They always call brakes DISC...so I will always call a drive a DISK.
Billy called it DOS...so I'm sticking with that!
Well... in the days of MS-Dos, these were the days of the 5.25 and 3.5
inch floppy. Those were diskettes, as in small disks. You can
probally call those "disks" if you care about such things. But 120mm,
the 5 inch ones... there is no doubt these are called discs... whether
Compact Disc or Digital Video/Versatile Disc.
But even "disk operating system" is dated, you can have your OS on
something other than disk. But "boot up" is still used, from back when
we used a circular piece of tape which looked like a bootstrap, and to
"pull you up by the bootstraps" was the orgin of the term "boot up".
But my point is this... "disc" is 100% correct when talking current
generation optical media, 120mm/90mm round things, probally for the
same reason they are called "disc brakes" in cars, the C makes it look
cool.