Places bring new support for message-passing parallelism to Racket. This paper gives an overview of the programming model and how we had to modify our existing, sequential runtime-system to support places. We show that the freedom to design the programming model helped us to make the implementation tractable; specifically, we avoided the conventional pain of adding just the right amount of locking to a big, legacy runtime system. The paper presents an evaluation of the design that includes both a real-world application and standard parallel benchmarks.

Many language implementations, particularly for high-level and scripting languages, are based on carefully honed runtime systems that have an internally sequential execution model. Adding support for parallelism in the usual form -- as threads that run arbitrary code in parallel -- would require a major revision or even a rewrite to add safe and efficient locking and communication. We describe an alternative approach to incremental parallelization of runtime systems. This approach can be applied inexpensively to many sequential runtime systems, and we demonstrate its effectiveness in the Racket runtime system and Parrot virtual machine. Our evaluation assesses both the performance benefits and the developer effort needed to implement our approach. We find that incremental parallelization can provide useful, scalable parallelism on commodity multicore processors at a fraction of the effort required to implement conventional parallel threads.

This paper demonstrates that careful tuning of the OBEX and IrLAP negotiated parameters allows OBEX to scale well for use with large data objects and high transmission rates. Due to the substantial time overhead inherent in link turnarounds, minimizing turnarounds during the transmission of a large object helps to maximize link efficiency. The IrLAP window size and OBEX packet size significantly impact the number of required turnarounds during the transmission of a large object. When these parameters are properly tuned, maximum throughput can be achieved, and OBEX performs efficiently at high data rates.

As the Internet began its exponential growth into a global information environment, software was often unreliable, slow and had difficulty in interoperating with other systems. Supercomputing node counts also continue to follow high growth trends. Supercomputer and grid resource management software must mature into a reliable computational platform in much the same way that web services matured for the Internet. DOGMA The Next Generation (DOGMA-NG) improves on current resource management approaches by using tested off-the-shelf enterprise technologies to build a robust, scalable, and extensible resource management platform. Distributed web service technologies constitute the core of DOGMA-NG's design and provide fault tolerance and scalability. DOGMA-NG's use of open standard web technologies and efficient management algorithms promises to reduce management time and accommodate the growing size of future supercomputers. The use of web technologies also provides the opportunity for anew parallel programming paradigm, enterprise web services parallel programming, that also gains benefit from the scalable, robust component architecture.