Hi Ankan,
I think nowadays you have to generate NC drill & these is a collection of coordinates, you can check it in some editor as i.e. note pad... In all cases my PCB vendors works all only with "NC-Drill".
But you can (of course) generate a Drill-file too in PCAD_ you need to go: Export GBR > set up output files, add "Drl" (or some similar/others named) layer as output file.
BUT you must set in smaller window(writen in blue) by "Drill Symboles": and than (usually) click on "All Holes"(or other selection) too
These IS ALL
After all Import pls Gerber (into your open PCAD PCB Design_you DONT NEED SOME EXTRA VIEWER!_ you can select than the to viewing wished file(s) from the GBR folder...
Click on import OK, & you will see your old style drill file yet
(as a over layer on your PCB)
Be CARE, as knowed, after checking in PCB the GBR/DRL files PLEASE DONT SAVE THE SITUATION= it will BLOWS UP your couple of 100KBytes design up to 20-30MBytes_or more)!!_you must loss it...
K.