The DEC RP06 disk drive was a remarkable piece of hardware. It seems to have been the last generation of drives that used rigid magnetic disks in removable packs, before their replacement by 'Winchester' fully enclosed hard disks.
Unscheduled loss of power has always been a bane of disk drives; what happens if there is a power cut, or someone hits the emergency power off button, while in the middle of writing a file? But I've heard of worse; there was one story about one of the old drives – I forget which model, but one of the ones the size of washing machines – where someone tripping over the power cable caused a prompt head crash, physically destroying the head and disk. At the other extreme, I've also heard of drives where the rotational energy would be used to finish writing the current chunk of data.
So, to be specific: What happens to a DEC RP06 when there is unscheduled loss of power in the middle of writing?