site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com Hi, Thanks once again, That assumes sparse file support... You need to design your own file system that incorporates HSM as one of its features... If you use internal APIs and/or unsupported APIs then things may break. Best regards, Anton -- Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @) Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK Linux NTFS maintainer, http://www.linux-ntfs.org/ _______________________________________________ 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... On 8 Dec 2007, at 10:37, Damir Dezeljin wrote: You cannot put an HSM application on top of an existing file system or at least not in a reliable way. For example what happens if people access the underlying file system without your HSM KEXT loaded? Yes, I'm aware of such a limitation and it is usually acceptable for HSM products. If the KEXT isn't loaded, there is no data returned. I see. However, I'm concerned about Darwin updates: - Is it possible to implement an entire file system as a KEXT in a supported way -> so to avoid multiple KEXT releases for every Darwin update? Of course! Well, maybe not across major releases like Tiger to Leopard but certainly all updates within Tiger and all updates within Leopard can be expected to continue working as long as your kext uses the supported KPI. - Is it possible to implement a file system as a KEXT at all or will I need to make the 'new file system' part of the kernel and so recompile the entire kernel -> in such a case I can forcast kernel installation problems or at least concern of reinstalling the kernel. Of course it is. Many file systems are implemented as KEXTs! For example MSDOSFS, NTFS, and UDF to name a few and they are not recompiled each time a new kernel is released in a new update (unless they are being updated themselves of course). If this was not the case each software update would be huge as a lot of drivers/file systems are KEXTs and not part of the core kernel. Well, this wasn't a good one :) A good news would now be an Apple commit to implement the SPARSE functionality ASAP << Am I asking too much? :) or at least a workaround :P You can always file a feature request bug report but given this would require massive changes to HFS+/the kernel I doubt very much it would be done in the Leopard time frame if at all ever... But unless you file a feature request people will not know you want this feature so it is definitely worth filing such a request. This email sent to site_archiver@lists.apple.com