A rugged (or ruggedized, but also ruggedised) computer is a computer specifically designed to operate reliably in harsh usage environments and conditions, such as strong vibrations, extreme temperatures and wet or dusty conditions. They are designed from inception for the type of rough use typified by these conditions, not just in the external housing but in the internal components and cooling arrangements as well. In general, ruggedized and hardened computers share the same design robustness and frequently these terms are interchangeable.