How can AI researchers save energy? By going backward

This loss is a fundamental aspect of how computers operate. For example, when a computer adds two numbers together, it returns a single number for the total: 2 + 2 = 4. There’s a loss of information as you go from two numbers to one. You could have added 2 and 2, or you could have combined 1 and 3. The missing information makes the calculation irreversible. Computers that process information this way — and almost all of them do — are always going to lose some information as heat, no matter what. Landauer wondered if a machine could get around this limitation by simply never deleting data. Such a device would need to keep a record of every operation, every pair of numbers added at every step. These records would rapidly fill its memory, making such a computer unusable in practice, despite the energy savings. Landauer soon moved on, convinced that reversible computing was a dead end. A decade later, he learned that he had been mistaken. Hitting Reverse Charles Bennett, a younger coll ... Read full article.