Steve Jobs has announced the availability of the fourth and final developer release of Mac OS X at Apple’s yearly developer conference. He showed off features in the forthcoming operating system, which he said will improve multimedia playback and boost the performance and usability of Apple's computers for its users. "Mac OS X is to our software what the G4 and iMac are to our hardware," Jobs said in a keynote speech at the start of the week-long show. "They are taking things to the next level in performance and capability, but at the same time making them simpler and more beautiful." Apple at one time had pledged to deliver a ‘shrink-wrapped’ version of Mac OS X for the public by the middle of this year, and to begin preinstalling the new operating system on computers in January 2001. Plans now call for the company to release a public beta, or preview version, of the OS at the middle of the year, with a commercial release that will be preinstalled on Apple computers to follow in January 2001, Jobs said. The developer version released today, Developer Preview 4, includes a Mac OS X version of Microsoft Internet Explorer 5.0 and support for Sun Microsystems’ Java 2 Platform, Jobs said. He also highlighted new graphical interface features in the developer release that are likely to be included in the product that is shipped to consumers. They included improvements to the dock, a Macintosh equivalent of the tool bar on a Windows PC, that are designed to make it easier to keep track of documents and applications in use. Jobs also showed how users will also be able to drag Internet addresses from the URL field of their Web browser into the dock, creating a link that will take them directly to that Web page in the future, relaunching the browser if necessary. Despite the delay in delivering OS X to the public, developers have much to cheer about, according to Jobs. For starters, the Apple CEO announced a dramatic price cut in the price of its WebObjects application development software. Starting today developers can purchase the WebObjects developer tools and a high-end deployment license for unlimited usage on a single server for US$699 (£430). The same software sold together was previously priced at $50,000 (£31,000), according to Jobs. Apple will ship a version of WebObjects later this year that will be "completely written in Java," allowing it to work with any server software that supports Sun Microsystems Inc.'s programming language, Jobs said. To keep the momentum going, Apple in the middle of the year plans to launch a new version of Quicktime, its multimedia playback software. The new Quicktime will support MPEG-1 and MPEG-2 video, which should improve playback quality, as well as the latest version of Macromedia Web animation technology, Flash 4. The new Quicktime will also include an enhanced QuickTime VR (Virtual Reality) playback function that provides users with a new way to navigate through three dimensional (3D) images on the Web. In a demonstration, Jobs showed how the software allows users to pan up and down as well as left and right when viewing an image.