The biggest bitmap What is the largest volume we can map with a bitmap? On a 32 bit system, it is 2^32 page cache blocks * 2^12 bytes per block * 2^3 bits per byte * 2^12 block size = 2^59. One bit short of the promised exabyte maximum Tux3 volume size. The limitation is the size of the page cache index on a 32 bit system; on a 64 bit system there is no such limitation. Even if a filesystem is created on a 64 bit system it still should be readable on a 32 bit system. We could just say ...