Analog Computers

Reference / Paper · 2023

The Unbelievable Zombie Comeback of Analog Computing

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A long-form WIRED feature article (May 2023) by Charles Platt examining whether analog computing is experiencing a genuine renaissance. The article surveys historic analog devices, interviews researchers at Mythic, IBM, Columbia University (Yannis Tsividis, Glenn Cowan, Ning Guo), and MIT (Sara Achour), and traces the development of chip-scale hybrid analog-digital computers such as the HCDC. It concludes that energy efficiency demands from AI workloads—where the human brain operates on approximately 20 W versus megawatts for digital equivalents—are the primary driver for renewed interest, and that differential-equation fluency will be a key skill for any analog computing revival.

Manufacturer
WIRED / Condé Nast
Author
Charles Platt
Year
2023
Type
Reference / Paper
Language
English
Learning track
introduction
Pages
1
Credit
Charles Platt, WIRED, published March 30, 2023 / May 2023 issue. © Condé Nast.
  • WIRED / Condé Nast
  • analog computing revival
  • hybrid analog-digital chips
  • differential equations
  • AI hardware efficiency

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The Unbelievable Zombie Comeback of Analog Computing

ILLUSTRATION: KHYATI TREHAN CHARLES PLATT THE BIG STORY MAR 30, 2023 6:00 AM The Unbelievable Zombie Comeback of Analog Computing Computers have been digital for half a century. Why would anyone want to resurrect the clunkers of yesteryear? Let's Get Physical How to Love Tech Again I Saw God in a Chip Factory The Never-Ending Fight to Repair The Future Is Analog Now Reading Who’s Watching the Watchers? Weapons of Gas Disruption Listen to this story 00:00 31:09 1x 15 MOST POPULAR 15 POLITICS machines to come crawling back from oblivion. Floppy diskettes, VHS tapes, cathode- He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US ray tubes—they shall rest in peace. Likewise, we won’t see old analog computers in data BY DAVID GILBERT WHEN OLD TECH dies, it usually stays dead. No one expects rotary phones or adding centers anytime soon. They were monstrous beasts: difficult to program, expensive to maintain, and limited in accuracy. POLITICS Or so I thought. Then I came across this confounding statement: Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It BY MAKENA KELLY Bringing back analog computers in much more advanced forms than their historic ancestors will change the world of computing drastically and forever. ARTIFICIAL INTELLIGENCE Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ The most ambitious, future-defining stories from our favorite writers. BY JASON KOEBLER COMPUTERS AND SOFTWARE SIGN UP Inside Intel's Hail Mary to Reclaim Chip Dominance By signing up, you agree to our user agreement (including class action waiver and arbitration provisions), and acknowledge our privacy policy. BY LAUREN GOODE Seriously? I found the prediction in the preface of a handsome illustrated book titled, simply, Analog Computing. Reissued in 2022, it was written by the German mathematician Bernd Ulmann—who seemed very serious indeed. I’ve been writing about future tech since before WIRED existed and have written six books explaining electronics. I used to develop my own software, and some of my friends design hardware. I’d never heard anyone say anything about analog, so why would Ulmann imagine that this very dead paradigm could be resurrected? And with such far-reaching and permanent consequences? I felt compelled to investigate further. FOR AN EX AMPLE of how digital has displaced analog, look at photography. In a pre-digital This article appears in the May 2023 issue. Subscribe to WIRED. ILLUSTRATION: ALVARO DOMINGUEZ camera, continuous variations in light created chemical reactions on a piece of film, where an image appeared as a representation—an analogue—of reality. In a modern camera, by contrast, the light variations are converted to digital values. These are processed by the camera’s CPU before being saved as a stream of 1s and 0s—with digital compression, if you wish. Engineers began using the word analog in the 1940s (shortened from analogue; they like compression) to refer to computers that simulated real-world conditions. But mechanical devices had been doing much the same thing for centuries. The Antikythera mechanism was an astonishingly complex piece of machinery used thousands of years ago in ancient Greece. Containing at least 30 bronze gears, it displayed the everyday movements of the moon, sun, and five planets while also MOST POPULAR predicting solar and lunar eclipses. Because its mechanical workings simulated real- POLITICS world celestial events, it is regarded as one of the earliest analog computers. As the centuries passed, mechanical analog devices were fabricated for earthlier He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US purposes. In the 1800s, an invention called the planimeter consisted of a little wheel, a BY DAVID GILBERT