An upgrade to IBM’s Unix server operating system enhances security and virtualization capabilities, while providing continuous application availability even during planned downtimes.

AIX 6, announced Thursday, is the first version of AIX to be released in a public beta, a move IBM says demonstrates its desire to win customers away from competitors HP and Sun.

AIX 6 shows IBM is still serious about Unix because it’s not a mere “dot release,” says Tony Iams, senior analyst in systems software research at Ideas International. While new features related to security and management simply let IBM keep pace with HP and Sun, IBM has broken new ground in the area of virtualization, says Iams.

IBM says its new Workload Partitions feature is a “software-based virtualization technology that reduces the number of operating system images that have to be managed when consolidating workloads to increase energy efficiency and reduce costs.”

A related upgrade is called Live Application Mobility, which lets users move a workload partition from one server to another even while the workload is running, providing continuous availability similar to a mainframe.

Weakening the bond between workloads, operating systems and hardware is a key goal of virtualization, Iams notes.

“This gives you a very powerful way to migrate workloads from one server to another,” he says. “Not just an application but an entire workload, consisting of several applications and middleware.”

While AIX 6 won’t have quite the same capabilities of a mainframe, Iams says it’s notable that IBM is willing to give Unix servers mainframe-like functions even as the company touts the viability of the mainframe.

With previous releases of AIX, IBM offered beta trials to only 30 or 40 existing customers. This time, it is making the beta version freely available on the Web. It can be downloaded here.

“We didn’t do much broad testing of this before,” says Scott Handy, IBM vice president of worldwide marketing and strategy for System p servers. “A lot of this has to do with the fact that we are targeting our existing customers but are also targeting (Sun) Solaris and HP customers.”

IBM expects the final version to come out in November. Pricing will remain the same at $750 per blade server, including one year of support. Existing customers get a free upgrade to AIX 6.