9boot(8) update

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cinap_lenrek 2011-06-12 14:33:14 +00:00
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commit 69f33ad54d

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.TH 9BOOT 8
.SH NAME
9bootfat, 9bootiso, 9bootpxe \- bootloaders for pc FAT, ISO and PXE network booting
9bootfat, 9bootiso, 9bootpxe \- PC bootloader for FAT, ISO and PXE network booting
.SH SYNOPSIS
started by BIOS or chainloaded by partition bootsector
started by PC BIOS or chainloaded by partition bootsector
.SH DESCRIPTION
The bootloader is responsible for reading the
9boot is the bootloader used on PCs to start the Plan 9 kernel.
Its task is to read and parse the
.IR plan9.ini (8)
boot parameters and booting a kernel. It interprets the
configuration file, gather some basic system information like
the amount of usable system memory, do some low level system
initialization and load the kernel from the boot media into memory.
After reading the configuration, the loader will automatically
attempt to boot the kernel that was specified by the
.B bootfile=
parameter as a file path on the current boot media
to locate the kernel image. The path should be in all
lower case except for
.IR 9bootpxe
wich supports case sensitive file names. Read parameters
are echoed on the console. The boot procedure
can be interrupted by pressing any key after the configuration
was read. The interactive boot console is indicated with a
.B >
prompt. The syntax of the boot console is the same as in
parameter. If there is no such parameter, a key
gets pressed on the keyboard or the kernel file was not
found then the loader enters the interactive
boot console.
The syntax of the boot console is the same as in
the
.IR plan9.ini (8)
file. The word
.B clear
will reset all current parameters. The word
file.
.BR
The word
.B clear [
.I prefix
]
can be used to remove parameters from the current configuration.
If a
.IR prefix
is specified, the first parameter that matches the prefix
is removed. If the
.IR prefix
argument is omited, the whole configuration will be reset.
.BR
The word
.B boot
will end the console and resume booting the kernel. The boot
console is entered automatically when: boot failed, no
.B bootfile=
parameter was specified or no
.IR plan9.ini (8)
was found.
will end the console and resume booting the kernel.
There are many ways to boot a PC so
.IR 9boot
was split into a number of distinct programs one for each boot
method.
.SH FAT BOOTING
The
.IR 9bootfat
program is responsible for loading the kernel from
the
When booting Plan 9 from a harddisk or USB pen drive, a
FAT16/32 partition (
.IR 9fat
partition into memory and passing it the
) is used to store the kernel and
.IR plan9.ini (8)
boot parameters. It is chainloaded by
.IR pbs,
wich locates it in the root of the active
FAT partition. The
.IR plan9.ini (8)
file is read from the root directory of the FAT
filesystem.
configuration. Due to size limitations, instead of loading
the kernel directly, the bootsector (
.IR pbs
) of the FAT partition loads
a 2nd stage bootloader
.IR 9bootfat
from the root directory of the filesystem.
.SH CD-ROM BOOTING
Booting from CD-ROM requires
Booting from CD-ROM requires only
.IR 9bootiso
to be included in the ISO-9660 image under
.B 386/9bootiso,
set as a non emulation bootblock (see
.IR mk9660 (8)).
The BIOS loads the first 2K of
.B 386/9bootiso
into memory and then executes the program. The remainder
of the file is then read to complete the chainloading process.
Boot parameters are read from
.B cfg/plan9.ini.
.SH NETWORK BOOTING
With a PXE capable BIOS and network card it is possible for
a machine to download
With a PXE capable BIOS and network card one can download
.IR 9bootpxe
and a kernel from a tftp server. The location of
.IR 9bootpxe
is defined by the
.B bootf=/386/9bootpxe
line in the tftp server's
and boot the kernel from a TFTP server (see
.IR dhcpd (8),
.IR ndb (6)
entry.
.BR
Once started,
for details). Once started,
.IR 9bootpxe
will read the file
.B /cfg/pxe/$ether
@ -82,3 +84,14 @@ in lower case hex, and use this as its
file.
.SH SOURCE
.BR /sys/src/boot/pc .
.SH FILES
.TP
.B /386/pbs
.TP
.B /386/9bootfat
.TP
.B /386/9bootiso
.TP
.B /386/9bootpxe
.SH "SEE ALSO"
.IR plan9.ini (8)