ipc = interprocess communication.
shm = shared memory
i did not know the answer to this, but it looked interesting, so I googled
"linux /dev/shm" which led me to http://linuxfromscratch.org/pipermai...er/039568.html
a bit hairy, but there are probably other hits that explain better
You can "man ipcs", ipcs -m to see which processes are using shared memory,
which, I currently think. is probably not /dev/shm