site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com On Jul 25, 2007, at 12:28 AM, Arvind Dalvi wrote: = 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... Then it means, all file I/O needs to be handled in user space..... And if the file I/O needs to be done from or within the kernel, it is done by the file system code (file system kext/driver) correct ? You are correct; file operations should not as a rule be invoked from within the kernel. Any specific design issue/rule for not implementation file I/O from or within the kernel ? The general rule is "unless it has to be inside the kernel, it must be outside". In six-plus years of working on Darwin, I have yet to see a single case where file operations needed to be performed from within the kernel. Almost every case is "we do this on Windows, so of course we should do it on Darwin". p.s. The Windows folks hate it when you do file I/O inside their kernel, too. This email sent to site_archiver@lists.apple.com