FRIENDS - A flexible architecture for implementing fault tolerant and secure distributed applications

FRIENDS is a software-based architecture for implementing fault-tolerant and, to some extent, secure applications. This architecture is composed of sub-systems and libraries of metaobjects. Transparency and separation of concerns is provided not only to the application programmer but also to the programmers implementing metaobjects for fault tolerance, secure communication and distribution. Common services required for implementing metaobjects are provided by the sub-systems. Metaobjects are implemented using object-oriented techniques and can be reused and customised according to the application needs, the operational environment and its related fault assumptions. Flexibility is increased by a recursive use of metaobjects. Examples and experiments are also described

Object-Oriented Concurrent Reflective Languages can be Implemented Efficiently

Computational reflection is beneficial in concurrent computing in offering a linguistic mechanism for incorporating user-specific policies. New challenges are (1) how to implement them, and (2) how to do so efficiently. We present efficient implementation schemes for object-oriented concurrent reflective languages using our language ABCL/R2 as an example. The schemes include: efficient lazy creation of metaobjects/meta-groups, partial compilation of scripts (methods), dynamic progression, self-reification, and light-weight objects, all appropriately integrated so that the user-level semantics remain consistent with the meta-circular definition so that the full power of reflection is retained, while achieving practical efficiency. ABCL/R2 exhibits two orders of magnitude speed improvement over its predecessor, ABCL/R, and in fact compares favorably to the ABCL/1 compiler and also C + Sun LWP, neither supporting reflection. 3 To be presented at ACM OOPSLA'92, Vancouver, Canada, Oct. 199..