Quad-precision floats will be widespread before applications that use >256TiB of memory are common. In that case, we can NaN-box the quad float and have up to

Quad-precision floats will be widespread before applications that use >256TiB of memory are common. In that case, we can NaN-box the quad float and have up to 112 bits of pointer space to play with. Lets assume we double the number of pointer bits to 96 - we can support YiBs of address space.