Messages in this thread |  | | | Date | Mon, 12 May 1997 12:53:34 +0200 (MET DST) | | From | Geert Uytterhoeven <> | | Subject | Re: Kernel Debugging Hardware |
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On Mon, 12 May 1997, Harald Koenig wrote: >On May 12, Steven S. Dick wrote: >> I believe it would be possible for <$50 to make a small device that could >> sit on a serial port and look for kernel OOPS messages and record them >> so that they can be examined after a reboot. >> >> One possible implementation would use a serial eeprom and a pic chip >> as a ring buffer and controller. It could be set up to just remember >> the last several K of messages, or stop recording before overwriting >> the first OOPS it sees, or something like that. > >good idea, I'd need it for better debuging of Xservers when the PC completely >locks up (and of course for kernel stuff too). > >a few questions/remarks (not being too good in circuityr anymore): > >- how many write cycles are possible for eeproms these days ? I remeber of some 10k cycles ?! > if this is still a limitation there would be no chance to log data online until > the system will crash (ok, it would be enough to record the oops once it happend > but that's usually not my subject) > > what about using a 8k SRAM or similar ? using e.g. Tx etc. for power supply... > loosing data after power off is usually no big problem
Another solution that we have on Linux/m68k on Amiga: kernel messages are logged in an otherwise unused 256K chunk of Chip RAM. In most cases the data isn't destroyed by the crash, and you can get it back with a small AmigaOS program that searches for some magic number at the start of the 256K chunk.
Maybe this can be extended for other architectures.
Greetings,
Geert
-- Geert Uytterhoeven Geert.Uytterhoeven@cs.kuleuven.ac.be Wavelets, Linux/m68k on Amiga http://www.cs.kuleuven.ac.be/~geert/ Department of Computer Science -- Katholieke Universiteit Leuven -- Belgium
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