I'm backing up to a NTFS partition on an external USB drive with dump. I'm seeing failures in /var/log/messages reading sector 0xFFFFFFF that cause the verify pass to fail. Are there any known problems in the USB driver? Kernel via uname -a: Linux segw2.mpa.lan 2.6.18-92.1.6.el5 #1 SMP Wed Jun 25 13:49:24 EDT 2008 i686 i686 i386 GNU/Linux Message reported. (Note the number 268435455, which is 0xFFFFFFF, and occurs every time I see this happen. But a subsequent attempt to read this region with dd succeeds, so it appears to be intermittent, or dependent on some other precondition.) Sep 7 10:48:39 segw2 kernel: sd 5:0:0:0: Device not ready: <6>: Current: sense key: Not Ready Sep 7 10:48:39 segw2 kernel: Add. Sense: Logical unit not ready, cause not reportable Sep 7 10:48:39 segw2 kernel: Sep 7 10:48:39 segw2 kernel: end_request: I/O error, dev sdb, sector 268435455 Sep 7 10:48:39 segw2 kernel: Buffer I/O error on device sdb1, logical block 33554424 Sep 7 10:48:39 segw2 kernel: sd 5:0:0:0: Device not ready: <6>: Current: sense key: Not Ready Sep 7 10:48:39 segw2 kernel: Add. Sense: Logical unit not ready, cause not reportable Sep 7 10:48:39 segw2 kernel: Sep 7 10:48:39 segw2 kernel: end_request: I/O error, dev sdb, sector 268435455 Sep 7 10:48:39 segw2 kernel: Buffer I/O error on device sdb1, logical block 33554424