The paper reports on an experiment to provide the Erlang programming language with a tool package for convenient trace generation, collection and to support analysis of traces using a set of techniques. Due to the frequent use of statebased software design patterns in Erlang programming we can in many cases recover not only the events from a trace log, but also the program states causing these events. This makes it possible to obtain program models from execution traces. In our work we make use of these program models for program visualization and model checking.

Abstract. This position paper envisions making large-scale distributed applications self managing by combining component models and structured overlay networks. A key obstacle to deploying large-scale applications running on Internet is the amount of management they require. Often these applications demand specialized personnel for their maintenance. Making applications self-managing will help removing this obstacle. Basing the system on a structured overlay network will allow extending the abilities of existing component models to large-scale distributed systems. Structured overlay networks provide guarantees for efficient communication, efficient load-balancing, and self-manage in case of joins, leaves, and failures. Component models, on the other hand, support dynamic configuration, the ability of part of the system to reconfigure other parts at run-time. By combining overlay networks with component models we achieve both low-level as well as high-level self-management. We will target multi-tier applications, and specifically we will consider three-tier applications using a self-managing storage service. 1

We present a framework for formal reasoning about the behaviour of software written in ERLANG, a functional programming language with prominent support for process based concurrency, message passing communication and distribution. The framework contains the following key ingredients: a specification language based on the -calculus and first-order predicate logic, a hierarchical small-step structural operational semantics of ERLANG, a judgement format allowing parametrised behavioural assertions, and a Gentzen style proof system for proving validity of such assertions. The proof system supports property decomposition through a cut rule and handles program recursion through well-founded induction. An implementation is available in the form of a proof assistant tool for checking the correctness of proof steps. The tool offers support for automatic proof discovery through higher-level rules tailored to ERLANG. As illustrated in several case studies this framework provides the expressive power required by the open and dynamic nature of distributed systems.

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.

The same component isolation that made it effective for large distributed telecom systems makes it effective for multicore CPUs and networked applications. By Joe aRmstrong Erlang is a concurrent programming language designed for programming fault-tolerant distributed systems at Ericsson and has been (since 2000) freely available subject to an open-source license. More recently, we’ve seen renewed interest in Erlang, as the Erlang way of programming maps naturally to multicore computers. In it the notion of a process is fundamental, with processes created and managed by the Erlang runtime system, not by the underlying operating system. The individual processes, which are