Weighted Reference Counting is a low communication distributed storage reclamation scheme for loosely-couple multiprocessors. The algorithm we present herein extends weighted reference counting to allow the collection of cyclic data structures. To do so, the algorithm identifies candidate objects that may be part of cycles and performs a tricolour mark-scan on their subgraph in a lazy manner to discover whether the subgraph is still in use. The algorithm is concurrent in the sense that multiple useful computation processes and garbage collection processes can be performed simultaneously. Keywords: Memory management, Distributed memory, Reference counting, Garbage collection. Introduction Computation on distributed systems involving several processors is already a reality. In a distributed multiprocessor system each processor is responsible for allocating and reclaiming structures residing in its local memory; interprocessor communication is far less efficient than local memory access...

model for garbage collection.

Garbage collection is important in object-oriented databases to free the programmer from explicitly deallocating memory. In this paper, we present a garbage collection algorithm, called Transactional Cyclic Reference Counting (TCRC), for object oriented databases. The algorithm is based on a variant of a reference counting algorithm proposed for functional programming languages The algorithm keeps track of auxiliary reference count information to detect and collect cyclic garbage. The algorithm works correctly in the presence of concurrently running transactions, and system failures. It does not obtain any long term locks, thereby minimizing interference with transaction processing. It uses recovery subsystem logs to detect pointer updates � thus, existing code need not be rewritten. Finally, it exploits schema information, if available, to reduce costs. We have implemented the TCRC algorithm and present results of a performance study of the implementation. 1

We present a garbage collection scheme based on reference counting and region inference which, unlike the standard reference counting algorithm, handles cycles correctly. In our algorithm, the fundamental operations of region inference are performed dynamically. No assistance is required from the programmer or the compiler, making our algorithm particularly well-suited for use in dynamically-typed languages such as scripting languages. We provide a detailed algorithm and demonstrate how it can be implemented efficiently.

this paper is to present the details of our new allocator, it is important to demonstrate that the allocator can work in conjunction with (at least) a simple collector without compromising the worst-case behaviour. We therefore present in this section a garbage collector that is both scalable and non-disruptive (though it does not collect cycles).