OK - let me give a run down of what I am wondering is even remotely possible.

I have one PC with 2 S-ATA drives. Both drives are identical in size and specs. Can I have a dual boot machine in Linux that will select 1 of 2 versions of Linux from 2 seperate physical drives?

Drive 1 = Debian Linux
Drive 2 = CentOS Linux

I want to fire up my machine and have GRUB give me the option of which physical drive I want to mount and boot into. Is this possible? I don't see why not if GRUB allows you to mount a specific partition of one physical drive, why can't it do the same for 2 physical drives.

Hopefully I was pretty clear.

Thanks!

Yes. You can have numerous operating systems on a machine and use GRUB or LILO to select between them. It's just a matter of having the correct record in the grub menu.lst file.

I run 4 disks. Between them there are 140+ partitions. Last time I checked there were less than 5 empty partitions. Typically I place one OS in each partition. One Grub boots the whole lot. Thus my conclusion is "yes".

Grub must be having a holiday when working for you.

By the way I ask Grub to boot the empty partitions too before they are filled. An empty partition won't boot but fires up as soon as I install an OS inside.