I had no idea were to put this but i thought it would be a good post to help anyone who has ever tried to triple boot.

Reason for writing this is i have been trying to triple boot Ubuntu,BackTrack3,and Gentoo and have made many stupid mistakes.Just thought id share with you how i pulled it off.

For this tutorial i will use the same 3 distros.

This tutorial assumes that you are installing to a formated hard drive.

First things first get the iso's.
Gentoo2008 = www.gentoo.org
Ubuntu*.* = www.ubuntu.com
BackTrack3 = www.remote-exploit.org

Next thing is to burn them to a disk using your favorite cd burning software.
*If your using cd's that are exactly the same make sure to label them makes life easy*

After all this is done you now need to partition your hard drive. To do this pop the Ubuntu cd into your cd drive and restart your computer. *Hopefully you have set your bios to were it will try to boot from a cd before the hard drive*

After it is done loading click System-Administrator-gParted

gParted is a partition editor that you can use to well edit your partitions.

We will install BackTrack3 first because it has a habit of writing to other partitions if they are present.

Now right click on the part of the application that says unallocated space and click new. Make a primary ext3 partition at what ever size you would like BackTrack3 to be i choose 25gb. After you do this make a new Linux-Swap partition the size of this is double your ram so if you have 512 make the swap 1gb etc.... After you do this click ok then apply gParted will now create your new partition. When it is done click the red power button in the top right hand corner and click restart. While Ubuntu is shutting down it will prompt you to take out the cd. Replace it with the BackTrack3 cd and press enter.

Now let backtrack boot up. When it does click the Blue k in the bottom left hand corner from there go to BackTrack-InstallBackTrack. So now a graphical installer should have popped up all you have to do is click the box that says real *this will make it a full Linux install not a live one* Now click install this will take some time depending on your hardware. When its finished just close it and shutdown backtrack.

*yay 1/3*
*don't bother trying to boot into backtrack we haven't installed a boot loader yet so no way to chose it*
*Now for Gentoo*

Now stick your Ubuntu cd back into the cd drive and boot up again navigate to the gParted tool. This is the last time you will have to see this tool. Now you are going to make a extended partition reason being that you can only hold 4 primary partitions on a single hard drive a extended lets you hold more then this. So make a extended partition any size you want i made mine 25gb again. From here it gets kinda tricky now what you need to do is click the unallocated space below the extended partition it should look something like this.

/dev/sda4 Extended partition
unallocated space

Now click the unallocated space and create a new ext3 make sure to leave at least 100mb free because you will need it. After you make the new ext3 partition you will want to create another one using the remaining 100mb *remember to take note on the /dev/sda names it gives the new partitions. After you create them click apply and when gparted finishes you can shutdown Ubuntu and now put in your Gentoo cd.

When Gentoo boots you will be greeted with a very nice xface Desktop :). The Gentoo2008 graphical install doesn't show progress on the packages being installed and sometimes stalls so i will be covering the terminal install. Double click the terminal install and press enter till it ask you to partition your drive but guess what you already did it in Ubuntu so just click done.
Next it will ask you for mount points this is fairly easy as well. Click add new mount point. Click your Gentoo partition and mount it as / . Then make another new mount point and mount it as /boot. It will get to a point were it will ask for your root password make sure to get it right both times because Gentoo doesn't compare them :/ After this it will ask you to add a user. So click add new user and give it a user name and password. Then click Groups and add the user to wheel so you can use su.*Use space to check*
Now the rest is fairly straight forward. When it asks if you want to install grub say no. We will use Ubuntu's version. It will get to packages make sure to check every package unless you know what you want and what you don't. To check a package just press space. When all that is done press next.One final note this install will take some time and i mean some time depending on hardware.
When this is done just restart your computer and insert your Ubuntu disk one last time.

*woot 2/3 just one more thing to do*
*Now Ubuntu*

Finally we can install Ubuntu witch completes the circle. We will use Ubuntu's gui installer because it is super easy :) So boot up Ubuntu and double click the installer. This is all really easy so just fallow the steps till it gets to the partition dialog. Check the manual box and click forward. WOW what do you know another app that looks like gParted. Good thing about it is you already know how to use it so click the unallocated space and create a new ext3 partition just use the space left on your hard drive. make its mount point /. Now if you don't want Ubuntu to mount all your other partitions when it starts up just delete the other partitions mount points by click them and clicking edit and just deleting the mount point. Click next and finish the rest of the dialogs then click install :) this shouldn't take long.When it finishes just restart your computer.

< 2(1/2)/3 the way there just a tad more>

Now you load up to a beautiful boot loader and you can see Ubuntu and backtrack but were is Gentoo and why cant you boot BackTrack3 kernel panic OMG.
Ok don't worry this is all going to be fixed right now. Boot into Ubuntu open up a terminal Applications-Accessories-Terminal. Now you should see the most powerful tool on any Linux box. Type in sudo gedit /boot/grub/menu.lst . Now another window should pop up with a lot of gibberish scroll down till you see something similar to this.

title Ubuntu 7.10, kernel
root (hd0,3)
kernel *************
initrd *************
quiet

title Ubuntu 7.10, kernel (recovery mode)
root (hd0,3)
kernel *************
initrd *************
quiet

title Ubuntu 7.10, kernel + MemTest
root (hd0,3)
kernel *************
initrd *************
quiet

title BackTrack (on /dev/sda* )
root (hd0,4)
kernel /boot/vmlinuz root=current ro vga=769
savedefault
boot

Now in order to get backtrack booting you just need to change root=current to root=/dev/sda*(whatever partition that you installed backtrack to)


title BackTrack (on /dev/sda*)
root (hd0,4)
kernel /boot/vmlinuz root=/dev/sda* ro vga=769
savedefault
boot


The next thing you want to do is add a new one right under the backtrack one do like this


title Gentoo
root (hd0,6)
kernel /boot/kernel-2.6.24-gentoo-r5 root=/dev/sda3
initrd /boot/initramfs-genkernel-x86-2.6.24-gentoo-r5


make sure to edit root(hd0,2) put the number of the partition you installed Gentoo's boot partiton -1 so if you installed to sda4 change that number to 3. Then edit root=/dev/sda3 to what ever partition you installed it to. now remember you will have to edit Gentoo's kernel line in grub every time you install/compile a new kernel.

That should do it you should now have a tri-boot system yay! If this was somewhat helpful please tell me and i will make more pertaining to these 3 os's