How can I make my home Linux most closely resemble the Linux used at my school?

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http://unix.stackexchange.com – We have to ssh into our school's server to make sure our programming assignments work on the system that will be used to test them by the teacher. It's running RHEL 6.2. When I test my program on my Mac running RHEL 6.2 in VirtualBox, I get different results than the school's. Are there any steps I can take to get my RHEL running similarly enough to the school's so that we get the same results, or are there too many variables for it to be plausible (hardware, root settings, etc)? EDIT: The programming is in C++ for an Operating Systems class. We're working with system calls and whatnot. (HowTos)