Chris, An article in Nature last year presents a calculation of the theoretical minimum energy required to erase a bit - independent of the computer: > > Antoine BĂ©rut, Artak Arakelyan, Artyom Petrosyan, Sergio Ciliberto, Raoul > Dillenschneider & + et al. > Nature 483, 187-189 doi:10.1038/nature10872 > L.W.Sterritt

On Sep 20, 2013, at 1:22 PM, Chris de Morsella <cdemorse...@yahoo.com> wrote: > >> A computation always takes a nonzero amount of energy to perform, > >> theoretically you can make the energy used be as close to zero as you > >> like, but the less energy you use the slower the calculation. > How does that square with the increased (well measured) energy efficiency per > fundamental unit of logic (single machine operation) -- it takes far less > energy to perform an elementary logic operation on a modern CPU than it did > on say a CPU from ten years ago (even if the modern CPU may suck down more > total power -- it is performing far more work) > > Modern CPUs clearly are also operating at much higher speeds. I think you are > not factoring in the dimension of scale or the physical size of the logic > container/state-machine. As the size of a logic gate is scaled down it takes > less energy and can operate at a higher clock speed. > > http://en.wikipedia.org/wiki/Performance_per_watt > "For example, the early UNIVAC I computer performed approximately 0.015 > operations per watt-second (performing 1,905 operations per second (OPS), > while consuming 125 kW). The Fujitsu FR-V VLIW/vector processor system on a > chip in the 4 FR550 core variant released 2005 performs 51 Giga-OPS with 3 > watts of power consumption resulting in 17 billion operations per > watt-second.[1][2] This is an improvement by over a trillion times in 54 > years." > > Size (or rather the lack of it) matters in this equation. > -Chris > > From: John Clark <johnkcl...@gmail.com> > To: everything-list@googlegroups.com > Sent: Friday, September 20, 2013 10:38 AM > Subject: Re: What gives philosophers a bad name? > > On Thu, Sep 19, 2013 at 6:10 PM, LizR <lizj...@gmail.com> wrote: > > >> As Rolf Landauer said "Computation is physical", all computations must use > >> energy and generate heat. And what's the difference between a physical > >> process and a non-physical process anyway? > > > I thought it was only erasing the results of computations that had to use > > energy and increase entropy? - if so - quibbling, I know, but sometimes > > quibbles have important consequences. > > A computation always takes a nonzero amount of energy to perform, > theoretically you can make the energy used be as close to zero as you like, > but the less energy you use the slower the calculation. > > John K Clark > > > > > > > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to mailto:everything-list%2bunsubscr...@googlegroups.com. > To post to this group, send email to everything-list@googlegroups.com. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/groups/opt_out. > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to everything-list+unsubscr...@googlegroups.com. > To post to this group, send email to everything-list@googlegroups.com. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/groups/opt_out. > > > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to everything-list+unsubscr...@googlegroups.com. > To post to this group, send email to everything-list@googlegroups.com. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.