SCO has released the latest version of its Unix OS, OpenServer, after three years of development.

The name of the company's lead product is somewhat ironic considering SCO has become known simply as the company attempting to win property rights over open-source Linux in a huge array of lawsuits. The enormous resources dedicated to the legal battle is also thought to be behind the lengthy wait between successive versions.

OpenServer 6, codenamed Legend, has been in beta testing since last year and was originally scheduled for release at the start of this year.

The update is intended to modernise OpenServer, which SCO markets to small and medium-size businesses. It supports file sizes up to 1TB, increases memory support from 4GB to 64GB, and adds new security features. Performance enhancements were a major focus: SCO executives claim OpenServer 6 runs two to three times faster than version 5.0.7.

SCO is fighting to stay relevant in a competitive server operating system market that includes Linux, Windows, and Unix vendors like IBM, HP and Sun. Last year, SCO saw its revenue sink to $43 million - down 46 percent. Its highly publicised lawsuit against IBM for allegedly violating SCO's Unix copyrights in IBM's Linux work is costing SCO millions each quarter. As of 30 April, the company was down to $14.2 million in cash and liquid assets, having used $17.7 million in cash over the prior six months.

One customer at SCO's OpenServer 6 launch event, Home Hardware Stores technical specialist Stan Hubble, said he's unfazed by SCO's financial and legal issues. Hubble works on development of a custom inventory management application that is used by around 350 of Home Hardware Stores' 1,100 independently operated stores throughout Canada. The 15-year-old application runs on OpenServer. "They were the most stable game in town at the time," Hubble said of the decision in 1990 to choose the operating system. "There weren't really other choices."

Hubble said his customers haven't been clamoring for advances in OpenServer but will likely appreciate the new version's capabilities. He expects upgrade decisions to be driven by hardware lifecycles: Most of Hubble's clients use HP servers, and as those die or are retired, they upgrade.

As ever, SCO's CEO Darl McBride was in bullish mood at the OS' official launch, held at the New York Yankees' baseball stadium. "We're in the middle of a comeback here," he told the gathered. "We're putting on our rally caps. Some people say 'you're too far down, you can't come back'. To those people I would say, did you watch the game last night here at Yankee Stadium?'"

The Yankees had staged a stunning comeback the previous night, rallying from eight runs down to beat the Tampa Bay Devil Rays 20-11. Unfortunately after SCO's event, the team went on to lose to the Devil Rays, 5-3.