I have just connected an external RAID1 enclosure (a Lacie Quadro2) through FireWire800 interface to my iMac 24.
I copied all my internal "Machintosh HD" to the new disk, setted the system to use the external disk as Startup Disk, the volume is named "My HD".
After restarting, I run Disk Utility and resized the internal disk 1st partition to 100GB, then made a new partition of about 500GB, named "TM HD".
Then I configured Time Machine to use "TM HD" and runned it ...
.. all works very very fine, but ...
I'd like to made "Machintosh HD" hidden when the system is started using the external disk ... and eventually have it to be the boot disk if and only if the external HD ("my HD") is not available or not connected in order to avoid unwanted filesystem modification.
Is it possible to tell Mac to not visualize a given partition on the internal disk?
Any idea is wellcome, thanks in advance :)