For free-l, --lohi                Show detailed low and high memory statistics.Are the statistics calculated over a period of time? How is the period defined?Why is the high all zero below?$ free -l             total       used       free     shared    buffers     cachedMem:       8067524    7392888     674636     440536      53880     861080Low:       8067524    7392888     674636High:            0          0          0-/+ buffers/cache:    6477928    1589596Swap:     15625212    7562728    8062484
How are statistics output by `free -l` calculated?
memory