Mac Pro: The QuadBoot Machine

Main steps
Hereafter is the list of the main steps we will have to perform:

• • Install Mac OS X on the volume "OS X".
• • Format the volume "Other" with the "MBR" format using a disk utility. Create at least 4 partitions (with the following settings for example : 2GB, 48GB, 50GB and 150GB for a 250GB total).
• • Copy the LiveCD Linux on the first partition of the volume "Other" with the command dd.
• • Install Windows XP on the last partition of the volume "Other".
• • Install Windows Vista on the third partition of the volume "Other".
• • Boot from the LiveCD partition and install Linux on the second partition of the volume "Other".
• • Install and set parameters of GRUB on the MBR of the volume "Other".
• • Reboot and enjoy :-)

Of course, this short list includes some traps to be avoided and we will describe them.
Installing Mac OS X
This should not be a problem, installing OSX on a single drive or on a RAID volume.
There is not much to say, except that you will not need BootCamp.
Prepare the MBR volume
You need an empty SATA HD in your Mac Pro for having alternative OSes installed on.
In MacOSX, open Disk Utility and format this empty SATA drive using the good old MBR format. Create at least 4 FAT32 partitions, the first one should be small (around 2GB), while the other one can have different size depending on your needs or main applications, the last partition will have Win XP installed on.

While being on MacOSX, copy the content of the LiveCD Linux on the first partition of the volume "Others". To do so, get the id of the Volume "Others" with the command diskutil or via the Disk Utility (should be something like disk3).
Recover the iso image of the LiveCD Linux; then copy the iso on the first partition via the command dd:
$sudo umount /dev/disk3
$sudo dd if=/Users/gui/Desktop/gentoo2006.1_amd64.iso of=/dev/disk3s1
This step should take couple of minutes.
If you do not understand the command lines, please look at the command "man".
From that time, you should not need MacOSX anymore till the end of the procedure. I would recommend to physically remove the HDs of the volume "OSX" from the MacPro, it will avoid any mistakes or unrecoverable damage to other drives other than the one you have just created.
Installing Windows XP
Insert Windows XP SP2 Installation CD in the Mac, then boot the Mac Pro from it. After loading drivers, chose to install WinXP on the last partition of the volume "Others". If you have left more than one HD in you Mac Pro, be sure to install WinXP on the right partition/HD!
You can format this partition using the FAST NTFS procedure (it is not required but recommended for WinXP). Then the installation should proceed till the end. You might have to force the reboot during the installation of XP, for this purpose use the "alt" key.
Once running WinXP, you can install Mac drivers or wait for the "quad boot" installation to be completed.
At the end, you should be able to boot from this partition without any problem from the EFI.

Installing Windows Vista
You have 2 possibilities to perform this operation.
Either you launch Vista installation DVD from WinXP, then perform the installation on the third partition after having formatted it in NTFS.
Or you reboot the computer directly from Vista Installation DVD, this is what I have done as I only had a 32bits WinXP CD and 64bits for Vista.
At the end the result is the same, after formatting in NTFS the partition, then copying the files, the Mac Pro reboots (if you get a blue screen, no stress simply force rebooting with the "alt" key, then from the EFI menu choose booting from Windows partition). After the EFI bootloader, the Vista bootloader will display the following messages "Microsoft Vista Setup" or "Earlier version of Microsoft Windows".
Choose"Microsoft Vista Setup", till Vista installation is complete. Be careful, the Mac might look like "frozen" at some point, but it is normal, once more you have to be patient.
Interesting point during Vista installation, it automatically get the Mac drivers, so at the end we have a fully functional computer.
Another comment regarding the RAM installed and the performance of the Mac Pro while running Vista. During my first test, I was using Vista version RC1 32bits which was supporting only 2GB over the 6GB installed in my computer. If I was running performance test, the result was 5.3, while getting 5.6 for the RAM. Then when using Vista RC2 64bits, supporting 6GB of RAM, the performance index dropped to 4.8 for the RAM while the other scores were identical. So getting larger RAM supported but losing performance might not always be the right deal.
So after having a computer able to boot OSX, WinXP and WinVista, let's proceed to Lunix installation.