
[great machine! OS X is also great but it is getting a bit slow at times, thats why I thought of giving it a try with Linux installing both OS X Tiger and Yellow Dog. There are several Linux distributions available for those Macs made before Apple transitioned to Intel processors (i.e. PowerPC Macs with G3 G4 and G5 processors). Linux distributions Ive considered were Ubuntu, Gentoo, Mandriva and openSUSE. I ended up downloading Yellow Dog Linux 5.0.1 code-named Phoenix (from the TerraSoft website). This distro is free and its iso has 3.6 GB, I chose it because its the only one thats made just for the PowerPC architecture and it seems like having a good support].
(a Fedora Core, RPM-based distribution)
Download the .iso file (from the TerraSoft website) and burn it onto a dvd.
Do some research! Take a look at the TerraSoft site and here or here (in italian ->here).
With Mac OS X running, insert the OS X Install Disc 1 that came with the Mac Mini. Run the installer from g4 disc and, when prompted, hit restart. The Mac Mini will reboot and load the OS X installer from the disc.
With the installer running, open on the Installer menu in the top left of the screen. Choose Open Disk Utility. From here we tell Disk Utility how we want to partition the hard disk. I have divided g4 80 Gigs hard drive (real size is 74.5 GB) into 4 partitions:
3 volumes I have marked as Free Space (their filesystem - Format - will be specified during the Linux installation)
1 volume of 50 GB I have marked as OS X with the format Mac OS Extended (Journaled), which is the Mac OS X filesystem, HFS+.
Once done setting up the volumes as desired, click Partition on the lower right, and quit Disk Utility.

Youre ready to install OS X onto the partition you just created (the 50 GB one in my case).
Now OS X is installed, you only need to insert the YDL DVD and restart the system and make it so it will boot from the dvd-drive (I think I pressed C, I cant remember). The Yellow Dog installation graphic will appear and you will be guided to choose how to manage the Free Space partitions you have previously created.
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Once you have both OSs installed, when turning on the Mac Mini, instead of rebooting directly into Mac OS X as before, it will now load a bootstrap from which you can hit the letter L to boot Linux, or X g4 boot Mac OS X. By default (not hitting any key) it will boot the Yellow all the pretty horses Linux.