Enterprise IT shops looking for more options in computer operating systems now have another choice to evaluate -- Apple's Mac OS X Leopard client software and Mac OS X Leopard Server have both been officially certified as meeting the latest Unix 03 standards.

On Monday, the San Francisco-based open standards and interoperability consortium, The Open Group, announced that it had awarded certificates of conformance to the Unix 03 standards to both versions of Leopard. The certifications mean that the software meets the latest UNIX product standards developed by The Open Group Platform Forum for the Single UNIX Specification version 3, according to the group.

"For over 10 years, the Single UNIX Specification has consistently provided both scalability and stability to end users -- one hallmark of a tried and true technology standard," Allen Brown, president and CEO for The Open Group, said in a statement. "Operating platforms conforming to the UNIX 03 standard assures enterprises with industrial strength products, as well as an opportunity to avoid limited choice in vendor partnership. In achieving UNIX 03 certification, Apple has shown true commitment to its customers in providing open solutions that are warranted and fully supported."

Adding both Mac desktop and server OSes to the list of compliant systems allows a popular desktop OS to be included on the list of available options for enterprise users, according to the group.

Mac OS X is also the first operating system derived from the open source BSD Unix project to meet the certification requirements, according to the group.