Hi, Naveed-
To address your question #1: this program uses OpenMP to parallelize. You can set the number of threads (constrained by number of threads on your computer) with an environment variable.
For example, if using bash, you can put this into your ~/.bashrc file:
export OMP_NUM_THREADS=30
and analogously for tcsh.
I don't know about #2. I'm just guessing that "no" is the answer about HDF5, but someone else can weigh in on that.
--pt