Microsoft's Australian MD Steve Vamos has revealed the latest line in its battle against Linux: Linux, it seems, is not open source.

As the concept of open-source takes hold, not only with fanatical individuals but with governments across the world who like the idea of a freely accessible source code, Microsoft is attempting to drive a wedge between the idea of open source and the reality of Linux.

Stressing that Linux is "not free", Vamos said open source is a development methodology that should not be confused with the commercial nature of Linux distributions.

"Open source is not [solely] Linux," Vamos said. "That's probably a little bit out there in the sense that Linux has been developed using open source development models. I guess what I'm saying is that when you talk about open source - the way open source is being described - is that people generally talk about it as being Linux and I think you really need to look at the two separately."

Vamos said Linux has a place, and that "it is already doing some good work for customers" but separates it from open source because "the open source debate tends to be one that's about philosophy and views". And then he gets to the punch: "When you talk about Linux versus Windows, you're talking about which operating system is the best value for money and fit for purpose. That's a very basic decision customers can make if they have the information available to them."

If it's a case of two operating systems face-to-face, Microsoft would win hands down, since it is the undisputed master of the dark arts of promotion and publicity. But this pesky philosophical difference is giving Linux a leg-up and the software giant now appears determined to break one free of the other.

He went on: "There's a good quote from Red Hat that says, 'yes we are based on open source, but that doesn't mean it's free'. Quite frankly if we lose to Linux because our customers say it's better value for money, tough luck for us. Those that provide open source, like the Red Hats, need to provide commercial services and extensions. They'll need to invest and that's a commercial activity."

And on: "The choice between open source and commercial is really about selecting products and technology that is the best value for money and best suits the purposes."

And on: "For those of you engrossed in the decision about is it open source or is it commercial software, I'd probably respectfully suggest that you're spending a lot of time on issue number four or five in the pecking order."

And on: "I get disturbed when people say open source is the way to go, because it's more secure. It's food for thought that security advisories for Linux and Unix-based operating systems were greater during 2003 than those for Windows and also Linux vulnerabilities are growing faster than Microsoft vulnerabilities."

Of course, all of this could be laughed off if it wasn't for the fact that he actually has a good point. Last week, Red Hat announced that it would no longer support Red Hat Linux 9. Instead, it is directing all users to its Red Hat Enterprise Linux Platform.

And what's the difference between the two? Why, one is free and the other isn't. Guess which is which. Red Hat also announced yesterday that it is producing a desktop version that it will aim directly at enterprise customers - a move that it knows full well puts it directly in the way of Microsoft.

Only time will tell whether Red Hat's growing confidence has caused it to face up to Microsoft too soon, but one thing is for certain - by appearing to cut ties with the open source movement, it has given Microsoft a new and potentially ruinous line of attack.

Does Microsoft have a point here? What is open source and is Linux moving away from it - especially with big vendors like IBM and HP getting involved? Or is this just another effort by Microsoft to confuse the issue? Tell us what you think on the discussion forum.