booting – bootstrapping procedures




This manual page collects the incantations required to bootstrap Plan 9 machines. Some of the information here is specific to the installation at Bell Labs; some is generic.

If a CPU server is up, BOOTP/DHCP and TFTP will run from there; if not, the necessary files and services must be available on a separate machine, such as a Unix system, to use these protocols for bootstrapping.

Be sure to read boot(8) to understand what happens after the kernel is loaded.


To bootstrap a diskless terminal or a CPU server, a file server must be running.


On a PC, the 9boot(8) program is used to load the kernel /386/9pc into memory.

Once the kernel is booted, it behaves like the others. See boot(8) for details.

CPU Servers

The Plan 9 CPU servers are multi-user, so they do not request a user name when booting.

PC CPU Server

Proceed as for the PC terminal, but have service=cpu set in plan9.ini(8).

SGI Challenge multiprocessor CPU Server

The Challenge ROM monitor can boot from the Ethernet. To boot from the Ethernet, type



or use the ROM command setenv to set the variable bootfile to that same string and type boot. To load a different file, tell bootp which file to load, and to force the download to come from a particular system, bootp()system:file. Any arguments after bootp()file are passed to /boot. If you are running a Plan 9 BOOTP server (see dhcpd(8)), the file name can be omitted and the file specified by the bootf parameter for the machine in /lib/ndb will be downloaded by default.

Once the kernel is loaded, it prompts for the Ethernet protocol to use to reach the root file server; request the default.

ARM CPU Servers

All ARM systems are started by U-boot using similar commands. The kernels (and thus ndb bootf parameters) are /arm/9gd for the Marvell PXA168-based Guruplug Display, /arm/9plug for all Marvell Kirkwood plugs (Sheevaplug, Guruplug, Openrd, etc.), and /arm/9beagle for TI OMAP3 boards (IGEPv2 from ISEE, Gumstix Overo). In the following, replace MAC with your board’s MAC address without colons, in lower case (the format of the ether ndb attribute).

First, establish a /cfg/pxe (\c plan9.ini) file for the new CPU server. For Kirkwood plugs,


cd /cfg/pxe; cp example-kw MAC

and edit /cfg/pxe/MAC to taste. For PXA plugs, replace kw with pxa; for OMAP boards, replace kw with omap and be sure to edit the line for ether0 to set



Second, configure U-boot to load the appropriate kernel and /cfg/pxe file at suitable addresses and start the kernel. For Sheevaplugs and Openrd boards, type this at U-boot once:


setenv bootdelay 2
# type the next two lines as one
setenv bootcmd 'bootp; bootp; tftp 0x1000 /cfg/pxe/MAC; bootp;
	tftp 0x800000; go 0x800000'

For Guruplugs Displays, do the same but type this after setenv bootcmd instead:


 'dhcp; tftpboot; tftpboot 0x1000 /cfg/pxe/MAC; bootz 0x500000'

For Kirkwood Guruplugs, type this after setenv bootcmd :


 'dhcp 0x800000; tftp 0x1000 /cfg/pxe/MAC; go 0x800000'

For IGEPv2 boards, type this after setenv bootcmd :


 'tftp 0x80300000 /cfg/pxe/MAC; dhcp 0x80310000; go 0x80310000'

For Gumstix Overo boards, type this after setenv bootcmd :


 'bootp 0x80310000; bootp 0x80300000 /cfg/pxe/MAC; go 0x80310000'

Thereafter, the boards will automatically boot via BOOTP and TFTP when reset.


ndb(6), 9boot(8), boot(8), init(8), plan9.ini(8)


Sources for the various boot programs are under /sys/src/boot.