The level of safety within a system represents its ability to operate without catastrophic failure. For example, a system that controls an airplane’s flight systems is regarded as being a safety-critical system due to the fact that the software can pose a threat to human life. Safety-critical software systems fall into two classes, primary safety-critical and secondary safety-critical. The primary class represents systems that would result in human injury or environmental damage should they malfunction. The secondary class represents systems that can indirectly result in injury due to a malfunction. For example, a malfunction within a system that maintains a medical database could result in the wrong dosage being administered.
Although currently developed P2P applications have not been safety-critical, it is unwise to assume that this will always be the case. Consequently safety could have an important influence on the P2P architecture used.