NAME
boot —
Macppc system bootstrapping
procedures
DESCRIPTION
Power fail and crash
recovery
Normally, the system will reboot itself at power-up or after crashes. An
automatic consistency check of the file systems will be performed as described
in
fsck(8), and unless this
fails, the system will resume multi-user operations.
Cold starts
The boot ROM performs a Power On Self Test (POST) then loads Open Firmware.
Depending on the Open Firmware variable
‘
auto-boot?
’ it will either stop at the
Open Firmware prompt or attempt to boot an operating system. Depending on the
contents of the ‘
use-nvramrc?
’,
‘
boot-command
’,
‘
boot-device
’, and
‘
boot-file
’ Open Firmware variables, it
will attempt to boot MacOS, MacOS X, or
NetBSD.
To boot
NetBSD, Open Firmware loads the bootloader
macppc/ofwboot(8)
from the specified ‘
boot-device
’. The
bootloader then loads the kernel from the
‘
boot-file
’, (if it exists). Otherwise, it
tries to load (in the following order):
netbsd,
netbsd.gz, or
netbsd.macppc on the
“a” partition of the same device that had the bootloader.
Open Firmware Commands
An essential but incomplete list of Open Firmware commands follows. A more
thorough list is contained in the FAQ.
http://www.NetBSD.org/ports/macppc/faq.html#ofw-use
boot [
boot-device
[boot-file]]
[
options]
Boot an operating system. The default arguments for this command are taken from
the Open Firmware environment variables:
- boot-device
- primary bootloader location
- boot-file
- kernel location
- options
- flags passed to the kernel
reset-all
Reset the system, and proceed as specified by the
‘
use-nvramrc?
’ and
‘
auto-boot?
’ variables. If
‘
use-nvramrc?
’ is set to
‘
true
’, then the system will attempt to
execute the commands stored in the
‘
nvramrc
’ variable. If
‘
auto-boot?
’ is set to
‘
true
’, the system will attempt to use the
values stored in ‘
boot-command
’,
‘
boot-device
’, and
‘
boot-file
’ to boot the system. If
‘
auto-boot?
’ is set to
‘
false
’, the system will halt at the Open
Firmware prompt.
shut-down
Power off the system.
setenv variable
value
Set an Open Firmware variable, e.g.,
setenv auto-boot? false
setenv boot-device hd:,\ofwboot.xcf
setenv boot-file netbsd-GENERIC.gz
set-default variable
Set an Open Firmware variable to its default value.
printenv
[
variable]
Show Open Firmware variables and values.
eject fd
Eject floppy disk on systems with on-board floppy drives.
mac-boot
Attempt to boot MacOS on an Open Firmware 3 system.
bye
Attempt to boot MacOS on an Open Firmware 1.0.5, 2.0.x, or 2.4 system.
Open Firmware Variables
An essential but incomplete list of Open Firmware variables follows. A more
thorough list is contained in the FAQ.
http://www.NetBSD.org/ports/macppc/faq.html#ofw-variables
-
-
auto-boot?
- What Open Firmware will do at system startup or reset:
-
-
- true
- automatically bootstrap an operating system using
values from the ‘
boot-command
’,
‘boot-device
’, and
‘boot-file
’ variables.
-
-
- false
- stop at the Open Firmware prompt.
-
-
use-nvramrc?
- If ‘
true
’ runs commands
in variable ‘nvramrc
’.
-
-
real-base
- Kernel memory location. Do not modify this
value on Open Firmware 3 systems — you may damage
your computer. All other Open Firmware versions should use
F00000
.
-
-
load-base
- Bootloader memory location. Do not modify
this value on Open Firmware 3 systems — you may
damage your computer. All other Open Firmware versions
should use
600000
.
-
-
boot-command
- The command to use for booting. Typically, the default of
‘
boot
’ is used.
-
-
boot-device
- Device from which to load primary bootloader. Value depends
on a variety of factors. See
macppc/ofwboot(8).
-
-
boot-file
- Kernel location. Value depends on a variety of factors. See
macppc/ofwboot(8).
-
-
input-device
- What type of console input device (ADB keyboard, USB
keyboard, or serial port).
-
-
- kbd
- ADB keyboard on models with ADB, USB keyboard on models
with USB, and built-in keyboard on laptops. This is the default on
some Open Firmware 2.0.x machines and all Open Firmware 2.4 and 3
machines.
