Getting back to the pdc prompt from Never Never Land

What is your goal here? You want to be able to reboot the machine remotely? Or just reboot more gracefully than by cycling power? Or reboot with some debug info? Or ...?

We have a couple of techniques to help debug or recover from hangs:

We catch the TOC trap and force a crash dump and reboot. This way you can push the little TOC button on the front/back of the machine and have the machine take a dump and reboot. This approach should work very early in the kernel boot process provided you use the PDC to do the crash dump. This is *not* what TOC was intended for and isn't what HP-UX does, so HP people may not approve :-)

If you have an HIL, there is a "non-maskable" interrupt you can generate via the keyboard (shift-reset? I don't remember any more...) and then do a similar thing. On the 68k boxes this was a real NMI, but on the PAs its just a plain ole interrupt so it will not work if you hang with interrupts masked. It also only works if the keyboard is in "cooked" mode (i.e., you don't have X running).

You can build or buy remote power-cycling boxes which are effectively just a switch on the power cord that you control over an rs232 line. APC (the UPS people) makes one of these or you can build them from components. This is what we use for our PC test boxes.

We have also used the "packet of death" approach, sending a magic packet over the LAN to force a reboot. Requires that the interface be up and running and interrupts not masked of course.

I don't understand --

Are you saying HP-UX doesn't use the TOC button to cause a dump and reboot? That's exactly what happens on HP-UX!

Rich