9BOOT(8) 9BOOT(8) NAME 9bootfat, 9bootiso, 9boothyb, 9bootpxe, bootia32.efi, bootx64.efi, efiboot.fat - PC bootloader for FAT, ISO and PXE network booting SYNOPSIS Started by PC BIOS/EFI or chainloaded by partition bootsector DESCRIPTION 9boot is the bootloader used on PCs to start the Plan 9 kernel. Its task is to read and parse the plan9.ini(8) con- figuration 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 automati- cally attempt to boot the kernel that was specified by the 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 plan9.ini(8) file with key=value pairs setting boot parame- ters. In addition a few command words are recognized that are intended for interactive use: clear[prefix] can be used to remove parameters from the configura- tion. If a prefix is specified, the first parameter that matches the prefix is removed. If the prefix argu- ment is omitted, the whole configuration will be reset. show displays the current configuration in memory. wait will return to the console prompt after processing the configuration file preventing automatic boot. boot will end the console and attempt booting the kernel. There are many ways to boot a PC so 9boot was split into a number of distinct programs one for each boot method. FAT BOOTING When booting Plan 9 from a harddisk or USB pen drive, a FAT16/32 partition (9fat) is used to store the kernel and plan9.ini(8) configuration. Due to size limitations, instead of loading the kernel directly, the bootsector (pbs) of the 9BOOT(8) 9BOOT(8) FAT partition loads a 2nd stage bootloader (9bootfat) from the root directory of the filesystem. CD-ROM BOOTING Booting from CD-ROM requires only the 9bootiso bootloader to be included in the ISO-9660 image under /386/9bootiso, set as a non-emulation bootblock (see -B in mk9660(8)). Boot parameters are read from /cfg/plan9.ini. ISO HYBRID BOOTING With the 9boothyb loader, an ISO image can be made into a bootable disk by creating a MBR and appending a bootable DOS partition containing 9boothyb renamed to 9bootfat. The loader will read the ISO filesystem as if it were stored on a CD-ROM drive. NETWORK BOOTING With a PXE capable BIOS and network card one can download 9bootpxe and boot the kernel from a TFTP server (see dhcpd(8) and ndb(6) for details). Once started, 9bootpxe will read the file /cfg/pxe/$ether or, if this file is not present, /cfg/pxe/default from the tftp server, where $ether is the MAC address of the client's network card in lower case hex, and uses this as its plan9.ini(8) file. EFI BOOTING EFI firmware looks for the files bootia32.efi (for 386) or bootx64.efi (for amd64) in the boot media and executes them. For local disk media, these files are located in the direc- tory /efi/boot of the FAT formatted boot partition. For CD-ROM media, the boot partition is provided as a embedded FAT filesystem image efiboot.fat (see -E in mk9660(8)). In the network boot case, the bootia32.efi or bootx64.efi files are used as the BSP program instead of 9bootpxe. Once started, the boot media (PXE, ISO, FAT) is discovered and plan9.ini(8) configuration is read from it in the same way as with the BIOS-based 9boot* loaders. FILES /386/pbs /386/9bootfat /386/9bootiso /386/9boothyb /386/9bootpxe /386/bootia32.efi /386/bootx64.efi /386/efiboot.fat SOURCE /sys/src/boot/pc /sys/src/boot/efi 9BOOT(8) 9BOOT(8) SEE ALSO plan9.ini(8), mk9660(8), dhcpd(8), ndb(6) HISTORY 9boot first appeared in 9front (April, 2011). EFI support first appeared in 9front (Oct, 2014).