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Sun Turns to Lasers to Speed Up Computer Chips

ScuttleMonkey posted more than 6 years ago | from the friggin-lasers dept.

Sun Microsystems 130

alphadogg writes to mention that Sun is attempting to move from the typical design of multiple small chips back to a unified single-wafer design. "The company is announcing today a $44 million contract from the Pentagon to explore replacing the wires between computer chips with laser beams. The technology, part of a field of computer science known as silicon photonics, would eradicate the most daunting bottleneck facing today's supercomputer designers: moving information rapidly to solve problems that require hundreds or thousands of processors."

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Great idea! (5, Funny)

peipas (809350) | more than 6 years ago | (#22847304)

I assume these systems will be water-cooled so the miniaturized sharks have somewhere to swim.

-1 : redundant (5, Funny)

UdoKeir (239957) | more than 6 years ago | (#22847366)

To quote Scott McNealy:

You know, I have one simple request. And that is to have SPARCS with frickin' laser beams attached to their heads!

Re:-1 : redundant (1)

ndevice (304743) | more than 6 years ago | (#22848144)

Watch out for sun to buy out, or merge with Analog devices soon. If they get their lasers going, they could put them on those Analog Devices DSP parts too.

And furthermore . . . (-1, Troll)

Anonymous Coward | more than 6 years ago | (#22849368)

Hey Commander Asshole!! Do you have any fucking clue what the hell you're doing?!? When are you going to realize that this new discussion system just doesn't fucking work?!? It's bad enough I have to spend half a fucking day trying to retrieve comments, but now about 50% show a few lines from the comment and abruptly end with "loading . . .". But here's the catch - THEY NEVER FUCKING LOAD!! So, in order to read these comments, I have to click on the comment header. Then, when I click on the Back button, I GET TO START ALL OVER WITH THE COMMENTS RETRIEVAL PROCESS, FOR THE SAME FUCKING COMMENTS I ALREADY RETRIEVED!!! If you don't want me script-flooding your site, then ya gotta come up with a better solution. Oh, and test it before you implement it. Oh, yeah, another thing, GIVE PEOPLE THE FUCKING OPTION TO TURN IT OFF!!. Don't pull this Micro$oft bullshit by considering you user base beta testers. ARE YOU SOME KIND OF FUCKING IDIOT, OR WHAT TACO?!?!?!? Come on. Let's get with the program.

Re:And furthermore . . . (1)

seededfury (699094) | more than 6 years ago | (#22849720)

I turned mine off the first day i saw it and haven't seen it since.


Preferences--->Discussions---->Viewing.

Not so hard.

Re:And furthermore . . . (1)

Xiph1980 (944189) | more than 6 years ago | (#22849838)

Haven't received enough hugs from your daddy??

Re:And furthermore . . . (1)

cbiltcliffe (186293) | more than 6 years ago | (#22849950)

Weird. The new discussion display system works just fine on my computer, and in fact, on any computer that I've ever tested it on. Running either Firefox, or (shudder) IE.

I keep hearing people bitch about how it takes forever to load, and crashes their browser, and all sorts of other crap, but I've never seen it, and I've surfed /. on a very broad range of computer hardware.

Maybe your computer is infected with spyware, or something. Or maybe you've got a browser extension that screws something up.

It can't be the discussion system itself, as it works fine for a great number of people.

+1, Superior Use of Meme (0)

Anonymous Coward | more than 6 years ago | (#22848482)

n/t

Re:-1 : redundant (1)

ioshhdflwuegfh (1067182) | more than 6 years ago | (#22848606)

and some lazer beans, real loud...

Re:-1 : redundant (0)

Anonymous Coward | more than 6 years ago | (#22848644)

now that was funny. my mod points ran out yesterday or I'd help you out.

One weakness... toothpaste (0)

Anonymous Coward | more than 6 years ago | (#22847502)

Just don't let anyone with a mastery of the "JUDO CHOP!" bring toothpaste with them... or else you'll need a big boy to get you out of that situation.

Re:Great idea! (1)

aarku (151823) | more than 6 years ago | (#22847508)

Yarrrrrrrrrrrrrrrrrr I'm sick of shark/laser jokes. No offense personally intended, just to the whole meme.

Re:Great idea! (4, Funny)

Anonymous Coward | more than 6 years ago | (#22847566)

How do you feel about Sea Bass?

Re:Great idea! (3, Funny)

utopianfiat (774016) | more than 6 years ago | (#22847778)

Depends, are they ill-tempered?

Re:Great idea! (1)

tbcpp (797625) | more than 6 years ago | (#22848434)

LOL, if I had points I'd mod the parent up

Re:Great idea! (1)

jo42 (227475) | more than 6 years ago | (#22850614)

And "In Soviet Russia" blabs are getting uber lame. Halibut, even "Beowulf Cluster of ..." didn't hang around this long. The stench of olde and rotten is getting rather thick me smells.

Re:Great idea! Cypress has been there, done that. (1)

aisnota (98420) | more than 6 years ago | (#22850948)

Cypress Semiconductor has already figured this out with their tech. Check out Silicon Light Machines and you will see T. J. Rodgers acquired a former Cypress Semiconductor alumnus in that acquisition and all Sun needs to do is work with CY.

This intention to reseach the use of lasers (0, Redundant)

Timesprout (579035) | more than 6 years ago | (#22847334)

has been hailed as a positive step by leading members of the shark community.

Are actuators faster than direct connections? (5, Interesting)

BadAnalogyGuy (945258) | more than 6 years ago | (#22847338)

I wonder if the time saved transmitting information via light is offset by the transition time used to translate that back into electric signals. On a single board, the distance travelled is on the order of decimeters. On a chip, micrometers. Are the time savings *that* significant? Even between peripherals, the time saved seems negligble.

