Gustafson is a noob. Both his Unum I and II proposals are completely impractical, making absolutely no consideration for how hardware would implement his ideas.

Gustafson is a noob. Both his Unum I and II proposals are completely impractical, making absolutely no consideration for how hardware would implement his ideas. But by writing only about the imagined merits he managed to convince a lot of people that his ideas were great. Unum III/Posits can work, but mainly it is just a number compression format. Working with say 64 bit Posits pretty much requires implementing arithmetic equivalent to that of 80 bit IEEE floats, and then throwing away a larger or smaller portion of the mantissa depending on the exponent. And the extra accuracy around the sweet spot of 1 still comes at the cost of lost accuracy for large and small numbers, so some workloads will suffer.