Diagnostics via OpenFirmware

V.Yakob

Tinkerer
Sep 6, 2023
63
26
18
Hi!

I have long seen reports that OpenFirmware (OFW) can run tests of equipment that is equipped with self-testing instructions. On different sites you can find many similar messages that mainly link to this site.
I tested it on QS and MDD.

So, I enter the OFW and turn on diag-switch? And disable Mac OS startup
Code:
setenv diag-switch? true
setenv auto-boot? false

Reboot
Code:
reset-all

After rebooting, the system starts for about 15 minutes, instead of booting the OS, the system immediately enters OFW. As I understand it, testing is being done all this time.
But commands entered manually, such as "test-all" to test all devices or "test /memory" to test RAM are not executed, a message is returned "test-all, unknown word".

Does anyone know how to use it in PowerMac? How do I get a report after enabling "diag-switch?" after booting the OS?
Maybe I need to additionally change "diag-device" and "diag-file"?

Or is diagnostics fully implemented only in SUN computers, and here in PPC it works with restrictions?
 

joevt

Tinkerer
Mar 5, 2023
73
32
18
Looking at MDD Open Firmware dump, it appears that diagnostic boot doesn't do anything except try to do this command:

boot enet:,diags

where enet is the default diag-device and ,diags is the default diag-file
I don't say any code for handling ,diags
Another default for diag-file is bootp
There seems to be a lot of code for boot.

Try one of these commands?
.log
.time-stamps
.time-stamps\

You can't enter Open Firmware after booting the OS.

Maybe you want to boot a Apple Hardware Test CD? You can find a download link, burn a CD and try that.

An alternative to diag-switch? is a key press: Command-Option-D

Here's a list of key presses in the MDD Open Firmware:
Code:
Key presses                    Notes
===================================================================
Command Option O F             Open Firmware
Control Command Option O F     Open Firmware using serial port
Command E                      eject
Command Shift Option D         skip boot-device
Command Option ?               snag optional tbxi in root
Command ?                      snag optional tbxi in root
Command .                      cancel gui-bootdev-search
C                              snag cd
D                              snag hd
N                              snag enet (bootp)
Z                              snag zip
Option                         multi-boot
Command Option P R             reset-nvram
Command Option D               diagnostic-boot
T                              target-mode
Return or Enter                return key
 
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V.Yakob

Tinkerer
Sep 6, 2023
63
26
18
@joevt, I'm interested in the built-in diagnostic tools. For some reason, I always believed that Power Mac has it. 🤔 Perhaps various materials about OpenFirmware in SUN computers have created confusion in my head.

Indeed, if I do not connect the network cable to MDD and reboot after turning on diag-switch?, the system starts quickly, and at the top there is a message:
BOOTP/DHCP failed : SERVER is not responding can't OPEN: enet:,diags
Diagnostics-Boot Failed!!

So the system is trying to find a BOOTP server on the network that will transmit a diagnostic script?

Has anyone ever seen such scripts? I googled for a long time, but I didn't find anything.