Sun has sold off its mainframe re-hosting business to Chicago's Clerity Solutions.

Looking to cut costs, the struggling server maker sold its intellectual property assets and employees in the business to Clerity for an undisclosed sum.

Sun's re-hosting business, part of its Mainframe Migration offerings, was set up to help customers move their mainframe applications over to Sun's Unix-based hardware. To date, the group has done more than 1,200 re-hosting implementations.

Sun had written two major mainframe programs to run on its Solaris version of Unix, both of which have now been acquired by Clerity, the company said. These two programs are the called Mainframe Transaction Processing (MTP) and Mainframe Batch Manager (MBM).

Sun is in the middle of a major restructuring designed to save as much as $590 million annually. The plan, which was implemented by Sun CEO Jonathan Schwartz soon after he took over the company last April, is expected to claim as many as 5,000 jobs.

Sun has rarely been profitable since its server business was decimated by the dot-com implosion six years ago.