via http://zerox86.patrickaalto.com/zblog.html

This version has actually quite a large number of fixes, but the fixes themselves are not all that big or complex. A couple of new features (which I probably need to improve in the future versions), and quite a few game-specific fixes, mostly for games mentioned on the compatibility wiki as not working. I also noticed that my FAQ did not yet have a comprehensive list of options you can use in the zerox86.ini configuration file, so I added a section for those.
Implemented simple CD-ROM emulation

This version of zerox86 now includes a very simple CD-ROM emulation. There is no support for ISO images yet, but now you can configure a certain directory on your SD card to be used as the CD-ROM contents (which shows up as the D: drive in DOS). This can be configured per-game using the zerox86.ini, so you can have several games that need data from different CDs on your SD card. If you configure this in the default section, then you can access the D: drive also from the DOS prompt.

As an example, I copied two CD-ROM games, Fragile Allegiance and Realms of the Haunting on to my sd card. I copied the games to directories GAMES/FragAlle and GAMES/ROTH respectively. ROTH has a separate subdirectory "CD" that should be used for the CD-ROM contents, while Fragile Allegiance wants to have the same contents on the CD-ROM as are in the game directory. Thus I added the following configuration sections to my zerox86.ini:
[roth]CDROM=/media/sdcard/GAMES/ROTH/CD[fragile]CDROM=/media/sdcard/GAMES/FragAlleBoth of those games run in 640x480 SVGA resolution, and even play videos at that resolution, so they are not all that fast (or readable) on GCW-Zero. They do work and are playable in this version of zerox86, though.