[Update, June 12, 5 pm: This article is based on reporting the statements of an Apple representative who subsequently said he had misspoken about ZFS's role in Leopard. A second article reporting the complete, corrected details about ZFS can be found here.]

An Apple official on Monday said Sun Microsystems' open-source file system would not be in the next version of the Mac operating system, contradicting statements made last week by Sun's chief executive.

During an interview with InformationWeek, Brian Croll, senior director of product marketing for the Mac OS, said, "ZFS is not happening," when asked whether Sun's Zettabyte File System would be in Leopard. Instead, Leopard would use Apple's current hierarchical file system, called HFS+. The Apple file system was first introduced in 1998 in Mac OS 8.0.

Leopard is Apple's sixth iteration of its Mac OSX operating system and is expected to ship in October of this year. Apple CEO Steve Job highlighted its near completion at the company's Worldwide Developers Conference in San Francisco on Monday.

Croll declined to comment on statements made last week by Sun Chief Executive Jonathan Schwartz, who said the use of ZFS would be announced at the Apple Worldwide Developers Conference in San Francisco. Upon further questioning, Croll would only confirm that Apple had never said ZFS would be a part of Leopard.

A representative with Sun did not have any immediate comment.

During a Sun event in Washington, D.C., last week, Schwartz said, "In fact, this week you'll see that Apple is announcing at their Worldwide Developers Conference that ZFS has become the file system in Mac OS 10," Schwartz said. A video of Schwartz's speech making the claim also is available online.

Introduced in May, 2006, the 128-bit ZFS is part of Sun's commercial operating system Solaris and its OpenSolaris project. With a higher bit count than typical file systems, ZFS can create more unique addresses for storing data and files. Linux, Microsoft Windows Vista, and most Unix systems employ either 32-bit or 64-bit file systems, which are expected to meet the needs of even the largest computer systems for the next 10 years. With ZFS, Sun is thinking beyond the next decade.

ZFS, available under the Common Development and Distribution License, was introduced by Sun in 2004. Unlike traditional file systems, ZFS has built-in data integrity and disk volume-management capabilities, instead of requiring its users to add on storage software that tries to overcome a file system's shortcomings.

Skeptics have said that ZFS as the default file system in Leopard made no sense. Among the problems in using ZFS is that it wasn't designed for consumer use, and it uses up a lot of processing power.