Linus: Actually, just yesterday we had a git performance issue, where ZFS was orders of magnitude slower than UFS for one user (not under Linux, but git is gaining a lot of traction even outside of kernel development). So I think a lot of the 'new file system' mania is partly fed by knowing about the issues with old filesystems, and then the (somewhat unrealistic) expectation that a 'new and improved' filesystem will make everything perfect.

In the end, this is one area where you just let people fight it out. See who comes out the winner -- and it doesn't need to be (and likely will not) be a single winner. Almost always, the right choice of file system ends up depending on the load and circumstances.

One thing that I'm personally more excited about than any of the filesystems you mention is actually the fact that Flash-based hard disks are quickly becoming available even for 'normal' users. Sure, they're still expensive (and fairly small), but Flash-based storage has such a different performance profile from rotating media, that I suspect that it will end up having a large impact on filesystem design. Right now, most filesystems tend to be designed with the latencies of rotating media in mind.

Q: The soon to be released Windows Longhorn is touted to be Microsoft's answer to the Linux threat, as Windows NT was for Novell in the 90s. Are there any improvements planned in Linux, keeping the technology advancements of Longhorn in mind?

Linus: I actually don't worry about MS at all. Their strength is in their marketing, and in the (obvious) market share they have. They've never been all that interesting from a 'technical' angle. And since all I personally care about is the technology, I don't end up being all that interested in what MS does.