As IBM and Sun Microsystems laid out a new agreement to have more IBM x86 servers and blades run on Solaris, the two companies were already looking ahead to another partnership, which could see IBM mainframes support the Sun operating system.

The tie-up between IBM's x86 servers and Sun's operating system is likely the first of several such relationships, according to Bill Zeitler, senior vice president of IBM's systems and technology group. "This could hopefully be the beginning of what could be a stronger collaboration between our two firms," he said Thursday during a conference call. "There are a large number of customers interested in Solaris on the mainframe."

Although there's nothing formal in place yet, IBM is interested in actively collaborating with research and engineering firm Sine Nomine Associates to move OpenSolaris, the open-source version of Solaris, to IBM's System z mainframe, Zeitler said.

In a blog posting on its website, Sine Nomine said it welcomed IBM's interest in the project, which Sine Nomine has been working on since July 2006.

"We'd love to see Solaris running on the mainframe," said Jonathan Schwartz, president and CEO of Sun. "We'd love to make it happen." The tenor of the agreement announced on Thursday is that for both Sun and IBM, "our eyes are wide open and we're interested in serving more customers," he added.

As teams from IBM and Sun work closely together on optimising and testing Solaris on IBM's System x and BladeCenter servers, IBM's Zeitler expects they'll find more and more areas to collaborate on.

Zeitler wouldn't speculate on what might happen with IBM's System p servers, which use its Power processor, and Solaris. However, he added, "it's something I'd like to see; it certainly makes sense." The open-source community has already ported OpenSolaris to IBM's Power chip.

Back in January, Sun chairman Scott McNealy said he'd like to see Solaris running on Power, with or without IBM's help. McNealy was speaking just after Sun signed a major alliance with chip giant Intel and he said he'd welcome a similar arrangement with IBM.

The agreement with Intel enabled Sun to once more begin selling servers based on Intel's processors, while the chip vendor committed to evangelising Solaris. Sun abandoned Intel as a chip supplier several years ago in favour of rival processor vendor AMD. Sun also makes its own Sparc and UltraSparc chips.