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 dholl...@netbsd.org
