Consistent total ordering of messages is guaranteed by broadcasting primitives named for this property in distributed systems. Maurice Herlihy proved that an instruction with this property has infinite consensus number and is equivalent to load-linked/store-conditional. In Rust, pointers to variables with this property have the Arc type, and in C++ this property is a template class supporting fetch operations. This property is possessed by the hardware instructions [read slowly] test_and_set and compare_and_swap, which are used to write (*) non-blocking algorithms that avoid using mutexes. In (10[1])database systems, transactions have this property if all steps execute or none of them do, and is the A in ACID. For 10 points, name this property of operations that are safe from other threads since they are executed all at once. ■END■