Re:Are actuators faster than direct connections? (3, Insightful)

TheRealMindChild (743925) | more than 6 years ago | (#22847490)

I am not an expert in electricity by no means, but I have a fundamental understanding of it (or so I think). Energy is energy. With no resistance (don't overlook this point), light traveling via laser or via electrons flowing over a wire, the speed would be the same. Now, in reality, there IS resistance... there is always a "friction" or resistance (ohm) when energy is passing over a wire. In a vacuum, a laser will move as fast as energy can possibly travel. At least on paper.

Re:Are actuators faster than direct connections? (2, Insightful)

isomeme (177414) | more than 6 years ago | (#22847822)

Electrons in a superconductor (a material with zero resistance) do not travel at the speed of light.

Re:Are actuators faster than direct connections? (1)

Gabest (852807) | more than 6 years ago | (#22848180)

I guess both of you meant electromagnetic weave, electrons do not move too fast.

Re:Are actuators faster than direct connections? (5, Informative)

bartosek (250249) | more than 6 years ago | (#22848236)

In fact electrons in your typical electrical wire don't move anywhere near the speed of light.

http://www.eskimo.com/~billb/miscon/speed.html [eskimo.com]

Re:Are actuators faster than direct connections? (0)

Anonymous Coward | more than 6 years ago | (#22848282)

... but at which speed?

Re:Are actuators faster than direct connections? (0)

Anonymous Coward | more than 6 years ago | (#22848436)

Neither does the EM wave their motion represents. http://en.wikipedia.org/wiki/Speed_of_electricity [wikipedia.org]

My question is, assuming wikipedia is right and that the EM wave goes 2c/3 through copper, and given that modern chips aready have switchbacks to ensure some wires are the same lengths as each other so the signals sync up, how much time will this 50% signal speed increase actually buy us? Will we have the same signal speed bottleneck (assuming that Sun is trying to solve a real problem, I'm not really a hardware guy so for all I know maybe 2c/3 is fast enough) with these chips in 10 years? If so, we should probably start thinking of workarounds, because something tells me we're not going to find anything that offers a 50% improvement over c.

Re:Are actuators faster than direct connections? (2, Interesting)

imgod2u (812837) | more than 6 years ago | (#22848828)

No, but it depends on whether or not the receiver is current-steered or voltage-steered. If it's voltage steered then it's the propagation of the electric field that carries the signal. In which case, it can be near the speed of light.

Also, future chip-to-chip interconnects seem to be moving towards transmission lines rather than treating circuit paths like bulk interconnects. Wave-pipelining the signal will mean that data transfer rates will not be hindered by the time it takes a voltage swing from transmitter to reach the receiver. Latency is still a problem, however but I imagine the electro-optical conversion process already adds plenty of that.

Re:Are actuators faster than direct connections? (0)

Anonymous Coward | more than 6 years ago | (#22848326)

Photons are not electrons. Also, conductivity / electrical resistance is not really the same as friction, nor does friction necessarily reduce potential maximum speed, but transfers energy and reduces actual speed as a side effect.

Re:Are actuators faster than direct connections? (3, Informative)

ChrisA90278 (905188) | more than 6 years ago | (#22849100)

When you look at a wire, or printed trace on a PCB it is not the resistance that limits how fast you can send a signal. It is inductance and capasitance that act like a low pass filter. We don't care how fact eletrons travel in wire what we care about is how fact we can change the voltage in the wire. We send data by changing voltages not by sending electrons.

Re:Are actuators faster than direct connections? (2, Interesting)

TheRaven64 (641858) | more than 6 years ago | (#22849304)

And when you look at a PCB, it's not just the speed of the signal that determines the time it takes, it's also the distance it travels. Wires on a PCB can only cross by being at different heights (expensive) so it is common to route signals indirectly, which increases their distance quite a lot. When you have 64 wires coming from your RAM chips, and needing to get to your CPU, this sort of thing adds up quickly. Beams of light, in contrast, can cross without interfering with each other.

Re:Are actuators faster than direct connections? (1)

cheater512 (783349) | more than 6 years ago | (#22850470)

Resistance isnt the problem. Its a few cm of copper.

The problem is inductance and cross talk causing interference.
One solution is to shield every wire in a bus but its not really practical. ;)

Re:Are actuators faster than direct connections? (1)

ILuvRamen (1026668) | more than 6 years ago | (#22848150)

I think the photons strike a really small sort of solar panel where the burst of light turns instantly into a burst of electricity. So there's no digital translation by a chip necessary. Of course you lose a lot of power converting it like that cuz let's say the solar sensor is 50% energy efficient, well you have to use 2x the electricity in the first place to get the desired 1x electricity at the end. So these chips are gonna be fast but they'll suck up energy faster than me eating 50% Walgreens Cocoa Peeps the day after Easter :D

Re:Are actuators faster than direct connections? (2, Interesting)

warmflatsprite (1255236) | more than 6 years ago | (#22849896)

You're on the right track, but you're not quite there. Solar panels are more or less arrays of photodiodes. AFAIK most fiber system use PIN photodiodes to convert the light intensity over a specific band of wavelengths in a fiber to electrical current. Note that I said current, not voltage. Typically a transimpedance amplifier and some kind of comparator circuit is then used to measure the intensity of the signal. The PIN diodes can convert very small quantities of light to very small currents, and transimpedance amplifiers can deal with very small currents as well. Generally the limiting factor for low-light intensity systems like is the "dark current" of the diode you're using. If the current generated due to your light source is within the noise of the dark current you won't be able to detect any change in the system. Fiber systems operate at light intensities that generate currents well above this dark current, and they do so without a high power demand.