shaft, and a linkage. You traced a pointer around the edge of a shape on a piece of paper, and the area of the shape was displayed on a scale. The tool became an POLITICS indispensable item in real-estate offices when buyers wanted to know the acreage of an Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It irregularly shaped piece of land. BY MAKENA KELLY Other gadgets served military needs. If you were on a battleship trying to aim a 16-inch gun at a target beyond the horizon, you needed to assess the orientation of your ship, its ARTIFICIAL INTELLIGENCE motion, its position, and the direction and speed of the wind; clever mechanical components allowed the operator to input these factors and adjust the gun Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ appropriately. Gears, linkages, pulleys, and levers could also predict tides or calculate BY JASON KOEBLER distances on a map. COMPUTERS AND SOFTWARE In the 1940s, electronic components such as vacuum tubes and resistors were added, because a fluctuating current flowing through them could be analogous to the behavior Inside Intel's Hail Mary to Reclaim Chip Dominance of fluids, gases, and other phenomena in the physical world. A varying voltage could BY LAUREN GOODE represent the velocity of a Nazi V2 missile fired at London, for example, or the orientation of a Gemini space capsule in a 1963 flight simulator. But by then, analog had become a dying art. Instead of using a voltage to represent the velocity of a missile and electrical resistance to represent the air resistance slowing it down, a digital computer could convert variables to binary code—streams of 1s and 0s that were suitable for processing. Early digital computers were massive mainframes full of vacuum tubes, but then integrated circuit chips made digital processing cheaper, more reliable, and more versatile. By the 1970s, the analog-digital difference could be summarized like this: The last factor was a big deal, as the accuracy of analog computers was always limited by their components. Whether you used gear wheels or vacuum tubes or chemical film, precision was limited by manufacturing tolerances and deteriorated with age. Analog was always modeled on the real world, and the world was never absolutely precise. WHEN I WAS a nerdy British schoolboy with a mild case of OCD, inaccuracy bothered me a lot. I revered Pythagoras, who told me that a triangle with sides of 3 centimeters and 4 centimeters adjacent to a 90-degree angle would have a diagonal side of 5 centimeters, precisely. Alas, my pleasure diminished when I realized that his proof only applied in a theoretical realm where lines were of zero thickness. In my everyday realm, precision was limited by my ability to sharpen a pencil, and when I tried to make measurements, I ran into another bothersome feature of reality. Using a magnifying glass, I compared the ruler that I’d bought at a stationery store with MOST POPULAR a ruler in our school’s physics lab, and discovered that they were not exactly the same POLITICS length. How could this be? Seeking enlightenment, I checked the history of the metric system. He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US The meter was the fundamental unit, but it had been birthed from a bizarre BY DAVID GILBERT combination of nationalism and whimsy. After the French Revolution, the new government instituted the meter to get away from the imprecision of the ancien régime. POLITICS The French Academy of Sciences defined it as the longitudinal distance from the Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It equator, through Paris, to the North Pole, divided by 10 million. In 1799, the meter was solemnified like a religious totem in the form of a platinum bar at the French National BY MAKENA KELLY Archives. Copies were made and distributed across Europe and to the Americas, and then copies were made of the copies’ copies. This process introduced transcription ARTIFICIAL INTELLIGENCE errors, which eventually led to my traumatic discovery that rulers from different Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ sources might be visibly unequal. BY JASON KOEBLER Similar problems impeded any definitive measurement of time, temperature, and mass. The conclusion was inescapable to my adolescent mind: If you were hoping for absolute COMPUTERS AND SOFTWARE precision in the physical realm, you couldn’t have it. Inside Intel's Hail Mary to Reclaim Chip Dominance My personal term for the inexact nature of the messy, fuzzy world was muzzy. But then, BY LAUREN GOODE in 1980, I acquired an Ohio Scientific desktop computer and found prompt, lasting relief. All its operations were built on a foundation of binary arithmetic, in which a 1 was always exactly a 1 and a 0 was a genuine 0, with no fractional quibbling. The 1 of existence, and the 0 of nothingness! I fell in love with the purity of digital and learned to write code, which became a lifelong refuge from muzzy math. Of course, digital values still had to be stored in fallible physical