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On 12/04/2011 04:52 PM, Darren New wrote:
> On 4/12/2011 7:15, Invisible wrote:
>> So if this technology is the future... where is it? How come it's
>> completely
>> vanished off the face of existence?
>
> http://en.wikipedia.org/wiki/Optical_computing
Oh, is that what they call it now?
>> There seemed to be some suggesting that the entire IC might work by
>> processing light instead of electricity. I'm sceptical about whether that
>> could work. I'm not aware of any light-based switching technology.
>
> The very effect that makes you not need wires means the entire IC can't
> work with nothing but light. You don't need wires because photons don't
> interact with each other - they only interact with electrons. Hence, you
> can't easily switch light without involving electricity.
The article linked claims that materials with a "non-linear refractive
index" can be used to make signals interact. It also suggests that this
is much less efficient than semiconductors.
>> On the other hand, just using light for implementing long-range
>> connections? That could *totally* work!
>
> You mean, like, microwave communication towers and fiber optic cable?
No, I mean like if component A needs to be connected to component Z at
the other end of the die, you could stick in an optical link, rather
than trying to route a trace the entire way across the die. And doing so
might be a big win in terms of signal propogation speed, capacitance, etc.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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>> So if this technology is the future... where is it? How come it's
>> completely vanished off the face of existence?
>
> It hasn't - some of it didn't work out.
I meant optical computing specifically. Nobody talks about it any more.
So what happened to it?
>> So why is absolutely nobody using this stuff? I can only imagine that
>> the answer is the same as for the 3D IC. In other words, "it's too
>> expensive" combined with "we haven't reached the hard limits of current
>> methods yet".
>
> There is a certain amount of technological inertia to overcome - current
> methods are cheap, developing new methods costs a lot of money,
> especially when you start talking about large-scale production.
>
> So in essence, you're correct. :)
Heh. Thought so.
In that case, presumably once current technologies start hitting
hard(er) limits, new ones will start to be viable.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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> I also remember something rather puzzling. Apparently somebody
> discovered that if you etch silicon with a certain kind of acid, it
> produces a special microscopic structure which has an unexpected
> property: it can transform electricity into like, and the reverse. This
> was hailed as the future of IC technology. In the future, we were told,
> interconnects on an IC would work using light rather electricity. For
> light has one really critical advantage: beams of light can pass through
> each other.
>
> By contrast, if you want to move signals around using wires, you either
> have to have extremely long and convoluted wire routes to get around all
> the obstacles in your way, or complex multiple-layer wiring designs. But
> with light, a signal can just go straight from A to B, intersecting as
> many other signal paths as you like.
>
> So if this technology is the future... where is it? How come it's
> completely vanished off the face of existence?
>
> There seemed to be some suggesting that the entire IC might work by
> processing light instead of electricity. I'm sceptical about whether
> that could work. I'm not aware of any light-based switching technology.
>
> On the other hand, just using light for implementing long-range
> connections? That could *totally* work! By strategically using optical
> signals in place of electronic ones, you might be able to drastically
> reduce signal path lengths, which reduces propagation delays. More to
> the point, if I'm understanding this right, long traces have the problem
> of high capacitance too, which an optical signal path would seemingly
> also avoid.
>
> So why is absolutely nobody using this stuff? I can only imagine that
> the answer is the same as for the 3D IC. In other words, "it's too
> expensive" combined with "we haven't reached the hard limits of current
> methods yet".
>
For optical computers, there are several working prototypes in several labs.
The good:
Multiple parallel use of the same switch/circuit by using light of
different colours, over 100 simultaneous computing channels on 1
component at the same time! Brings up realy massive parallel
multiprocessing.
Digital circuits having 5 discreet stable signal level. Base 5 computing
anyone?...
No cross interference.
No capacitance nor inductance.
Capable of theoretical clock speed in the THz.
Capable of mixed digital and analogic processing.
Dirrect intercomponents data paths.
The bad:
Most of those components are cm sized, or monstrously huge compared to
electronic parts.
Mostly organic material based can compromise longevity and stability.
Non-organic based solutions tend to be very brittle and devlop faults
and minute cracks.
There are problems with the RAM side. Low capacity and retention time.
