The VCDROM virtual device driver enables audio support for CD-ROM applications running in virtual DOS machines. In native DOS, audio and other IOCTL support is provided by the pass-through function of the CD-ROM file system driver, MSCDEX. VCDROM provides two features necessary to support DOS CD-ROM applications:
VCDROM provides only audio IOCTL support and not a full emulation of MSCDEX, as most DOS CD-ROM applications use the standard DOS interface for file system services and the MSCDEX interface for audio services only. Any application that calls MSCDEX for file system services will not run in a virtual DOS machine.