This isn't specifically about cent os, but I am running cent os on this machine. I've got a Dell Dimension 2400 desktop pc. I've tried on a number of occasions to put a second hard drive in the machine, but I can't get the machine to recognize the second drive in BIOS. I'm going to try and keep this short and sweet. I've tried all that I know to try. I've set the jumpers on the drives to master and slave, I've tried setting the jumpers to cable select. I've changed the IDE ribbon cable. As far as I know, I've done all the trouble shooting steps that you'd do when having this problem. The only conclusion I can come up with, is that it's the BIOS. The one thing I haven't done is flash the BIOS, and I'm reluctant to do that. One other thing that I did try, was on the secondary IDE, I tried connecting a second CD drive, and the BIOS would not see it either. The machine will only see the drives that are connected to what would be the Master drive connection on the ribbon cable. Anyone have any ideas? Thanks Jim