Refreshing dynamic RAM is difficult and static RAM not realy functional.
Storage loops have huge latency or very low capacity.
Nobody can yet take advantage of 5 digital states.
Alain
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On 4/12/2011 11:33, Orchid XP v8 wrote:
> The article linked claims that materials with a "non-linear refractive
> index" can be used to make signals interact.
Guess what causes something to have a non-linear refractive index? Electrons.
> No, I mean like if component A needs to be connected to component Z at the
> other end of the die, you could stick in an optical link, rather than trying
> to route a trace the entire way across the die. And doing so might be a big
> win in terms of signal propogation speed, capacitance, etc.
Maybe. But you still have to convert it from electronics to light and back
again.
--
Darren New, San Diego CA, USA (PST)
"Coding without comments is like
driving without turn signals."
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On 4/12/2011 10:25, Stephen wrote:
> On 12/04/2011 5:52 PM, Warp wrote:
>> and flatscreen monitors:
>
> I remember reading an article in the late 50's or early 60's saying that
> flatscreen monitors would be impossible. Of course it was talking about CRTs
There's also a version where the guns are at the bottom and the beam gets
curved as it passes up the back of the plate. IIRC, they had two guns, one
for purplish and one for greenish, so the colors weren't as good.
--
Darren New, San Diego CA, USA (PST)
"Coding without comments is like
driving without turn signals."
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On 4/12/2011 11:35, Orchid XP v8 wrote:
> I meant optical computing specifically. Nobody talks about it any more. So
> what happened to it?
I hear about it pretty regularly, as research. People are still trying to
figure out how to get it interfaced to the electronics efficiently and so on.
--
Darren New, San Diego CA, USA (PST)
"Coding without comments is like
driving without turn signals."
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Le 2011/04/12 14:33, Orchid XP v8 a écrit :
> The article linked claims that materials with a "non-linear refractive
> index" can be used to make signals interact. It also suggests that this
> is much less efficient than semiconductors.
>
There are cases where an interface can switch from pass through to
reflective depending on a controll light beam.
You can selectively change the reflective capacity of very narow bands.
You can reflect at 952nm but not 950nm nor 954nm if you want to.
Alain
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On Tue, 12 Apr 2011 19:35:37 +0100, Orchid XP v8 wrote:
>>> So if this technology is the future... where is it? How come it's
>>> completely vanished off the face of existence?
>>
>> It hasn't - some of it didn't work out.
>
> I meant optical computing specifically. Nobody talks about it any more.
> So what happened to it?
I've read a few articles on it recently. Seems that *some* people are
still talking about it.
>>> So why is absolutely nobody using this stuff? I can only imagine that
>>> the answer is the same as for the 3D IC. In other words, "it's too
>>> expensive" combined with "we haven't reached the hard limits of
>>> current methods yet".
>>
>> There is a certain amount of technological inertia to overcome -
>> current methods are cheap, developing new methods costs a lot of money,
>> especially when you start talking about large-scale production.
>>
>> So in essence, you're correct. :)
>
> Heh. Thought so.
>
> In that case, presumably once current technologies start hitting
> hard(er) limits, new ones will start to be viable.
Yep.
Jim
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Alain <aze### [at] qwerty org> wrote:
> The bad:
> Most of those components are cm sized, or monstrously huge compared to
> electronic parts.
Guess what the size of the first transistors (well, the equivalent of
transistors used in the first electronic computers) were.
--
- Warp
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On 12/04/2011 07:46 PM, Darren New wrote:
> On 4/12/2011 11:33, Orchid XP v8 wrote:
>> The article linked claims that materials with a "non-linear refractive
>> index" can be used to make signals interact.
>
> Guess what causes something to have a non-linear refractive index?
> Electrons.
I'll take your word for it. ;-)
>> No, I mean like if component A needs to be connected to component Z at
>> the
>> other end of the die, you could stick in an optical link, rather than
>> trying
>> to route a trace the entire way across the die. And doing so might be
>> a big
>> win in terms of signal propogation speed, capacitance, etc.
>
> Maybe. But you still have to convert it from electronics to light and
> back again.
Indeed. A hybrid optical-electronic IC looks far more plausible to me
than a purely optical one.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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