- Physical storage media can be classified by access speed, cost per unit of data, and reliability. This includes cache, main memory, flash memory, magnetic disks, optical disks, and magnetic tapes. - Faster but more expensive media like cache and main memory are primary storage, while magnetic disks represent secondary storage. Tapes and optical disks provide tertiary, offline storage. - Volatility also differs, with volatile storage like main memory losing data on power loss, while nonvolatile media like disks and flash retain data. The database typically resides on nonvolatile secondary storage for long-term access.