Kernel debugging hardware - blinkenlights

Pavel Machek (
Tue, 8 Jul 1997 22:34:20 +0200


Some time ago it was debate here about what hw could be used for
debugging kernel... Here's what I built:

8 leds connected to paralel port, so what goes on hw port 378 can be
easily seen. (Actually they are 12, but 4 remaining due not shine too
much - not worth that work).

I make them display stage of kernel booting, and after bootup low bits
of PID of current process. You can see _much_ of what happens on such

And now questions:
1) How many other similar devices are out there? [Something similar is
put on port 0x80, I saw something similar on sun 4/330 - do newer suns
have this?]
2) I would like some led to indicate ppp & eth0 activity. Where should
I add a hook?


I'm really 	   Pavel
Look at ;-).