1. A computer system comprising: a plurality of processing modules, each mountable in a carrier rack and each including a processor and a volatile memory; a storage module including non-volatile memory, wherein the storage module is external to the plurality of processing modules and stores operating system instructions of a common operating system of the plurality of processing modules; and a switching module coupled to each of the plurality of processing modules and the storage module, wherein the switching module is configured to provide operating system instructions of the common operating system to each of the plurality of processing modules in order to permit each of the plurality of processing modules to execute the common operating system on its respective processor from its respective volatile memory.