Page type: project

The Horus Project;The Company of;the Gods rejoiced, rejoiced, at the coming of Horus, the son of Osiris,;whose heart was firm, the triumphant, the son of;Isis, the heir of Osiris.;¹;The Horus project has developed a modular and extensible process-group;communication system,;addressing the requirements of a wide variety;of robust distributed applications.;Horus, the son of Isis and of Osiris, was a god whose attributes appealed;strongly to the Egyptians from one end of Egypt to the other, because;in him every man and woman saw the type of what he or she wished to possess,;that is to say, renewed life, and life as opposed to death, and movement;as opposed to inactivity.;²;;Horus provides a framework for the development of distributed applications;based on group communications, a style of computing that can arise in;fault-tolerant systems, managed distributed systems, applications that;exploit data replication or coherent caching, and groupware. Within the;overall Horus framework a large collection of system and application;protocols have been developed that allow the application designer to;construct a communication module that exactly meets the application;requirements at minimal cost.;The Horus project was originally launched as an effort to redesign the;Isis group;communication system, but has evolved into a general purpose communication;architecture with advanced support for the development of robust;distributed systems in settings for which Isis was unsuitable, such as;applications that have special security or real-time requirements. Besides;the practical uses of our software, the project has contributed;towards the theory of virtually synchrony, a runtime model used;for our implementation of data replication and fault-tolerance. At the same;time, our software is much faster and lighter weight than the Isis system.;Horus exists as two systems: an initial version coded in C, which can be;used for research purposes at no fee but has restricted commerical;rights,;and a new version called Ensemble, written in ML but usable from many;other languages, which is available for all classes of users at no;fee. Ensemble is actively under development and we will do series of;releases over the fall of 1996 and spring of 1997. By early in;1997, Ensemble;will be an outstanding environment for building Java-based groupware;applications that do multimedia conferencing on the Web.;Horus and Ensemble are designed to be platform independent, and are;available for different;classes of workstations, personal computers, parallel processors and on;next-generation cluster environments using standard high-speed;communications networks.;The Horus effort collaborates closely with many other distributed systems;projects, including Transis, NavTech, and the StormCast and TACOMA;projects. Links to these and other projects can be found elsewhere in these;pages.;Introductions to Horus;Visit the;papers;and;abstract;pages for an overview of all publications and reports related;to the Horus project. The following are recent articles that present a;high-level introduction to Horus:;;Kenneth P. Birman and Robbert van Renesse,;Software for;Reliable Networks, in;Scientific American, May, 1996.;Robbert van Renesse, Kenneth P. Birman and Silvano Maffeis,;Horus, a flexible;Group Communication System, Communications of the ACM, April 1996.;¹;Final sentence in the;Hyme to Osiris;from the Papyrus of Ani, better know as the;Book of the Dead.;²;E.A. Wallis Budge, The Gods of the Egyptians or Studies;in Egyptian Mythology, Volume 1, pages 486-487, The Open Court Publishing;Company, London, 1904.;Comments to;Werner Vogels;