I want to boot from a Ultra ATA 100 disk and other files are on SATA disk this is my mobo do I make the drive a master or some other thingy?

thanks in advance

Its really easy, as I do it on two of my computers. I load the OS and such onto the IDE disc and specifiy it in the BIOS as the third boot disc priority, with my floppy as first boot priority and the CD/DVD drive as second boot priority. Then I enable SATA and shut down. I plug the SATA disc into a SATA port, any one will do, and start the computer, going first to BIOS, where I specify the SATA disc as forth priority.

This will cause the computer to look first for a disc in the floppy drive, the for a disc in the CD/DVD drive, and then the IDE drive as the third drive from which the OS loads.

Your mobo should allow for the same thing. Read the manual and see if it gives any differences then the outline I gave. If you don't have a floppy drive, then your CD/DVD drive would be first priority, the IDE drive as second priority, and the SATA drive as third priority.

Designate your IDE drive as the first boot drive. That should be all.

Why are you going with the s-l-o-w-e-r drive as a primary?

I have an MSI board and it came with a really good manual. You should check it to make sure you set all the bios settings correctly. I know that my board's manual specifically talked about setting the bios for using both ATA and SATA.