If you have a CD-ROM drive using the ATAPI protocol, say Y. ATAPI is
a newer protocol used by IDE CD-ROM and TAPE drives, similar to the
SCSI protocol. Most new CD-ROM drives use ATAPI, including the
NEC-260, Mitsumi FX400, Sony 55E, and just about all non-SCSI
double(2X) or better speed drives.

If you say Y here, the CD-ROM drive will be identified at boot time
along with other IDE devices, as "hdb" or "hdc", or something
similar (check the boot messages with dmesg). If this is your only
CD-ROM drive, you can say N to all other CD-ROM options, but be sure
to say Y or M to "ISO 9660 CD-ROM file system support".

To compile this driver as a module, choose M here: the
module will be called ide-cd.

source code:

drivers/ide/