Apple will officially release the latest version of its OS X operating system for Mac desktops and servers in April 2005. The update will add many new features, including full 64bit application support to take advantage of systems with PowerPC G5 processor chips; and a built-in desktop search capability.

First announced last May, Mac OS X 10.4, codenamed Tiger, is being touted as a vital upgrade by Apple. The release contains a new version of Apple's QuickTime multimedia player; as well as the new Spotlight desktop search engine; and Core Image, a revamped graphics system. Like earlier OS X releases, Tiger is based on a version of Unix.

Apple has previously compared Tiger to Microsoft's forthcoming Longhorn version of Windows, and has indicated that this version of Mac OS X will have much of the feature set that Microsoft is promising to deliver in Longhorn by the end of 2006.

As an example, OS X ships with Spotlight, a new search feature that is probably the most significant new capability in the operating system. It allows fast searching by keyword of documents and other content stored on the Mac. "Tiger's ground-breaking new features like Spotlight and Dashboard will change the way people use their computers, and drive competitors nuts trying to copy them," argued Apple chief executive Steve Jobs.

The new Dashboard feature in OS X 10.4 is a platform for pop-up information widgets. These are web-based applets for displaying information on the Mac OS X desktop.

Tiger will ship with 14 pre-built widgets, providing access to information on topics such as flight arrivals, stock quotes and weather forecasts; and a toolkit for developing additional applets. Because the applets are based on standard web technologies such as HTML and JavaScript, it will be easy for developers to add new ones, according to Apple.

Mac OS X 10.4 also includes Automator, which is a visual front-end for scripting various system tasks. It allows users to automate repetitive tasks without requiring complex programming. Users can select from a library of more than a hundred customisable actions to create automated workflows.

There is also a new iChat instant messaging and video chat tool that supports video conferencing with colleagues. Tiger also adds a new set of graphics technologies that greatly enhance image handling and manipulation on the Mac. The new QuickTime 7 video format is based on the high-definition H.264 video codec, which is ratified as part of the Mpeg-4 standard. A new version of Apple's Safari web browser now features support for Really Simple Syndication (RSS) data feeds.

Apple also said that OS X 10.4 has improved Windows compatibility to make it easier for Mac users to access Windows-based servers and authenticate using Microsoft's Active Directory.

The desktop version of Mac OS X 10.4 will be priced at £89 in the UK. The server version of the operating system will ship at the same time and will be priced at £349 for a 10-client version, and £699 for an unlimited-client version.