.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 basic 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
+file.
+.BR
+The word
.B clear
-will reset all current parameters. The word
+[
+.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 omitted, the whole configuration will be reset.
+If the word
+.B wait
+appears in the configuration then
+.IR 9boot
+will return to the console prompt after processing the file.
+
+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
-.IR 9fat
-partition into memory and passing it the
+When booting Plan 9 from a harddisk or USB pen drive, a
+FAT16/32 partition
+.IR (9fat)
+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
-.B plan9.ini
-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 the
.IR 9bootiso
-to be included in the ISO-9660 image under
+bootloader 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.
+set as a non-emulation bootblock (see
+.IR mk9660 (8)).
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
-.IR 9bootpxe
-and a kernel from a tftp server. The location of
+With a PXE capable BIOS and network card one can download
.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)
+and
.IR ndb (6)
-entry.
-.BR
-Once started,
+for details). Once started,
.IR 9bootpxe
will read the file
.B /cfg/pxe/$ether
in lower case hex, and use this as its
.IR plan9.ini (8)
file.
+.SH FILES
+.B /386/pbs
+.br
+.B /386/9bootfat
+.br
+.B /386/9bootiso
+.br
+.B /386/9bootpxe
.SH SOURCE
-.BR /sys/src/boot/pc .
+.BR /sys/src/boot/pc
+.SH "SEE ALSO"
+.IR plan9.ini (8)
projects / plan9front.git / blobdiff