3 9bootfat, 9bootiso, 9boothyb, 9bootpxe, bootia32.efi, bootx64.efi, efiboot.fat \- PC bootloader for FAT, ISO and PXE network booting
5 Started by PC BIOS/EFI or chainloaded by partition bootsector
7 9boot is the bootloader used on PCs to start the Plan 9 kernel.
8 Its task is to read and parse the
10 configuration file, gather some basic system information like
11 the amount of usable system memory, do some basic system
12 initialization and load the kernel from the boot media into memory.
14 After reading the configuration, the loader will automatically
15 attempt to boot the kernel that was specified by the
17 parameter. If there is no such parameter, a key
18 gets pressed on the keyboard or the kernel file was not
19 found then the loader enters the interactive
22 The syntax of the boot console is the same as in the
26 pairs setting boot parameters. In addition a few command
27 words are recognized that are intended for interactive use:
30 can be used to remove parameters from the configuration.
33 is specified, the first parameter that matches the prefix
36 argument is omitted, the whole configuration will be reset.
39 displays the current configuration in memory.
42 will return to the console prompt after processing the
43 configuration file preventing automatic boot.
46 will end the console and attempt booting the kernel.
48 There are many ways to boot a PC so
50 was split into a number of distinct programs one for each boot
53 When booting Plan 9 from a harddisk or USB pen drive, a
56 is used to store the kernel and
58 configuration. Due to size limitations, instead of loading
59 the kernel directly, the bootsector
61 of the FAT partition loads
62 a 2nd stage bootloader
64 from the root directory of the filesystem.
66 Booting from CD-ROM requires only the
68 bootloader to be included in the ISO-9660 image under
70 set as a non-emulation bootblock (see
74 Boot parameters are read from
76 .SH ISO HYBRID BOOTING
79 loader, an ISO image can be made into a bootable disk by
80 creating a MBR and appending a bootable DOS partition containing
84 The loader will read the ISO filesystem as if it were stored
87 With a PXE capable BIOS and network card one can download
89 and boot the kernel from a TFTP server (see
93 for details). Once started,
97 or, if this file is not present,
99 from the tftp server, where
101 is the MAC address of the client's network card
102 in lower case hex, and uses this as its
106 EFI firmware looks for the files
112 in the boot media and executes them.
113 For local disk media, these files are located in the directory
117 formatted boot partition.
120 media, the boot partition is provided
129 In the network boot case, the
133 files are used as the
137 Once started, the boot media
143 configuration is read from it in the same way as
167 .BR /sys/src/boot/efi
175 9boot first appeared in 9front (April, 2011).
176 EFI support first appeared in 9front (Oct, 2014).