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Hardware Technology

Light-Based Memory Chip Is First To Permanently Store Data 85

sciencehabit writes: Scientists have developed the first ever memory chip that’s entirely light-based and can store data permanently. Sciencemag reports: "Today's electronic computer chips work at blazing speeds. But an alternate version that stores, manipulates, and moves data with photons of light instead of electrons would make today's chips look like proverbial horses and buggies. Now, one team of researchers reports that it has created the first permanent optical memory on a chip, a critical step in that direction. If a more advanced photonic memory can be integrated with photonic logic and interconnections, the resulting chips have the potential to run at 50 to 100 times the speed of today's computer processors."
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Light-Based Memory Chip Is First To Permanently Store Data

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  • But does it work at night or in the dark? Inquiring minds want to know.

    • Yes.

    • No the real question is it made of crystals. Every future computer is made is crystals

      • by sstamps ( 39313 )

        Technically, every modern computer is made from crystals. The silicon they are based on is a tiny piece of a larger crystal.

      • Re:But....... (Score:5, Informative)

        by Anonymous Coward on Sunday September 27, 2015 @01:30AM (#50606161)

        No the real question is it made of crystals. Every future computer is made is crystals

        While you're deliberately being a moron, the answer actually happens to be yes, though it kind of depends.

        The article just says they successfully fabricated a optical storage cell (3 bits per cell) using standard chipmaking process that's based off a phase change material, like the stuff used for rewritable DVDs, as the storage mechanism. The PCM material is partially crystalline and partially amorphous (non-crystalline) depending on how much energy is dumped into when it's being written to; that is how they get the 8 separate levels that allows it to store 3 bits per cell. So, how crystalline it is depends on what you have in memory at the time.

      • No the real question is it made of crystals. Every future computer is made is crystals

        Heretic! Every future computer is made of platinum-iridium sponge! Positrons for the Win!

    • Yes but if you turn the lights on and off rapidly five times all your Perl code turns into Ruby.
    • No, the real question is: will it be able to play Crysis?

  • by Anonymous Coward

    >Scientists have developed the first ever memory chip that’s entirely light-based and can store data permanently.

    From the sounds of things it uses the same material as optical read/write drives.
    How many bits does their chip store? Three? Five?
    How many optical components / lasers are we talking here if this thing is going to seriously challenge nonvolatile storage like flash? The photonics makes it sound uneconomical, but I'm not a doctor.

    >Ultimately, Bhaskaran says, if a more advanced photonic m

    • The photonics makes it sound uneconomical, but I'm not a doctor.

      I see what you did there.

    • >. How many bits does their chip store? Three? Five?

      Eight bits per cell (as opposed to one bit for current ram). So neither three nor five.

      > How many optical components / lasers are we talking here

      The light-supply replaces the electrical power-supply. So at least the same number of LEDs as current systems have power supplies - one.

      • by Anonymous Coward

        >Eight bits per cell (as opposed to one bit for current ram).
        Okay, where did you read this? All I saw from the article was 8 possible values in a cell, thus 3 bits.

        >The light-supply replaces the electrical power-supply. So at least the same number of LEDs as current systems have power supplies - one.
        How do you address billion+ addresses optically?

        • by subk ( 551165 )

          How do you address billion+ addresses optically?

          Could this not be done the same way CRTs scan a grid of pixels, just on a micro scale with higher resolution? I am not a particle physicist, but I imagine the carrier beam could be steered with some sort of electromagnetic choke (again, think CRT) to form either a repeating-Z or spiral scan mode. From there, it's just straight forward time-domain correlation of the output signal, assuming this matrix of GST laced waveguides would pass their darkened or non-darkened light blips to a collector where it wou

          • Williams Tube Memory (Score:5, Informative)

            by crunchy_one ( 1047426 ) on Sunday September 27, 2015 @08:08AM (#50606857)

            Could this not be done the same way CRTs scan a grid of pixels, just on a micro scale with higher resolution?