components, but margins of error took care of that. In a modern 5-volt digital chip, 1.5 volts or lower would represent the number 0 while 3.5 volts or greater would represent the number 1. MOST POPULAR Components on a decently engineered motherboard would stay within those limits, so POLITICS there shouldn’t have been any misunderstandings. Consequently, when Bernd Ulmann predicted that analog computers were due for a He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US zombie comeback, I wasn’t just skeptical. I found the idea a bit … disturbing. BY DAVID GILBERT HOPING FOR A reality check, I consulted Lyle Bickley, a founding member of the POLITICS Computer History Museum in Mountain View, California. Having served for years as an Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It expert witness in patent suits, Bickley maintains an encyclopedic knowledge of everything that has been done and is still being done in data processing. BY MAKENA KELLY “A lot of Silicon Valley companies have secret projects doing analog chips,” he told me. ARTIFICIAL INTELLIGENCE Really? But why? Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ “Because they take so little power.” BY JASON KOEBLER Bickley explained that when, say, brute-force natural-language AI systems distill COMPUTERS AND SOFTWARE millions of words from the internet, the process is insanely power hungry. The human brain runs on a small amount of electricity, he said, about 20 watts. (That’s the same as Inside Intel's Hail Mary to Reclaim Chip Dominance a light bulb.) “Yet if we try to do the same thing with digital computers, it takes BY LAUREN GOODE megawatts.” For that kind of application, digital is “not going to work. It’s not a smart way to do it.” Bickley said he would be violating confidentiality to tell me specifics, so I went looking for startups. Quickly I found a San Francisco Bay Area company called Mythic, which claimed to be marketing the “industry-first AI analog matrix processor.” Mike Henry cofounded Mythic at the University of Michigan in 2013. He’s an energetic guy with a neat haircut and a well-ironed shirt, like an old-time IBM salesman. He expanded on Bickley’s point, citing the brain-like neural network that powers GPT-3. “It has 175 billion synapses,” Henry said, comparing processing elements with connections between neurons in the brain. “So every time you run that model to do one thing, you have to load 175 billion values. Very large data-center systems can barely keep up.” That’s because, Henry said, they are digital. Modern AI systems use a type of memory called static RAM, or SRAM, which requires constant power to store data. Its circuitry must remain switched on even when it’s not performing a task. Engineers have done a MOST POPULAR lot to improve the efficiency of SRAM, but there’s a limit. “Tricks like lowering the POLITICS supply voltage are running out,” Henry said. Mythic’s analog chip uses less power by storing neural weights not in SRAM but in flash He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US memory, which doesn’t consume power to retain its state. And the flash memory is BY DAVID GILBERT embedded in a processing chip, a configuration Mythic calls “compute-in-memory.” Instead of consuming a lot of power moving millions of bytes back and forth between POLITICS memory and a CPU (as a digital computer does), some processing is done locally. Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It What bothered me was that Mythic seemed to be reintroducing the accuracy problems BY MAKENA KELLY of analog. The flash memory was not storing a 1 or 0 with comfortable margins of error, like old-school logic chips. It was holding intermediate voltages (as many as 256 of ARTIFICIAL INTELLIGENCE them!) to simulate the varying states of neurons in the brain, and I had to wonder Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ whether those voltages would drift over time. Henry didn’t seem to think they would. BY JASON KOEBLER I had another problem with his chip: The way it worked was hard to explain. Henry laughed. “Welcome to my life,” he said. “Try explaining it to venture capitalists.” Mythic’s COMPUTERS AND SOFTWARE success on that front has been variable: Shortly after I spoke to Henry, the company ran out of cash. (More recently it raised $13 million in new funding and appointed a new Inside Intel's Hail Mary to Reclaim Chip Dominance CEO.) BY LAUREN GOODE I next went to IBM. Its corporate PR department connected me with Vijay Narayanan, a researcher in the company’s physics-of-AI department. He preferred to interact via company-sanctioned email statements. For the moment, Narayanan wrote, “our analog research is about customizing AI hardware, particularly for energy efficiency.” So, the same goal as Mythic. However, Narayanan seemed rather circumspect on the details, so I did some more reading and MOST POPULAR found an IBM paper that referred to “no appreciable accuracy loss” in its memory POLITICS systems. No appreciable loss? Did that mean