Although some 70 percent of Solaris users are already running the operating system on Intel-based platforms, Sun CEO Jonathan Schwartz said, the deal cements the relationship between the two companies.

In a teleconference, Sun and Intel officials detailed what they called a long-term collaboration to optimize Solaris on Intel processors, as well as conduct some joint research and development efforts.

"Solaris is evolving as a mainstream operating system," said Paul Otellini, Intel's CEO and president, explaining why Intel wants a closer relationship with Sun. "It is becoming the mission-critical Unix for Xeon," he said.

Sun's Schwartz said, "It's evident that customers wanted us to work together, and so clearly we wanted to do exactly that," he said.

Intel has agreed to promote Solaris and, in return, Sun will "be building a complete line of Xeon servers as well as workstations," said Schwartz. Sun will start shipping systems by June.