Multi-boot and iMac (Triple boot with Mac OS X, Ubuntu, & Windows 7)

[xptional]

Please I have some questions ..

Do we need rEFIt only for triple boot i.e. Mac OS X, Windows, Linux ??

I am concerned to install Ubuntu 10.04 LTS on my MacBook (Mid-2007) on separate partition. I already installed Snow Leopard 10.6.8, now I want to install Ubuntu 10.04. i.e. Dual Boot ,

Do I need to install to rEFIt for dual boot also ?

Without installing rEFIT, when I press Alt/Opt key on MacBook while starting it shows me two disks, one with Macintosh HD and other is Windows provided Live CD Ubuntu 10.04 LTS is in DVD-CD-ROM.

I created two partition while installing Snow Leopard. Do I need to create third partition SWAP before inserting Ubuntu CD for installation ?? Couldn't I create SWAP partition while installing Ubuntu ?

Last, .. Do I need to install GRUB ? what is GRUB, what it function ? I dont know at all ....

[phillat5dock]

Please I have some questions ..

Do we need rEFIt only for triple boot i.e. Mac OS X, Windows, Linux ??

I am concerned to install Ubuntu 10.04 LTS on my MacBook (Mid-2007) on separate partition. I already installed Snow Leopard 10.6.8, now I want to install Ubuntu 10.04. i.e. Dual Boot ,

Do I need to install to rEFIt for dual boot also ?

Without installing rEFIT, when I press Alt/Opt key on MacBook while starting it shows me two disks, one with Macintosh HD and other is Windows provided Live CD Ubuntu 10.04 LTS is in DVD-CD-ROM.

I created two partition while installing Snow Leopard. Do I need to create third partition SWAP before inserting Ubuntu CD for installation ?? Couldn't I create SWAP partition while installing Ubuntu ?

Last, .. Do I need to install GRUB ? what is GRUB, what it function ? I dont know at all ....

I might be wrong, but from what I could gather reading the rEFIt pages, once you have Ubuntu installed, you should be able to disable rEFIt and switch OS's using the normal Mac startup manager ... holding down Option at boot.
You can disable rEFIt simply by renaming the EFI folder on Macintosh HD. Just add a space before the name and enter your administrator password when asked.
As for creating the swap partition, I think you can just let the Ubuntu installer do what it needs to do. Just be sure that you don't install Ubuntu over the top of Mac OS X. Mac OS X should be on sda2 (sda1 is the EFI partition on the Hard disk and is mandatory to install Mac OS X, although it is not used for Mac OS X). Ubuntu will create two or three extra partitions. If you use the 64 bit version of Ubuntu 11.10 it might even install an EFI version of grub. I haven't been able to do this myself though, because Windows 7 must have an MBR.

"Without installing rEFIT, when I press Alt/Opt key on MacBook while starting it shows me two disks, one with Macintosh HD and other is Windows provided Live CD Ubuntu 10.04 LTS is in DVD-CD-ROM. " If you have installed Ubuntu, Mac OS X sees it as Windows apparently, that is if you choose not to install rEFIt. You definitely need rEFIt to triple boot. I can not find a way of not going through a chain loader with my triple boot.