Introduction

Nexus is a portable library that provides multi-threaded communication facilities within heterogeneous parallel and distributed computing environments. Its targeted use is in the development of advanced languages and libraries on such platforms. It is not primarily intended as an application level tool, and the information provided here is minimal.

Nexus has been redesigned and streamlined as a component of Globus, implemented on top of core Globus services such as the Globus thread library. The design of Globus is based on the idea that it should provide a "bag of services" from which users can select components. Thus, a user interested only in Nexus can use it alone, as a module independent of other Globus services.

Nexus is the communication component of Globus, and it supports multiple communication protocols as well as resource characterization mechanisms that allow automatic selection of optimal protocols. It also provides a global memory model.

Users

Nexus is intended for use by library and compiler developers rather than application developers. The following is a list of compilers for parallel languages that rely on Nexus:

• CC++
• Compositional C++
• Fortran M
• The DOE 2000 Collaboratory Interoperability Framework project.
• The Globus Toolkit
• High Performance C++
• The Linear Systems Analyzer (LSA) project
• MPICH-G is a wide-area implementation of the Message Passing Interface (MPI) that uses Globus and Nexus
• NexusJava, a subset of Nexus implemented in Java
• The Portable Runtime System (PORTS)

• the I-WAY wide area computing experiment and
• the CAVERNSoft libraries.

Evaluation

NERSC has not evaluated Nexus but you can submit your own evaluation of Nexus if you would like to.

Status

The latest version of Nexus (4.1.1) can be downloaded as part of the Globus toolkit.

Documentation

• Nexus Function Reference
• The Nexus 4.1.1 to Globus transition

Developers

Nexus is a joint project of the Distributed Systems Laboratory, in the Mathematics and Computer Science Division at Argonne National Laboratory, the USC/Information Sciences Institute (Carl Kesselman), The Aerospace Corporation, and the High-Performance Computing Lab at Northern Illinois University.