Architectural Support for Extensibility and Autonomy in Wide-Area Distributed Object Systems1

The Legion system defines a software architecture designed to support metacomputing, the use of large collections of heterogeneous computing resources distributed across localand wide-area networks as a single, seamless virtual machine. Metasystems software must be extensible because no single system can meet all of the diverse, often conflicting, requirements of the entire present and future user community, nor can a system constructed today take best advantage of unanticipated future hardware advances. Metasystems software must also support complete site autonomy, as resource owners will not turn control of their resources (hosts, databases, devices, etc.) over to a dictatorial system. Legion is a metasystem designed to meet the challenges of managing and exploiting wide-area systems. The Legion virtual machine provides secure shared object and shared name spaces, application adjustable fault-tolerance, improved response time, and greater throughput. Legion tackles problems not solved by existing workstation-based parallel processing tools, such as fault-tolerance, wide-area parallel processing, interoperability, heterogeneity, security, efficient scheduling, and comprehensive resource management. This paper describes the Legion run-time architecture, focussing in particular on the critical issues of extensibility and site autonomy. 1. The Legion project is partially supported by NFS CDA-9724552, DARPA contract #N66001-96-C-8527, DOE grant DE-FD02-96ER25290, DOE contract Sandia LD-9391, Northrup-Grumman (for the DoD HPCMOD/ PET program), DOE D459000-16-3C, and DARPA (GA) SC H607305A Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 03 JUN 1998 2. REPORT TYPE 3. DATES COVERED 00-00-1998 to 00-00-1998 4. TITLE AND SUBTITLE Architectural Support for Extensibility and Autonomy in Wide-Area Distributed Object Systems 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University of Virginia,Department of Computer Science,151 Engineer’s Way,Cahrlottesville,VA,22094-4740 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 57 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Table of