From owner-freebsd-hackers Thu Feb 1 23:39:53 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from mobile.wemm.org (c1315225-a.plstn1.sfba.home.com [65.0.135.147]) by hub.freebsd.org (Postfix) with ESMTP id 678F237B491 for ; Thu, 1 Feb 2001 23:39:34 -0800 (PST) Received: from netplex.com.au (localhost [127.0.0.1]) by mobile.wemm.org (8.11.1/8.11.1) with ESMTP id f127dUW23005; Thu, 1 Feb 2001 23:39:31 -0800 (PST) (envelope-from peter@netplex.com.au) Message-Id: <200102020739.f127dUW23005@mobile.wemm.org> X-Mailer: exmh version 2.2 06/23/2000 with nmh-1.0.4 To: Lars Eggert Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: capturing an early kernel dump In-Reply-To: <3A7A3180.35697C0E@isi.edu> Date: Thu, 01 Feb 2001 23:39:30 -0800 From: Peter Wemm Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Lars Eggert wrote: > [Repost from last week, no answer then.] > > How do I capture an early kernel dump (before rc executes and sets > dumpdev)? > > The dump partition used to be an option in the kernel config file, but that > seems to have changed in 3.X or 4.X. > > Thanks, > Lars How early? We could dump if you were prepared to hardwire in the minor and major device numbers to get to the devsw[] vectors and manually set the offsets. The biggest problem is that if it is Really Early (TM) we may not have read the disk label and may not be able to see what the partitions look like. It may need to be blindly dumped using a magic offset that you supply somewhere and *hope* that you get the numbers correct so you dont trash something. Alternatively.. dedicate a disk for it and just start dumping to the beginning of the disk and work upwards... Cheers, -Peter -- Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message