Apple chief executive Steve Jobs used the company's annual Worldwide Developers Conference in San Francisco to talk up the forthcoming OS X Leopard operating system.

The Apple co-founder boasted that the software due in October will "set a higher bar".

The new features that Jobs outlined and demonstrated include a revamped interface for the desktop and finder, as well as several new components for searching and viewing files.

A new Stacks system will attempt to reduce clutter on the desktop by allowing the user to store items such as application shortcuts and documents as a group of items on the dock.

This pile or stack of information will expand when the user clicks on the icon, freeing up space on the desktop.

Apple also plans to make the iTunes Cover Flow feature an everyday component in Leopard as part of the new Quicklook technology.

Cover Flow lets users flip through music files by navigating the album cover art. Similarly, Quicklook displayes a full-sized preview of documents including videos, PDFs, Word documents and Excel spreadsheets.

'Spaces' will offer four virtual desktops that let users organise their windows into separate environments.

A businessman preparing a sales pitch, for instance, might open his presentation and a spreadsheet in one space, and have his email and calendar in another.

Jobs also emphasised the completion of OS X's transition to 64-bit. The current version of the software supports 64-bit applications at the Unix layer only.

Leopard will extend this support to the user interface and the Cocoa application programming interface that allows for third-party applications. This makes it far easier for outside developers to create 64-bit versions of their software.