"We figured out how to really hit our stride, and I think we’re just driving forward," Ballmer said.

Hitting that stride involved encouraging the cooperation of engineers from two huge software companies that have been isolated from one another for years and have accused each other of intellectual property theft, anticompetitive behavior, flawed product design and gross overpricing.

"I have to tell you, it wasn't all easy," McNealy said. "There were times over the last year where it just looked like we were going to centrifugal force or antibodies were going to make this thing not happen, and over the last three to six months it's really come together very nicely."

One of the most difficult parts was communicating down each company's corporate ladder what the relationship meant. "I also think the message might have gotten a little convoluted up front," he said. "We're not merging .NET and the Java Enterprise System, we're not merging Windows and Solaris, we're providing interoperability," McNealy said. "Once they got over the fact that they just needed to make the stuff play nice and could still go out and innovate and provide a different choice to the customer, I think that was a big issue in getting everybody comfortable that they could work forward while still adding value."

Ballmer described a separate problem he characterized as the nature of the engineering beast.

"It's a little bit like when the Berlin Wall came down there wasn't a lot of sort of natural contact between folks from the East and folks from the West. We probably spent three months, six months, where engineers on both sides were literally getting to know each other and learning to speak common language," Ballmer said. "As executives it was a little frustrating; we were saying, 'OK, stop with the getting to know you stuff and start with the making the progress stuff.'"

The relationship has also involved a lot of meetings between McNealy and Ballmer, meetings between Sun CTO Greg Papadopoulos and Microsoft chief software architect Bill Gates and work by Sun's Brian Sutphin and Microsoft's Hank Vigil, McNealy said.

Ballmer says the high-level meetings will continue, but "really the work is going on now between the engineers, and the work starts going on really in front of the customer as we make sure these systems knit together and allow our customers to get the kind of productivity they want out of their enterprise IT infrastructure in really quite a unique way."

To ensure they were prioritizing the right tasks, Microsoft and Sun created a technical advisory committee of 10 large enterprise customers.

"They actually put a very detailed, very precise focus list of something like 20 separate items and areas in priority order, and clearly the whole single sign-on, directory and access manager, identity management, interoperability architecture was key," McNealy said.

General Motors CTO Fred Killeen attended the joint news conference to demonstrate a proof of concept project called GM Online Desktop. GM is working on the project with support from Microsoft and Sun to integrate GM's Windows and Sun directories to simplify sign-on for its million-plus international users.

McNealy, whose colorful barbs were often aimed at Microsoft in the past, instead directed his jokes at Oracle and IBM on Friday. Nonetheless, he is still willing to beat up on Microsoft and vice versa, just with new rules. McNealy said, "[When customers ask], 'What are you guys, friends or foes or what are you?' I say we're like two boxers when we shake hands and tap gloves at the start of the fight. We're going to abide by the rules and neither of us is going to bite each other's ear off. Nobody is going to grab a chair and do the WWF clunk over the head or anything like that; we're going to play it by compatible rules."