The JPVM library is a software system for explicit message-passing-based parallel programming in Java. The library supports an interface similar to the C and Fortran interface of the parallel virtual machine (PVM) system, with modifications to better suit Java programming styles. The similarity between JPVM and the widely used PVM system supports a quick learning curve for experienced PVM programmers. At the same time, JPVM offers novel features not found in standard PVM such as thread safety, multiple communication end-points per task, and default-case direct message routing. JPVM is implemented entirely in Java, and is thus highly portable among platforms supporting a version of the Java Virtual Machine. This feature opens up the possibility of utilizing resources such as Macintosh and Windows based workstations, which are commonly excluded from network parallel computing systems. Initial applications performance results achieved with a prototype JPVM system indicate that the Java-implemented approach can offer good performance at appropriately coarse granularities. © 1998 John Wiley & Sons, Ltd.

Distributed concurrent computing based on lightweight processes can potentially address performance and functionality limits in heterogeneous systems. The TPVM framework, based on the notion of ‘exportable services’, is an extension to the PVM message-passing system, but uses threads as units of computing, scheduling, and parallelism. TPVM facilitates and supports three different distributed concurrent programming paradigms: (a) the traditional, task based, explicit message-passing model; (b) a data-driven instantiation model that enables straightforward specification of computation based on data dependencies; and (c) a partial shared-address space model via remote memory access, with naming and typing of distributed data areas. The latter models offer significantly different computing paradigms for network-based computing, while maintaining a close resemblance to, and building upon, the conventional PVM infrastructure in the interest of compatibility and ease of transition. The TPVM system comprises three basic modules: a library interface that provides access to thread-based distributed concurrent computing facilities, a portable thread interface module which abstracts the required thread-related services, and a thread server module which performs scheduling and system data management. System implementation as well as applications experiences have been very encouraging, indicating the viability of the proposed models, the feasibility of portable and efficient threads systems for distributed computing, and the performance improvements that result from multithreaded concurrent computing. © 1998 John Wiley & Sons, Ltd.

The TPVM (Threads-oriented PVM) system, is an experimental auxiliary subsystem for the PVM distributed system, which supports the use of lightweight processes or "threads" as the basic unit of parallelism and scheduling. TPVM provides a library interface which presents both a traditional, task based, explicit message passing model, as well as a data-driven scheduling model that enables straightforward specification of computation based on data dependencies. Our system design is still under development, but a prototype implementation has allowed us to perform a number of preliminary experiments. These have provided strong evidence that TPVM can offer improved performance, processor utilization, and load balance to several application categories. Through our experiments we have also determined that the current TPVM design is not very well suited to certain types of applications, most notably highly synchronous, SPMD-style algorithms.

Local or wide-area connected workstation cluster-based computation systems are inherently failure-prone, particularly for long running computations. In this work we introduce a variety of features for failure resilience in the EcliPSe system for replicative applications. Key characteristics of fault-tolerant EcliPSe are ease of use, low statesaving costs, system scalability and good performance.