Shared register

In distributed computing, shared-memory systems and message-passing systems are two means of interprocess communication which have been heavily studied. In shared-memory systems, processes communicate by accessing shared data structures. A shared (read-write) register, sometimes just called a register, is a fundamental type of shared data structure which stores a value and has two operations: Read, which returns the value stored in the register, and Write, which updates the value stored. Other types of shared data structures include read-modify-write, test-and-set, compare-and-swap etc. The memory location which is concurrently accessed is sometimes called a register.