Debugging techniques and core dumps (was Re: ebay - cardamatic)

From: Eric Smith <eric_at_brouhaha.com>
Date: Mon Feb 14 18:31:32 2005

Tom Jennings wrote:
> Also, no one debugs from memory dumps anymore -- UGH! What
> masochism that is! Only did it once.

Actually, some of us still do that under Linux (or Unix). I'm
not sure whether there's an equivalent of a core dump for Windows.

When I get a core dump, if it's not immediately obvious what was
wrong, I load it into the debugger (gdb) to investigate it. For
gdb, the core dump filename is an optional command line parameter
after the executable file.

When I worked at Telebit on the Netblazer multiprotocol dialup
router (the world's first dial-on-demand IP router), core dumps from
customers were the best debugging capability we had. In addition
to being able to use them in the debugger for postmortem analysis,
one of our most talented engineers, Bill, wrote a tool to "reanimate"
a Netblazer core dump. This worked because the Netblazer ran on
a 386, and we had 386 and 486 BSDI Unix systems for development.
Bill's tool took the core dump file, loaded it into the memory of
a Unix process, patched some of the I/O routines, and let you
execute it. This was handy because we'd built a lot of special
debug facilities into the Netblazer code, accessible through its
CLI.

So I wouldn't write off the core dump debugging technique nearly as
quickly as desk checking and patching.

Eric
Received on Mon Feb 14 2005 - 18:31:32 GMT