This may be more of a myth than a notion, Gartner analyst John Enck said during a session comparing the two operating systems at the Gartner Symposium ITxpo here.
"We're just not seeing any sort of motion away from Windows towards Linux," Enck said.
Enck said that by 2011, users who do migrate to Linux will do so because of the quality of applications built on top of the operating systems, from software distributors like Red Hat and Novell, as well as the variety of new-fangled distros such as Debian, Gentoo and Ubuntu.
"We think that these are significant platforms that are going to really be able to maintain a significant place in the enterprise going forward," Enck said.
Moreover, Microsoft and Linux will continue to scarf new license market share, making the race an interesting one to watch.
Something has to give, of course: Unix will remain an entrenched player at the high-end thanks to superior scalability and a large install base, but it is limping along in picking up new license revenues.
That pretty much leaves Microsoft and Linux to continue to duke it out in the quest for new market share, thanks to x86 chip architecture innovations, such as distributed utilities and scalability from Intel and AMD.
Gartner expects x86 machines push further into supporting business applications in the enterprise, markets traditionally dominated by RISC-based Unix servers.
This will mean Linux and Windows machines won't be largely relegated to edge and Web servers, which could open a glut of new revenue opportunities.
With so many similar opportunities, where will Windows and Linux differentiate?
Gartner analyst George Weiss said one of the areas where either OS might separate from the pack is virtualization management, which includes policy-based automation, virtual hard disk, lifecycle management, live migration and real-time resource allocation.
Such functionality is already available in the Xen Hypervisor, a thin layer of software that can host multiple operating systems.
Shortly after its Longhorn server software arrives in 2007 or 2008, Microsoft plans to offer a hypervisor to compete with the Xen Hypervisor that will ship with Red Hat's and Novell's SuSe Linux systems.
That's where the next Windows vs. Linux battle will play out, Enck and Weiss said, because hypervisors offer so many more opportunities for businesses to consolidate servers and cut costs.
"This is a crucial area for Microsoft and the Linux world distributors to hone in on... and may be the decisive factor about where users are leaning in one direction or another depending on what kind of capabilities they can get out of that operating system and serve their environment," Weiss said.