Re: write alignment matters?

[David Holland <dholland-tech%netbsd.org@localhost>]

On Fri, Jun 24, 2011 at 01:43:34AM +0200, Johnny Billquist wrote:
 > >In other words, Erik is right, at least if we're talking historically.
 > >Of course, at least there it's documented.  (I took a quick glance
 > >at the code, too -- it did appear to check for erroneous parameters,
 > >though I think it just truncated the count in some drivers.)
 > 
 > That's because of a hardware limitation of many controllers on a
 > PDP-11. They can only start DMA to even addresses. And that in turn
 > is partly because of the whole design of the PDP-11 itself. It
 > really is, in many ways, a word addressable machine, and only
 > partially 8-bit byte oriented.
 > 
 > So I'm not sure how relevant that is for a general case. It would
 > seem to be very architecture specific.

Well, the point is, more or less, that this property is/was exposed by
the kernel.

-- 
David A. Holland
dholland%netbsd.org@localhost