Had to break this out tonight. Who knows what it is?*
* Under 40s, only. 
Discussion
CD-ROM Drive
/D:
CD-ROM driver not ready
(A)bort or (R)etry :
Back then I bought a case like this to remove the cd drive from my mac and install a new hard disk…
Sounds like serious surgery.
Weighing scale for small ducks.
Have one of these tucked away just in case too