Depends.
usually programs depend on symbolic links to your cdrom and dvd drives in order to find them easier. Generally they aren't smart enough which drive device is which simply by looking at them. (and usually permission setups prevent that from happenning in the first place.)
So what they look for is:
/dev/cdrom
or
/dev/dvd
The majority of the time this is done automaticly at install time, so I don't know why mandrake didn't do that. (if that is realy your problem)
So in order to create a symbolic link, I'd would have /dev/dvd point to your dvd player, and /dev/cdrom point at your burner. It's not realy going ot affect the functioning of either device what the symbolic link is, but most burning programs look for /dev/cdrom, I think. So it may be easier.
So if your secondary master is your dvd burner, and your primary slave is your dvdrom drive then you would go like this (as root):
ln -s /dev/hdb /dev/cdrom
ln -s /dev/hdc /dev/dvd
And that should do it. Most programs in addition to that can be configured to specificly use a device other then their default guess, check out the documentation on your application you want to use.
Also another issue is often permissions. So check out your /dev/hd# permissions by going:
ls -l /dev/hd(whatever)
and seeing the permissions. If you get a permission setup like:
brw-rw---- root audio (some date) /dev/hdc
Then it may be a permissions issue, HOWEVER, for more modern distros like Fedora Core3 the system is setup so that permissions are automaticly granted to local users. Not sure exactly how that works, so do a "ls -l /dev/hdc" as your user you want to be able to access the hardware and make sure that that is correct.
if the permissions are still incorrect you can add your user to the audio group (as in this case), or do a
chmod +r /dev/hdc
as a root user, although that permission change may not survive a reboot.
Also since your using Mandrake the first thing I'd try to do is go thru the gui configuration tools and see if you can manually set devices thru some dialog.
Check out the mandrake forums at mandrakeuser.org for better advice, maybe. I don't use mandrake so this is more generic linux stuff rather then something specific for that distro.