Faster storage devices cannot solve the I/O bottleneck problem for large multiprocessor systems if data passes through a file system on a single processor. Implementing the file system as a parallel program can significantly improve performance. Selectively revealing this parallel structure to utility programs can produce additional improvements, particularly on machines in which interprocessor communication is slow compared to aggregate I/O bandwidth.We have designed and prototyped a parallel file system that distributes each file across multiple storage devices and processors. Naive programs are able to access files just as they would with a conventional file system, while more sophisticated programs may export pieces of their code to the processors managing the data, for optimum performance. Theoretical and early empirical data indicate nearly linear speedup on critical operations for up to several dozen devices.

The Real-Time Specification for Java is now about two years old. It has been implemented, formed the basis for research and used in serious applications. Some strengths and weaknesses are becoming clear. This paper reviews the current status of the specification, outlines the challenges ahead and discusses areas where there is likely to be future design work.

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The Real-Time Specification for Java (RTSJ) was the first Java Community Process' Java Specification Request (JSR-1). The initial version of the specification was produced in June 2000 in parallel with a Reference Implementation. Inevitably, the completion of the RI showed us bugs and inconsistency. Many of these were been removed in the 1.0.1 version of the specification that was released in August 2004, and the 1.0.2 version of the specification that was released in July 2006 (see www.rtsj.org). However, minor releases such as these are limited to issues that can be construed as bug fixes or clarifications. As commercial products have appeared and user experienced has been accrued, some enhancements to the RTSJ have been requested. These enhancement requests form the basis for the scope of JSR 282. This short paper summarizes the progress that has been made.