Apple has publicly released functioning code and source code for its Mac OS X port of the ZFS filesystem, the most substantial sign yet of its support for Sun's next-generation storage technology.

Over the weekend, Apple posted binaries and source code for ZFS on Mac OS X on Apple's own Mac OS Forge, a website the company uses for hosting some of its open source projects.

Previously, Apple had only made available a read-only version or a "seed" limited to OS X beta-testers. The release means that any developer can manually install ZFS on the Mac and tweak the software, though Apple has acknowledged several serious bugs.

ZFS (the Zettabyte File System) is considered by developers to be an enormous advance in capability over existing file systems. Its advantages include greater space for files, hugely improved administration and greatly improved data security.

ZFS is built into Sun's Solaris 10 and has been made open source via the OpenSolaris project, which has paved the way for its being ported to other versions of Unix (including Unix-based OS X) and even, perhaps, eventually to Windows.

Sun chief Jonathan Schwartz made waves in June of last year when he asserted at Apple's WWDC developer conference that ZFS "has become the file system in Mac OS X."

In the end, Apple in fact included ZFS in its latest OS X release, "Leopard," but only in a read-only version.

In the meantime, in October Apple also released a "developer seed" of ZFS for developers beta-testing Leopard, a sign of its commitment to the file system.

The latest release is likely to be intended to rally open source developers behind the project, which still has some serious limitations.

For instance, the Spotlight search tool isn't yet supported on ZFS, and songs can't be downloaded from iTunes to a ZFS volume. OS X can't boot from ZFS and a terminal command line must be used to empty the trash.

Even so, some Mac developers have praised the port, saying that it is already largely usable, particularly in a server setting.

"It's very easy to set up, much easier than setting up a RAID in Linux," wrote one developer in a discussion on the Slashdot.org news site. "If you're just using it for a server volume, you'll probably be happy with it."

Even a developer who said ZFS crashed his system repeatedly found the technology "promising".

"OS X has gone from having a wonky 1/0 implementation to having one of the better software raid systems available," he wrote on Slashdot.

Network Appliance is currently suing Sun over ZFS, but Sun has assured that it is indemnifying ZFS users such as Apple from such legal attacks.

Techworld's Chris Mellor contributed to this report.