If you are uncertain of the hardware configuration of your system, but you know that the primary hard disk is attached to an IDE controller, the following information will allow you to determine the most likely configuration. This information is displayed at boot time.
Entries for the ATAPI CD-ROM will take a similar form,
displaying the string
%cd-rom - - - type=IDE ctlr=pri cfg=mst drv=Srom->wdHere,
ctlr=priindicates that the ATAPI CD-ROM drive is attached to the Primary IDE controller.
%cd-rom - - - type=IDE ctlr=sec cfg=mst drv=Srom->wdHere,
ctlr=secindicates that the ATAPI CD-ROM drive is attached to the Secondary IDE controller.
If you are in doubt as to your system configuration, check the documentation that was supplied with your hardware.