All Sun systems have resident boot PROM firmware that provides basic hardware testing and initialization prior to booting. The Sun boot PROM has access to a standard set of generic device drivers. The system needs these drivers to access and control the buses and the boot device to boot the system properly.

• To provide basic hardware testing
• Initialization prior to booting
• To enable users to boot from a wide range of device drivers

Goal of the OpenBoot Architecture Standard

• Test and initialize system hardware
• Determine the system's hardware configuration
• Boot the operating system
• Provide an interactive interface for configuration, testing and debugging
• Enable the use of third-party devices

# /usr/platform/`uname-m/sbin/prtdiag -v

--or--

prtconf -V

One of the first test POST runs is to check to determine if a keyboard is connected to the system and if a Stop-key option is present.

Stop-D key sequence is initiated when Stop and D keys are hold down simultaneously. This switches the system to diagnostic mode. This mode runs more extensive POST diagnostics on the system hardware. 

Stop-A key sequence interrupts any program that is running and puts the system into the command entry mode for the OpenBoot PROM. Pressing Stop and A simultaneously will achieve this state and presents an ok prompt for the user.

To diable the abort key sequence, edit the /etc/default/kbd file. 

Inside the file, "KEYBOARD_ABORT=disable" line is commented out. That line should be uncommented and after the file is saved, execute the command "kbd -i". 

The Stop-A key sequence will only be allowed during the boot process.

banner: Displays the power-on banner / system boot version / mac address

boot: Boots the system

help: Lists the main help categories

printenv: Displays all parameters’ current and default values

setenv: Sets the specified NVRAM parameter to some value

reset-all: Resets the entire system; similar to a power cycle

set-defaults: Resets all parameter values to the factory defaults

probe-scsi: Identifies the devices on the internal Small Computer System Interface (SCSI) bus

probe-scsi-all: Identifies the devices on all SCSI buses

probe-ide: Identifies devices on the internal integrated device electronics (IDE) bus

probe-fcal-all: Identifies devices on all Fibre Channel loops

show-devs: Displays the entire device tree

devalias: Identifies the current boot device alias for the system

nvalias: Creates a new device alias name

nvunalias: Removes a device alias name

show-disks: Displays and allows a selection of device paths for the disks to be used for nvalias

sync: Manually attempts to flush memory and synchronize file systems (take dump)

test: Runs self-tests on specified devices

show-nets: Show network devices

eeprom Commands

Use the /usr/sbin/eeprom command to view and to change the NVRAM parameters:

eeprom: lists all of the parameters with their current values.

eeprom boot-device: lists a sigle parameter and its value ( the parameter of boot-device in this statement).

eeprom boot-device=disk2: this changes the value of the default boot device to disk2.

eeprom auto-boot?=true: this changes the value of the auto-boot? to true.