On-line debugging techniques: a survey

One consequence of recent interest in the development of large-scale time-sharing systems to provide on-line computer access to a large number of users has been the widespread realization that the usefulness of such a system is critically dependent on the quality of the software provided to facilitate the interaction between user and machine. In particular, one area of critical importance for effective utilization of such a system is that of facilities for program debugging. In view of the important role they play, surprisingly little attention has been paid to the development of facilities to aid in the process of on-line program debugging. Furthermore, much of the work in this field has been described only in unpublished reports or passed on through the oral tradition, rather than in the published literature. The purpose of this paper is to survey the existing work in this area and discuss some possible extensions to it, with the dual goal of acquainting a wider public with currently-existing techniques and of stimulating further developments.