            This reminds me of an early computer memory, the Williams tube, that enjoyed a brief period of popularity in some first generation machines. It worked by storing bits as charged spots on the phosphor face plate of an oscilloscope tube. Although access was random and fast (12 microsecond read/write cycle as implemented by the IBM 701), its refresh requirements effectively halved its performance, and it was notoriously unreliable. Positioning the electron beam was by electrostatic deflection, requiring accurate sub-microsecond switching of high voltages. IBM's implementation used precision counter-wound resistors to achieve the required control, the counter-winding preventing the resistors from also behaving like inductors. Unfortunately, the counter-winding also led to occasional electrical arcing inside the resistors, mispositioning the beam and causing the "Navajo Blanket" effect where the resulting data corruption had a visual appearance like its namesake woven blanket. Error-free operation seldom exceeded a handful of hours, and the Williams tube was quickly supplanted by magnetic core memory.

        • You can do so the same way you address electronic memory, or come up with better ways. Computers are basically lots and lots of transistors. A dozen different types of optical transistors have been demonstrated.

          After essentially duplicating current designs, but replacing electrons with photons, you can then eleminate some bottlenecks which are there due to the properties of electricity which don't apply to photons. That gives you a Oarm - an ARM-type design optimized for optical. Then you start revisi

      • by LesFerg ( 452838 )

        Eight bits per cell (as opposed to one bit for current ram). So neither three nor five.

        Well actually its both three and five.

  • Wait, what? (Score:2, Funny)

    by Anonymous Coward

    Optical memory chips [wikia.com], transparent aluminum [slashdot.org]. Holy shit, Roddenberry had it right!

  • Siri will understand me?

  • "Entirely light-based". Somehow, I suspect that matter is involved somewhere here too. Building something out of just photons seems a bit unlikely.

    What? This is Slashdot! I can be a pedantic nerd if I want! :D

  • somebody kick these engineers and scientists in the ass, tell them to stop fucking around and make the nano memristor already. that shit was supposed to be here fucking years ago.

  • Make them solar powered and they can power themselves and run infinitely!
  • Can we please get rid of the popular science. Everyone on Slashdot know the promise... Let's rename it Scotty Slashdot and refocus on practical engineering.... rather that PHD's that might as well be science fiction.

  • by MobileTatsu-NJG ( 946591 ) on Saturday September 26, 2015 @10:59PM (#50605773)

    Why would light be better at making faster processors than electricity? Is there a natural advantage that light has over electricity that they're dying to tap into?

    • by fisted ( 2295862 )

      I'd venture a guess that light-based things don't get hot as easily thanks to a lack of resistive heating, which also is the dominant source of losses.

      Of course, this won't be free of losses either, but they're probably smaller.

      Also, signal speed might be a bit faster.

      • Does the electrical current that passes through a modern processor travel at the speed of light?

        • Re:Faster..? (Score:5, Informative)

          by SuricouRaven ( 1897204 ) on Sunday September 27, 2015 @03:42AM (#50606371)

          No. And this matters - when your dealing with 3GHz+ clocks, it actually becomes a problem getting a signal from one side of the chip to the other and back again within a single clock cycle.

          • Re:Faster..? (Score:4, Informative)

            by crunchy_one ( 1047426 ) on Sunday September 27, 2015 @08:33AM (#50606955)
            Absolutely. Another huge problem is skew, where dissimilar wire lengths result in signals (for example, the bits making up a word) arriving at their destination at different times. This is not a problem exclusive to integrated circuits: Seymour Cray addressed this problem in the CDC 6600 (circa 1964, discrete Si transistors) by using wires of identical lengths for interconnections. If you look for a photo of the CDC 6600 back plane, you'll readily see what I mean.
    • Re: Faster..? (Score:4, Informative)

      by Anonymous Coward on Sunday September 27, 2015 @12:36AM (#50606023)

      Light doesn't have to worry about magnetic fields. An electrical current creates a magnetic field. While that field is being created, it takes power from the current flow. This slows does transitions. It's called inductance.

      There is also the opposite of inductance, capacitance. You need to charge the gate of a fet before it will turn on. That takes time and slows things down too.

