Bruce R. Montague

REINAS: the Real-time Environmental Information Network and Analysis System

The Real-Time Environmental Information Network and Analysis System (REINAS) is a distributed system supporting the conduct of regional environmental science research at the desk top. Continuous real-time data acquired from dispersed sensors is stored in a logically integrated but physically distributed data base. An integrated problem-solving environment is under development which supports visualization and modeling. REINAS is intended to provide insight into historical, current, and predicted oceanographic and meteorological conditions. REINAS permits both collaborative and single-user scientific work in a distributed environment.

JN: OS for an embedded Java network computer

In early 1996, the Computer Science Department at UC Santa Cruz agreed with National Semiconductor to design a custom embedded operating system to support the Java Virtual Machine (JVM). Our goal was to tightly integrate Java with a realtime kernel on a small, single-chip, embedded PC attached to the Internet. By the end of 1996, we had succeeded in implementing the first operating system designed and developed in an academic environment specifically to support Java. This article reviews the lessons we learned from what is most likely the first custom designed operating system-other than JavaSofts JavaOS-that runs the complete JVM. Our current system, the Java nanokernel (JN), supports a simple Web server written in Java and provides a Java interface to a color Connectix camera.

JAVACAM: trimming Java down to size

JavaCam is an embedded sensor device that connects to the Internet and operates with as little as 1.5 Mbytes of total system memory. To determine how small a Java system we could build that would still support a Java Virtual Machine, we wrote the Java Nanokernel, a very thin operating system. We then ported Suns Java Development Kit 1.0.1 to JN. This port included the complete Java language and all of the core Java packages except java.awt. In this article, we begin by describing JN and the port of JDK 1.0.1 to it. We then describe our first significant application, JavaCam, a camera that is remotely programmable in Java and Internet accessible.

Synchronous/reactive programming of concurrent system software

Synchronous languages are intended for programming reactive systems. Reactive systems, which include real-time systems and key operating system components, interact continually with their environment. This paper considers the applicability of imperative synchronous/reactive languages to the development of general system software, that is, to the implementation of operating system kernels, file systems, databases, networks, server architectures, device drivers, etc.. The languages Esterel and Reactive C (RC) receive special attention as Esterel is the oldest and most developed such language and RC is specifically designed for compatibility with C systems programming. An alternative soft-instruction software architecture is described which is well suited to real-world system programming.