Sun Microsystems CEO Jonathan Schwartz has blunted whatever public niceties existed between his company and Microsoft with a revealing attack on Redmond's lawsuit threats around open source software.

In his post, Schwartz recounts struggles to deal with defectors from Sun's Solaris operating system to the open source Linux. "Our computer business had failed to keep pace with the rest of the industry - which meant our volume systems looked expensive," he writes. "In combination, and with a poor track record of supporting Solaris off of Sun hardware, we gave customers one choice - leave Sun. Many did. Those were the dark days."

Those upfront statements already prove rare for a public company's CEO. Schwartz, however, went on to charge even more sacred ground.

With business down and customers leaving, we had more than a few choices at our disposal. We were invited by one company to sue the beneficiaries of open source. We declined. We could join another and sue our customers. That seemed suicidal. We were offered the choice to scuttle Solaris, and resell someone else's operating system. We declined. And we were encouraged to innovate by developers and customers who wanted Sun around, who saw the value we delivered through true systems engineering.

We're guessing SCO was the company that wanted to sue open source. The second one wanting to sue customers proves trickier - Microsoft perhaps? And the last must be Red Hat and other open source chums, hoping to wipe Solaris.

This prelude, while interesting, may leave some wanting to know the point of Schwartz's exercise. Why the recap on Solaris's woes?

Well, Schwartz used the setup to deliver a response to Microsoft's recent threats to sue open source software makers and maybe even its own customers.

"You would be wise to listen to the customers you're threatening to sue - they can leave you, especially if you give them motivation," Schwartz tells Microsoft. "Remember, they wouldn't be motivated unless your products were somehow missing the mark."

More than attacking Microsoft, Schwartz seems to be trying to ingratiate Sun with open source developers. He wants to present Sun as a major open source force with your best interests at heart. It's an interesting way to make use of Microsoft's gaffe.

Of course, not all members of the open source crowd have swallowed Schwartz's line. One commenter on Schwartz's blog writes,

Jonathan, Ballmer and Gates can certainly use a few reality checks, but your vision of the world does as well. If you compare Microsoft's market capitalization and earnings growth to Sun's over the last years, it's quite obvious that what Sun is doing is not working. Sure, you get a lot of brownie points from the Slashdot community for all the open source handwaving, but this is not how you grow a company. From where non-insiders like myself stand, your choice to innovate and not sue was born out of necessity: you simply didn't have the cash to do anything else. As for the supremacy of Java, it happened way before you open-sourced the JDK, and your choice of the GPL made this brilliant move one that is completely inconsequential (ask mobile software companies what they think of a GPL JDK). Yes, Sun has done a good job at trying to reinvent itself and attempting to innovate. You're still alive, congratulations for that. But you haven't grown, you keep following and copying software ideas from your competitors (Microsoft, Google and Apple for the most part) and most of the software you back up (NetBeans, Glassfish, Looking Glass and more recently, JavaFX) are being completely ignored by the industry.

Ouch. ®