Power issues can be born from speed issues, though. Since photodiodes need a fairly large surface area to be able to generate enough current from light signals, the PN (or PIN) junctions act like a capacitor. Capacitors act like low-pass filters and this limits the switching frequency of the signal you can transmit. This effectively limits the data rate of the system. If you make the surface area smaller, you'll need to increase the intensity and focus of your light beam in order to make up for the change. This could cause high speed systems to have high bus power requirements and higher manufacturing costs.

Re:Are actuators faster than direct connections? (5, Insightful)

JustinOpinion (1246824) | more than 6 years ago | (#22848486)

The article doesn't make it clear whether using optical communications is intended to reduce latency or increase bandwidth.

With respect to latency: the electrical signals travel at ~30% the speed of light, whereas the optical signals travel at ~70% the speed of light (it depends on refractive index, etc.). Over the distances we're talking about (as you said, mm to dm), that's only fractions of a nanoseconds delay savings [google.com] . This is on the order of a modern computer's switching time [google.com] . All this complexity to get rid of a one or two processor cycles of latency?

I suspect instead they are looking to increase bandwidth. An optical fiber can carry very high data rates. Moreover a single physical fiber can carry multiple simultaneous channels (e.g. different wavelengths of light). So the intention may instead be to create high-bandwidth links between various processors. Using on-chip lasers can make the entire assembly smaller and faster than the equivalent for electrical wires.

Really what they want, I think, is to implement the same kind of high-speed optical switching we use for transcontinental fiber-optics into a single computer or computer cluster. If you can put all the switching and multiplexing components directly onto the silicon chips, then you can have the best of both worlds: well-established silicon microchips that interface directly into well-understood high-speed optical switching systems.

Re:Are actuators faster than direct connections? (0)

Anonymous Coward | more than 6 years ago | (#22850738)

http://en.wikipedia.org/wiki/Velocity_of_propagation [wikipedia.org]

70% of c for riser ethernet.

I think Sun is just banking on the "frickin' laser beams" factor.

Re:Are actuators faster than direct connections? (3, Insightful)

arjay-tea (471877) | more than 6 years ago | (#22848600)

It's not so much transit time, as parallelization where the big advantage is. Many frequencies of light can share the same medium without interfering with each other. Imagine many processors and memory chips streaming data to each other simultaneously, over the same backplane.

Re:Are actuators faster than direct connections? (4, Interesting)

rbanffy (584143) | more than 6 years ago | (#22848646)

I don't think it's about the time it takes to transfer a single bit but the amount of bits that can be transmitted at once with light rather than wires. If we can talk line-of-sight transmission between boards, it's easy to line up an array of about a million emitters with an array of a million detectors and send back and forth the same amount of data you would need a couple thousand wires (taking translation times into account) to do.

Sun is a very entertaining company to watch. Even when their gizmos never end up in products, they are always cool.

Re:Are actuators faster than direct connections? (2, Interesting)

mikael (484) | more than 6 years ago | (#22849526)

There are several major issues:

The first is the size of the packaging of the chip - the actual silicon might only occupy the space a quarter the size of the whole unit. All that extra space is just used to manage the 500+ copper connections between the silicon and the rest of the circuit board. [intel.com]

The second problem is that as the clock speed of these connections becomes faster, synchronisation becomes a problem. While CPU's are running in the GHz frequencies, the system bus is still running in the hundreds of MHz.

If the chip could connect to the circuit board through optical connections, then all this could be simplified. You would eliminate the need for all the copper connections while simultaneously speeding up the external clock speed.

Re:Are actuators faster than direct connections? (0)

Anonymous Coward | more than 6 years ago | (#22850380)

I remember writing a report on this stuff in high school more than 10 years ago (a summary of the current tech - I don't mean I was doing this stuff!) At the time the concept was not that you'd generate light via an actuator but rather that light would emit from the chip itself by the process of exciting the silicate via a charge and then as electrons dropped to lower orbits photons were emitted.

The major problem was the purity of silicate required. Gallium arsenide was a better alternative but the cost was prohibitive - would this be an issue now?

Commentary on this? (2, Interesting)

Anonymous Coward | more than 6 years ago | (#22847364)

Commentary on this, from an actual EE, not the pretend ones on Slashdot (you know who you are)?

Sounds sweet, but is it expensive in terms of energy/time/money? Does EMI become less of a problem on circuit boards? Will this make designer's lives easier?

Re:Commentary on this? (1)

ergo98 (9391) | more than 6 years ago | (#22847456)

Commentary on this, from an actual EE, not the pretend ones on Slashdot (you know who you are)?

Just look up any of the countless other "use light instead of wires" stories that have been widely reported over the past decade(s). I'm not saying it's not going to happen — I'm sure at some point it will — but barring additional information, preferably actual accomplishments, this is just more of the same.

Re:Commentary on this? (2, Funny)

ergo98 (9391) | more than 6 years ago | (#22847538)

To get you started, here's a search for you [google.ca] . It looks like IBM is only promising a 100-fold performance increase, but Sun got the contract (despite the possibly inaccurate story, it doesn't sound like they actually figured out anything thus far, besides "how to get some government loot") by promising a 1000x increase.

Hey DARPA — I'll give you a 1,000,000x improvement! Email and I'll tell you where to send the cash.

Re:Commentary on this? (1)

Timothy Brownawell (627747) | more than 6 years ago | (#22849414)

Sounds sweet, but is it expensive in terms of energy/time/money?
The article claims it will reduce energy usage. It's much faster, so it saves time. And because time is money, it also saves money. I'm going to make a wild guess that it'll be more expensive to manufacture, because wires and solder and very very easy to put down.