there was some loss? Then there was the He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US durability issue. Another paper mentioned “an accuracy above 93.5 percent retained over a one-day period.” So it had lost 6.5 percent in just one day? Was that bad? What should it be compared to? BY DAVID GILBERT So many unanswered questions, but the biggest letdown was this: Both Mythic and IBM POLITICS seemed interested in analog computing only insofar as specific analog processes could Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It reduce the energy and storage requirements of AI—not perform the fundamental bitbased calculations. (The digital components would still do that.) As far as I could tell, BY MAKENA KELLY this wasn’t anything close to the second coming of analog as predicted by Ulmann. The computers of yesteryear may have been room-sized behemoths, but they could ARTIFICIAL INTELLIGENCE simulate everything from liquid flowing through a pipe to nuclear reactions. Their Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ applications shared one attribute. They were dynamic. They involved the concept of BY JASON KOEBLER change. COMPUTERS AND SOFTWARE Inside Intel's Hail Mary to Reclaim Chip Dominance BY LAUREN GOODE Engineers began using the word analog in the 1940s to refer to computers that simulated real-world conditions. ILLUSTRATION: KHYATI TREHAN ANOTHER CHILDHOOD CONUNDRUM: If I held a ball and dropped it, the force of gravity made it move at an increasing speed. How could you figure out the total distance the ball traveled if the speed was changing continuously over time? You could MOST POPULAR break its journey down into seconds or milliseconds or microseconds, work out the POLITICS speed at each step, and add up the distances. But if time actually flowed in tiny steps, He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US the speed would have to jump instantaneously between one step and the next. How could that be true? BY DAVID GILBERT Later I learned that these questions had been addressed by Isaac Newton and Gottfried Leibniz centuries ago. They’d said that velocity does change in increments, but the POLITICS increments are infinitely small. Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It So there were steps, but they weren’t really steps? It sounded like an evasion to me, but BY MAKENA KELLY on this iffy premise, Newton and Leibniz developed calculus, enabling everyone to calculate the behavior of countless naturally changing aspects of the world. Calculus is ARTIFICIAL INTELLIGENCE a way of mathematically modeling something that’s continuously changing, like the distance traversed by a falling ball, as a sequence of infinitely small differences: a Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ differential equation. BY JASON KOEBLER That math could be used as the input to old-school analog electronic computers—often COMPUTERS AND SOFTWARE called, for this reason, differential analyzers. You could plug components together to represent operations in an equation, set some values using potentiometers, and the Inside Intel's Hail Mary to Reclaim Chip Dominance answer could be shown almost immediately as a trace on an oscilloscope screen. It BY LAUREN GOODE might not have been ideally accurate, but in the muzzy world, as I had learned to my discontent, nothing was ideally accurate. To be competitive, a true analog computer that could emulate such versatile behavior would have to be suitable for low-cost mass production—on the scale of a silicon chip. Had such a thing been developed? I went back to Ulmann’s book and found the answer on the penultimate page. A researcher named Glenn Cowan had created a genuine VLSI (very large-scale integrated circuit) analog chip back in 2003. Ulmann complained that it was “limited in capabilities,” but it sounded like the real deal. GLENN COWAN IS a studious, methodical, amiable man and a professor in electrical engineering at Montreal’s Concordia University. As a grad student at Columbia back in 1999, he had a choice between two research topics: One would entail optimizing a MOST POPULAR single transistor, while the other would be to develop an entirely new analog computer. POLITICS The latter was the pet project of an adviser named Yannis Tsividis. “Yannis sort of convinced me,” Cowan told me, sounding as if he wasn’t quite sure how it happened. He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US Initially, there were no specifications, because no one had ever built an analog BY DAVID GILBERT computer on a chip. Cowan didn’t know how accurate it could be and was basically making it up as he went along. He had to take other courses at Columbia to fill the gaps POLITICS in his knowledge. Two years later, he had a test chip that, he told me modestly, was “full Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It of graduate-student naivete. It looked like a breadboarding nightmare.” Still, it worked, so he decided to stick around and make a better version. That took another