Faculty Colloquium

Speaker:Richard D. Schlichting
Department of Computer Science
The University of Arizona
Topic:Cactus: An Integrated Framework for Dynamic Fine-Grain QoS
Date:Thursday, October 7, 1999
Time:9:30 AM
Place:Gould-Simpson, Room 701

Refreshments will be served in the 7th-floor lobby of Gould-Simpson at 9 :15 AM


Middleware services are increasingly being used to enforce Quality of Service (QoS) guarantees for applications executing on networked collections of computers. This talk describes Cactus, a system for building middleware services with highly-customizable QoS related to fault tolerance, real time, and security. With Cactus, a service is realized as a composite protocol that is constructed from smaller micro-protocol objects that provide fine-grain task execution and network communication guarantees. In addition to presenting the overall approach, I will describe two prototype implementations and a collection of example middleware services being constructed using these prototypes. The first prototype is implemented in C on a cluster of PentiumPCs running OpenGroup/RI MK + CORDS (version 7.3), and supports real-time guarantees. The second is implemented in C++ on Sun workstations running Solaris and uses CORBA (Orbix) as the underlying communication mechanism. The services being built include highly-customizable versions of group RPC, multicast, group membership, a distributed file service, and a security service. These services explore customization and tradeoffs between QoS attributes such as reliability, availability, security, performance, and consistency.