporate crowd.

However, next year may see more "OS-agnostic" applications, forecasts Gartner, which could provide a boost to Chrome OS and Android in the consumer PC market.