To
netboot a
Mac, you will need the following:
Drop into Open Firmware by rebooting the machine and holding down
command option o f. Note that certain versions of Open Firmware do not include
video drivers and so you will need a
serial terminal hooked up to the serial port of the Mac. Type
boot enet. The Mac will now bootp and tftp a file. If you're using
Linux and an
Old World Mac, you can simply throw a standard
kernel at it.
New world Macs require you to use
yaboot in conjunction with a kernel.
NetBSD appears to be capable of running on Old World and New World Macs without requiring any sort of extra loader - simply give it a kernel.
As an added bonus, typing boot enet:filename will allow you to grab any file you want off the TFTP server and attempt to boot it. A sample yaboot.conf that makes use of this is shown below:
timeout=0
default=linuxppc
image=enet:vmlinux
label=linuxppc
append="root=/dev/nfs nfsroot=131.111.229.7:/kl/linuxppc video=aty128fb:vmode:18,cmode:16
Yaboot will automatically read its configuration file from the same location that Open Firmware grabbed Yaboot, so yaboot.conf should live on the same TFTP server as yaboot.
Once configured, New World Macs may be netbooted simply by holding down the N key while booting.