DMA transfers below 1MB physical memory?

Edgar Vonk (
Thu, 10 Apr 1997 11:38:55 +0200


does anyone know if it's possible to let a device driver allocate DMA
memory below the 1MB (physical memory)?

I read in the KHG that the memory allocated for devices starts at 1MB.

Is there any way to address physical memory below the 1MB at all?

I need this because our Data Acquisition Card can only address memory
(DMA) below the 1MB.
In DOS this is no problem since there is no protection whatsoever; in
Linux the memory management seems very much an internal kernel affair.


Edgar Vonk
Delft University of Technology
Dept. of Electrical Engineering, Information Theory Group
Tel: 015-2786213