Mounting and a device being a block device or not had zero relation in classic unix though :) Tapes by nature are block devices due to only being accessible in

Mounting and a device being a block device or not had zero relation in classic unix though :) Tapes by nature are block devices due to only being accessible in block increments, and writing them in transparent way is a bit more problematic than with disks, as being able to just re-read a block to do read-update-write cycle isn't guaranteed - or necessarily easy. And yes, there used to be a time where you could mount tape as filesystem ;)