On PowerPC OpenFirmware machines, like Apple NewWorld hardware or newer IBM workstations and servers yaboot is used to load the kernel image. Yaboot falls into the category of new-generation loaders that are able to read filesystems natively.

Some care needs to be taken in the way the configuration file is looked up by the loader. On Apple systems the OpenFirmware loads the kernel image from a specially blessed system folder on a HFS volume - and yaboot (in fact ybin inside a running Linux system) stores the binary and config file inside this tiny volume.

On IBM machines (like the RS6000/B50) the OpenFirmware just load any data from the partition of type '41 PPC PReP Boot'. Since there is not a file-system structure on it yaboot can not store information on it. This is way it just scans all file-system for a /etc/yaboot.conf files and utilizes the first match ...

Configuration Example for Manual Installation

The layout of configuration file /etc/yaboot.conf is quite simple and simillar to the one used by lilo as explained in section the section called “LILO”.

In addition some global options might be needed in order to configure yaboot for your platform, for example on Apple NewWorld systems the bootstrap partition (a tiny HFS format partition) needs to be specified via 'boot=' keyword, the default OpenFirmware device with 'device=', the yaboot partition via 'partition=' and the OpenFirmware CHRP script via 'magicboot='. All of this global options are not needed on IBM PowerPC hardware.

So a basic configuration looks mostly like the one for lilo expect some global option needed to setup yaboot on Apple NewWorld hardware:


image = /boot/vmlinuz
  root = /dev/ide/host0/bus0/target0/lun0/part2
  label = t2

In contrast to lilo, yaboot is able to read the filesystems natively - and so reads the configuration file and the kernel images each time it is executed during system boot-up. There is no need to run yaboot (or more exactly the bootstrap installation helper ybin) when the configuration file changed. Only on Apple systems that boot from the HFS volume, it is necessary to run ybin to store a copy of the configuration file on the tiny HFS bootstrap volume.