Subject: Re: Single file system (buf) read size
To: =?iso-8859-1?Q?P=E5l_Halvorsen?= <>
From: Manuel Bouyer <>
List: tech-kern
Date: 03/13/2001 21:20:41
On Tue, Mar 13, 2001 at 10:24:52AM +0100, Ignatios Souvatzis wrote:
> On Mon, Mar 12, 2001 at 10:19:38PM -0800, Chuck Silvers wrote:
> > there's the MAXPHYS constant that you should bump up to the maximum i/o size
> > you want to use.  I wouldn't be surprised if you ran into trouble though,
> > since I imagine hardly anyone tests drivers with an increased MAXPHYS.
> It's worse.
> The amiga/dev/asiop driver (and its descendants) have a static area of
> dma regions allocated in the address space written by the driver and
> read by the downloaded script code... it's scaled as MAXPHYS / MMUpagesize.

Same for the MI siop driver.
The IDE drivers are also limited to 64K/xfer, and that's a hardware limit.

Manuel Bouyer <>