A comparison of two formal languages to specify a simple user interface

Safety Critical Systems are the ones whose failure may lead to death, injury, loss or damage to an equipment or environmental harm. These systems need proper monitoring and concrete background software in order for their smooth running over a period of time.This research uses a specification of user interface for a critical system and translates it from one source specification language (ASLAN) to target specification language(PVS).This conversion is effective because PVS is higher level language where as ASLAN works on state transitions. The simple user interface used in this research is based on a mouse-window display that could be used at engineering work stations to control safety critical systems. The context of this user interface is a ‘mission control’, where engineers at work stations monitor different aspects of a safety critical process. The ASLAN specification was converted to PVS and PVS proved to be robust than ASLAN. PVS reduced the lines of specification because it has in built functions that can handle same functionality. PVS allows partial implementation with greater scope for reuse.Unlike PVS, complex functions are unmanageable in ASLAN because every function is expressed in terms of state transitions.