Take a look at this:
http://www.geocities.com/ender7007/
This is what I used to get my ATA100 HDs working. I don't know what your computer profile is, however, this may help. Pay special attention to the append command that is needed in your lilo.conf
The problem for me was to get my ATA100 HDs recognized at all. I originally had RedHat 7.0 installed, but read that 7.1 did a better job of recognizing peripherals. When I originally installed V7.1, I had both HDs on the IDE channel. Then I decided to change over to the ATA100 connector. Was not successful in getting the HDs recognized. So I
- re-installed V7.1 with HDs on IDE
- edited my lilo.conf and added the append line
- Moved HDs from IDE to ATA
- rebooted
After that, everything worked fine.
Also, if this doesn't help you, go to Google.com and search on "ATA100" and "UDMA" to get more info.