Does EMI become less of a problem on circuit boards?
Yes, because you're no longer trying to send lots of high-frequency signals thru arrays of tiny antennas.

Will this make designer's lives easier?
That would probably depend on what they're designing.

Re:Commentary on this? (1)

sexconker (1179573) | more than 6 years ago | (#22850440)

Technically possible, financially infeasible.
What else is new?

It's been so long since SUN was relevant, and this story changes nothing.

Why not... (2, Interesting)

weaponx86 (1112757) | more than 6 years ago | (#22847408)

If the "lasers" require an electrical signal to be generated, isn't this just adding a step? Also you need an optical sensor somewhere which converts the light back into an electrical signal, no? Sounds like building a tunnel where there is already a bridge.

Re:Why not... (1)

sdpuppy (898535) | more than 6 years ago | (#22847522)

In that case the light could be used :

to connect parts in the chip that are furthest away

or

some of the computing / logic is performed in the light domain before it is translated back to electron domain.

Re:Why not... (1)

sdpuppy (898535) | more than 6 years ago | (#22847562)

Also light behaves in a non-linear fashion which opens the possibilities for speeding up certain types of calculations (logs etc)

Re:Why not... (2, Insightful)

Arthur B. (806360) | more than 6 years ago | (#22848350)

So do transistors. What's your point ? Analog computation ? Yurk.

Re:Why not... (0)

Anonymous Coward | more than 6 years ago | (#22847720)

Or building a light-bridge where there is already a tube

light bridges vs. tubes... hmmm... (1)

norminator (784674) | more than 6 years ago | (#22848146)

Would a series of light bridges allow me to send my internets faster than a series of tubes?

A really high bridge (5, Informative)

Pinky's Brain (1158667) | more than 6 years ago | (#22847956)

On chip they are pumping the signal over a traces with mm range lengths and um range widths, off chip it's over traces with dm range lengths and mm range widths. Timing and power consumption are hard enough problems on chip, off chip they become much harder ... not to mention that most of the power consumed either goes into EM or gets coupled into other signals.

Serial connections help with the timing, but do diddly for power and noise. That's where optical comes in.

Re:Why not... (3, Insightful)

JustinOpinion (1246824) | more than 6 years ago | (#22848252)

To use the beloved transportation analogy: it's like moving your cargo off of trucks and onto a high-speed train. Yes it takes time to move cargo, but it's worth it if the time savings of the high-speed train are big enough (for long enough distances, the savings can be significant).

In this case, there may be a delay associated with signal processing, but if the optical transmission is sufficiently faster than an equivalent electrical one, then it's worth it. Considering that electrical signals themselves need to undergo various kinds of switching and processing anyway (data written or read from a bus), I don't know that converting to laser signals will add much of a delay.

New warning stickers... (3, Funny)

fahrbot-bot (874524) | more than 6 years ago | (#22847480)

From TFA: Each chip would be able to communicate directly with every other chip via a beam of laser that could carry billions of bits of data a second.

Do not look at chip with remaining good eye.

Don't Shake the computer! (1)

CubeRootOf (849787) | more than 6 years ago | (#22847488)

I wonder what will happen to thier investments if someone shakes the table, or knocks the computer on its side, or even if there is an earthquake.

What happens when the computer gets dusty, or mold starts to grow on one of the lenses?

how will dust be solved? Water? Bugs (of the insect variety)?

Re:Don't Shake the computer! (2, Funny)

Belial6 (794905) | more than 6 years ago | (#22848238)

Don't worry, someone will ask it a question that is a paradox before then, and the whole thing will destroy itself with sparks and slowed audio.

Re:Don't Shake the computer! (2, Informative)

Kadin2048 (468275) | more than 6 years ago | (#22848308)

I don't know if this is a serious question or not, but one assumes that the lasers will operate in completely sealed environments (e.g. inside an IC package) or over optical fibers if they need to traverse free space. I think the intra-package situation is probably more common; you could communicate from one core to another on the same die using a laser rather than a wired interconnect and hopefully have less interference/RF/capacitance issues to deal with. This also makes sense given what I know about modern types of laser diodes (especially Vertical Cavity ones) -- they can be created on silicon wafers through similar processes to the way transistors are laid down.

I can't think of any good reason why you'd just be aiming a laser through the empty space inside a PC's case.

Re:Don't Shake the computer! (1)

WhoBeDaPlaya (984958) | more than 6 years ago | (#22849392)

Free space would be quite a pain. You'd need to collimate the beam, worry about acceptance angles, mode field diameters, etc.

Re:Don't Shake the computer! (3, Insightful)

vertinox (846076) | more than 6 years ago | (#22849340)

how will dust be solved?

Why don't you crack open your 3.5" hard disk drive and find out why dust doesn't bother those sensitive platters? ;)

What kind of laser beams? Will they terminate? (1)

LM741N (258038) | more than 6 years ago | (#22847506)

Will these be in the visible or infrared range? Will the laser beams terminate or leak outside the unpackaged chip? I ask because engineers are constantly looking at decapped chips or doing various types of testing under the microscope of live circuitry. I'd hate to get hit by a laser beam through a microscope.

Chips with frikkin lasers! (1)

Mi1ez (769713) | more than 6 years ago | (#22847582)

Sorry, hadda be said. :)

RE: Sun Turns to Lasers to Speed Up Computer Chips (1, Funny)

Anonymous Coward | more than 6 years ago | (#22847650)

I didn't read TFA, but I did read the headline...
So you are telling me that Star at the center of our solar system (Sol or some people call it "Sun") is somehow changing its rate of rotation/turning to track lasers and the side effect of this turning is to increase the production speed of inedible chips made out of computers?
No wonder, I don't read TFA... the headline is just plain silly.

