HIGHER CPU registers: inverter based memory cells --> SRAM semiconductor (0.5-0.25 ns)
MIDDLE Main Memory (RAM)--> DRAM semiconductor (50-70ns)
LOWERLong Term Memory: disk --> flash memory(5,000-50,000ns), magnetic disk (5.0e6 -2.0e7ns/ 5-20 milliseconds, slow latency also depends on the queue, 10-40 million clock cycles, a factor of about 100 slower than flash)
cost per GB goes up as the response time/storage size gets faster, why would you use slow/small memory when fast/more memory is cheaper
Memory that responds quickly is put closer to the cpu, so that it is not wasted with communications overheads.
