There are several brands of ATA drives, each of which has different jumper settings as to the master, slave, or stand-alone parameters. It is imperative that you have this setting correct in order for Yellow Dog Linux to boot properly. Yes, Mac OS may work because it does not necessarily look to a specific partition, instead, it scans for a bootable sector anywhere while Yellow Dog is partition specific in its boot settings.
So, if a) you have a single drive, b) you have installed Yellow Dog Linux successfully, and c) upon reboot, you receive only the blinking question mark --then it is likely your drive is mis-configured.
Understanding the situation
Shutdown your computer. Open it up and look to the label on the top of the drive for partition settings. If not found there, you may need to visit the drive OEM's website and enter the model number for jumper settings.
If your drive is set as MASTER but a) is the only drive in the chain, and b) prefers to be set as STAND-ALONE, then it is likely that the install went fine, but post-install it fails. Had you noticed, it is likely the drive found would have been /dev/hdb/ which is incorrect if there is only one drive.
How to fix this
Correct the jumper settings and re-install (simplest method), or if you are so inclined, you may boot into rescue mode and fix /etc/fstab settings.
This HOWTO was written by Kai Staats, Terra Soft