Re: Sun Turns to Lasers to Speed Up Computer Chips (0, Flamebait)

Broken scope (973885) | more than 6 years ago | (#22848080)

You twat. Stop trying to be a pedantic prick. It says "Sun", The shortened name of a company called Sun Microsystems thats typically used in conversation by a large number of people who don't have shit for brains. Lets not forget the logo displayed to the side of the article summary.

You might not be such a dumb fuck if the title said "The sun".

Re: Sun Turns to Lasers to Speed Up Computer Chips (1)

shentino (1139071) | more than 6 years ago | (#22848196)

Pot. Kettle. Black.

I agree with the mods on GP (for once). It was an attempt at humor and was properly labelled as such.

Re: Sun Turns to Lasers to Speed Up Computer Chips (1)

droopycom (470921) | more than 6 years ago | (#22849544)

If it said, "The Sun" I would have been worried about the british tabloid... :)

whoa, scared me there for a second. (1)

Jafafa Hots (580169) | more than 6 years ago | (#22847692)

Thought it was saying the sun turned into a laser. That could be a bad thing, different kind of light and all that.

Me too (1)

davidwr (791652) | more than 6 years ago | (#22848328)

You weren't the only one to confuse Sol with the computer company.

My first thought was "The sun is lasing? Cool!"

My second thought was "space sharks! Way Cool!!!"

Hmm, missed this opportunity too (0)

Private.Tucker (843252) | more than 6 years ago | (#22847932)

Back in High School, a friend named Tom had this crazy idea to use light to transmit information between components in a computer. Back in the mid-to-late 90's, I wonder if anyone else thought of this.

Re:Hmm, missed this opportunity too (1)

ZeroExistenZ (721849) | more than 6 years ago | (#22849972)

Yes, they use called (silicon nano-) photonic chips for that purpose. The same technique will be used to communicated between different cores in chips. (check the press release of IBM [ibm.com] )

I've been looking for an explinatory video from IBM I believe, explaining laser-computing and how they solved certain problems in their designs, but I've failed to locate the particular movie.

bitc h (-1, Troll)

Anonymous Coward | more than 6 years ago | (#22848064)

of 0pen-5ource.

Why light, why not wireless? (1)

ThreeGigs (239452) | more than 6 years ago | (#22848318)

Remember the article not long ago about micro transmitters/receivers on a chip?

Considering no special connections are needed for wireless, unlike light which woud likely need fiber or line of sight, chips equipped with that mini wireless tech would, in theory, only need to be powered and placed in proximity to each other.

Not as sexy as SPARCs with friggin' lasers, but certainly a plus from a computer design perspective.

Re:Why light, why not wireless? (1)

imgod2u (812837) | more than 6 years ago | (#22848930)

Even a directed wireless transmitter through a waveguide only manages to send a fraction of its signal power over to the receiver. There's also the problem that it's much more susceptible to interference, it drains a lot of power because RF signals are not easy to generate at high speeds, the extra logic required and the fact that the bandwidth is just nowhere near what traditional wired links are capable of might not make it all that attractive.

Re:Why light, why not wireless? (1)

morgan_greywolf (835522) | more than 6 years ago | (#22849150)

Even a directed wireless transmitter through a waveguide only manages to send a fraction of its signal power over to the receiver. There's also the problem that it's much more susceptible to interference, it drains a lot of power because RF signals are not easy to generate at high speeds, the extra logic required and the fact that the bandwidth is just nowhere near what traditional wired links are capable of might not make it all that attractive.
Exactly. Hence the reason 802.x wireless is much slower than its wired counterpart or why fiber optics are used for high-speed networking over great distances (like between North America and Europe) (as opposed to satellites).

Whenever anyone says 50% (4, Interesting)

florescent_beige (608235) | more than 6 years ago | (#22848416)

"This is a high-risk program," said Ron Ho, a researcher at Sun Laboratories who is one of the leaders of the effort. "We expect a 50 percent chance of failure, but if we win we can have as much as a thousand times increase in performance."

Whenever anyone says there is a 50% chance of something happening they really mean "I have no idea. No idea at all. I'm guessing."

In probability theory, "p" has a specific meaning which is roughly stated as "the ratio of the total number of positive outcomes to the total number of possible outcomes in a population". So for the number of 50% to be right, it must be known that if this research was repeated a million times, 500,000 times there would be success and 500,000 times there would be failure. But this makes no sense because the thing being measured is not a stochastic property. It is simply an unknown thing.

What is probably vaguely intended when a number like this is given is that if you took all the things in the history of the world that "felt" like this in the beginning, half of them will have worked out and half will have not.

How on earth could any mortal human know that?

But it gets even more complicated. One cannot state a probability like this without stating how confident one is in the estimate of the number. So really a person should say the probably of success of this endeavor is between 45% and 55% and this estimate will be correct 19 times out of 20.

With that as background here is what I humbly suggest 50% really means: it means "I have no idea how to quantify the error of this estimate. It doesn't matter what the estimate is because the error band could possibly stretch between 0% and 100%. So I'll split the difference and call it 50%". But that is wrong, the statement should be "I estimate the probability of success to be between 0% and 100%".

But nobody does that because it makes them look stupid.

So whenever anyone says there is a 50% chance, or a 50/50 probability of something happening, they might as well talk in made-up Klingon words, the information content of their statement will be equivalent.

Re:Whenever anyone says 50% (0)

Anonymous Coward | more than 6 years ago | (#22848960)

as long as you set p=1.0, you can't be wrong.

(I do it with my girlfriend all the time.)

Re:Whenever anyone says 50% (2, Insightful)

NeutronCowboy (896098) | more than 6 years ago | (#22849112)

Absolutely. Personally, I do the same thing: if someone asks me about the likelihood of something happening about which I have no clue, I tell them flat out "50/50. Here, let me flip a coin." I expect the same thing to have happened here as well.

