Sun continues building out its flagship Unix operating system, Solaris 10, with a new update that adds new virtualization features that may be chiefly of interest to users of older Solaris systems.

The Solaris 10 5/08 update for the three-year-old OS also continues the evolution of the platform, as Sun attempts to gain operating system share.

Its latest effort centers around broadening the capabilities of Solaris's Containers, the core virtualization technology that enables guest operating systems, including Solaris 9, to run on Solaris 10.

With the new update, Solaris 10's Containers add support for Solaris 8 environments.

"Solaris 8/9 Containers allows us to take an existing physical Solaris 8 or 9 environment that might be running on an older piece of hardware that you want to move away from and allows you to host that in Solaris 10 environment," Larry Wake, group manager for Solaris Software explained during a Webcast.

The addition of Solaris 8 means that even more legacy Solaris users will be able to move to Solaris 10, and newer, compatible hardware.

Sun is also improving how its virtualization technology handles individual Containers as well. A new feature called CPU capping enables the OS to put absolute limits on CPU utilization for each Container.

Wake said CPU capping would be especially useful in helping to provide guarantees for both minimum and maximum service levels.

Solaris is also getting improved support for the PostgreSQL open source database. Sun has been supporting the PostgreSQL database in Solaris since at least 2006.

"We've been doing a lot of work with the PostgreSQL community, and that includes supporting their GUI administrative model," Wake said. "So it's now even easier to administer a PostgreSQL database with Solaris, and that's integrated in."

However, Wake did not mention any specific improvements in the update for Sun's MySQL open source database, which was acquired earlier this year for $1 billion.

Support for the new Intel SpeedStep power management technology is also included in the Solaris 10 5/08 update.

In a blog post announcing the Solaris update, Sun spokesperson Daniel Berthiaume said that Intel technology support comes as the result of collaboration between Intel and Sun that first began a year ago.

Since Sun first released Solaris 10 in 2005, the company has issued updates to include new security with Trusted Extension and for ZFS files system support, among other items.

A Sun spokesperson was unavailable for additional comment by press time.