two years. BY MAKENA KELLY A key innovation of Cowan’s was making the chip reconfigurable—or programmable. ARTIFICIAL INTELLIGENCE Old-school analog computers had used clunky patch cords on plug boards. Cowan did the same thing in miniature, between areas on the chip itself, using a preexisting Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ technology known as transmission gates. These can work as solid-state switches to BY JASON KOEBLER connect the output from processing block A to the input of block B, or block C, or any other block you choose. COMPUTERS AND SOFTWARE His second innovation was to make his analog chip compatible with an off-the-shelf Inside Intel's Hail Mary to Reclaim Chip Dominance digital computer, which could help to circumvent limits on precision. “You could get an BY LAUREN GOODE approximate analog solution as a starting point,” Cowan explained, “and feed that into the digital computer as a guess, because iterative routines converge faster from a good guess.” The end result of his great labor was etched onto a silicon wafer measuring a very respectable 10 millimeters by 10 millimeters. “Remarkably,” he told me, “it did work.” When I asked Cowan about real-world uses, inevitably he mentioned AI. But I’d had some time to think about neural nets and was beginning to feel skeptical. In a standard neural net setup, known as a crossbar configuration, each cell in the net connects with MOST POPULAR four other cells. They may be layered to allow for extra connections, but even so, they’re POLITICS far less complex than the frontal cortex of the brain, in which each individual neuron He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US can be connected with 10,000 others. Moreover, the brain is not a static network. During the first year of life, new neural connections form at a rate of 1 million per second. I saw no way for a neural network to emulate processes like that. BY DAVID GILBERT GLENN COWAN’S SECOND analog chip wasn’t the end of the story at Columbia. POLITICS Additional refinements were necessary, but Yannis Tsividis had to wait for another Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It graduate student who would continue the work. BY MAKENA KELLY In 2011 a soft-spoken young man named Ning Guo turned out to be willing. Like Cowan, he had never designed a chip before. “I found it, um, pretty challenging,” he told me. He ARTIFICIAL INTELLIGENCE laughed at the memory and shook his head. “We were too optimistic,” he recalled Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ ruefully. He laughed again. “Like we thought we could get it done by the summer.” BY JASON KOEBLER In fact, it took more than a year to complete the chip design. Guo said Tsividis had required a “90 percent confidence level” that the chip would work before he would COMPUTERS AND SOFTWARE proceed with the expensive process of fabrication. Guo took a chance, and the result he named the HCDC, meaning hybrid continuous discrete computer. Guo’s prototype was Inside Intel's Hail Mary to Reclaim Chip Dominance then incorporated on a board that could interface with an off-the-shelf digital BY LAUREN GOODE computer. From the outside, it looked like an accessory circuit board for a PC. When I asked Guo about possible applications, he had to think for a bit. Instead of mentioning AI, he suggested tasks such as simulating a lot of moving mechanical joints that would be rigidly connected to each other in robotics. Then, unlike many engineers, he allowed himself to speculate. There are diminishing returns on the digital model, he said, yet it still dominates the industry. “If we applied as many people and as much money to the analog domain, I think we could have some kind of analog coprocessing happening to accelerate the MOST POPULAR existing algorithms. Digital computers are very good at scalability. Analog is very good POLITICS at complex interactions between variables. In the future, we may combine these advantages.” He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US THE HCDC WAS fully functional, but it had a problem: It was not easy to use. BY DAVID GILBERT Fortuitously, a talented programmer at MIT named Sara Achour read about the project and saw it as an ideal target for her skills. She was a specialist in compilers—programs POLITICS that convert a high-level programming language into machine language—and could Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It add a more user-friendly front end in Python to help people program the chip. She reached out to Tsividis, and he sent her one of the few precious boards that had been BY MAKENA KELLY fabricated. ARTIFICIAL INTELLIGENCE When I spoke with Achour, she was entertaining and engaging, delivering terminology at a manic pace. She told me she had originally intended to be a doctor but switched to Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ computer science after having pursued programming as a hobby since middle school. “I BY JASON KOEBLER had specialized in math modeling of