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 Bérut, 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 <[email protected]> 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 <[email protected]> > To: [email protected] > 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 <[email protected]> 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%[email protected]. > To post to this group, send email to [email protected]. > 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 [email protected]. > To post to this group, send email to [email protected]. > 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 [email protected]. > To post to this group, send email to [email protected]. > 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
