Can't dual boot SUSE in MacBook Pro

English Install/Boot/Login
#1

Thanks to everybody in advice for reading my post.

[LEFT]I followed the instructions found in internet, the ones of this community too.

I installed rEFIt to have the dual boot at the start-up of the machine, but I confess I did not understand very well how this software works.

I opened Disc Utility and made a 100 gb partition (my HDD is 500 gb in total). I rebooted the machine running the dvd of openSUSE.

It took some tries to make the computer to read the dvd and to install the OS. I do not remember if I clicked on “Install” or on “Boot from Hard Drive”. The fact is SUSE set-up went well and I played a little bit with my new OS. Then I turned off the machine and discovered that SUSE is not running without its DVD.

[LEFT]I thought I made something wrong. I switched back to OSX to uninstall rEFIt and to delete new partition (which, in the meanwhile was cutter down in three/four smaller pieces - some gigabyte each - and a bigger, 90 gigas of emptiness). I was trying to restart everything to fix my mistakes.

[/LEFT]
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Now:

A) I didn’t understand what went wrong;
B) Disc Utility can’t make my partition to return to 500 gigabytes. It continues to show me 400 gigas of free space;
C) I read all the beginners tutorials. Probably I’m not a genius but I can’t understand clearly the game I’m playing. I always see that lots of stuff is required to understand basic guides too.

How can I fix everything?

I am really sorry for this uncomfortable request, thank to all of you.

#2

openSUSE normally uses 3 partitions. Don’t know Mac but I have found that it is best to let the Installer use free space. So don’t pre make the partitions and If you do make 3 swap ~=RAM, root (/) 20 (if using EXT4,) 40 (if using BTRFS the default) and home this is where you files live so as much as you expect to use. You can specify no separate home but it is recommended you do have one. You do need a swap or you need to set up a swap file and that can be tricky if you have never done it.

You can pre set up the partitions, but you manually have to set which partitions are mounted at which points and how formatted in the installer. It is hard for an installer to guess what you want. You must tell it since this is not what you would call standard. Pay attention to all screens and understand them before moving on. Questions ask here.

For IBM style EFI you need to boot the installer in EFI mode (if you see options at the bottom of the first menu then you are in legacy mode not EFI). You will should then use grub-efi you will mount the boot efi partition as /boot/efi (do not format it should be FAT and the 3 partitions as enumerated above.

Avoid random Web pages giving instruction. they can be old and lead you astray.

That is the best I can do until someone that know Macs shows up.