ref: e7a3cd0fd0f41e03f7b861d5e092f8a4a51f5fa8
dir: /sys/man/8/9boot/
.TH 9BOOT 8 .SH NAME 9bootfat, 9bootiso, 9bootpxe \- PC bootloader for FAT, ISO and PXE network booting .SH SYNOPSIS Started by PC BIOS or chainloaded by partition bootsector .SH DESCRIPTION 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) 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. 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 with .IB key = value pairs setting boot parameters. In addition a few command words are recognized that are intended for interactive use: .TP .BI clear [prefix] can be used to remove parameters from the 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. .TP .B show displays the current configuration in memory. .TP .B wait will return to the console prompt after processing the configuration file preventing automatic boot. .TP .B boot will end the console and attempt booting the kernel. .SS 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 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) 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 only the .IR 9bootiso bootloader to be included in the ISO-9660 image under .B 386/9bootiso, 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 one can download .IR 9bootpxe and boot the kernel from a TFTP server (see .IR dhcpd (8) and .IR ndb (6) for details). Once started, .IR 9bootpxe will read the file .B /cfg/pxe/$ether or, if this file is not present, .B /cfg/pxe/default from the tftp server, where .B $ether is the MAC address of the client's network card in lower case hex, and uses 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 .SH "SEE ALSO" .IR plan9.ini (8) .SH HISTORY 9boot first appeared in 9front (April, 2011).