Yes, Sun Microsystems Inc."s new OpenSolaris really is an open-source project. And no, it"s not likely to be much like the Linux open-source project. How are they alike? Both projects will produce a production-grade version of Unix, including source code, that we"ll be able to download and use without paying for. So from where corporate IT sits, there"s lots of similarity.

But where OpenSolaris and Linux came from, how they"re licensed, how the code can be used -- that"s all different, in some cases very different. And yes, that may matter to IT after all.

Why? Competition. As in: That"s what we get the benefits of.

And not just competition between two similar operating systems, but between two very dissimilar ways of doing open-source.

Think about it. Linux was created from the ground up by Linus Torvalds and an army of programmers around the world. OpenSolaris was created by a major software vendor using a more traditional software-development process.

Linux has a large and growing installed base. OpenSolaris officially has none, though Sun"s existing Solaris customers are a good start.

Linux has propeller-head cachet and market credibility, along with billions of dollars in technical and marketing investment from companies such as IBM Corp., Red Hat Inc. and Novell Inc. OpenSolaris has one company behind it and Scott McNealy at its press conferences.

See? Dramatically different business models, both of which will be competing for the same pool of volunteer programmers to continue development, and for entrepreneurs to find ways of making money from these products.

Things get more interesting when we look at what"s usually the most boring part of a software package: the license agreements. Linux uses the popular GPL open-source license, which requires that any code that"s tightly linked with GPL-licensed code and then republished must also be GPL code. That way, everything stays open-source.

For OpenSolaris, Sun worked up its own open-source license, the Common Development and Distribution License. (Actually, the CDDL is modeled on the open-source license for the Firefox and Mozilla Web browsers.) A key feature of the CDDL is that it lets CDDL-licensed code be stitched together with non-CDDL code -- even proprietary code.

Sun"s CDDL also explicitly licenses patents, and Sun says it will include 1,670 patents that go along with OpenSolaris code. But those patents can only be used with Sun"s code. Changing the code means losing the patent protection. That"s a much more limited deal than IBM"s recent contribution of 500 patents for use with any open-source code.

Those CDDL features are heresy to Linux-style open-source advocates. And in practice, they mean it will be nearly impossible for anyone to distribute software that intermixes Linux and OpenSolaris code. The GPL and CDDL terms simply aren"t compatible.

What"s good about that? It guarantees that the OpenSolaris project won"t be a clone of Linux, no matter how similar the final products might be.

They"ll compete -- not just as operating systems, but in business model, development style and licensing approach.

Which version of open-source is better, and for what, and in what ways? That won"t be an academic argument. We"ll find out in the real world of the marketplace.

The competition won"t be pretty. It will bruise egos and force hard thinking on both sides. But out of it, we"ll get a better Linux, a better Solaris -- and a better understanding of what"s valuable in open-source.

Not bad for something we thought didn"t matter, eh?

And for you Linux partisans outraged by Sun"s open-source heresy that violates your every assumption about how it"s done, here"s a word of consolation:

Now you know how Bill Gates feels.

Frank Hayes, Computerworld"s senior news columnist, has covered IT for more than 20 years. Contact him at frank_hayes@computerworld.com.