it's a little bit complicated,
1. i have a script starts 20 xterms like this,
xterm -e "uml ..."
here uml is the open source virtual machine.
so basically i run 20 umls in my pc, each in a xterm so i can check
the progress.

2. each of uml will automatically start my application,
which is multithreaded, has pipes, sockets etc.
basically instead of 20 pcs run my app to stress test the server
in the other end. I use UML to do this in 1 pc.

when i do this, every once a while some xterms disappear.

if the UMLs don't run my app, i know it's fine.
but if my app has bug, how can it kill the xterm ?

During this procedure, i keep on checking pc memory by "free -m",
and seems it has plenty of free memory.
Total is ~3GB, but i never see the used memory exceed 2GB.

thanks !