site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com Hi Terry, Thanks. On May 21, 2009, at 10:32 AM, Terry Lambert wrote: -- Terry Hi all, I'm seeing a weird error from pread in the following setup: The copy is done in DKIOCGETMAXBLOCKCOUNTREAD chunks (128KB for ATA). Mac OS X 10.5.7 (Darwin 9.7) on Intel. Thanks for any help?_______________________________________________ Brian Bergstrand <http://www.bergstrand.org/brian/> PGP Key ID: 0xB6C7B6A2 _______________________________________________ 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... The code is not multi-threaded. It's a fairly simple command line tool. I don't have a custom KEXT installed either. I do a bunch of preflight to get disk sizes, make sure the devices are not mounted, etc. I then open a read handle on the source device and a read-write handle on the target device. The tool then enters a loop and just preads from the source and pwrites to the target. All on one thread. The tool is linked against CoreFoundation and libSystem - nothing else. If I have a read handle open on the device and something causes diskarb to attempt to remount any volumes on the device could that cause the problem? I don't see how, because I can open a read handle on a disk containing mounted volumes or on the mounted volumes themselves (just not a write handle). There is nothing directly in the normal code path that does kauth checks after the open is successful. So it's your driver or your code. Is you code multithreaded? If so, does it serialize the close? On May 20, 2009, at 2:55 AM, Brian Bergstrand wrote: Copying from a 300GB PATA drive connected via USB to another 300GB ATA drive connected via Firewire using the raw char devices for each. After copying about 37GB of data, pread fails on the source USB drive with EACCES (13). According to the man page, this is not a valid error return (although the man page may be out of date). So where is the EACCES coming from? The IOKit block drivers? And what does it mean in this situation? This email sent to site_archiver@lists.apple.com