The first and foremost layer of security you need to take into account is the physical security of the computer systems. How much physical security you need on a system is dependent on your situation and other logistics such as using shared labs, shared systems, deployments in a virtualized environment on a larger server, and so on. The various measures that need to be taken to ensure security involve things such as securing direct physical access to a machine and the security of connected peripheral and devices, as well as restricting access to system details such as BIOS passwords, screen-saver settings, password policies for console login, and so on.