Drive Genius has a “Scan” tool that destructively writes and reads every block on a drive, and will map all the bad blocks out (assuming any spares are still left). This may or may not solve your problem, depending on what your hardware problem actually is.
The other bad news is that the last time I ran this over an external 500GB drive (FireWire 800), the estimated time to complete was 11 days. Of course, as Murphy would have it, the system got rebooted to install updates after five days, and all the time spent on the job was out the window. On Mar 28, 2015, at 3:14 PM, Michael <keybou...@gmail.com> wrote: > So my external 500 GB drive is giving me I/O errors. I'd like some advice, > other than "throw it away". > > In the past, when I had drives directly attached inside the computer, I could > do a low-level format, and generally had good luck letting that solve errors. > > This is a USB drive. I don't know how to do a low-level format. > > I don't know if a simple "Flush and re-write" will solve things. I know that > hard drives have spare sectors for mapping bad sectors, so I'm assuming that > this is a read error somewhere. But the only thing the kernel tells me is > Mar 28 11:11:29 keybounceMBP kernel[0]: disk1s2: I/O error. > Mar 28 11:12:02 --- last message repeated 1 time --- > Mar 28 11:12:02 keybounceMBP kernel[0]: disk1s2: I/O error. > Mar 28 11:12:35 --- last message repeated 1 time --- > > No indication of which block ID, what kind of device status flags, etc. I > have never had a unix kernel report so little information. There is no > /var/log/kernel.log (10.9.5), so there's no place to look for more details. > > My current "best" thinking is to force random writes to the whole disk > (there's a diskutil command for that), and if that works without errors, and > a read of the disk (cat /dev/rdisk1) works without errors, then whatever > happened is probably "transient" enough to resume use of the drive. > > I do have a time machine backup, so excluding the concern of files suffering > bitrot on the backup drive, I'm good -- nothing is lost. This drive is USB > powered, so it's nice to have with a portable laptop. > > Advice? Anyone? > > (I have no idea how to read the smart status of the drive. I'm assuming it's > actually maintained in the drive, but I don't know of a tool to report the > smart status of a USB-connected drive) > > --- > Entertaining minecraft videos > http://YouTube.com/keybounce > > _______________________________________________ > MacOSX-talk mailing list > MacOSX-talk@omnigroup.com > http://www.omnigroup.com/mailman/listinfo/macosx-talk _______________________________________________ MacOSX-talk mailing list MacOSX-talk@omnigroup.com http://www.omnigroup.com/mailman/listinfo/macosx-talk
