From: Arne Vajhøj on 17 Jan 2010 19:58 On 12-01-2010 14:08, Lew wrote: > On Jan 12, 11:16 am, Wojtek<nowh...(a)a.com> wrote: >> Arne Vajh�j wrote : >>> On 11-01-2010 17:09, Maarten Bodewes wrote: >>>> Arne Vajh�j wrote: >>>>> BTW, even long would be too small for indexes if Java >>>>> will be used after 2074, but somehow I doubt that would >>>>> be the case. And besides we do not have the verylong datatype >>>>> yet. >>>> You are expecting memory sizes of 9,223,372,036,854,775,807 bytes???? >>>> That's 9,223 PETA bytes. Hmm, weird, may happen. But it is certainly >>>> rather large. >> >>> In 2074 ? Yes ! >> >> I am curious. Just what WOULD need such a large index? Every sand grain >> on earth? Every star in every galaxy in the universe? > > Where will you store the array? Either you have a crapload of RAM > (one bit per atom storage density?) or the largest-capacity storage > device ever invented (one bit per atom storage density?). > > What's the average retrieval latency? Even at one bit per atom > storage density, it must take even a light beam noticeable time to > reach the further reaches of the storage device; anything slower like > a semiconductor must take a really long time. > > A silicon crystal lattice has a lattice spacing of just over half a > nanometer, or 5.4 x 10^-10 m. A three-dimensional storage medium for > a 9 x 10^18-element array would hold juar over 2 x 10^6 elements to > the side. An average access would be halfway in each dimension, or > 10^6 elements, which in a silicon lattice is about 5.4 x 10-4 m, times > three for a total traversal distance of about 1.6 x 10^-3 m. Each > way. For a round trip slightly over 3 x 10^-3 m. A light beam > travels that in 0.1 microseconds (10^-7 s). That's about 200 clock > cycles of latency on a modern processor, far more on the future > processors of 2074. With correction: >Drat! Mixed up my CGS and MKS. That's 10-5 s, or 10 microseconds. Neither looks correct to me. s = 3 x 10^-3 m v = 3 x 10^8 m/s => t = s/v = 1 x 10^-11 s Arne
From: Lew on 17 Jan 2010 21:34 Lew wrote: >> Drat! Mixed up my CGS and MKS. That's 10-5 s, or 10 microseconds. Arne Vajhøj wrote: > Neither looks correct to me. > > s = 3 x 10^-3 m > v = 3 x 10^8 m/s > => > t = s/v = 1 x 10^-11 s Sigh. You are, of course, absolutely correct. -- Lew
From: RedGrittyBrick on 19 Jan 2010 04:36 Arne Vajhøj wrote: > On 12-01-2010 11:16, Wojtek wrote: >> Arne Vajhøj wrote : >>> On 11-01-2010 17:09, Maarten Bodewes wrote: >>>> Arne Vajhøj wrote: >>>>> BTW, even long would be too small for indexes if Java >>>>> will be used after 2074, but somehow I doubt that would >>>>> be the case. And besides we do not have the verylong datatype >>>>> yet. >>>>> >>>> You are expecting memory sizes of 9,223,372,036,854,775,807 bytes???? >>>> >>>> That's 9,223 PETA bytes. Hmm, weird, may happen. But it is certainly >>>> rather large. >>> >>> In 2074 ? Yes ! >> >> I am curious. Just what WOULD need such a large index? Every sand grain >> on earth? Every star in every galaxy in the universe? > > I don't know. > > What I do know is that several times during the last 50 years > somebody has said that you will never need more than X memory. > And they have been wrong every time. > > I think it is most logical to assume that trend will continue > and that we indeed will find something to use such huge > address spaces for. And if we don't, Microsoft's Office team will ;-) -- RGB
From: Arne Vajhøj on 19 Jan 2010 21:37 On 19-01-2010 04:36, RedGrittyBrick wrote: > > Arne Vajhøj wrote: >> On 12-01-2010 11:16, Wojtek wrote: >>> Arne Vajhøj wrote : >>>> On 11-01-2010 17:09, Maarten Bodewes wrote: >>>>> Arne Vajhøj wrote: >>>>>> BTW, even long would be too small for indexes if Java >>>>>> will be used after 2074, but somehow I doubt that would >>>>>> be the case. And besides we do not have the verylong datatype >>>>>> yet. >>>>>> >>>>> You are expecting memory sizes of 9,223,372,036,854,775,807 bytes???? >>>>> >>>>> That's 9,223 PETA bytes. Hmm, weird, may happen. But it is certainly >>>>> rather large. >>>> >>>> In 2074 ? Yes ! >>> >>> I am curious. Just what WOULD need such a large index? Every sand grain >>> on earth? Every star in every galaxy in the universe? >> >> I don't know. >> >> What I do know is that several times during the last 50 years >> somebody has said that you will never need more than X memory. >> And they have been wrong every time. >> >> I think it is most logical to assume that trend will continue >> and that we indeed will find something to use such huge >> address spaces for. > > And if we don't, Microsoft's Office team will ;-) It seems to be a rather universal rule, that if the HW guys can produce some new HW that are N times faster/bigger then us SW guys will find a way to make our apps require the same N times more resources. Arne
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