Resource management in open tuple space systems

This thesis investigates the problem of resource management (memory and I/O) in open distributed implementations of the LINDA model. The principal focus of the research is to deal with the problem of memory exhaustion by implementing garbage-collection techniques at the kernel level of LINDA since explicit methods that rely on users or computational languages are not feasible. The problem of I/O is also explored as it side-effects the solution based on garbage collection. This dissertation shows that the main problem to overcome when implementing a garbage-collection scheme in LINDA is the lack of information about processes’ use of tuple spaces. In order to solve this problem a graph is maintained at the kernel level with all the necessary information. Two ways of maintaining the graph are explored: centralised and distributed. To construct the graph in question two new techniques have been proposed: Process Registration/Checkout and Tuple Monitoring. These techniques form the basis of the graph maintenance at the kernel level. A model, named LIGIA, is proposed incorporating such techniques and an implementation of this model is presented. When looking at a general solution for garbage-collection, problems related to I/O operations became apparent. After proving that I/O is a coordination problem, the solution presented was to bring I/O into the LIGIA model. This is achieved with the introduction of a new operation called which enables I/O to be done via tuple spaces.