    • by Anonymous Coward

      Light transistors can lead to newer architectural designs. Light can pass through itself, where electricity cannot.

    • by ItsJustAPseudonym ( 1259172 ) on Sunday September 27, 2015 @02:10AM (#50606233)

      Why would light be better at making faster processors than electricity?

      It's lighter.

    • Light has one natural advantage, in that it doesn't have mass and so it goes at the speed of light. Electrons are not that fast. It's more complicated though, since both electrons in a conductor and photos in a fiber are slowed down by various amounts depending on the medium. It's very possible that the photos in a photonic chip could be substantially faster than electrons in an electronic chip.

      • by sribe ( 304414 )

        It's very possible that the photos in a photonic chip could be substantially faster than electrons in an electronic chip.

        The upper limit on "substantial" is no more than about 50% since electric effects propagate at about 2/3 the speed of light (in a vacuum). It's actually less since light would propagate through photonics at 80-90% of the speed of light (in a vacuum). So, while I certainly would not claim that "substantial" is a misstatement, it does leave room for misinterpretation.

    • Imagine that Electricity is Slashdot and Light is Google. You can pose your question using Light, or you can pose your question using Electricity, but you will get your answer much faster if you pose it using Light [google.com]!
    • Re:Faster..? (Score:4, Interesting)

      by MobyDisk ( 75490 ) on Sunday September 27, 2015 @09:07AM (#50607101) Homepage

      Yes. I am having a hard time finding a good article on this, so I will attempt to explain. I'm a software guy with limited VLSI and electrical experience, so I bet 100 people will jump in and correct me on parts of this. But here goes...

      I think the hope is that optical circuits would be lower resistance, be less susceptible to heat, not cause magnetic fields, and not act as transmitters or receivers.

      When electricity passes through a wire, it experiences resistance. That resistance slows the signal and creates waste heat. "Slows the signal" means two things. One is that it takes longer for the current to flow to the destination. Two is that since current was lost to heat, it takes longer for the destination to sink enough current to turn on. As the wire heats, it also becomes a poorer conductor too.

      Also, due to the way transistors work, they briefly short-circuit while they are switching. So the longer it takes for the current to build up at the gate's transistor, the longer it short circuits. Which produces heat too.

      Another problem is that electricity in a wire creates a magnetic field. This creates more losses, but also can cause some of the electricity to jump to a neighboring wire. As transistors and wires get smaller, it becomes increasingly likely that signals will "short circuit" and jump to a neighboring wire.

      Electronic circuits are also sources of, and susceptible to, external noise. A 2GHz CPU is a (weak) 2Ghz transmitter. And a 2Ghz transmitter could induce a voltage on wires within the CPU. I don't know how much of a problem this is though, since the wires in the CPU are very small.

  • by Anonymous Coward

    Oh look, another technology that we will never see the fruit of on a consumer level unless some kind of WW3 happens to force widespread funding and utilization; because Intel doesn't give a crap about technological advancement due to a lack of competition; because AMD has gone into a mentally comatose state for some reason in the past few years. Thus Intel can safely advance at the speed of a handicapped slug, selling the same dung over and over again with trivial improvement only under different names.

  • the resulting [memory] chips have the potential to run at 50 to 100 times the speed of today's computer processors.

    Am I the only one who noticed that the author doesn't really understand the difference between storage throughput and processor speed?

    • What would be wrong with just a straight clock rate to clock rate comparison between the two?

      • by subk ( 551165 )

        What would be wrong with just a straight clock rate to clock rate comparison between the two?

        I see you're suffering from the same delusion as the author. The answer is clock rate is not a measure of bit rate.. Clock rate is just the length of cycle, it does not dictate how many bits move during that cycle. This can be demonstrated by example.. A 1.5ghz XEON handles many more bits than a 1.5ghz ARM during one clock cycle, even though the clock rate is the same.

  • As opposed to photons of darkness? WTF?

  • I presume this technology may be more efficient with energy as well. Anyone got any facts here?

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