Worldwide computing with universal actors: Linguistic abstractions for naming, migration, and coordination

The goal of the World-Wide Computer (WWC) project is to effectively turn the Web into a unified, dependable, distributed computing infrastructure. The WWC harnesses under-utilized computing resources by providing application programmers with the potential to globally distribute computations. Several applications in multiple domains—as diverse as massively parallel computing, remote collaboration, coordinated computing, and Internet agents—motivate the WWC.; To realize this vision, we develop mechanisms for naming, migration, and coordination of software components and applications running on top of the Web. We represent software components as collections of actors. Therefore, the WWC project uses the actor model of concurrent computation as a basis for studying and implementing different strategies for distributed software component naming, migration, and coordination.; The WWC's naming strategy, based on Uniform Resource Identifiers (URI), enables transparent migration and interconnection of actors. While a Universal Actor Name (UAN) persists over the life-time of an actor, Universal Actor Locators (UAL) change according to the actor's current location, and prescribe a protocol for communication with the actor.; Data and code migration enable scalability, more efficient network usage, improved graphical user interfaces, and mobile users and resources. This thesis describes a model for both fine-grained and coarse-grained migration, which enables the development of applications with transparent actor mobility, yet allows programming control on the locality of the participating actors.; This thesis develops a scalable hierarchical model for coordination. We develop an operational semantics for the hierarchical model of actor coordination to help guide future language and system implementations.; To demonstrate the viability of the proposed naming, migration and coordination schemes, the WWC project has developed a programming language (SALSA) and its run-time architecture.; The thesis provides experimental results for a few sample programs: three multicast protocols, a messenger carrying remote exception-handling code, a worldwide migrating agent, and a buffering messenger. (Abstract shortened by UMI.)...