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Date: Mon, 5 Sep 2011 20:18:30 -0400
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From: Arnaud Lacombe <lacombar@gmail.com>
To: Adrian Chadd <adrian@freebsd.org>
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Cc: freebsd-net@freebsd.org, "K. Macy" <kmacy@freebsd.org>
Subject: Re: No IPFW binary compat across versions ?
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Hi,

On Mon, Sep 5, 2011 at 7:50 PM, Adrian Chadd <adrian@freebsd.org> wrote:
> That's not what the COMPAT_* hooks are for.
>
> They're for backwards compatibility of normal userland binaries, not
> binaries which use a FreeBSD-specific kernel ABI.
>
What do you define as "normal" and where do you draw the line ?

>From my point of view, I should be able to run a FreeBSD 9.0 kernel
(when released) on top of a FreeBSD 5 userland without such issues.
That's what backward compatibility is. _Every_ piece of the ABI
exposed by the kernel[0] should be kept compatible, even funky
behavior userland might ends up relying on.

However, if as you say, you (the committers folks) willingly break the
exposed ABI, well, sorry, but that can no longer be called "backward
compatible"...

That said, this has turned out of context.

Now, to come back to my original issue, how am I supposed to track
down cross-release issue ? swap storage ? [sic...]

Regards,
 - Arnaud

[0]: ... with very few exception, such are security issue when there
is no other choices available.