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Date:      Mon, 20 May 1996 22:54:05 +0200 (MET DST)
From:      J Wunsch <j@uriah.heep.sax.de>
To:        freebsd-hackers@freebsd.org (FreeBSD hackers)
Cc:        dennis@etinc.com (Dennis)
Subject:   Re: Involking DDB
Message-ID:  <199605202054.WAA06407@uriah.heep.sax.de>
In-Reply-To: <199605201438.KAA21695@etinc.com> from Dennis at "May 20, 96 10:38:25 am"

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As Dennis wrote:
> 
> Is there a way to start DDB without a system crash...ie run the kernel in
> some sort of monitoring mode on demand?

Several of them.

Boot with `-d'.  This drops you into DDB early in the game, so you can
even trace the device probing.  Since interrupts are not yet enabled,
the ``hot keys'' described below won't work however.

Hit the ``hot key'' on the PC keyboard.  This is Ctrl-Alt-ESC by
default, though i think some syscons keymaps tweak it onto another
combination (which i forgot).

Compile your kernel with option ``BREAK_TO_DEBUGGER'', use a serial
console, and force a line break on the RS-232.  This will drop you
into DDB on the serial console.  (If you've got a PC keyboard + driver
as well, its ``hot key'' will do the same, even though the console is
a serial one.)

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)



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