HORUS DISTRIBUTED COMPUTING ENVIRONMENT

Kenneth Birman (ken@cs.cornell.edu)
Robbert van Renesse (rvr@cs.cornell.edu)

Cornell's Horus effort has developed a programming environment for reliable distributed computing. During the last year, Horus was used to demonstrate groupware and fault-tolerance over high performance networks, and was found to offer higher performance than other similar systems. Novel features of Horus are its flexible software architecture, in which applications pay only for features that they use, and support for virtually synchronous process groups, a technology that we developed in our prior work on the Isis Toolkit, which has become a significant commercial success. Horus also offers a fault-tolerant security and privacy technology, which we view as an important research advance.

During 1995, we will be extending Horus to provide extremely low latency, high performance real-time capabilities. Our approach combines elements of a communication technology called Active Messages with a multi-media playback system called Continuous Media. By the end of the year, we expect to demonstrate high speed interactive applications with remote multimedia servers, such as might be used in remote telemedicine applications or video on demand systems. All of this will retain the existing fault-tolerance and security options of Horus, and its virtual synchrony programming model.

Prior work on Isis has created a substantial user base, and we expect rapid uptake of Horus within this community as it matures. Isis users span a wide range of industries, including telecommunications systems, financial trading systems, stock market automation, factory-floor process control for discrete electronic component manufacture, air traffic control, and space-based communications system management and control. Applications of Isis are being explored in several branches of the military, as well as the NSA and other non-military government branches. Among the more visible military efforts is the Naval Hiper-D project, which is exploring the use of Isis in a new system that prototypes technologies for future enhancements of the AEGIS battle radar system. The more demanding applications in this user base would benefit from access to Horus, and our initial plan is to make it possible to migrate Isis applications to Horus with few changes, thus benefiting this community in a direct way. Technology transition has occured through licensing agreements with Isis Distributed Systems Inc., a subsidiary of Stratus Computers. However, all of our Cornell work is also available to researchers at no fee, and is described through detailed publications and programming manuals.

Looking to the future, we hope that a mixture of Isis and Horus technologies will permit us to develop some of the very demanding applications that will be seen in next-generation groupware and planning systems. The illustration below shows such an application: a military mission control and planning system that integrates data from a variety of space, air and ground resources and uses this to coordinate actions of various theatre assets. Systems of this sort will demand the utmost in performance, reliability and security, while also tolerating failures and rapidly reconfiguring to respond to changing demands. Success in our project will thus impact a wide range of both civilian and military technology efforts.