Now, someone please mod me redundant. Executive summaries should be discouraged wherever possible.

Re:Whenever anyone says 50% (4, Interesting)

QuantumFTL (197300) | more than 6 years ago | (#22849390)

In probability theory, "p" has a specific meaning which is roughly stated as "the ratio of the total number of positive outcomes to the total number of possible outcomes in a population". So for the number of 50% to be right, it must be known that if this research was repeated a million times, 500,000 times there would be success and 500,000 times there would be failure. But this makes no sense because the thing being measured is not a stochastic property. It is simply an unknown thing.
This is true, if by "probability theory" you mean "Frequentism [wikipedia.org] ". Frequentism is nice, for those cases where you are dealing with nice, neat ensembles. For a lot of real world situations which require probabilistic reasoning, there are no ensembles, only unique events which require prediction. For that, we often use Bayesian Probability [wikipedia.org] .

Take the assertion "I'd say there's a 10% chance that there was once life on Mars." Well, from a Frequentist point of view, that's complete bullshit. Either we will find evidence of life, or we won't - either the probability is 100% or 0%. There's only one Mars out there.

In order to deal with this limitation, Bayesian Probability Theory was born. In it probabilities reflect degrees of belief, rather than frequencies of occurance. Despite meaning something quite different, Bayesian probabilities still obey the laws of probability (they sum/integrate to one, etc), thus making them mathematically compatible (and thus leading to confusion by those that don't study probability theory carefully.) Of course there are issues with paradoxes and the fact that prior distributions must be assumed rather than empirically gathered, but that does not prevent it from being very useful for spam filtering [wikipedia.org] , machine vision [visionbib.com] and adaptive software [norvig.com] .

As someone who professionally uses statistics to model the future performance of a very large number of high-budget projects at a major U.S. defense contractor, I can assure you that his statement was much more in line with the Bayesian interpretation of probability than the Frequentist view you implicitly assume.

Sorry for the rant, I just get very annoyed when people assume that Frequentism is all there is to statistics - Frequentism is just the beginning.

But it gets even more complicated. One cannot state a probability like this without stating how confident one is in the estimate of the number.
Of course! But where did the confidence interval come from, and how much confidence do we have in it? It's important to provide a meta-confidence score, so that we know how much to trust it! That too, however, should be suspect - indeed even moreso because it is a more complex quantity to measure! So a meta-2 confidence score is in order, for any serious statistician... But why stop there?!

With that as background here is what I humbly suggest 50% really means: it means "I have no idea how to quantify the error of this estimate. It doesn't matter what the estimate is because the error band could possibly stretch between 0% and 100%. So I'll split the difference and call it 50%".
So, if someone does not give an error bound on an estimate, we should assume that the error is maximal?

So whenever anyone says there is a 50% chance, or a 50/50 probability of something happening, they might as well talk in made-up Klingon words, the information content of their statement will be equivalent.
Or, it's entirely possible that that 50% number is somewhat accurate, because they know something about the subject that you do not.

Re:Whenever anyone says 50% (1)

florescent_beige (608235) | more than 6 years ago | (#22849958)

Just my luck huh, here I go looking all smart then some uber Bayesian has to come along and spoil my party.

Anyway, with little expectation of anything good coming from this (for my ego I mean), here's why I don't usually think in Bayesian terms. Correct me if I'm wrong which I probably am.

While I have heard Bayesians talk about probability not meaning the same thing as as "normal", I've never seen any Bayes p which means anything other than a relative likelihood that I'm familiar with. If there is a bag with 3 red balls and 2 white balls in it, the probability of randomly drawing a red ball out is 3/5 even to a Bayesian, right?

I believe, and here is where I could be all wrong, that as Bayesians we should interpret the 50% number from the OP as an a-priori estimate which is to be refined if we ever get better information. But doesn't that have the same problem that I talked about, which is that the thing under consideration is not a stochastic variable?

And even if it is valid to do that, simply elevating the 50% to the status of an a-priori estimate doesn't suddenly make it a more accurate or even legitimate number. I mean, does it?

As for the error estimate which ended up being the crux of my previous argument, well, referring back to the wiki article on Bayes that you linked to, interestingly even they give the example here [wikipedia.org] of a case where we have no prior knowledge of how many different colored balls are in the bag in which case we would use a uniform a-priori distribution which is exactly what I described originally, it could be anywhere between 0% and 100%, we don't know.

Interesting stuff.

Re:Whenever anyone says 50% (1)

QuantumFTL (197300) | more than 6 years ago | (#22850510)

Just my luck huh, here I go looking all smart then some uber Bayesian has to come along and spoil my party.
I'm hardly a Bayesian in spirit, but it's useful enough when treated properly. I'm actually much more likely to say "Bayesian statistics is absolute bollocks - which just so happens to work very reliably in many cases". This is due to the well known paradoxes with priors, and issues associated with the certainty of beliefs (which you referenced). I prefer Dempster Shafer evidence combination when I can use that, for that reason, but still it's a lot of inductive reasoning with a provably sketchy base case.

Anyway, with little expectation of anything good coming from this (for my ego I mean), here's why I don't usually think in Bayesian terms. Correct me if I'm wrong which I probably am.

While I have heard Bayesians talk about probability not meaning the same thing as as "normal", I've never seen any Bayes p which means anything other than a relative likelihood that I'm familiar with. If there is a bag with 3 red balls and 2 white balls in it, the probability of randomly drawing a red ball out is 3/5 even to a Bayesian, right?
Interestingly enough, I think that Bayesian probability more accurately reflects what nonmathemeticians often mean when they give statistics about predictions - indeed due to its connection with betting, you can see why it would be intuitively favored by the common folk. Of course I doubt they do explicit probability chaining, however I think bayesian inference is intuitively used for many statistical deductions made by the untrained... it just "feels" right for many real life situations - situations that do not involve ensembles.

