Hi,
I have read all the old messages on shared memory and nothing has helped.
I have been attempting to use shared memory as is spelled out in the paper
"Using Shared Memory in Real-Time Linux" by Fredrick M. Proctor and in your
"HOWTO." I am confused and if you have any suggestions I'd appreciate it.
1. I have gotten shared memory to work with two non-real time applications.
But, when I try and add a rt application the real-time application appears
to be accessing different memory because if I write a new value to the
shared memory the applications don't see it. I have verified that the
pointer to memory in the real-time application and the pointers in the linux
applications all contain the same address. I did this by passing the rt_ptr
through a FIFO to the non-real time application and doing an fprintf.
what I mean is that the user_ptr = (BLOCK *) mmap ( .... ) from the linux
applications is the same as the address pointer in the real-time application
char *rt_ptr = ADDRESS
So, why aren't the accessing the same memory?? user_ptr = 0x7d00000 and
rt_ptr = 0x7d00000 but why doesn't the application see it when the rt
process initializes the block structure to a value ?? i.e. rt_ptr->block[0]=
500 or rt_ptr->block[10] = 444;
I use a common header file where
struct {
unsigned short block[5000];
} BLOCK;
Any suggestions ??
I am using Kernel 2.0.36 and RTL v1.1
I have 128Mbytes of memory on a pentinum II and I want to use close to
4Bytes maximum eventually, so my lilo.conf has append="mem=125m"
I am very new to Linux so would appreciate any help in finding the answer.
Thanks
Janet Estabridis
Electrical Engineer
NAWC Code 473E00D
China Lake, CA 93555
(760) 939-2896 FAX (760) 939 -3075
application/ms-tnef
