Apple's latest operating system, Leopard, has been declared a true breed of Unix by The Open Group.

The group is a vendor- and technology-neutral consortium that focuses on open standards and global interoperability.

It yesterday confirmed both Mac OS X Leopard and Mac OS X Server Leopard to have been awarded a certificate of conformance to the Unix 03 standard.

That certification mark confirms Apple's system meets the requirements of the latest Unix product standard developed by The Open Group Platform Forum for the Single Unix Specification version 3.

This is significant as Mac OS X is the first major operating system derived from the open source BSD base of historical Unix products to meet the certification requirements.

Operating systems that support the specification offer a set of standard interfaces allowing the rich catalogue of back office and other Unix applications to be easily ported between Unix-supporting systems.

"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," said Allen Brown, Open Group president and CEO.

"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."