boot_macppc - macppc system bootstrapping procedures
When powered on, after a panic, or if the system is rebooted
reboot(8) or shutdown(8), the Open Firmware will proceed to
and will boot an operating system if the auto-boot?
set to ``true'', or will wait for interactive commands otherwise.
Boot process description [Toc] [Back]
The Apple Open Firmware will normally load the kernel from
the device and
filename as instructed by the boot-device and boot-file
the boot-file variable is empty, the OpenBSD bootloader will
look for a
kernel named bsd, unless a different filename has been specified in the
boot command. To reset this variable to its default, empty,
ok set-default boot-device
The OpenBSD bootstrap program is named ``ofwboot''. It can
either in a HFS partition or in a MSDOS partition on the
disk. If MBR
partitioning is chosen for the disk, the bootstrap program
will be installed
automatically during the OpenBSD installation procedure. For HFS
shared disks, the ofwboot file must be installed manually.
program can be loaded from any Open Firmware recognized disk
Boot process options [Toc] [Back]
If invoked manually without parameters, or if the specified
not be loaded, the OpenBSD bootloader will let the user enter a boot device,
kernel filename and boot options.
If the special line exit is entered, the bootloader will attempt to
restart the machine.
The file specification used is of the form:
where: ``promdev'' is an optional Open Firmware device name
``hd'' or ``ide'') and ``partition'' is an optional disk
Normal line editing characters can be used when typing
The following options are recognized:
-a Prompt for the root filesystem and swap devices
after the devices
have been configured.
-c Enter the ``User Kernel Config'' mode upon
-d Enter the debugger, ddb(4), as soon as the kernel console has
-s Boot the system single-user. The system will be
unless this option is specified.
Abnormal system termination [Toc] [Back]
In case of system crashes, the kernel will usually enter the
ddb(4), unless it is not present in the kernel, or
it is disabled
via the ddb.panic sysctl. Upon leaving ddb, or if ddb was
the kernel will halt the system if it was still in device
phase, or attempt a dump to the configured dump device, if
crash dump will then be recovered by savecore(8) during the
boot cycle. It is also possible to force other behaviours from ddb.
Accessing the PROM [Toc] [Back]
The prom can only be accessed during system reset, or at
enter Open Firmware, press and hold ``Cntrl'' ``Cmd'' ``o''
``f'' as the
machine resets until it enters the Open Firmware debugger.
On an Xserve using serial console the System Identifier button is used to
enter Open Firmware instead of the keyboard. To enter Open
hold down the System Identifier button while pressing the
When the upper LED bank begins lighting up in sequence, repeatedly press
the System Identifier button until the seventh LED from the
highlighted in the lower bank. Now hold the System Identifier button for
two seconds, until all the top row LEDs light up.
/bsd default system kernel
/usr/mdec/ofwboot system bootstrap (usually installed on a
FAT partition or an Apple HFS partition,
to be readable
by Open Firmware)
ddb(4), boot_config(8), halt(8), init(8), installboot(8),
OpenBSD 3.6 September 22, 2002
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