murphi

Murphi is a model checker developed at Bell Labs. It is used for the formal verification of hardware and software systems. Murphi works by exploring the state space of a system and checking if any of the reachable states violate a given property. The system to be verified is described in a specialized language called Murphi description language (MDL). MDL allows the specification of the system's states, transitions, and properties.

The model checking process in Murphi involves translating the MDL description into a finite state machine. This machine represents all possible configurations of the system. Murphi then systematically traverses this state space, using techniques like state compression and symmetry reduction to manage the size of the state space. During the traversal, it checks if any state violates the specified properties, which are typically expressed as assertions or invariants. If a violation is found, Murphi reports a counterexample, which is a sequence of operations leading to the erroneous state.

Murphi is particularly effective for verifying systems with concurrent or distributed behavior. Its ability to handle large state spaces makes it suitable for complex designs. The tool has been used in various applications, including the verification of network protocols, distributed algorithms, and hardware designs. The development of Murphi has contributed to the advancement of formal verification techniques and their practical application in ensuring the correctness of critical systems.