Running a EXTERNAL Samsung 840 PRO, 512GB SSD via Thunderbolt as my primary system disk for a 27" iMac. Works great. Fast FAST F A S T Question: I would like to use my internal 1TB HDD as the Time Machine disk. If my SSD should fail, can I totally rebuild my system without data loss from the internal 1TB HDD running Time Machine? I have only used Time Machine in the past for restoring individual files; not sure it can boot and run as primary drive when it has been running as Time Machine. Thanks for your help.