Physical memory access with SystemV/AT
Larry Williamson
larry at focsys.UUCP
Sat Jun 11 01:25:07 AEST 1988
How does one obtain access to physical memory in System V/AT?
I have a video processor board that I need to access. This board
is accessed through a 1Meg buffer mapped on any 1Meg boundry in
the 286's address range.
I would ideally like to be able to do whatever shmcreate does and
create a shared memory segment that I would then use to access the
memory on this board. But I would like to be able to create a
segment that is the full 1 Meg memory size, or at least be able
to create 4 256K segments.
I would like to do something like:
shmcreate 0x800000 800000 1048560
to create a 1Meg shared memory segment at the 8meg address location.
Shmcreate restricts segment sizes to 64K. So I must use something
else, but what?
If my only option is to use shmcreate and I have to restrict my
segment size to 64K, then I will. But even this may not work as
there may be a limit to the number of 64K segments that can be
created. I would need at least 16 of them.
Thanks, larry
--
Larry Williamson Focus Automation Systems
UUCP: watmath!focsys!larry 608 Weber St. N, Waterloo, Ontario N2V 1K4
+1 519 746 4918
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