“Terminal failure” in the data recovery world means something is not recoverable – due generally to physical media damage.
If your hard drive’s read/write heads have crashed and the drive has been left running interminably, eroding the magnetic coating on the platters, that’s as terminal as you get. Your data is sitting in minuscule dust particles mere microns in diameter, scattered about the inside of your hard drive.
That said, we’ve recovered many RAID arrays that have been described by other recovery companies as being terminal. We don’t classify something as terminal unless it cannot, and for the foreseeable future will not, be recoverable by any means.
