Hi there, I Introduce myself, I'm managing an small cluster running rocks (rocksclusters.org), CentOS 5, and Sun sge job scheduler. I had to install idl 7.1 on this compute grid, so we can submit idl jobs on compute nodes with the qsub tool. IDL works fine but I have issues when I try to manage virtual memory limits outside idl. Example with the greatest helloword idl script you've ever seen: qsub -l h_vmem=256M -l hostname=compute-0-5 -b y -m e -M someone@somewhere.com -cwd idl hello_world but idl complains about the h_vmem(or s_vmem) argument (hard or soft limit) when trying to allocate memory. here is the error msg: % Internal threading error: Unable to create thread (IDL_ThreadCreate() calling pthread_create()). Cannot allocate memory the same job submission w/o the "-l h_vmem=INFINITY" works fine ... So ... Is it possible to manage vmem from outside idl ? What is the best way to manage memory with idl except within the developer's code ? Thanx a lot for your help Fred