Does anyone have any opinions on the best way to have four operating systems on one hard drive? and it work?
I'd guess Grub. I say "guess", because I only have three OS's (actually, 3 Linux distributions) on mine, I set the fourth partition as an extended partition and made a logical volume at the end of that space for a Swap partition that's used by whichever OS I'm running. I see no reason that I couldn't set up four different OS's if I wanted to do without a swap partition. Grub is free, and easy to configure providing you don't forget where it's going to look for the configuration files.
Grub can boot any OS. At least, any OS that I have seen. Remember, an IDE hard disk can only handle 4 primary partitons. Four OS's each need at least one partition each. Linux, BSD, Solaris, etc need a SWAP partition too. That makes five partitions needed for four OS's. The way to get around this is what Gaston mentioned. Make your SWAP partition inside of a Logical partition. This will mean you have four primary partitions and one extended. I had a test system running Windows 98, Fedora Core 4, OpenBSD, and BeOS, all on one hard disk. It can be done.
Some OS will boot from a logical partition. Actually, I think you have to set a small primary partition to redirect the various OS during boot, but that's beyond my skill level. A search for "boot lvm" should lead you to better information. I've been playing with various Linux distros lately and can't remember which, but I believe one of them offered an "Install to LVM" option during install. I suspect Fedora, since it will set up LVM if you take the default partitioning options. Isn't there still a limit of 15 partitions (primary + logical) for most PC OS?
