“Bus Fault” when trying to probe-scsi-all on a Sun Ultra 5

I had a customer recently call me with a “bus fault” when he was trying to probe-scsi-all from the ok prompt. On separate occasions, I had sold him an Ultra 5 and a Dual Differential SCSI card (part# 375-0006) and he had just recently installed the SCSI Card into the Ultra 5 with the aforementioned error arising whenever he tried to do a probe-scsi-all from the ok prompt.

After asking him the steps he had taken to install the card and making sure that he had the minimum necessary OBP version (i.e. firmware) installed on the Ultra to avoid any possible conflicts, I had him do the following (all from the ok prompt)

ok set-defaults

This sets all the NVRAM settings back to factory default values.

ok setenv auto-boot? false

Since in the first command we set all NVRAM settings to default, we now have to tell the computer to stop at the OK prompt. That’s what this command does.

ok reset-all

This command reboots the machine. When the machine reboots and comes up to the OK prompt, we re-try the command that caused the error:

ok probe-scsi-all

When we tried this, the customer was no longer getting the “bus fault” error. It simply showed him the SCSI cards installed in the system (this will usually take anywhere from 30 seconds up to a minute or two) and then returned him back to the OK prompt. Walla! Problem solved. To make sure the card was now detectable in in Solaris, I then had him do:

ok boot -r

This command boots the operating system (Solaris) while reconfiguring the kernel to detect new devices installed in the system (i.e. the new card) and install their respective drivers.

PS: Don’t forget to stop by AnySystem.com for all your Sun hardware and consulting needs.

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