Implementation of the GARF replicated objects platform

Abstract

This paper presents the design and implementation of the GARF system, an objectoriented platform that helps programming fault-tolerant distributed applications in a modular way. The originality of GARF is to separate a distributed object into several objects, the complexity of distribution and fault-tolerance being encapsulated in reusable classes. The use of those classes by the GARF system is based on a run-time mechanism of invocation redirection, where most other systems use inheritance, a compile-time mechanism. Our runtime, which supports the GARF object model, is written in Smalltalk. It is presented in detail, as well as the reusable classes that support fault-tolerance. Fault-tolerant objects are implemented using groups of replicated objects. Our Dependable Object Toolkit provides group management facilities at the object level. Object groups are built on top of the Isis toolkit, which provides group management facilities at the Unix process level. Our mapping of object groups on process groups and our interfacing of Smalltalk and Isis are detailed. Performance analysis and a rst evaluation of our prototype are also presented.

Reflective fault-tolerant systems: from experience to challenges

“…The MAUD [4] and GARF [5] architectures propose reflective mechanisms for intercepting base-level events at the meta-level (redirecting messages by renaming destinations in the first case, and making a tricky use of the Smalltalk exception handling mechanism in the second case). The reflective capabilities defined in these MOPs are, however, limited to behavioral reflection.…”

Adaptive fault tolerant systems: reflective design and validation

“…In particular, security and fault tolerance have benefited from this concept as demonstrated by several projects and prototypes worldwide (e.g. [5,6,7]). Our previous research in the field was a contribution to the development of fault-and intrusion-tolerant systems using reflective languages.…”

A Multi-Level Meta-Object Protocol for Fault-Tolerance in Complex Architectures

“…Platforms such as GARF [4], MAUD [1], and FRIENDS V2 [11] are representative of this trend. These systems use the reflective features of their implementation language (Smalltalk, HAL and OPENC++ respectively) to provide reflective capabilities dedicated to fault-tolerance and security.…”