A Time- and Space-Efficient Garbage Compaction Algorithm

Given an area of storage containing scattered marked nodes, one may wish to rearrange them into a compact mass at one end of the area, meanwhile revising all pointers to marked nodes to show their new locations. An algorithm is here described which accomplishes this task in Iinear time relative to the size of the storage area, and in space of the order of one bit for each pointer. The algorithm operates by reversibly encoding the situation that a collection of locations point to a single location by a linear list, emanating from the pointed-to location, passing through the pointing locations, and terminating with the pointed-to location\u27s transplanted contents

Garbage collection in distributed systems

PhD ThesisThe provision of system-wide heap storage has a number of advantages. However, when the technique is applied to distributed systems automatically recovering inaccessible variables becomes a serious problem. This thesis presents a survey of such garbage collection techniques but finds that no existing algorithm is entirely suitable. A new, general purpose algorithm is developed and presented which allows individual systems to garbage collect largely independently. The effects of these garbage collections are combined, using recursively structured control mechanisms, to achieve garbage collection of the entire heap with the minimum of overheads. Experimental results show that new algorithm recovers most inaccessible variables more quickly than a straightforward garbage collection, giving an improved memory utilisation