biological systems,” she said. “We did macroscopic modeling of gene protein hormonal dynamics.” Seeing my blank look, she added: “We COMPUTERS AND SOFTWARE were trying to predict things like hormonal changes when you inject someone with a Inside Intel's Hail Mary to Reclaim Chip Dominance particular drug.” BY LAUREN GOODE Changes was the key word. She was fully acquainted with the math to describe change, and after two years she finished her compiler for the analog chip. “I didn’t build, like, an entry-level product,” she said. “But I made it easier to find resilient implementations of the computation you want to run. You see, even the people who design this type of hardware have difficulty programming it. It’s still extremely painful.” I liked the idea of a former medical student alleviating the pain of chip designers who had difficulty using their own hardware. But what was her take on applications? Are there any? MOST POPULAR POLITICS “Yes, whenever you’re sensing the environment,” she said. “And reconfigurability lets going to be relegated to a niche model. Analog computation makes a lot of sense when He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US you’re interfacing with something that is inherently analog.” Like the real world, with all BY DAVID GILBERT you reuse the same piece of hardware for multiple computations. So I don’t think this is its muzziness. POLITICS GOING BACK TO the concept of dropping a ball, and my interest in finding out how far Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It it travels during a period of time: Calculus solves that problem easily, with a differential equation—if you ignore air resistance. The proper term for this is “integrating velocity with respect to time.” BY MAKENA KELLY But what if you don’t ignore air resistance? The faster the ball falls, the more air ARTIFICIAL INTELLIGENCE Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ resistance it encounters. But gravity remains constant, so the ball’s speed doesn’t increase at a steady rate but tails off until it reaches terminal velocity. You can express BY JASON KOEBLER this in a differential equation too, but it adds another layer of complexity. I won’t get into the mathematical notation (I prefer to avoid the pain of it, to use Sara Achour’s COMPUTERS AND SOFTWARE memorable term), because the take-home message is all that matters. Every time you introduce another factor, the scenario gets more complicated. If there’s a crosswind, or Inside Intel's Hail Mary to Reclaim Chip Dominance the ball collides with other balls, or it falls down a hole to the center of the Earth, where BY LAUREN GOODE gravity is zero—the situation can get discouragingly complicated. Now suppose you want to simulate the scenario using a digital computer. It’ll need a lot of data points to generate a smooth curve, and it’ll have to continually recalculate all the values for each point. Those calculations will add up, especially if multiple objects become involved. If you have billions of objects—as in a nuclear chain reaction, or synapse states in an AI engine—you’ll need a digital processor containing maybe 100 billion transistors to crunch the data at billions of cycles per second. And in each cycle, the switching operation of each transistor will generate heat. Waste heat becomes a serious issue. Using a new-age analog chip, you just express all the factors in a differential equation and type it into Achour’s compiler, which converts the equation into machine language that the chip understands. The brute force of binary code is minimized, and so is the MOST POPULAR power consumption and the heat. The HCDC is like an efficient little helper residing POLITICS secretly amid the modern hardware, and it’s chip-sized, unlike the room-sized behemoths of yesteryear. He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US Now I should update the basic analog attributes: BY DAVID GILBERT POLITICS Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It BY MAKENA KELLY ARTIFICIAL INTELLIGENCE Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ BY JASON KOEBLER COMPUTERS AND SOFTWARE Inside Intel's Hail Mary to Reclaim Chip Dominance BY LAUREN GOODE You can see how the designs by Tsividis and his grad students have addressed the historic disadvantages in my previous list. And yet, despite all this, Tsividis—the prophet of modern analog computing—still has difficulty getting people to take him seriously. BORN IN GREECE in 1946, Tsividis developed an early dislike for geography, history, and chemistry. “I felt as if there were more facts to memorize than I had synapses in my brain,” he told me. He loved math and physics but ran into a different problem when a teacher assured him that the perimeter of any circle was three times the diameter plus 14 centimeters. Of course, it should be (approximately) 3.14 times the diameter of the circle, but when Tsividis said so, the teacher told him to be quiet. This, he has said, “suggested rather strongly that authority figures are not always