I have RH9 on my machine, but I wanted to install winXP on a second drive.
Is it possible to do it without reinstalling RH? And how to configure GRUB?

yes it can be done. thats exactly the setup i have on my box. Install the second drive and proceed to install xp on it. Then, edit the grub.conf file. I have never done that, so i'll let some of the gurus give some advise on that topic. Good luck

Does the second drive have to be set as a secondary master or slave?

set the windows drive as primary slave and linux drive as primary master.

Easy way to do it is to pull linux drive out of the system.

Put windows drive in as slave and install.

After that put linux drive back in and it will default to linux again.

then

edit you /boot/grub/grub.conf file to include something like

title Windows XP Professional
map (hd0) (hd1)
map (hd1) (hd0)
rootnoverify (hd1,0)
chainloader +1
makeactive
boot




this tells grub to make windows think it is the master when really it is the slave. now you can boot into windows or linux.