Application of Dynamic Slicing in Program Debugging

A dynamic program slice is an executable part of a program whose behavior is identical, for the same program input, to that of the original program with respect to a variable(s) of interest at some execution position. In the existing dynamic slicing tools dynamic slices are represented in a textual form, i.e., a dynamic slice is displayed to programmers in the form of highlighted statements or in the form of a subprogram. Although dynamic slicing does narrow the size of the program, it is still up to the programmer to analyze the text of a dynamic slice and identify a faulty part in the program. The textual representation of a dynamic slice does not provide much guidance in program debugging and understanding of program behavior, which frequently is a major factor in efficient debugging. During dynamic slice computation different types of information are computed and then discarded after computation of the dynamic slice. In this paper we propose new dynamic slicing related features that exploit this information to improve the process of program debugging. These features were implemented in our dynamic slicing tool that can be used for program debugging. 1

Special Issue on best papers from ICSM 04

In systems developed without aspect-oriented programming, code implementing a crosscutting concern may be spread over many different parts of a system. Identifying such code automatically could be of great help during maintenance of the system. First of all, it allows a developer to more easily find the places in the code that must be changed when the concern changes and, thus, makes such changes less time consuming and less prone to errors. Second, it allows the code to be refactored to an aspect-oriented solution, thereby improving its modularity. In this paper, we evaluate the suitability of clone detection as a technique for the identification of crosscutting concerns. To that end, we manually identify five specific crosscutting concerns in an industrial C system and analyze to what extent clone detection is capable of finding them. We consider our results as a stepping stone toward an automated "aspect miner” based on clone detection

Highly Integrated Task and Resource Scheduling for Mission-Critical Systems

We report on considerable extensions of the DRAGON SLAYER/ MELODY file system which significantly enhance Melody's missioncritical capabilities (hard real-time responsiveness, adaptability, dependability, graceful degradation, fault tolerance). Time criticality of tasks and their sensitivity with respect to latest file information are explicitly used for novel flexible task scheduling algorithms and file replication management policies, in a fully integrated model. The achieved adaptability by far outweighs the additional overhead. In order to avoid unnecessary and very costly locking of (remote) file copies, task scheduling in the MELODY model is done prior to resource/ file allocation. Although thus being based on estimates of execution times only (no guaranteed tasks), in the 2 different models of integrating task and resource scheduling developed, MELODY distinctively outperforms the classical model, most clearly in mission-critical applications