Previous 1 27 28 29 30 31 Next 1,499 Replies Latest reply: Feb 11, 2016 3:07 PM by SN225 Go to original post Branched to a new discussion.
  • autnagrag Level 1 (45 points)

    I think I see now. It doesn't matter what parent directory is in the focus of the shell. Would the right command structure be


    myuser$ dd if=/dev/disk0s5 of=/path-to-output-file




    My contention that it is unmounted now is that it does not appear in the output of


    myuser$ cd /Volumes

    myuser$ ls -al

  • Christopher Murphy Level 3 (555 points)

    A more reliable command for finding mounts is either 'df' or 'mount'.


    For a Windows partition at disk0s5 the command to copy it to a file is something like:


    sudo dd if=/dev/rdisk0s5 of=/Volumes/externaldiskname/somefolder/Windows_backup.bin bs=256k


    You can use .bin or .img, both are common, and .iso will work but it's not strictly correct (I think that's for CD/DVD's based on ISO 9660); but funny enough if you give it a .iso and double click on it in OS X, Disk Utility will open and mount it as a read only "DMG" like file. So you can read the contents.


    So in the above command it's important to use sudo so the command has root privilage; that you use rdisk (with r) so you're using the raw block device; that you're pointing to an external disk with enough space; and the bs=256k means a block size of 256k at a time which will make this go way faster. You get no command prompt (it seems like it's hung) for the duration of the process, at the end there's a summary that's kinda important to make sure the records in and out are the same values.

  • Christopher Murphy Level 3 (555 points)

    That sudo dd command is all one line, even though it's soft wrapping in the browser...

  • autnagrag Level 1 (45 points)

    myuser$ sudo dd if=/dev/rdisk0s5 of=/Volumes/external/directoryname/POCTOBAM.iso bs=256k


    dd: /dev/rdisk0s5: Input/output error

    98207+0 records in

    98207+0 records out

    25744375808 bytes transferred in 598.608368 secs (43007043 bytes/sec)


    Is this telling me there was an error?

  • Gatormac2112 Level 1 (0 points)

    The third partition gave me a hex code of af again instead of that ok?


    Screen Shot 2013-01-24 at 8.50.32 PM.png

  • Christopher Murphy Level 3 (555 points)

    Yes. If you go back to your gpt -v -rr show output for this disk, it reports the Windows partition is 89004032 sectors, which is 45570064384 bytes. But dd was interrupted and only copied 25744375808 bytes, or 56%. The resulting file is next to useless. And it raises the question what this IO error is about. Down the rabbit hole... This is usually the result of a disk read error which means it encountered a bad sector.


    In terminal, type


    and report the results. It might be long. You might also open Console and see if the system.log reports anything suspicious at the time this error was received.

  • Christopher Murphy Level 3 (555 points)

    Yeah it's fine, it looks like the HDD does not have a Recovery HD on it, but two HFS+ disks and one Windows disk. So that's AF, AF, 07. The SSD is the one with Recovery HD.

  • Christopher Murphy Level 3 (555 points)

    Worth trying the command again. Try a bs=128k this time. If it's a persistent read error it'll happen again at the same point and it means you've got bigger issues going on. If it works, great. You should end up with a file that's the same size as this partition. You can delete the one that was interrupted halfway through.

  • Gatormac2112 Level 1 (0 points)

    Chris, it worked perfectly...I have access to everything now and everything that is supposed to boot does as expected. I can't thank you enough! If Apple isnt paying you they should....I feel like I should make a Paypal contribution or something LOL. Thank you so much.

  • Berend de Meyer Level 1 (10 points)

    Hi Chritopher,


    Thansk for your reply! As I am a bit unsure what terminal commands I have to use to make a new hybrid MBR, copy 2 3 4 to it and make 4 bootable, I would like to ask you to list the commands step by step for me.

    I hope it's not to much trouble for you and thanks in advance for your time and help! Cheers

  • autnagrag Level 1 (45 points)

    myuser$ sudo dd if=/dev/rdisk0s5 of=/Volumes/external/directoryname/POCTOBAM.iso bs=128k


    dd: /dev/rdisk0s5: Input/output error

    196415+0 records in

    196415+0 records out

    25744506880 bytes transferred in 612.548041 secs (42028551 bytes/sec)



    The target disk has given me I/O errors in other settings. The source disk has never given any I/O errors. I will choose a different target.

  • autnagrag Level 1 (45 points)

    Oh my. This just came in:


    SMARTReporter has detected an 'I/O Error' on the disk named

    MtnLion1,SnoLeopard (/dev/disk0)! This is not a S.M.A.R.T. error, but repeated errors still can indicate a failing disk - please consult SMARTReporter's FAQ for recommendations how to proceed.

    Full message from 'kernel.log':

    Jan 25 06:58:54 Figaro71 kernel[0]: disk0s5: I/O error.

  • autnagrag Level 1 (45 points)

    The output of

    myser$ sudo dmesg


    is a bit long. Here it is. I can post it directly if you prefer. The USB power notifications are new and unprecedented. TCFigHit1 is a remote backup volume targeted by Time Machine.


    The source drive is a 2.5 inch, and it is 4 years old. It might have suddenly begun to fail. Sigh

  • Christopher Murphy Level 3 (555 points)

    disk0s5 is is what it's complaining about and is the source; so while the USB power notifications are a problem too I'm not sure it's related. Is the only USB device the drive? I'd disconnect the hub and everything else you can and directly plug the drive into the computer. Also, I see spurious behavior like this with USB bus powered drives all the time, which is why I don't use them anymore. I only use USB enclosures with a separate power supply. Firewire has more power available so that's workable for bus powered.

  • Christopher Murphy Level 3 (555 points)

    Nope sorry. I've done that one a bunch of times already in this thread, the UI is interactive and very straightforward. And gdisk is well documented. If you post the result from the o and p commands from the recovery and transformation menu, I'll look at those before you commit the write, just leave gdisk running after you issue the o and p commands, post the result and leave gdisk to hang out while you wait back for a response.

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