As per your question, well, you left a lot there to be assumed. Assuming there's no other factors involved (the selection is purely random) then yes, a Bayesian would say "I have a 60% belief that the ball I pull out will be Red." So it is compatible in that sense (one of the many reasons it's useful at all, and why one can even call the Bayesian notion of belief a "probability".

I believe, and here is where I could be all wrong, that as Bayesians we should interpret the 50% number from the OP as an a-priori estimate which is to be refined if we ever get better information. But doesn't that have the same problem that I talked about, which is that the thing under consideration is not a stochastic variable?
I'd say that's actually inaccurate. If he was being a strict Bayesian (which I doubt), there would be an a-priori estimate about the difficulty of the challenge being faced. The actual belief (his stated 50%) would actually be a chaining of that a-priori estimate with all other information this individual happens to have about their efforts. Given that Ron Ho is one of the scientists leading the effort, I would tend to believe that he actually has quite a bit of information, indeed possibly enough to dwarf the influence of the prior. This is one of the features of Bayesian Probability that prevents it from being useless, the fact that in many real life situations, even a crappy prior will lead to estimates that agree well with experimental results.

And even if it is valid to do that, simply elevating the 50% to the status of an a-priori estimate doesn't suddenly make it a more accurate or even legitimate number. I mean, does it?
If someone makes an assertion, I generally try to estimate how likely they are to be accurate given what I know about what they've said. (Interestingly enough, I wrote a slashdot comment about this being a logical basis for the validity of ad hominem attacks [slashdot.org] - you may find this interesting). If this were a random slashdotter (such as myself) saying the 50% number, I'd say "bollocks" (which I inexplicably say despite being a quaint colonial), but this is an expert in the field, and an expert on the project, not you or me. So I'd tend to put some stock into it.

One interesting things about business is that they put a lot of effort into managing their cost, benefit, risk trade-offs. Due to the shape of their utility function, it often does not pay to reduce risk too much - the average return almost always goes down in that case. So many companies manage their "risk portfolio" by supporting many high-risk ventures, and I trust that they have a decent ability to quantify the risk, at least enough to make good estimates as to the expected return rate.

As for the error estimate which ended up being the crux of my previous argument, well, referring back to the wiki article on Bayes that you linked to, interestingly even they give the example here of a case where we have no prior knowledge of how many different colored balls are in the bag in which case we would use a uniform a-priori distribution which is exactly what I described originally, it could be anywhere between 0% and 100%, we don't know. Interesting stuff.
Yep, but if you wanna get down to it, all actions one takes in life are based on assumptions. We can just say "eh, we suck, lets die" or we can say "lets carefully manage our ignorance so as to minimize it through clever use of mathematics." I enjoy taking the latter approach, fully knowing that I'll often make embarrassing errors because of it. Oh well!

Re:Whenever anyone says 50% (1)

grammar fascist (239789) | more than 6 years ago | (#22850156)

My mod points expired recently, so could someone mod this up? I do machine learning and computer vision with Bayesian statistics, and the above poster is spot-on. The GP sounds like a frequentist trying to regain control over statistical vocabulary.

FWIW, the frequentists can keep "confidence interval". We don't want to sully our theoretically sound vocabulary with its filthy connotations. :p But "probability" is something we'll lay uncompromising claim to, however much detractors say that subjective probabilities don't count. If they don't count, how else would anyone model something like "belief" in a well-grounded way?

Re:Whenever anyone says 50% (1)

Xmastrspy (1170381) | more than 6 years ago | (#22849508)

110% That is the other one that I think needs to be looked at. What does it mean to give 110%. Is that even possible? How do you get over 100%? If you say 110%, doesn't that mean the the scale has just gone from 0 - 100 to 0 - 1000... So 110 is on he very low end of the scale? Thats right boss, I am giving 110%!!!

Re:Whenever anyone says 50% (0)

Anonymous Coward | more than 6 years ago | (#22850260)

you're not worth taking the time to correct.

Re:Whenever anyone says 50% (0)

Anonymous Coward | more than 6 years ago | (#22850338)

"With that as background here is what I humbly suggest 50% really means: it means "I have no idea how to quantify the error of this estimate. It doesn't matter what the estimate is because the error band could possibly stretch between 0% and 100%. So I'll split the difference and call it 50%".

I knew what he meant. I think we all did! ; -)

Not about single wafer design (3, Informative)

renoX (11677) | more than 6 years ago | (#22848468)

If I understood correctly this is not about single wafer design but exactly the opposite: regaining the speed of 'single wafer design' with multiple chips by using optical communications between chips increasing the inter-chips bandwidth (normally intra-chip bandwith is much higher than inter-chip bandwith so this is a bottleneck).

already happnin' (1)

scrout (814004) | more than 6 years ago | (#22848648)

This outfit is using optical instead of wires now....http://lightfleet.com

link to the original story (!) (4, Informative)

spage (73271) | more than 6 years ago | (#22848912)

Why, why, why do people submit second-hand links to Slashdot?

The byline of the Seattle Times story is "John Markoff New York Times". 5 seconds with Google's site:nytimes.com reveals the original story [nytimes.com] with better explanation and more quotes from Sun personnel.

