Sun Microsystems has confirmed that Apple will use Sun's Zettabyte File System (ZFS) for the forthcoming OS X 10.5 Leopard due in October. 

Sun chief executive Jonathan Schwartz said at a company event in Washington DC on Wednesday that Apple will officially reveal the technology at its World Wide Developer Conference scheduled for San Francisco next week. 

ZFS is the world's first 128-bit file system, supporting 18 billion times the storage capacity of current-generation 64-bit systems. A zettabyte is equal to 1,024 exabytes or 1,000,000,000,000,000,000,000 bytes.

Sun developed the technology and has released it under an open source licence. The file system is currently deployed in Sun's Solaris operating system.

ZFS promises improved data integrity compared with Apple's current Journaled HFS+ file system.

The technology does not overwrite data on a disk like current file systems, but saves the new data first and then deletes the information that it replaces.

These features are likely to power Leopard's Time Machine that lets users restore documents and operating system to a previous state. It also keeps a complete copy of all data on a second hard drive. 

In case of a hard drive failure the user simply swaps out the broken drive for a new one and can continue to use the system without restoring any backups.

Sun first disclosed Apple's plans to use ZFS in April 2006. 

Apple did not respond to a request for comment. The company has a policy of not commenting on products before they are released.