In 2011, we saw, according to IDC’s latest Worldwide Quarterly Server Tracker, factory revenue in the worldwide server market grew for Linux while it shrank for Windows and Unix. What I find especially interesting about this is that IDC doesn’t measure when you or your company install Linux on a bare-metal server or a re-purposed server, which is historically how Linux got into companies, but only servers with Linux already pre-installed.

That means more and more customers are asking IBM, HP and Dell, the big three server hardware vendors, for Linux on their hardware. Specifically, IDC found that “Linux server demand was positively impacted by high performance computing (HPC) and cloud infrastructure deployments, as hardware revenue improved 2.2% year over year in 4Q11 to $2.6 billion. Linux servers now represent 18.4% of all server revenue, up 1.7 points when compared with the fourth quarter of 2010.

Its competitors? “Windows server demand subsided slightly in 4Q11 as hardware revenue decreased 1.5% year over year. Quarterly revenue of $6.5 billion for Windows servers represented 45.8% of overall quarterly factory revenue, up 2.6 points over the prior year’s quarter.”

As has long been the case, Unix is the server operating system that really got knocked around. “Unix servers experienced a revenue decline of 10.7% year over year to $3.4 billion representing 24.2% of quarterly server revenue for the quarter. IBM grew Unix server revenue 2.5% year-over-year and gained 7.9 points of Unix server market share when compared with the fourth quarter of 2010.”

Linux servers keep growing, Windows & Unix keep shrinking. More >