A GALS Language for Dynamic Distributed and Reactive Programs

Abstract

We propose a Globally Asynchronous Locally Synchronous language DSystemJ for designing dynamic distributed systems. DSystemJ, an extension of the reactive asynchronous SystemJ language, enhances it with dynamic creation and process mobility, and uses the Java language for programming sequential data computations. Moreover, DSystemJ is equipped with a formal semantics, which allows, formal system specification, reasoning, and automatic code generation. Compared to special purpose languages, DSystemJ is better in terms of implementation, scalability, and features. Compared to general purpose languages, DSystemJ is better because it exposes, at the language level, OS features like communication, concurrency, process creation and migration, therefore making it better suited for system level design of complex distributed systems.

libDGALS: A library-based approach to design dynamic GALS systems

“…The DGALS MoC is built upon the GALS MoC, which it extends with features for designing dynamic and distributed systems. The only known approach to designing such systems is Dynamic SystemJ (DSystemJ) [5] which extends SystemJ [6], which is used for systematic design of a complex GALS systems. We address the features lacking in DSystemJ, and use Figure 1 as the illustration of a typical DGALS system, with synchrony, asynchrony and dynamicity, which cannot be implemented in DSystemJ but can be implemented with libDGALS.…”

“…Languages modeling the GALS MoC (Globally Asynchronous Locally Synchronous) have been proposed [10], but these do not target the same class of dynamic, resource and time constrained systems as us. Dynamic SystemJ (DSystemJ) [5] extends SystemJ [6] to a domain of dynamic systems. DSystemJ has a number of limitations: (1) it requires the Java Virtual Machine (JVM), which is significantly abstracted from the underlying platform to efficiently utilize heterogeneous execution architectures, with a heavy price on requirements on memory footprint; and (2) it is unable to create channels dynamically for newly spawned clock domains.…”

“…However, they lack the ability to abstractly program reactions on events from the environment, which is essential for reactive systems. Multi-agent systems, such as JADE [15] provide reactivity, but at the expense of a significant execution overhead shown in [5].…”

“…A combination of the two, the GALS [3] [4] MoC, lends itself well to a significant number of complex DRSs. To address the dynamic nature of the majority of DRSs, the GALS MoC naturally extends from the static to the dynamic case, called Dynamic GALS or DGALS [5].…”