We have designed a tool to simplify model checking of Erlang programs by translating Erlang into a process algebra with data, called µCRL. As a case-study for this tool we focused on a simplied locker implementation after the locker that is present in the control software of the AXD 301 switch. The translation algorithm has been developed to handle this production-like code. We use the tools accompanying CRL to generate the transition systems from the specification generated by our tool. With the Caesar/Aldebaran tool set, we verified properties for our case-study.

Erlang is a concurrent functional programming language, mainly being employed in telecommunication systems. To satisfy the high quality demands in this application area, formal methods are becoming more and more popular. We provide a contribution to this field by outlining the design of a tool supporting the verification of Erlang programs by means of model-checking methods. It includes a novel, distributed model checker which validates the given program with respect to a user-defined correctness property, specified in a temporal logic.

Several years of experience with the functional language Erlang have learned Ericsson that it is highly beneficial to use this language for programming control software for large systems. Systems that could not be built before, have been constructed in less time and with fewer lines of code than one would need with conventional languages. The success of Ericsson in the business area of telephone switches is partly because of their solid fault tolerant architecture, both in hardware and in software. A lot of time and money have been invested in the development of this fault tolerant architecture, all to catch these errors that are overlooked in numerous tests. By using Erlang and its extensive libraries, the number of these uncaught errors decreases; the fault recovery mechanism of the system is used less. One saves on maintenance costs and the overall performance of a system increases. The additional use of formal verifiation aims on reducing even more the number of uncaught errors.