The Sixth International Workshop on Persistent Object Systems was held at Les Mazets des Roches near Tarascon, Provence in southern France from the fifth to the ninth of September 1994. The attractive context and autumn warmth greeted the 53 participants from 12 countries spread over five continents. Persistent object systems continue to grow in importance. Almost all significant uses of computers to support human endeavours depend on long-lived and large-scale systems. As expectations and ambitions rise so the sophistication of the systems we attempt to build also rises. The quality and integrity of the systems and their feasibility for supporting large groups of co-operating people depends on their technical founda tion. Persistent object systems are being developed which provide a more robust and yet simpler foundation for these persistent applications. The workshop followed the tradition of the previous workshops in the series, focusing on the design, implementation and use of persistent object systems in particular and persistent systems in general. There were clear signs that this line of research is maturing, as engineering issues were discussed with the aid of evidence from operational systems. The work presented covered the complete range of database facilities: transactions, concurrency, distribution, integrity and schema modifica tion. There were examples of very large scale use, one involving tens of terabytes of data. Language issues, particularly the provision of reflection, continued to be important.

The Ninth International Workshop on Persistent Object Systems (POS 9) took place at the SAS Radisson Hotel in Lillehammer, Norway, from 6th to 8th September 2000. Previous workshops in the series have been held in Scotland (1 and 2), Australia (3), the USA (4), Italy (5), France (6), and the USA (7 and 8). In keeping with those workshops, POS 9 was short but intensive, fitting 28 papers and panel sessions, a boat 1 excursion, and some memorable meals into two and a half days. The participants’ concentration was no doubt helped by the Northern European weather that prevailed for most of the workshop. Continuing a trend experienced over the previous few workshops, POS 9 had difficulty attracting a high number of papers. Of course it is hard to tell whether this is a problem with the field of persistent systems itself, or merely a consequence of the increasing number of workshops, conferences, and journals competing for submissions. In his Epilogue to the proceedings, Ron Morrison makes some interesting suggestions for possible improvements to future POS workshops. Out of a total of 26 submitted papers, 19 were accepted for presentation at the 2 workshop. Breaking down by region, 6 1/2 came from the USA , 1 from Africa, 3 1/2 from Australia, and 8 from Europe. In a new development for POS, an equal number of papers came from England and from Scotland.

Persistent object systems are systems which support the creation and manipulation of objects in a uniform manner, regardless of how long they persist. This is in direct contrast with conventional systems where temporary objects are created and manipulated using one mechanism (typically programming language data structures) and permanent objects are maintained using a different mechanism (usually a filestore). The unification of temporary and permanent objects yields systems which are smaller and more efficient than conventional systems and which provide a powerful and flexible platform for the development of large, data intensive applications. This volume presents the proceedings of a workshop at which latest research in this area was discussed. The papers are grouped into sections on the following topics: type systems and persistence, persistent programming languages, implementing persistence, object stores, measurement of persistent systems, transactions and persistence, and persistent machines.

Proceedings of the biennial International Workshops on Persistent Object Systems.

\My tailor is Object-Oriented". Most software systems that have been built - cently are claimed to be Object-Oriented. Even older software systems that are still in commercial use have been upgraded with some OO ?avors. The range of areas where OO can be viewed as a \must-have" feature seems to be as large as the number of elds in computer science. If we stick to one of the original views of OO, that is, to create cost-e ective software solutions through modeling ph- ical abstractions, the application of OO to any eld of computer science does indeed make sense. There are OO programming languages, OO operating s- tems, OO databases, OO speci cations, OO methodologies, etc. So what does a conference on Object-Oriented Programming really mean? I honestly don’t know. What I do know is that, since its creation in 1987, ECOOP has been attracting a large number of contributions, and ECOOP conferences have ended up with high-quality technical programs, featuring interesting mixtures of theory and practice. Among the 183 initial submissions to ECOOP’99, 20 papers were selected for inclusion in the technical program of the conference. Every paper was reviewed by three to ve referees. The selection of papers was carried out during a t- day program committee meeting at the Swiss Federal Institute of Technology in Lausanne. Papers were judged according to their originality, presentation qu- ity, and relevance to the conference topics.