Submit Hint Search The Forums LinksStatsPollsHeadlinesRSS
14,000 hints and counting!

Manual mount external drives in target disk mode System
A few days ago, I got a system-wide Spinning Beachball of Doom while installing the Mac OS X 10.3.9 Combo Updater, and was forced to restart. The system refused to boot, dropping me at a Darwin login prompt instead of the graphical progress bar. The obvious fix was to re-apply the update so the system is in a consistent state, by using something like target disk mode or booting from a custom boot CD. I decided to use target disk mode.

If you decide to use the target disk mode route, here's a warning: sometimes, OS X will mount an external drive in a way that ignores UNIX permissions. This enables any desktop user to access file on the drive, which is nice, but it will break a LOT of things if you try and install packages onto the external drive.

The solution is to unmount the drive and remount it manually from the Terminal. Once remounted, it will no longer ignore permissions, enabling you to correctly install packages onto the drive (thus fixing interrupted installs that broke the system, like mine) or do other things, like repair permissions. Open a Terminal window and run mount. Look for the FireWire drive in the list, note its /dev/ device, and then unmount and remount it -- you'll need to be an admin to do this.
$ mount
...
/dev/disk1s9 on /Volumes/Foo (local, journaled, nodev, nosuid)
...
$ sudo umount /dev/disk1s9
Password:
$ sudo mount -t hfs /dev/disk1s9 /Volumes/Foo
$
You should now be able to use the drive as usual, with the permissions intact.
    •    
  • Currently 2.67 / 5
  • 1
  • 2
  • 3
  • 4
  • 5
  (3 votes cast)
 
[25,279 views]  

Manual mount external drives in target disk mode | 9 comments | Create New Account
Click here to return to the 'Manual mount external drives in target disk mode' hint
The following comments are owned by whoever posted them. This site is not responsible for what they say.
Manual mount external drives in target disk mode
Authored by: sjonke on Jul 19, '05 09:45:11AM

Can't you just Get Info on the mounted volume and uncheck "Ignore ownership on this volume"? Or does this not do the same thing?

---
--- What?



[ Reply to This | # ]
Manual mount external drives in target disk mode
Authored by: Rusty L. on Jul 19, '05 11:45:22AM

Yes, unchecking the "Ignore ownership on this volume" is the simplest and fastest way to accomplish the same thing.

Rusty Little
Alsoft, Inc.
Co-author of DiskWarrior



[ Reply to This | # ]
Manual mount external drives in target disk mode
Authored by: jesboat on Jul 19, '05 09:44:29PM

Wow, I wouldn't have expected it to be exposed in the UI (much less in something as obvious as Get Info.) I was looking for options to mount, mount_hfs, etc.

-Jonathan

---
--
With no walls or fences on the 'net, who needs Windows or Gates?



[ Reply to This | # ]
Manual mount external drives in target disk mode
Authored by: jerobins on Jul 20, '05 05:26:46PM

Or, for the GUI impaired:

# vsdbutil -a /Volumes/DiskName

Regards...

---
--
James E. Robinson, III
http://www.robinsonhouse.com/



[ Reply to This | # ]
Manual mount external drives in target disk mode
Authored by: jesboat on Jul 20, '05 09:29:04PM

Thanks, that's good to know. (And now, I see there's already a hint for it and everything... oh well.)

-Jonathan

---
With no walls or fences on the 'net, who needs Windows or Gates?



[ Reply to This | # ]
Manual mount external drives in target disk mode
Authored by: rhowell on Jul 19, '05 09:47:25AM

The system is ignoring permissions of files on the drive, or its ignoring ownership of files on the drive?



[ Reply to This | # ]
Manual mount external drives in target disk mode
Authored by: jesboat on Jul 20, '05 12:59:40AM

It's was ignoring permissions. (If you think about it though, ownership doesn't matter much without permissions, so, it was essentially ignoring both.) You'd think that the update would still be able to set permissions on the files it was installing (even though they wouldn't take effect until the drive was unmounted from target disk mode), but, apparently, it can't.

-Jonathan

---
--
With no walls or fences on the 'net, who needs Windows or Gates?



[ Reply to This | # ]
Manual mount external drives in target disk mode
Authored by: foilpan on Jul 19, '05 10:45:33AM
disktool does the same thing.

disktool -l lists mounted disks.

disktool -u device name unmounts the chosen device.

disktool -r refreshes disk arbitration, causing it to find new mounts/unmounts.

disktool -m device name mounts the device.

in 10.4, it seems disktool is deprecated in favor of diskutil, which offers all the same commands and more.



[ Reply to This | # ]
Manual mount external drives in target disk mode
Authored by: jesboat on Jul 20, '05 01:04:31AM

I intentionally wanted to work at a lower level than the Disk Arbitration framework. Since DA originally was responsible for mounting the drive, somehow deciding to ignore permissions, and magically setting some flag somewhere to ignore them (I say magically because it didn't show up in the mount options, where you'd expect it to), I decided to mount the disk directly, where I could be sure no extra settings were getting in the way. Because I re-mounted the drive at the same node that it was originally mounted at, I didn't even need to touch Disk Arbitration.

-Jonathan

---
--
With no walls or fences on the 'net, who needs Windows or Gates?



[ Reply to This | # ]