If you have multiple disk controllers, and multiple disks, in your system, it can happen that BIOS discovers disks in one order, but the Linux OS discovers them in a different order. This can lead to unusual problems, such as the BIOS tries to boot to the "wrong" disk, GRUB getting installed onto the "wrong" disk, and partitions getting created on the "wrong" disk.
Dell worked with Red Hat and SuSE to add BIOS Enhanced Disk Drive Services 3.0 support into Anaconda and YaST respectively. This lets you specify, at install time, which disk to install onto, from a BIOS disk naming perspective.
For all of the below, 80 = BIOS disk 0x80 (as seen by int13), 80p2 = BIOS disk 0x80 partition 2 ( equivalent to sda2 if sda happens to be bios disk 0x80 )

Red Hat and Fedora Anaconda

You can specify at the boot loader boot: prompt this option to locate the kickstart file on BIOS Disk 80 partition 2:
ks=bd:80p2:/ks.cfg Inside of the kickstart file, you can specify locations of the install media, driver disks, and partitions using similar syntax.
harddrive --biospart=80p2 --dir=/
driverdisk --biospart=80p2
part /boot --fstype ext3 --size=1844 --onbiosdisk=80 --asprimary