Snapshots and software transactional memory

One way that software transactional memory implementations attempt to reduce synchronization conflicts among transactions is by supporting different kinds of access modes. One such implementation, Dynamic Software Transactional Memory (DSTM), supports three kinds of memory access: WRITE access, which allows an object to be observed and modified, READ access, which allows an object to be observed but not modified, and RELEASE access, which allows an object to be observed for a limited duration.