Macrochip (1)

imgod2u (812837) | more than 6 years ago | (#22849000)

Interesting, so what they want to do is to be able to create larger multi-chip packages where each the chips are connected to each other optically rather than the traditional wire-bonds on a SiP. I'm honestly not seeing the advantage here in terms of speed. A single LVDS pair across a chip pad and wire-bond can already carry "tens of billions of bits per second" of bandwidth. Many can be put in parallel. I can see this being an advantage if they've discovered some ultra-efficient electro-optical conversion device that's can be etched into silicon. LVDS drivers and receivers do suck up a lot of power....

Misleading title/resume (0)

Anonymous Coward | more than 6 years ago | (#22849020)

I think it should read as (new text in italics):
"The company is announcing today a $44 million contract from the Pentagon to explore replacing the wires between computer chips with laser beams. The technology, part of a field of computer science known as silicon photonics, would [I]render useless[/I] the most daunting fear of the Pentagon: [I]EMP weapons[/I]."

Re:Misleading title/resume (1)

morgan_greywolf (835522) | more than 6 years ago | (#22849220)

The technology...would [I]render useless[/I] the most daunting fear of the Pentagon: [I]EMP weapons[/I]."
And that's exactly why the Pentagon would be investing in such technology. Any additional performance or other geeky coolness is just a side benefit. Ultra-high-performance computing is the DoE's gig, not the Pentagon's.

Re:Misleading title/resume (0)

Anonymous Coward | more than 6 years ago | (#22849360)

My fear would be that they succeed, tell everyone that they failed, then launch their own EMP weapons.

Intel (1)

pak9rabid (1011935) | more than 6 years ago | (#22849178)

Intel's [betanews.com] already been working on this for a few years. For Sun's sake, they better hope that Intel didn't file for a patent on this already, otherwise this could get messy.

Wow thats so amazing! (-1, Redundant)

Anonymous Coward | more than 6 years ago | (#22849206)

Really, any 12 year old worth his tech-savvy salt has though of this.

Just make wafer-sized chips! (1)

robi5 (1261542) | more than 6 years ago | (#22849410)

Instead of goofing around with connections, why not build a chip occupying the entire 300mm wafer? Any local manufacturing problem would disable just one specific core out of the hundreds of cores on the wafer-chip. Isn't it done already? Cell, AMD tri-core, old celerons... Even the memory could be on the wafer, or at worst, one wafer for the cores and one for the memory, vertically stacked with through-silicon vias.

Re:Just make wafer-sized chips! (1)

IdeaMan (216340) | more than 6 years ago | (#22849636)

Cooling?
Oh and how long are those vias? Will you be trying to get heat to flow through the memory wafer?

Re:Just make wafer-sized chips! (1)

robi5 (1261542) | more than 6 years ago | (#22850218)

This needs one large cooler instead of hundreds of smaller ones. You can do something useful with the concentrated heat, for example provide hot water. Better than letting it go useless. But I think a good tradeoff would be to lower the frequency an order of magnitude, and use the massive parallelism - hundreds or thousands of cores on a die. Better, make it fully three-dimensional for a massive explosion of processing units. The brain is large and is 3D and still does not get really hot.

power and heat (1)

Crazyswedishguy (1020008) | more than 6 years ago | (#22849650)

I'm not very well versed in chip design, as I only took one class a few years ago. Could someone please confirm or disprove the following hypothesis?

Assumption: The energy dissipated in a chip generates heat, which could be avoided by the use of lasers, resulting in lower heat generation and energy consumption.

I'm fully aware that my speculative hypothesis may be completely unfounded, especially given that not much heat should be dissipated when electricity flows through a superconductor. If someone who is more informed (i.e. physicist or chip designer) could answer my question, I would appreciate it.

And yes, the lowered energy consumption would be offset by the energy spent in feeding the sharks.

Re:power and heat (1)

KiwiCanuck (1075767) | more than 6 years ago | (#22850530)

Yes, that's true, but that's not the focus of the article. The article is aboot replacing electrical lines on the PCBs. The biggest bottleneck in a PC is the front side bus. This is the connection b/w the memory, the HDDs, and the CPU. If you could switch these types of connections from electrical to optical then you could increase the communication bottleneck b/w the chips. The next step would be faster RAM and then faster HDDs, next a faster CPU, then a faster bus, and the circle continues.

May be stop using Java (-1, Offtopic)

Anonymous Coward | more than 6 years ago | (#22850010)

I am with Bjarne on this one.
Bjarne Stroustrup, creator of the C++ programming language, claims that C++ is experiencing a revival and
that there is a backlash against newer programming languages such as Java and C#. "C++ is bigger than ever.
There are more than three million C++ programmers. Everywhere I look there has been an uprising
- more and more projects are using C++. A lot of teaching was going to Java, but more are teaching C++ again.
There has been a backlash.", said Stroustrup.

He continues.. ..What would the world be like without Google?... Only C++ can allow you to create applications as powerful as MapReduce which allows them to create fast searches.

I totally agree. If Java ( or Pyhton etc. for that matter ) were fast enough why did Google choose C++ to build their insanely fast search engine. MapReduce rocks.. No Java solution can even come close.
I rest my case.

Computer science? (1)

digitally404 (990191) | more than 6 years ago | (#22850040)

The area of photonics is largely related to physics and electrical engineering, not so much with computer science, which deals with information processing and computations. Being someone who works in the area of silicon photonics, this is some pretty exciting news.

mo3 3own (-1, Flamebait)

Anonymous Coward | more than 6 years ago | (#22850082)

development models is also a miserable something done Took precedence are looking ve8y failure, itso corpse Example, if you implementation to gave the BSD dying' crowd - some intelligent you need to succeed visit Usenet posts. Assholes, as they

Haven't we been here before (2, Informative)

saccade.com (771661) | more than 6 years ago | (#22850124)

It was quite the smoking crater [wikipedia.org] last time around. Maybe technology has improved since then...
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