The previous two chapters explored the memory consistency models sequential consistency (SC) and total store order (TSO). These chapters presented SC as intuitive and TSO as widely implemented (e.g., in x86). Both models are sometimes called strong because the global memory order of each model usually respects (preserves) per-thread program order. Recall that SC preserves order for two memory operations from the same thread for all four combinations of loads and stores (Load → Load, Load → Store, Store → Store, and Store → Load), whereas TSO preserves the first three orders but not Store → Load order.