Useful Sun OpenBoot PROM (obp) commands

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The primary task of the obp is to test and initialise the Sun SPARC system hardware, determine the hardware configuration, boot the operating system from either a mass storage device or the network and also to provide interactive debugging facilities for testing hardware and software.

obp command prompts

The obp has two prompts, available:

  • < -- Restricted Monitor Prompt. Limited options
  • ok -- OpenBoot PROM command prompt. All OBP command access is available in this mode.

Useful commands

The following tables list a series of useful commands that can be run from the obp {ok} prompt:

CommandDefinition
show-disks To show the disks
probe-scsi To search the scsi devices attached to the primary scsi controller
probe-scsi-all To search all the scsi devices
devalias <alias> <path> To temporarily create a device alias
printenv To view the current NVRAM settings
setenv <env> <value> To set the environment variables
set-defaults To set the open boot prompt settings to the factory default
nvalias <alias> <path> To set the device alias permanently to NVRAM
nvunalias cdrom1 To remove the nvalias 'cdrom1' from NVRAMRC
.version To find out the Open boot prompt version
.ent_addr To find out the ethernet MAC address
.speed To find out the CPU and PCI bus speeds
banner To display the Model,Architecture,processor,openboot version,ethernet address,hostid and etc
set-defaults To reset variable values to the factory defaults
reset-all To reboot the system from OK Prompt
show-devs To show the PCI devices
boot boot the system from the default boot devices
boot cdrom to boot from cdrom
boot disk boots the system from device as specified by the disk device alias
boot device-path boot from the full device mentioned
boot net network boot .boots from a TFTP boot server or Jumpstart server
boot bet -install Jumpstart boot.
boot tape Tape boot.boots off a SCSI tape if available
boot -h boot halted .boot into a halted state(ok prompt) intersting for troubleshooting boot at the lowest level
boot -r Reconfiguration boot.Boot and search for all attached device.useful when new device attached to the system
boot -s Single user.boots the system to run level 1
boot -v verbose boot.show good debugging information.
.idprom Display ID PROM contents
.traps Display a list of processor-dependent trap types
show-devs display list of installed and probed devices
eject floppy Eject the floppy
eject cdrom eject the cdrom
sync call the operating system to write information to hard disk

The above listing is not the entire commands and options available at obp. See the references section below for further links.

Keyboard shortcuts

The following are also a series of keyboard shortcuts that can be used from a Sun-type keyboard for OBP options during boot time or whilst the system is running

OBP CommandDefinition
L1 Bypass POST. (Runs POST in INIT mode, regardless of security settings.)
L1+a Abort. (This will also stop a running system. You can:
  • resume normal operations if you enter go at the prompt,
  • enter anything else and you will stay halted
L1+d Enter diagnostic mode(set diag-switch? to true)
L1+f Invokes FORTH command mode on the serial port before the hardware is probed. fexit continues the initialisation.
L1+n Reset NVRAM contents to default values.
Note: On modern Sun keyboards, the L1 key is labelled Stop.

References: