Subject: C428 JGSI Review Resent-Date: Thu, 30 Sep 1999 23:17:22 -0400 Resent-From: Geoffrey Fox Resent-To: p_gcf@npac.syr.edu Date: Thu, 16 Sep 1999 17:29:09 -0700 From: Peter Cappello To: gcf@npac.syr.edu a) Overall Recommendation: Accept b) Words suitable for authors: I enjoyed this paper very much. The paper is well written and backed up with a lot of good experimental work. Also, Section 4, on Alternative programming models, is a good dissection of the issues. I imagine that the premise for this work---high-performance metacomputing applications will typically run on collections clusters or MPPs---is valid. In the introduction, code mobility is mentioned as one strength of the Java-centric approach. However, because Mantra uses a native compiler, it appears to me that Mantra code is not mobile, although it does support heterogeneity. True? In Subsection 2.3, Mantra on the wide area DAS system, it is noted that Panda uses one dedicated gateway machine per cluster. Are there concerns about, or attempts to implement, fault tolerance? I realize that fault tolerance is not the focus of this work. In the discussion of SOR, I appreciated the detail given on effecting asynchronous RMI via multiple threads. Similarly, I appreciated the detail in the discussion about multiple threads used to implement broadcast for the All pairs shortest path problem. Along these lines, for the TSP problem, I would appreciate a bit more detail on how exactly the program does an RMI to all other workers to update their value for the best solution; no code was given for this. Specifically: does the method scale? Later in the paper, the authors note that such updates are infrequent. I imagine that the frequency decreases over time, being quite frequent, at first. True? If not, please explain. For the IDA*, what is the victim selection method used for work stealing. Again, the comparison of alternative programming methods is clear and useful. I also think the conclusions about what is needed is correct (including JavaSpaces shortcomings). I hope Sun sees this! I also commend the authors on their Related work section: very professional. Overall, I think the paper makes several valuable contributions and is eminently publishable. -Pete