Expected Levels. Total hardness in freshwater is usually in the range of 15 to 375 mg/L as CaCO3. Calcium. hardness in freshwater is in the range of 10 to 250 mg/L, often double that of magnesium. hardness (5 to 125 mg/L). Typical seawater has calcium hardness of 1000 mg/L, magnesium.
Part of the Storage management glossary: A physical address is a binarynumber in the form of logical high and low states on an address busthat corresponds to a particular cell of primary storage(also called main memory), or to a particular register in a memory-mapped I/O(input/output) device.
Maintain a mapping of physical addresses allocated to each process and make sure one process cannot access the memory allocated to another process! Clearly, having actual physical addresses exposed to programs is not a good idea.