Fast processing of information represented in digital holograms is provided to facilitate generating a phase-only hologram for displaying 3-D holographic images representative of a 3-D object scene on a display device. Each of the local system and the remote system has an application server, a database server and a plurality of client computers. The bypass pre-cooler also includes a valve coupled to the inlet and configured to switch airflow between the heat exchanger and the bypass section and an outlet coupled to the heat exchanger and the bypass section.