Microsoft (NASDAQ:MSFT) enjoyed near-monopoly status with PC operating systems, web browsers, and enterprise productivity applications for many years. Although the company has lately relinquished its dominant position in the tech world to mobile devices titans such as Apple (NASDAQ:AAPL) and Google, it still makes boatloads of cash, primarily thanks to its huge user base for Windows OSs, Microsoft Office, and Windows Server technologies.

Linux is frequently touted as one of the most successful open-source projects ever. Since its release in the 90s, the versatile OS has gradually become more popular with users. With a 1.49% market share, Linux is now rated the third-most popular PC operating system after Windows and Mac OS X operating systems.

 PC Operating System

Market Share %

Windows 7

48.77

Windows XP

27.69

Windows 8

6.41

Windows 8.1

4.89

Mac OS X

3.75

Windows Vista

2.99

Linux

1.49

Others

4.01

Source: NetMarketShare

But, a January 2014 Tech Pro Research study revealed that about 11% of Windows XP users plan to shift to Linux once Microsoft withdraws support for Windows XP, with only 1% planning to switch to Mac OS X 10.9.

Source: Tech Pro Research

The findings of the study helped to reinforce two popular opinions:

  1. Microsoft's more popular Windows OSs, and not rival OSs such as Mac OS X 10.9, will continue to cannibalize their less-popular counterparts. 
  2. Windows OSs compete directly with Linux, but do not compete directly with Mac OSs.

Mac OS X is the latest Mac operating system to be released. The OS commands about 3.75% of the market, more than double Linux's share. But, if things pan out the way the Tech Pro Research predicts, Linux will end up with a 4.54% share of the overall market, while Mac OS X 10.9's share will increase marginally to 4.03%. Linux will, therefore, sport a bigger market share than Apple's most popular OS for the first time.

But, overall, Apple's Mac OS X operating systems will still hold the second slot with a combined market share of approximately 7.8%. All Windows operating systems command a combined 90.75% market share.

Mac OS X has certainly made impressive inroads as far as growing its market share. The platform had a mere 2% share of the market in 2000, which grew to 5% in 2009, and now sits just under 8%. But, that growth looks like a drop in the bucket since the platform still badly lags Windows.

IBM looks to challenge Windows dominance in servers
Last September, IBM (NYSE:IBM) announced that it was planning to invest $1 billion in Linux to drive new demand for its servers, and, presumably, help unseat Microsoft in the enterprise market. Microsoft commands 45% of the server market, but Linux has been coming on strong and now sports a 21% market share.

IBM introduced a Linux-only Power System in May 2012. The platform now boasts 2,500 open-source applications globally.

But, it appears as if the bold Linux gambit is not working out too well. IBM became the world's second-largest server vendor after HP overtook it last year. IBM saw server revenue decline a jaw-dropping 28.9% in the fourth quarter of 2013, from $5.1 billion in the previous year's comparable quarter to just $3.62 billion. That was, by far, the worst decline among major server vendors (Oracle's server revenue declined just 4.7%).

Microsoft countered IBM's move by finally announcing its own open-source servers in January, which will help drive its increasingly popular web services such as Windows Azure, Bing, and Office 365.

Microsoft's Server and Tools division is worth nearly $20 billion. Its Active Directory technology provisions and controls user access to enterprise systems, and is the linchpin that helps the company maintain its powerful grip on corporate IT.

Bottom line
Linux, not Apple's Mac OS X, will be the major beneficiary since Microsoft has finally withdrawn support for Windows XP. If the Tech Pro Research study turns out to be accurate, Windows could cede nearly 3.05% market share to Linux. However, Windows will still remain the most dominant PC and server OS, at least for the foreseeable future.

Joseph Gacinga has no position in any stocks mentioned. The Motley Fool recommends Apple. The Motley Fool owns shares of Apple, International Business Machines, and Microsoft. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.