On Monday, June 9, 2014 2:57:26 PM UTC+5:30, Steven D'Aprano wrote: > http://en.wikipedia.org/wiki/Landauer's_principle
Hey thanks for that! Always thought something like this should exist but did not know what/where/how! > On Sun, 08 Jun 2014 23:32:33 -0700, Rustom Mody wrote: > > On Monday, June 9, 2014 9:50:38 AM UTC+5:30, Steven D'Aprano wrote: > >> On Sun, 08 Jun 2014 19:24:52 -0700, Rustom Mody wrote: > >> > On Monday, June 9, 2014 7:14:24 AM UTC+5:30, Steven D'Aprano wrote: > >> >> CPU technology is the triumph of brute force over finesse. > >> > If you are arguing that computers should not use millions/billions of > >> > transistors, I wont argue, since I dont know the technology. > >> No. I'm arguing that they shouldn't convert 90% of their energy input > >> into heat. > > Strange statement. > > What should they convert it into then? > Useful work, duh. > Everything *eventually* gets converted to heat, but not immediately. > There's a big difference between a car that gets 100 miles to the gallon, > and one that gets 1 mile to the gallon. Likewise CPUs should get more > "processing units" (however you measure them) per watt of electricity > consumed. > See, for example: > http://www.tomshardware.com/reviews/fx-power-consumption-efficiency,3060.html > http://en.wikipedia.org/wiki/Performance_per_watt > Quote: > Theoretically, room-temperature computer memory operating > at the Landauer limit could be changed at a rate of one > billion bits per second with only 2.85 trillionths of a > watt of power being expended in the memory media. Modern > computers use millions of times as much energy. Right so we are still very much in theoretical zone. As the next para there says: | If no information is erased, computation may in principle be achieved | which is thermodynamically reversible, and require no release of | heat. This has led to considerable interest in the study of reversible | computing. Particularly interesting as no-information-erasure corresponds to functional (or maybe relational) programming. Of course still all theoretical. > Much to my surprise, Wikipedia says that efficiency gains have actually > been *faster* than Moore's Law. This surprises me, but it makes sense: if > a CPU uses ten times more power to perform one hundred times more > computations, it has become much more efficient but still needs a much > bigger heat sink. That was essentially my point -- https://mail.python.org/mailman/listinfo/python-list
