Commands

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Boot PROM FundamentalsAll Sun systems have resident boot PROM

firmwareProvides basic hardware testing and

initialization prior to bootingEnables to boot from wide range of devicesHas access to a standard set of generic

device drivers

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Goal of the OpenBoot Architecture StandardGoal of IEEE standard for the OpenBoot

Architecture Test and initialize system hardwareDetermine the system’s hardware

configurationBoot the Operating EnvironmentProvide an interactive interface for

configuration, testing, and debuggingEnable the use of third-party devices

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Boot PROMEach system has a boot PROM chip1 Mbyte chip is typically located on the same

board as the CPUBoot PROM chips are usually found in a

pluggable socket on older systemsAs of 3.x PROM, they are permanently

soldered to the main system board

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The Ultra workstations use a reprogrammable boot PROM called Flash PROM (FPROM)

Desktop systems have a write-protect jumper

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The main functions of the boot PROM are to test the system hardware and to boot the OE.

The boot PROM firmware is referred to as the “monitor program”

Also provides a user interface and firmware utility commands, known as the FORTH command set

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Generations of Sun boot PROM1.x - The first boot PROM used on SPARC

systems2.x - The first Openboot PROM3.x - The Openboot PROM with a flash

update feature4.x - The Openboot PROM that supports

the 64-bit UltraSPARC III processor5.x - Available on the Sun Enterprise

3500, 4500, 5500 & 6500 servers

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To determine which version of OpenBoot PROM is running on the system“# /usr/platform/’uname -m’/sbin/prtdiag -

v”

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NVRAMImportant hardware element Removable chip is often located on the

main system boardContains EEPROMEEPROM stores user-configurable

parameters that have been changed or customized from the boot PROM’s default parameter settings

Single lithium battery within the NVRAM module provides battery backup for the NVRAM and the clock

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NVRAM contains editable and noneditable areas.Non Editable areas

The Ethernet address The system host ID

Editable areas The time-of-day (TOD) clock value The configuration data describing system operating

parameters A diagnostic mode switch that enables or disables POST The device name and the path to the default boot device A location for customized programming that is used

during the boot process

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POSTWhen a system’s power is turned on, a low-

level POST is initiatedLow-level POST code is stored in the boot

PROM and is designed to test the basic functions of the system hardware

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On successful completion of the low-level POST phase, the boot PROM firmware takes the control and performs the following initialization sequence:Probes the memory and then CPUProbes bus devices, interprets their drivers,

and builds a device treeInstalls the console

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After the boot PROM initializes the system, the banner displays on the system console

The system checks parameters stored in the boot PROM and NVRAM determine if and how to boot the OE

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Controlling the POST phaseStop-D key sequence

Hold down the Stop and D keys simultaneously while system power is turned on, and the firmware automatically switches to diagnostic mode.

This mode runs extensive POST diagnostics on the system hardware.

The OpenBoot PROM variable “diag-switch?” is set to “true”

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Stop-N key sequenceHold down to set the NVRAM parameters to

the default valuesCan release the keys on seeing the LEDs on the

keyboard begins to flash

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Stop-A key sequenceTo interrupt any program that is running at the

time these keys are pressed and to put the system into the command entry mode for the OpenBoot PROM

Not recommended unless there is absolutely no alternative

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Disabling the Abort SequenceEdit the “/etc/default/kbd” fileRemove the comment from in front of

“KEYBOARD_ABORT=disable”Save the file and execute the command “kbd -

i”When the above steps are completed the

system allows Stop-A key sequence only during the boot process

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Displaying POST to the Serial PortCan attach a terminal to the serial port of a

system to capture a far greater amount of information from the POST output

When the power is turned on POST looks for a keyboard, if there is no keyboard present, POST diverts system output to serial port A

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POST runs more extensive tests when the system is in diagnostics mode with the PROM parameter “diag-switch?” set to “true”

Be sure to attach the correct type of null modem cable for your system type to serial port A

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