site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com Valentin, I can provide you with some code that shows how to do this if you need. -Rob -- Rob McKeever, robm@apple.com Mass Storage Group, CPU Software Engineering Apple Computer On Feb 21, 2008, at 5:47 AM, Valentin Slavov wrote: Hello I need to develop a virtual block device which will be used for testing filesystem operations with files larger than 16TB or so. Obviously all this space should be virtual (in a sparse image sense), however there should be some kind of backing store to hold the filesystem meta data. Since meta data is written at different places in the volume (hfs+ keeps a backup at the end of the device and so on, a backing store for certain "ranges" should be used. The backing stores should be configurable (I was thinking of providing bsd names and searching the I/O Kit registry for IOMedia objects, and attaching them to my driver). Another solution would be to implement the driver as a filter scheme but this is inflexible since backing store cannot be configured easily. Although the first solution seems more appropriate, I need to implement a whole driver stack for virtual devices (like the apple disk image drivers), but unfortunately I can't find sufficient documentation for this task. I'd like to know if there are more appropriate solutions and other hints that might be useful. Thanks in advance V. _______________________________________________ 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/robm%40apple.com _______________________________________________ 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... If I understand what you're trying to do, I don't think you need to recreate the entire stack. You should be able to subclass IOBlockStorageDevice and give it whatever backing store you want. This email sent to robm@apple.com This email sent to site_archiver@lists.apple.com