-
-
- ttya
- ‘Modem’ serial port on machines with serial
ports. Properties are 38400 bps, 8 bits, no parity, 1 stop bit, no
handshaking. This is the default on all Open Firmware 1.0.5 systems
and some Open Firmware 2.0.x systems.
-
-
- ttyb
- ‘Printer’ serial port on machines with
serial ports. Properties are the same as the ‘Modem’
port.
-
-
- scca
- Serial port on Xserve models. Properties are 57600 bps,
8 bits, no parity, 1 stop bit, no handshaking.
-
-
- output-device
- What type of console output device (On-board video, AGP
video, PCI video, built-in LCD, or serial console). Value depends on a
variety of factors. See
macppc/ofwboot(8)
and
http://www.NetBSD.org/ports/macppc/faq.html#ofw-input-output-devices
-
-
- nvramrc
- If ‘
use-nvramrc?
’ is
set to true, these FORTH commands will be run when the computer is
reset
Normal Operation
When Open Firmware loads the primary bootloader, it will print something like
the following:
loading XCOFF
tsize=CC50 dsize=14AC bsize=2668 entry=640000
SECTIONS:
.text 00640000 00640000 0000CC50 000000E0
.data 0064D000 0064D000 000014AC 0000CD30
.bss 0064E4B0 0064E4B0 00002668 00000000
loading .text, done..
loading .data, done..
clearing .bss, done..
When
macppc/ofwboot(8)
is started, it prints something like the following:
>> NetBSD/macppc OpenFirmware Boot, Revision 1.7
>> (autobuild@tgm.daemon.org, Thu Feb 6 17:50:27 UTC 2003)
When
macppc/ofwboot(8)
is loading the kernel, it prints something like the following:
4395364+254568 [220144+193803]=0x4d477c
start=0x100000
When the
NetBSD kernel has started it prints a banner
similar to the following:
Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
The NetBSD Foundation, Inc. All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
The Regents of the University of California. All rights reserved.
NetBSD 1.6ZC (GENERIC) #0: Tue Sep 30 13:09:10 UTC 2003
autobuild@tgm.NetBSD.org:/autobuild/HEAD/macppc/OBJ/autobuild/HEAD/src/sys/arch/macppc/compile/GENERIC
After bootstrap
Once the
NetBSD/macppc kernel is booted normally it
initializes itself and proceeds to start the system. An automatic consistency
check of the file systems takes place, and unless this fails, the system comes
up to multi-user operation.
The proper way to shut the system down is with the
shutdown(8) command.
If the system crashes, it will enter the kernel debugger,
ddb(4), if it is configured in
the kernel. If the crash occurred during initialization and the debugger is
not present or is exited, the kernel will halt the system.
If the crash occurred during normal operation and the debugger is not present or
is exited, the system will attempt a dump to the configured dump device (which
will be automatically recovered with
savecore(8) during the next
bootstrap cycle), and after the dump is complete (successful or not) the
kernel will attempt a reboot.
FILES
- /boot
- NetBSD secondary bootstrap program
(Open Firmware 1.x and 2.x)
- /netbsd
- default NetBSD system kernel
- /usr/mdec/bootxx
- NetBSD primary bootstrap program
(Open Firmware 1.x and 2.x) a.k.a. “partition zero”
bootloader
- /usr/mdec/ofwboot
- NetBSD secondary bootstrap program
(Open Firmware 1.x and 2.x)
- /usr/mdec/ofwboot.xcf
- primary bootstrap for netboot and “cd9660” (ISO
9660), “MS-DOS”, “HFS”, and “HFS+”
file systems.
SEE ALSO
ddb(4),
intro(4),
diskless(8),
halt(8),
init(8),
installboot(8),
macppc/ofwboot(8),
rc(8),
reboot(8),
savecore(8),
shutdown(8)
http://www.NetBSD.org/ports/macppc/faq.html
http://www.NetBSD.org/docs/network/netboot/
STANDARDS
IEEE Std 1275-1994 (“Open Firmware”)
http://playground.sun.com/1275/home.html
BUGS
The device names used by
NetBSD/macppc and Open Firmware
often have no relation to each other.
Apple Computer's Open Firmware implementation is easily confused. It is best to
reboot your computer after a failed boot attempt,
halt, or
shutdown -h. Use the Open Firmware
reset-all command.
Apple Computer's Open Firmware implementation is notoriously bad. Thorough
instructions for installing and booting
NetBSD are in
the install notes (
INSTALL.html) included with every release
of
NetBSD.