"Preserve one drive letter per socket on system startup" option doesn't work for CD-ROMs
Reason: Normally CardWare provides dynamic drive letters assignment. For example, if you have drives A, C, D and you insert SRAM/FLASH/ATA PC Card, the CardWare assigns to the new device the drive letter E (if ATA PC Card contains more as one partition several drive letters will be assigned starting from the drive letter E). When card is not inserted the corresponding drive letter(s) is (are) not available.

However some old applications (particularly) flash-file systems may expect that one drive letter is assigned to socket at startup and stay available regardless card is inserted or not. In order to deal with such software PCDisk options dialog (PCCard / Options menu) provides a checkbox "Preserve one drive letter per socket on system startup" (equivalent command line option /CM). By default this option is not selected.

If you would select this option one drive-letter per socket will be reserved at startup. However you should know that such mode of drive letters assignment has limitation: you cannot assign reserved drive letter for CD-ROM/CD-RW/DVD device.

Solution: Do not use above mentioned option if you expect to run any CD-ROM/CD-RW/DVD device connected via PC Card interface. In case you want CardWare to assign always the same specific drive letter to your device, you should select the drive letter from the "Free drive letters" combo box and move them to the left combo box, using "<< Include" button (equivalent command line option /SP). In this case CardWare will always assign selected drive letter (as long as it's free) for any device running in the specific socket. The only difference with "Preserve one drive letter per socket on system startup" option is that drive letter will be assigned dynamically when PC Card is inserted and will be destroyed on card removal.