--- /dev/null
+.\" Hey Emacs! This file is -*- nroff -*- source.
+.\"
+.TH YABOOT 8 "28 April 2001" "GNU/Linux PowerPC" "System Manager's Manual"
+.SH NAME
+.B yaboot
+\- PowerMac OpenFirmware boot loader
+.SH SYNOPSIS
+.B Yaboot
+is an OpenFirmware ELF executable that bootstraps the Linux kernel.
+.SH DESCRIPTION
+This manual page explains the \fByaboot\fR OpenFirmware boot loader.
+
+.B yaboot
+is \fInot\fR a Linux or MacOS executable file. Attempting to execute
+\fByaboot\fR from a Linux shell will only result in a Segmentation
+Fault. \fByaboot\fR is meant to be executed only by OpenFirmware.
+
+.B yaboot
+is executed from OpenFirmare in the following manner:
+.I boot hd:2,yaboot
+where \fIhd:\fR is the OpenFirmware path for the hard disk, and the
+\fI2\fR is the partition number \fByaboot\fR is located on. In this
+example, the hard disk path is actually an OpenFirmware alias which is
+present on all NewWorld powermacs. It usually points to the internal
+ATA hard disk. If you have a SCSI disk, then you might execute
+\fByaboot\fR with this command:
+.I boot /pci@80000000/pci-bridge@d/ADPT,2930CU@2/@1:2,yaboot
+This path will vary depending on what kind of SCSI host adapter you
+have. For a more detailed explanation of OpenFirmware's [disgusting]
+paths, see man \fBbootstrap\fR(8). On IBM hardware \fByaboot\fR is
+directly copied to the \fBbootstrap\fR(8) partition raw, without any
+filesystem. OpenFirmare will boot from a type 0x41 PReP Boot parition
+marked bootable, this must contain \fByaboot\fR. On IBM hardware the
+config file is read directly from the root filesystem. On PowerMac
+hardware it must be present on the \fBbootstrap\fR(8) partition but
+.BR ybin (8)
+will take care of that.
+
+Fortunately you do not normally have to execute \fByaboot\fR manually.
+If you have partitioned your disk with a \fBbootstrap\fR(8) partition
+and used \fBybin\fR(8) to install \fByaboot\fR then you will not have
+to execute \fByaboot\fR yourself. (If this does not work you can also
+set the \fIboot-device\fR variable in OpenFirmware to have it boot
+automatically, see man \fBbootstrap\fR(8).)
+
+Once \fByaboot\fR has been executed by OpenFirmware it will display a
+\fIboot:\fR prompt where you may enter a label for a kernel image
+defined in \fByaboot.conf\fR(5). If there is no kernel image defined
+in \fByaboot.conf\fR(5) you can still boot an arbitrary image by
+specifying its absolute OpenFirmware path, similar to the above
+commands for executing \fByaboot\fR itself. Simply omit the \fIboot\fR
+command and enter only the pathname. (See EXAMPLES below)
+
+When booting an image (either as a predefined label or absolute path)
+any arguments are passed to the image. For example:
+.I boot: linux root=/dev/hda3
+which would pass the argument \fIroot=/dev/hda3\fR to the kernel.
+
+.B yaboot
+should preferably be installed on a dedicated \fBbootstrap\fR(8)
+partition (type Apple_Bootstrap for PowerMacs, type 0x41 PReP Boot for
+IBM hardware). This allows the partition to be modified in such a way
+that OpenFirmare will load \fByaboot\fR or a boot menu automatically
+with a default OF configuration. If \fByaboot\fR cannot be installed
+on a \fBbootstrap\fR(8) partition it can be installed on the root of a
+MacOS boot partition instead. \fByaboot\fR however should not be
+installed in a subdirectory of the MacOS filesystem as this is less
+reliable and more difficult to execute from OpenFirmware. See the
+\fBybin\fR(8) man page for more details on installing \fByaboot\fR
+(\fBybin\fR(8) is a utility for installing \fByaboot\fR with minimal
+difficulty).
+
+The \fByaboot.conf\fR(5) file must be next to the yaboot executable on
+the \fBbootstrap\fR(8) partition. \fBybin\fR(8) will take care of this.
+
+OpenFirmware may be accessed by holding down the \fIcommand, option,
+o, f\fR keys immediately upon power-up.
+
+OpenFirmware's settings may be reset to default values by holding down
+the \fIcommand, option, p, r\fR keys while cold booting.
+
+If you have G4 hardware then your OpenFirmware may already have a
+graphical boot selector built in. This selector can be accessed by
+holding down the option key when booting the machine. You should see
+a screen with buttons for each bootable partition. The current
+version (included with \fBybin\fR(8) 0.13) of ofboot includes a
+badge icon, the button with a penguin icon is your \fBbootstrap\fR(8)
+partition. Thanks to Nicholas Humfrey for creating the Badge icon.
+
+The \fBbootstrap\fR(8) need not and
+.B should not
+be mounted anywhere on your filesystem, especially not on top of /boot. \fBYaboot\fR is able
+to load the kernels from the ext2fs root partition so that is where
+they should be kept.
+.SH EXAMPLES
+boot \fByaboot\fR from internal ATA disk, partition 2:
+
+.I boot hd:2,yaboot
+
+boot \fByaboot\fR from partition 2 of a disk with SCSI ID 2 attached to a
+Adaptec 2930 SCSI Host adapter (this is on a rev1 blue G3, it may vary
+on other models):
+
+.I boot /pci@80000000/pci-bridge@d/ADPT,2930CU@2/@2:2,yaboot
+
+boot a kernel image located on partition number 3 of internal ATA
+disk (from \fByaboot's\fR \fIboot:\fR prompt):
+
+.I hd:3,/boot/vmlinux
+
+boot a kernel image located on partition 3 of SCSI disk ID 2 on a
+Adaptec 2930 Host adapter (from \fByaboot's\fR \fIboot:\fR prompt):
+
+.I /pci@80000000/pci-bridge@d/ADPT,2930CU@2/@2:3,/vmlinux
+.SH FILES
+.nf
+/etc/yaboot.conf \- boot loader configuration file
+.fi
+.SH BUGS
+OpenFirmware
+.SH AUTHORS
+This man page was written by Ethan Benson <erbenson@alaska.net>.
+.P
+.B yaboot
+was written by Benjamin Herrenschmidt <benh@kernel.crashing.org>.
+.SH REPORTING BUGS
+Bugs in \fByaboot\fR should be reported to Benjamin Herrenschmidt
+<benh@kernel.crashing.org>.
+.SH SEE ALSO
+.BR bootstrap (8),
+.BR yaboot.conf (5),
+.BR ybin (8).
projects / yaboot.git / blobdiff