Newsgroups: comp.arch
Path: utzoo!utgpu!watserv1!watdragon!rose!ccplumb
From: ccplumb@rose.uwaterloo.ca (Colin Plumb)
Subject: Re: Computers for users not programmers
Message-ID: <1991Feb2.193322.24374@watdragon.waterloo.edu>
Sender: daemon@watdragon.waterloo.edu (Owner of Many System Processes)
Organization: University of Waterloo
References: <409@bria> <13252@lanl.gov> <2880@charon.cwi.nl> <1991Feb02.113032.6370@kithrup.COM>
Date: Sat, 2 Feb 91 19:33:22 GMT
Lines: 22

sef@kithrup.COM (Sean Eric Fagan) wrote:
>>> I want to go into the 'core' file
>>> and edit out the zero and restart the job from where it left off.  
>>> Oh,
>>> UNIX can't restart 'core' files.
>
>Neither can any other system I've seen (except some batch systems).  Mostly
>because they did not always have the equivalent of a core-dump.  NOS
>provided a way to do this, I believe, but you ended up doing what you would
>do in UNIX anyway:  turn the "core" into an executable after editing it, and
>patching things up such that it went the way you wanted it to.

Well, "undump" works in Unix to restart a core file, but from my
reading of the docs, Mach's "macho" file format is designed as both a
load format and a core dump.  So you could have multiple threads
running around, on calls abort(), and spits out a core file.  You could
then restart everything with "./core".  I think the existing 4.3
wrapper uses differnt formats for its core dumps, but the loader will
understand a macho file (as well as Berkeley a.out format) if you feed
it to it.
-- 
	-Colin
