Date: Tue, 15 Nov 2005 19:18:35 -0800 From: David Wolfskill <david@catwhisker.org> To: stable@freebsd.org Subject: Re: Swapfile problem in 6? Message-ID: <20051116031835.GS69015@bunrab.catwhisker.org> In-Reply-To: <20051116020933.72951.qmail@web36209.mail.mud.yahoo.com> References: <20051115103821.GJ39882@cirb503493.alcatel.com.au> <20051116020933.72951.qmail@web36209.mail.mud.yahoo.com>
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On Tue, Nov 15, 2005 at 06:09:33PM -0800, Rob wrote: > ... > > Yes. See above URL. The advantage is that you can > > (hopefully) capture a log of your debug session. > > Send a serial BREAK and you should get a DDB> > > prompt. > > What is this "serial BREAK"? > How do I "send a serial BREAK" at the serial > console? Is this some magic key combination? I'm probably saying something about my age by doing this.... :-} A "BREAK" (in serial communications) is an absence of start or stop bits for more than a character's worth of bits, is handled as a "framing error," and is distinct from any character. Now, to generate one, you would normally hit the BREAK key of your terminal (Control-BREAK on some; I think Hazeltine had this feature of dubious merit). If you are using a serial communications program (such as "tip") instead of an ASCII terminal, it depends on the program you're using. In the case of tip, the sequence "~#" at the beginning of a line will generate tip's best approximation of a framing error. In the case of kermit, Control-\B does it. > And, eh, at the moment of deadlock, there is no > response at all from the serial console; will the > "serial BREAK" not be bothered by that? The serial BREAK won't be bothered at all. :-} The issue is (if I understand properly) whether or not there's enough of the system to be able to have the tty driver recognize the framing error and do something appropriate as a result. Peace, david -- David H. Wolfskill david@catwhisker.org Prediction is difficult, especially if it involves the future. -- Niels Bohr See http://www.catwhisker.org/~david/publickey.gpg for public key.
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