Sun Microsystems is adding licenses for its Solaris 10 operating system at a rate of about 11,000 day, the company says, and has distributed more than 2 million free registered licenses.

Sun began offering the Solaris 10 operating system for free on Jan. 31, and announced it had registered its one millionth license in March.

"We've had tremendous momentum behind the Solaris 10 release since we began making it available broadly to the public," says Tom Goguen, VP of the operating platforms group at Sun. "We are really building up the ecosystem around Solaris and gaining acceptance across the board."

Solaris 10 is available as a free download at sun.com.