A Survey of Software based Distributed Shared Memory (DSM) implementation methodologies for Multiprocessor Environments

It is more important to optimize the distributed system features to obtain the maximum possible performance. A distributed shared memory (DSM) of distributed system is kind of mechanism that allowing system’s multiple processors to access shared data without using interposes communication(IPC). A DSM is a simple yet powerful paradigm for structuring multiprocessor systems. It can be designed using hardware and/or software methodologies based on various considerations of data being shared in multiprocessor environments. It is better to design DSM in software because sharing data becomes a problem which has to be easily tackled in software and not in hardware as in multiprocessor systems. This paper discussed various design methodologies based on granularity of data being shared like object based, shared variable based and page based with its features and drawbacks. This study also describes DSM requirements, advantages of software based DSM design over hardware based design, Semantics of concurrent access and replication, DSM algorithms and various issues of DSM with respect to underlying parameters of multiprocessor environments.