.TH 9BOOT 8
.SH NAME
9bootfat, 9bootiso, 9bootpxe \- bootloaders for pc FAT, ISO and PXE network booting
.SH SYNOPSIS
started by BIOS or chainloaded by partition bootsector
.SH DESCRIPTION
The bootloader is responsible for reading the
.IR plan9.ini (8)
boot parameters and boot a kernel. It interprets 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. Then a interactive boot console is shown with a
.B >
prompt. 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 and
.B boot
will end the console and start booting the kernel. The boot
console is entered automatically when boot failed, no
.B bootfile=
parameter is specified or no 
.IR plan9.ini (8)
was found.
.SH FAT BOOTING
The
.IR 9bootfat
program is responsible for loading the kernel from
the
.IR 9fat
partition into memory and pass it the
.IR plan9.ini (8)
boot parameters. It gets chainloaded by
.IR pbs
wich locates it in the root of the active
FAT partition as
.B 9BOOTFAT
file.
Then
.B plan9.ini
is read from the root directory of the FAT
filesystem.
.SH CDROM BOOTING
Booting from cdrom requires
.IR 9bootiso
to be included in the iso image under
.B 386/9bootiso
and also
set as a non emulation bootblock see
.IR mk9660 (8) .
The BIOS loads the first 2K of 
.B 386/9bootiso
into memory and passes execution to it. The program
then reads the rest of its code from the file to chainload itself.
Boot parameters are read from
.B cfg/plan9.ini
file.
.SH NETWORK BOOTING
With a PXE capable BIOS and network card, it is possible for
a machine to download
.IR 9bootpxe
from a tftp server and load the kernel from there. The
.B bootf=/386/9bootpxe
in the machines
.IR ndb (6)
entry will tell the PXE BIOS to use it.
.BR
Once started,
.IR 9bootpxe
will read the file
.B /cfg/pxe/$ether
from the tftp server, where
.B $ether
is the mac address of the used network card
in lower case hex, and use it as
.IR plan9.ini (8)
file.
.SH SOURCE
.BR /sys/src/boot/pc .