Unum is a number format that is similar to IEEE 754 format (floating point numbers) that is publicly proposed by John L. Gustafson in 2013. By August 2013, he had a working unum environment to explain and justify his number system. The book "The End of Error" authored by John in 2015 elaborates his comprehensive proposal to have unums replace floating point numbers for improvement in performance and accuracy. Unum has since evolved. The original Type I provides a compact way to express interval arithmetic. Type II enables a clean mathematic design based on projective reals. The latest version, Posits and Valids, has all the advantages of the original Type I and Type II and is additionally hardware-friendly, making it a favourite among many.
John L. Gustafson, the creator of unums and posits, is widely known in High Performance Computing field for his invention of Gustafson's law. He had also introduced the first commercial computer cluster and led the reconstrution of Atansoff-Berry computer. Most notably, John was a recipient of the Gorden Bell Prize in 1988, International Anasoff Award in 2006 and IEEE Computer Society Golden Core Award in 2007. John also received a prestigious internal Intel award in 2012 for Technology Strategic Long-Range Plan (TSLRP), which indicated his proposed technology, the underlying concepts of unum, possessed qualities to be a game-changer.