Messages in this thread |  | | Date | Thu, 12 Oct 2000 13:54:25 -0500 | From | Timur Tabi <> | Subject | Re: large memory support for x86 |
| |
** Reply to message from Jeff Epler <jepler@inetnebr.com> on Thu, 12 Oct 2000 13:08:19 -0500
> What the support for >4G of memory on x86 is about, is the "PAE", Page Address > Extension, supported on P6 generation of machines, as well as on Athlons > (I think). With these, the kernel can use >4G of memory, but it still can't > present a >32bit address space to user processes. But you could have 8G > physical RAM and run 4 ~2G or 2 ~4G processes simultaneously in core.
How about the kernel itself? How do I access the memory above 4GB inside a device driver?
> There may or may not be some way to support an abomination like the old "far" > pointers in DOS (multiple 4G segments), but I don't think it has been written > yet.
Yes, it's ugly, but it works and it's compatible. Well, compatible with 32-bit code, probably not compatible with Linux code overall.
Of course, you could define a pointer to be a 48-bit value, but I doubt that would really work.
-- Timur Tabi - ttabi@interactivesi.com Interactive Silicon - http://www.interactivesi.com
When replying to a mailing-list message, please don't cc: me, because then I'll just get two copies of the same message. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
|  |