What's on their mind? Linux and IBM

But the reason that these two longtime foes were talking friendly was the recognition that more dangerous mutual threats loom on the horizon.

In case you've been in outer space the last decade and a half or were otherwise not paying attention, the famously rancid feud between Microsoft and Sun Microsystems has been a constant spectacle in the high-technology pantheon.

Way back when, I remember Bill Gates curtly dismissing Sun's Java technology as "just another programming language"--and that was relatively high praise, when it came to a detested rival, whose mere mention was enough to contort Gates' face into a sneer. For his part, McNealy, who delighted in publicly ridiculing his opposite number, egged the trustbusters to go after Microsoft and liked to refer to Microsoft's top duo, CEO Steve Ballmer and Chairman Gates, as "Ballmer and Butt-head."

All that bad blood has now been consigned to history --at least for the duration of the 10-year deal, in which both companies agreed to collaborate in a variety of areas. Oh, and then there's the matter of Microsoft's eye-popping $1.95 billion payment to get Sun off its back.

Though it won't be as much fun covering high tech without the two sniping at each other, it's about time that these companies grew up. For Microsoft, it took a series of poundings by courts in the United States and Europe, including a near-death experience, in which a harebrained judge wanted to break the company in two. In Sun's case, it was a stunning fall from grace, after the Internet bubble popped, and shareholder equity evaporated.

Maybe this was just what the doctor ordered to put a check on some monumentally inflated egos.

Gates, who now spends most of his working day playing around with software, has since gone the John D. Rockefeller route, rehabbing his reputation with a series of very generous charity donations to help fight the spread of disease in the industrializing world.

McNealy remains one of the industry's top showmen with his ability to do crowd-pleasing shtick, but even he realizes that Sun can't operate as a solo act anymore. That may be one reason why he installed Jonathan Schwartz as president.

Both Microsoft and Sun are keenly aware of the challenges presented by Linux and the prospect of stepped-up competition from IBM. File this one under "The enemy of my enemy is my friend."

Sun's lukewarm adoption of Linux hasn't done much to slow the defection of customers from proprietary Unix systems like Solaris to open-source alternatives. And despite Microsoft's best efforts to FUD Linux into insignificance--fear, uncertainty and doubt aren't slowing the open-source groundswell.

All the while, there's Big Blue, relishing its new role as a champion of openness, as it fights the good fight against the SCO Group lawsuit.

But beyond the public relations benefit that comes from embracing open source, IBM also wants to push the spread of Linux on commodity x86-based hardware. That would shaft both Microsoft and Sun, and open the door to more sales of expensive IBM applications like WebSphere, not to mention any attendant service contracts down the road. Can Big Blue pull it off? Keep in mind that this is an infinitely more capable company than the Keystone Cop outfit that introduced OS/2 and PS/2 on this date in 1987.

Watching the way things are developing, Ballmer and McNealy simply chose pragmatism over dogmatism. Microsoft and Sun aren't ever likely to become close pals, but each benefits from deciding to close one chapter and start another.

They know that it is time to do the mature thing and get on with business.