site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com <http://developer.apple.com/qa/qa2001/qa1242.html> It hasn't yet been updated for Tiger. I will get to that shortly. Indeed. This is still true on Tiger. Share and Enjoy -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Technical Support * Networking, Communications, Hardware _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... First up, the Q&A that describes the current status of VFS development on Mac OS X is DTS Q&A 1242 "Developing for VFS". At 13:59 -0400 30/4/05, Bijoy Thomas wrote: I read that currently the kernel allows only leaf filesystems and not stackable ones. What is the difference between them? A stacking file system is one that's implemented in terms of another. The classic example is an encryption file system, where the underlying data is managed by a real file system and the encryption file system is stack on top of that to do the encryption. This is cool because the base file system doesn't need to know anything about encryption, and the encryption file system doesn't need to know anything about how data is stored on disk. The Mac OS X stacking architecture, such as it is, is derived from 4.4 BSD. To learn more about it, read "The Design and Implementation of the 4.4 BSD Operating System". Stacking isn't supported on Mac OS X, for a variety of reasons. Many of these persist in Tiger. Apple does, however, support a specific flavour of stacking, as demonstrated by the WebDAV file system. WebDAV uses HFS as a cache for the WebDAV data. This sort of stacking is supported and very useful for a certain class of problems. See the WebDAV source for details. This email sent to site_archiver@lists.apple.com