Hi. I am trying to get RHEL 3 to recognise a SATA hard disk drive. I've figured out that i need to load modules ata_piix and libata. However, when running insmod ata_piix, i receive the error message

"/lib/modules/2.4.21-4.ELsmp/kernel/drivers/scsi/ata_piix.o: unresolved symbol at a_scsi_release_Rsmp_c050395e"

and various other messages, all dealing with unresolved symbols. However, the only dependency for ata_piix is scsi_mod, which has been loaded.

Jumping the gun a little, once I get the module loaded, how do I then get Linux to detect the disk?

Hope you've run up2date and are running at least RHEL3 Update 4. Versions prior to that had trouble with SATA disks.
Check he output of "cat /etc/redhat-release". Hopefully it should tell you you're running Update 4 or higher.

If not, you will want to ensure that up2date is configured to install the new kernel as well (since that's what contains the drivers). To ensure this, use "up2date --configure".

Once you've updated your box with the latest kernel, and have rebooted your box, you're ready to detect your SATA disks. Check the output of "dmesg" or do "cat /proc/scsi/scsi" to see the SCSI disks recognized by your machine (SATA disks are treated as SCSI disks).

Privided you don't already have any SCSI disks / drives or USB disks or pen/thumb drives on your computer, your SATA disk should be seen as /dev/sda .