<u>Auto-boot</u>
Specifies if OF proceeds with booting using the set boot-device (auto-boot on)
or drops you into the OF interface (which is in Forth) so that you can 
change the boot variables, specify what to boot, and search for device ID's
(auto-boot off).  Even if you have auto-boot on you can still get into the
OF interface by holding cmd-option-o-f during and after the startup chord.
Be aware of what your Input/Output devices are, however.
 
<u>Input/Output:</u>
If you want to talk to Open Firmware when you boot-up, you can specify
the input-device and output-device.  The easiest thing to do is to use your
keyboard and monitor:
 
On most machines, you can set input-device to kbd for the 
keyboard (I haven't seen a machine yet which doesn't support this).
 
output-device is quite a bit more tricky, depending on the machine
you have.  screen is the most common alias that works, and should work
for the following machines:
 
4400, 6400, 5400(?), 6500(?), StarMax (and other Tanzania clones)
 
If your machine is not listed above, see the /LinuxPPC/Mac/ category for
other output devices.  If it's not listed there either, you can use a 2nd computer
and connect it to one of your serial ports with a cable (a standard mac printer
or modem cable will do).  Use a program such as zmodem to talk with the 1st
computer's interface through the 2nd computer.
Set both input-device and output-device to ttya (ttyb for printer
port), and setup the program on the 2nd computer (like zmodem) to interact at 38400
(8N1).  Turn auto-boot off.  Write and reboot on the 1st, and watch your 2nd 
computer for the loading of OF.  Once in OF, you can use 'devalias' and 
'dev / ls' to try and find the appropriate device ID's.  Info is 
elsewhere on the faq-o-matic on using OF.
 
<u>boot-device</u>
You can boot with 3 major methods:
1)	Floppy-boot
	This allows you to boot-up off a floppy and specify the partition
	to use as your root directory.  A good way to try out new kernels and
	fix things if your old kernel has gone bad.
	boot-device fd:vmlinux.coff
	boot-file    root=/dev/sdaX  (X is the partition # of your root directory)
						for IDE drives, use root=/dev/hdaX
 	vmlinux.coff can be found at cap.anu.edu.au/pub/linux-pmac/v2.1/
	and ftp.linuxppc.org/linuxppc/powermac/
 
 2)	SCSI hard-drive bootup
	If Linux is on a SCSI disk, use
	boot-device scsi/sd@1:0 if your machine has only one SCSI bus
	or it's on the external bus.
	boot-device scsi-int/sd@1:0 if it's on the internal bus of
	some machines with dual ports (7500, 7600, others?)
	you should replace '1' with the appropriate ID of the SCSI device.
 
	boot-file  /vmlinux (if vmlinux is the name of your kernel)
 
	This method requires running quik (MacOS or linux version) to set
	up boot-blocks correctly.
 
 3)	Internal IDE hard-drive bootup
	Tanzania motherboard machines (StarMax, 4400, PowerTools, APS):
	boot-device ata/ata-disk@0:0
	boot-file  /vmlinux root=/dev/hdaX   (X is partition no. of root)
 
	Others (6400, powerbase):
	boot-device ata/ATA-Disk@0:0
	boot-file  /vmlinux root=/dev/hdaX 
 
	Note that if linux isn't the first bootable partition on your drive,
	you'll have to specify the partition number in boot-file:
	boot-file  ata/ATA-Disk@0:X/vmlinux root=/dev/hdaX  (X is partition no. of root)
 
	You need to set up your boot-blocks with quik (linux only - MacOS version
	doesn't recognize IDE).  Boot-up off a floppy, and use quik to set up your
	boot blocks (quik -vf).
 
<u>Misc</u>
If OF can't find the boot-device drive when it first boots up (if the drive
isn't ready), you can add this option so that it tries again every second:
 
boot-command  begin ['] boot catch 1000 ms cr again
 
<u>Using Open Firmware as a Bootup Selector</u>
You can configure your boot variables so that you can use Open Firmware
to select which operating system to boot when you start up (I'm not sure
if it will work on the 7200 though):
 
- set auto-boot to false
- set boot-device and boot-file to what you normally would to
  boot-up linux (see above)
- set input-device to kbd
- set output-device to the device which will allow OF to display on your
  monitor (see above)
 
Each time you boot-up, you are taken to the OF interface.  At this point
you can type 'bye' to boot into MacOS, or 'boot' to boot into Linux.  It's
very convenient.
 
Last update: 8/04/97
8/04/97 - wj@acpub.duke.edu, moved output-device info to /LinuxPPC/Mac category
8/03/97 - aaron@schrab.com, screen works on 4400
7/30/97 - gargus@cs.ualberta.ca, added XClaim3d info
7/23/97 - antoine@eci.com, added PowerCenter Pro screen device.
6/30/97 - mlewinsk@newton.kamsc.k12.mi.us, added 7300 to /chaos/control.
6/17/97 - rewritten by wj@acpub.duke.edu with lots of new info.  Previous changes by
jcarr@linuxppc.org and haceaton@aplcomm.jhuapl.edu