conf/118255: savecore never finding kernel core dumps (rcorder problem)

[Antony Mawer]

The following reply was made to PR conf/118255; it has been noted by GNATS.

From: Antony Mawer <gnats at mawer.org>
To: bug-followup at FreeBSD.org, koitsu at FreeBSD.org
Cc:  
Subject: Re: conf/118255: savecore never finding kernel core dumps (rcorder
 problem)
Date: Fri, 30 Nov 2007 12:30:17 +1100

 There seems to be conflicting information about what constitutes the 
 correct behaviour here. The original 4.4BSD "Unix System Manager's 
 Manual (SMM)", found here:
 
      http://docs.freebsd.org/44doc/smm/02.config/paper-6.html
 
 Indicates the following (found under the "System dumps" heading):
 
      - Kernel dumps write from the end of swap and work backwards
      - The kernel uses swap from the front and works forward
      - This way it reduces the chance of swapping overwriting the dump
         during the boot process until savecore is run
 
 This somewhat more modern posting suggests that is still the case:
 
 http://unix.derkeiler.com/Mailing-Lists/FreeBSD/stable/2005-11/0703.html
 
 However the FreeBSD Developers' Handbook suggests a behaviour that does 
 not match the current reality:
 
 http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug.html#EXTRACT-DUMP
 
 Can anyone speak with more authority on this...?
 
 --Antony