There are plenty of features worth tracking, but taken as a whole they are not likely to boost the PC industry far beyond the 8 percent compound growth and 7 percent decline in average prices expected over the next four years.

As usual, Microsoft has no shortage of small, innovative design teams run by aggressive thirtysomethings, all trying to pack cool features into Longhorn. Hard to tell which strands of this spaghetti will stick to the wall.

Perhaps the most intriguing bit of work is a new architecture for copy protection that Microsoft hopes will convince broadcast and content companies to let digital TV and high-definition DVD content flow on the PC. Another team promises to upgrade audio and video performance on Longhorn PCs. It is developing a scheduler, a heap manager and fresh techniques for managing threads and storage. A related team is developing a whole new user-mode audio stack for Longhorn, promising professional-quality audio that will compete with consumer systems. It works, in part, by tapping into 500-microsecond timer resolutions in the kernel and by loading code and data into nonpageable memory. The promise is for a signal-to-noise ratio of 30 to 144 dB using XP-class CPUs and memory.

Yet another group is working on core performance, using a caching technique it calls superfetch and a fresh approach to how Windows uses flash and moves files on and off the disk. It's not clear whether this same team is working on the new, fast access techniques that Microsoft claims will let Longhorn systems boot from disk in just 15 seconds and come back from memory sleep states in 2 seconds.

There will also be a new Internet Protocol stack, with deeper support for IPv6, Microsoft said. And Longhorn will automate the way systems find and set up secure wireless connections and automatically move from one net to another. Finally, a 3-D user interface will bring a bit of sizzle to Longhorn, leveraging scalable vector graphics with pixel shading.

But there are also weaknesses. Microsoft scaled back an ambitious program called Next Generation Secure Computing Base (NGSCB) for putting a hardware-based root of trust in Longhorn PCs. Instead, it is commercializing a much simpler feature, called Secure Startup, to encrypt a hard drive automatically so that the drive is useless if someone breaks into a computer or finds a lost system.