Reduced checking sequences using unreliable reset

• An unreliable reset can be first verified and then used as a reliable reset.
• Using verified unreliable resets reduces the length of checking sequences.
• A synchronizing sequence can be used as an unreliable reset.
• Our method is widely applicable since almost all FSMs have synchronizing sequences.

The length of a checking sequence (CS) generated from a deterministic, minimal, and completely specified finite state machine model M of a system under test which does not have a reliable reset feature, is exponential when M does not have a distinguishing sequence. This is due to the exponential length locating sequences that need to be used in such a CS. In this work, we propose a method to decrease the number of locating sequences used in CS, by first verifying the reset input r and then using r as a reliable reset. When such a reset input is not available, a synchronizing sequence can be used as a compound reset input, which makes the proposed method applicable to a wide range of systems.