SCSA10-1 Objective 3.1 - SPARC Boot PROM, NVRAM and POST

Sun’s SPARC platforms employs the OpenBoot architecture for accessing low-level boot PROM system configuration inforamation, similar to the BIOS of an Intel x86 system. Other low-level concepts covered in this objective include NVRAM (nonvolitile RAM), POST (power on self test), and the boot abort sequence.

Given a scenario, explain boot PROM fundamentals, including OpenBoot Architecture Standard, boot PROM, NVRAM, POST, Abort Sequence, and displaying POST to serial port for SPARC.

Knowing how to handle low-level system configuration is a must for a system administrator. Much of the information for this objective is covered in a chapter available from Que Publishing. Although this chapter refers to Solaris 9, the information is appropriate for Solaris 10 since the OpenBoot environment is independent of Solaris in the same way that an Intel BIOS is independent of a Windows or Linux operating system.

Sun has Solaris documentation for OpenBOOT quick reference and NVRAM configuration parameters. The NVRAM parameters can be viewed and changed from the Solaris command line which prevents the need to reset the system.

The abort sequence is a key sequence that will stop the boot process or bring a running system to the ok> prompt. With an attached Sun keyboard, the default abort sequence is STOP-A (the STOP key and the letter A). If connected to a system through the console, the abort sequence is the ASCII break, typically available on a keyboard with a little hunting and finger gymnastics. Most terminal emulators will provide a “send escape” function. Solaris’ tip command sends a break when ~# is typed.

This Sun document describes using POST diagnostics including how to send POST output to the console ( dev-console ttya ).

In my experience, the most important things to know are: auto-boot?, reset-all, power-off, and probe-scsi-all.

The auto-boot? nvram parameter determines if the system will boot to the operating system when powered on. If set to false ( setenv auto-boot? false ), the system will stop at the ok> prompt. If a Sun box doesn’t boot and you see an ok> prompt on the console, don’t panic, do a printenv and look for this setting. If it is false, set it to true ( senetv auto-boot? true ) and reboot.

To reboot from the ok> prompt, use the reset-all command.

To power the system off, use the power-off command.

The main reason to set auto-boot? to false involves probe-scsi-all which iterates through the SCSI adapters and displays all SCSI devices. This command can hang a system that has been initialized past a certain point. Setting auto-boot? to false and resetting will ensure that the probe-scsi-all will succeed.

This entry was posted on Monday, November 28th, 2005 at 11:16 pm and is filed under SCSA I Solaris 10. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.