Re: Crash followed by green db> prompt

["Thomas Mueller" <mueller6724%bellsouth.net@localhost>]

> You probably activated ddb(4) by pressing <Ctrl>-<Alt>-<Esc> - see the ddb(4) 
> manpage for details.

Very unlikely: I was editing a file in the vi editor.  After running vi in 
recovery mode, I saw a bunch of garbage with null characters in the middle of 
the file.  When I went to delete that, I got another crash, apparently, as the 
screen went blank and couldn't be revived by an ordinary keypress.  I was 
fooled into power-off rebooting, but later found that it might have been 
screenblank running when it was not supposed to.

After a subsequent such false crash, I found I could revive the screen by 
Ctrl-Alt-F2, going to another virtual terminal, waiting for the login prompt 
that I couldn't see, and typing 
root(enter)

After waiting a few seconds for a password prompt that I couldn't see, I typed 
the root password(Enter), and then, in response to the command prompt that I 
couldn't see, typed
screenblank -u

Back to life!  Not wanting to depend on this, I turned off screenblank in 
/etc/rc.conf.

Thanks to Martin Husemann for suggestions regarding ddb and sysctl, but very 
doubtful if I will be able to reproduce that particular crash, and very 
doubtful that I would know how to do anything useful in the debugger.

Tom