For example, a compiler may choose to optimize a loop index variable by storing it in a register, or the cache may delay flushing a new value of a variable to main memory until a more opportune time.

The main reasons are medium erosion and flushing, and the welding specification.

Since the odorless flush toilet adopts a structure which takes the domestic wastewater as main flushing media, thereby the water saving and environmental protection effects are better.