A reader who is rather quite technically inclined writes to me saying:
I’m experimenting with installing Ubuntu Linux on my Macintosh, and it’s working great except now the default operating system upon boot is Linux, not Mac OS X. How do I fix that??
As it turns out, I too am experimenting with Ubuntu and Yellow Dog Linux on my PowerBook (and have had to reinstall Mac OS X three times, so far, but that’s another story) so I know just what you’re talking about.
For Ubuntu, which is based on Debian Linux, the bootstrap loader – the program that decides which OS you want to boot – the program that controls that first few seconds of your computer startup is called yaboot and it’s actually a project that lives at http://penguinppc.org/bootloaders/yaboot/.
To modify yaboot so that the default operating system is actually Mac OS X isn’t too hard. There’s a great yaboot reference document online at the yaboot site. It turns out that the change is trivially simple: in the file /etc/yaboot.conf on the Linux side of things, you simply needed to add the line defaultos=macosx.
The second – and critical – step is to actually install the new bootstrap loader configuration file, and that’s done with ybin -v which figures out where the new configuration file should be moved and does it.
And keep your eyes open as you go along: the most amusing line in the entire process is the output statement “Blessing /dev/hda6 with Holy Penguin Pee”. Only in the world of Linux!