Nectar Project applications

Video conferencing

The video conferencing system allows users sitting at their workstation to communicate using voice and video over gigabit Nectar and other networks. The systems includes a user interface that can be used to control what network, protocol or bandwidth is used. The bandwidth is controled by either changing the frame rate or the resolution of the picture. The video conferencing system was developed by Kam Lee.

Medical imaging

The purpose of the medical imaging project is to render an image of the brain, using MRI image slices, and to superimpose information about functionality of parts of the brain. The resulting image can for example be used by surgeons while preparing a patient for surgery. The first part of the application, the computation of the volume rendered image using a set of MRI images as inputs, has been finished. The application uses three systems: iWarp extracts volume information from MRI images, the PSC Cray does some data format conversion, and the paragon does the final rendering. Gigabit Nectar is used for communication: communication from iWarp to Cray runs as 40 MB/s sustained, while the Cray to Paragon communication is currently limited by the Paragon HIPPI interface to 2 MB/s. The second part of the computation, the mapping of functional information on the brain, is under development. It will use the PSC Alpha cluster and a workstation.

The medical imaging application is an example of heterogeneous computing application. The main motivation for using heterogeneous computing is that the application consists of components that were developed independently on different systems (iWarp, workstation cluster, ..). Heterogeneous computing makes it possible to bring up the application quickly, without having to port the components. The medical imaging project is lead by Doug Noll.


Dome is a distributed objects system that can be used to distribute applications over networks of workstations. It has been used to distribute kernels of scientific computations, a molecular dynamics code, and the evaluation of binary decision diagrams. Dome objects can do transparent load balancing and architecture independent checkpointing. BEE is used for monitoring.

Environmental modeling

The environment modeling application is used to evaluate policies for environmental pollution control. It consists of a fronted, GEMS, and a modeling program, called airshed. The system uses Nectar in two ways. First, airshed can be invoked from GEMS on different systems over gigabit Nectar. Second, airshed has been distributed so that it can run on different combinations of distributed systems, connected by gigabit Nectar.


DCABB is a programming environment that supports the development and execution of linear programming problems across clusters of workstations. Programmers specify program elements for node evaluation, prioritization of unevaluation nodes, termination detection, and cut plane processing. The DCABB system uses these routines to implement a distributed linear programming algorithm.

The DCABB environment is an example of an application-specific programming environment. By focussing on a specific class of applications it is possible to support a programming model with a high level of abstraction. The DCABB environment was developed by Gautham Kudva and Joe Pekny (Purdue). Last updated Oct 2, 1994