site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com According to a Wikipedia page about extents, it has stated HFS+ is among several filesystems that support extents. What do you mean by "support extents"? All the documentation I've seen about user level extent support in Mac OS X, as far as "any documentation" goes, is the Xsan programming guide (specifically, the F_ALLOCEXTSPACE fcntl flag.) Does F_ALLOCEXTSPACE work on HFS+, non-Xsan volumes? If not, what is the HFS+ generic equivalent? = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.appl... HFS uses extent-based allocation; that is, rather than enumerating every block that makes up an allocation, allocations are recorded as a starting block and a run length. However, since this is simply a means of tracking allocations, it's probably not what you're thinking of. I don't think that F_ALLOCEXTSPACE does what you think it does, but if all you mean is that you want a single contiguous slab of disk space at an offset within a file, you want F_PREALLOCATE which is documented in fcntl(2). This email sent to site_archiver@lists.apple.com