This item is from the Yet Another Enhanced IDE/Fast-ATA/ATA-2 FAQ, by John Wehman and Peter den Haan with numerous contributions by others. (v1.92).
The current versions of most operating systems support ATAPI CD-ROMs. That includes OS/2 3.0, Linux 1.2 and above, and Win95.
Unfortunately, hardware manufacturers have started designing these CD- ROM units while the ATAPI standard was still evolving, so there are now a couple of versions implemented in the real world. Moreover, the complexity and novelty of ATAPI means that there are some variations even among implementations of the same revision. Writing an OS ATAPI driver that works with all CD-ROMs, therefore, is a daunting task and not all have succeeded equally well. So although these OSs all support ATAPI, they do not work with all ATAPI equipment.
See Microsoft KnowledgeBase Q131499, "CD-ROM Drives Requiring Real- Mode Drivers", for more details on Win95 support. For OS/2, take a look at <http://www.austin.ibm.com/pspinfo/os2hw.html>; for updated drivers use the latest install disk upgrade or <ftp://ftp.pc.ibm.com/pub/os2_drivers/atapi.zip>.