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To: Mark Valentine <mark@valentine.me.uk>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Mon, 06 Oct 2003 23:20:06 -0000."
             <200310062220.h96MK7PI061345@dotar.thuvia.org> 
Date: Tue, 07 Oct 2003 00:36:30 +0200
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cc: arch@freebsd.org
cc: Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
Subject: Re: Alignment of disk-I/O from userland. 
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In message <200310062220.h96MK7PI061345@dotar.thuvia.org>, Mark Valentine write
s:


>It would be reasonable to enforce such restrictions on a raw device if
>we still had block devices around, but it doesn't seem reasonable now.

It would be reasonable to make such a statement if you could
demonstrate an actual application which must depend on this to work.

The fact is that we currently do not offer any guarantee for disk-I/O
even correctly reporting failure, unless your memory buffer is
aligned according to driver specific requirements.

And yet things still work.

If I thought there would be any significant breakage (of non-shitty
code), I would not be in doubt as to what the right thing to do
would be :-)

If shitty code breaks, I don't care.  We're trying to raise the
standard in and with FreeBSD, we're not trying to lower the bar
to make any visual basic programmer pass.


-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.