I was trying to figure out the problem with Mechwarrior 2: Mercenaries unable to detect the CD and I ran across this documentation: http://www.woodmann.com/fravia/rcgcd.htm from this project page http://www.woodmann.com/fravia/project4.htm

Following is testing done with DosBox 0.63

MERCS.EXE

Just game directory loaded and executing mercs.exe

MISC:MSCDEX: INT 2F 150B BX= 0000 CX=0000
MISC:MSCDEX: INT 2F 1500 BX= 0000 CX=0000

with mount D D:\ -t cdrom -label MERCENARIES -ioctl
Same with mount d d:\ -t cdrom

MISC:MSCDEX: INT 2F 150B BX= 0000 CX=0000
MISC:MSCDEX: INT 2F 1500 BX= 0000 CX=0000
MISC:MSCDEX: INT 2F 150C BX= 0001 CX=0001

With IMGMOUNT

MISC:MSCDEX: INT 2F 150B BX= 0000 CX=0000
MISC:MSCDEX: INT 2F 1500 BX= 0000 CX=0000
MISC:MSCDEX: INT 2F 150C BX= 0001 CX=0001

Okay so the way I understand it:

150B=Drive Check. Check Drive #.
1500=CDROM Installation Check. Checks # of CD-ROM drive letters used and starting drive letter.
150C=Get MSCDEX.EXE version.

Okay, so on all three NO CD Support, Mount with CD support, and IMGMOUNT in DosBox loaded I get BX=0 and CX=0. Which to me is saying that DosBox does not support these values?

Now with 150C we have BX=0001 and CX=0001. Since DosBox only posts 150C when Mount/IMGMOUNT is loaded and it gives it a value of 1, I'm assuming that it detects MSCDEX but I am unsure what 0001 means. According to the documentation I am reading 0000h=versions of MSCDEX.EXE prior to 2.00 but here we have 0001 so I'm assuming that DosBox is reporting v1.00 Mscdex version?