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Re: Audio



On Tue, 15 Sep 1998, Helge Hafting wrote:

> In <Pine.GSO.3.95q.980914165148.14025D-100000@jupiter>, on 09/14/98 
>    at 04:56 PM, " Raymond A. Ingles" <inglesra@frc.com> said:
[...]
> > Unfortunately, the PC ISA DMA controller can't address memory beyond the
> >first 16MB. So, when a DMA buffer is requested, the kernel has to find a
> >continuous chunk of memory that is physically below 16MB. If it can't
> >find it, too bad.
> 
> The kernel should then swap something below 16M out, or preferably push it
>  above 16M.  Anybody know why it doesn't do that?  I find it unlikely that
> *all* memory below 16M should be locked for i/o or something.

 I don't know all the details about why the kernel can't do that, but I'm
given to understand that performance would suffer, and some programs would
break. There was a discussion on linux-kernel a while ago, maybe it's
archived somewhere.

 Sincerely,

 Ray Ingles          (248)377-7735        ray.ingles@fanucrobotics.com

  Modern inductive method: 1) Devise hypothesis. 2) Apply for grant.
 3) Perform experiments. 4) Revise data to fit hypothesis. 5) Publish.


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