Prevent disk reordering on boot I have 3 physical drives in my Mac Pro with OSX 10.6.4. Occasionally after rebooting the machine, the disk numbering changes such that the /dev/disk# does not reference the same drive as it did before the reboot.

Example

/dev/disk0 -&gt; 64GB SSD drive
/dev/disk1 -&gt; 640GB Hitachi
/dev/disk2 -&gt; 160GB WD (BootCamp)


After rebooting the mapping might be

/dev/disk0 -&gt; 160GB WD (BootCamp)
/dev/disk1 -&gt; 640GB Hitachi
/dev/disk2 -&gt; 64GB SSD drive


Even more confusing is that the remapping is not consistent. For most stuff this is irrelevant. However I also have Parallels installed to allow access to the BootCamp partition from within OSX. Parallels uses the /dev/disk# path in it's configuration file so, after rebooting OSX I launch Parallels and it tells me that the disk is no longer present.

Is there a way to tell OSX to always assign a given drive to /dev/disk0?
There does not seem to be a way to specify a device for a given drive. Your best bet might be to not auto-mount, then use a LaunchAgent to mount them in the order you want with a pause between each mount, and see if it works that way. This method might get messed up if you have a USB key or something else that auto-mounts available to the system when you boot.