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Executing Boot PROM

Executing Boot PROM. Commands. Boot PROM Fundamentals. All Sun systems have resident boot PROM firmware Provides basic hardware testing and initialization prior to booting Enables to boot from wide range of devices Has access to a standard set of generic device drivers.

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Executing Boot PROM

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  1. Executing Boot PROM Commands

  2. Boot PROM Fundamentals • All Sun systems have resident boot PROM firmware • Provides basic hardware testing and initialization prior to booting • Enables to boot from wide range of devices • Has access to a standard set of generic device drivers

  3. Goal of the OpenBoot Architecture Standard • Goal of IEEE standard for the OpenBoot Architecture • Test and initialize system hardware • Determine the system’s hardware configuration • Boot the Operating Environment • Provide an interactive interface for configuration, testing, and debugging • Enable the use of third-party devices

  4. Boot PROM • Each system has a boot PROM chip • 1 Mbyte chip is typically located on the same board as the CPU • Boot PROM chips are usually found in a pluggable socket on older systems • As of 3.x PROM, they are permanently soldered to the main system board

  5. The Ultra workstations use a reprogrammable boot PROM called Flash PROM (FPROM) • Desktop systems have a write-protect jumper

  6. 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

  7. Generations of Sun boot PROM • 1.x - The first boot PROM used on SPARC systems • 2.x - The first Openboot PROM • 3.x - The Openboot PROM with a flash update feature • 4.x - The Openboot PROM that supports the 64-bit UltraSPARC III processor • 5.x - Available on the Sun Enterprise 3500, 4500, 5500 & 6500 servers

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

  9. NVRAM • Important hardware element • Removable chip is often located on the main system board • Contains EEPROM • EEPROM 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

  10. 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

  11. POST • When a system’s power is turned on, a low-level POST is initiated • Low-level POST code is stored in the boot PROM and is designed to test the basic functions of the system hardware

  12. 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 CPU • Probes bus devices, interprets their drivers, and builds a device tree • Installs the console

  13. 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

  14. Controlling the POST phase • Stop-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”

  15. Stop-N key sequence • Hold down to set the NVRAM parameters to the default values • Can release the keys on seeing the LEDs on the keyboard begins to flash

  16. Stop-A key sequence • To 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

  17. Disabling the Abort Sequence • Edit the “/etc/default/kbd” file • Remove 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

  18. Displaying POST to the Serial Port • Can 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

  19. 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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