right.” He taught himself English, started learning electronics, designed and built devices like radio transmitters, and eventually fled from the Greek college system that had compelled him to learn organic chemistry. In 1972 he began graduate studies in the United States, and over the years became known for challenging orthodoxy in the field of computer science. One well-known circuit designer referred to him as “the analog MOS freak,” after he designed and fabricated an amplifier chip in 1975 using metaloxide semiconductor technology, which absolutely no one believed was suitable for the task. These days, Tsividis is polite and down to earth, with no interest in wasting words. His attempt to bring back analog in the form of integrated chips began in earnest in the late ’90s. When I talked to him, he told me he had 18 boards with analog chips mounted on MOST POPULAR them, a couple more having been loaned out to researchers such as Achour. “But the POLITICS project is on hold now,” he said, “because the funding ended from the National Science Foundation. And then we had two years of Covid.” He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US I asked what he would do if he got new funding. BY DAVID GILBERT “I would need to know, if you put together many chips to model a large system, then POLITICS what happens? So we will try to put together many of those chips and eventually, with the help of silicon foundries, make a large computer on a single chip.” Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It I pointed out that development so far has already taken almost 20 years. BY MAKENA KELLY “Yes, but there were several years of breaks in between. Whenever there is appropriate ARTIFICIAL INTELLIGENCE funding, I revive the process.” Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ I asked him whether the state of analog computing today could be compared to that of BY JASON KOEBLER quantum computing 25 years ago. Could it follow a similar path of development, from fringe consideration to common (and well-funded) acceptance? COMPUTERS AND SOFTWARE It would take a fraction of the time, he said. “We have our experimental results. It has Inside Intel's Hail Mary to Reclaim Chip Dominance proven itself. If there is a group that wants to make it user-friendly, within a year we BY LAUREN GOODE could have it.” And at this point he is willing to provide analog computer boards to interested researchers, who can use them with Achour’s compiler. What sort of people would qualify? “The background you need is not just computers. You really need the math background to know what differential equations are.” I asked him whether he felt that his idea was, in a way, obvious. Why hadn’t it resonated yet with more people? MOST POPULAR “People do wonder why we are doing this when everything is digital. They say digital is the future, digital is the future—and of course it’s the future. But the physical world is analog, and in between you have a big interface. That’s where this fits.” POLITICS He Wrote a Book About Antifa. Death Threats Are Driving Him Out of the US BY DAVID GILBERT POLITICS Trump Wants to Take Over Cities. Influencers Are Giving Him the Fuel to Do It BY MAKENA KELLY ARTIFICIAL INTELLIGENCE Meta Tells Its Metaverse Workers to Use AI to ‘Go 5X Faster’ BY JASON KOEBLER COMPUTERS AND SOFTWARE Inside Intel's Hail Mary to Reclaim Chip Dominance BY LAUREN GOODE In a digital processor crunching data at billions of cycles per second, the switching operation of each transistor generates heat. ILLUSTRATION: KHYATI TREHAN WHEN TSIVIDIS MENTIONED offhandedly that people applying analog computation would need an appropriate math background, I started to wonder. Developing algorithms for digital computers can be a strenuous mental exercise, but calculus is seldom required. When I mentioned this to Achour, she laughed and said that when she submits papers to reviewers, “Some of them say they haven’t seen differential equations in years. Some of them have never seen differential equations.” And no doubt a lot of them won’t want to. But financial incentives have a way of overcoming resistance to change. Imagine a future where software engineers can command an extra $100K per annum by adding a new bullet point to a résumé: “Fluent in differential equations.” If that happens, I’m thinking Python developers will soon be signing up for remedial online calculus classes. Likewise, in business, the determining factor will be financial. There’s going to be a lot of money in AI—and in smarter drug molecules, and in agile robots, and in a dozen other applications that model the muzzy complexity of the physical world. If power consumption and heat dissipation become really expensive problems, and shunting some of the digital load into miniaturized analog coprocessors is significantly cheaper, then no one will care that analog computation used to be done by your math-genius grandfather using a big steel box full of vacuum tubes. Reality really is imprecise, no matter how much I would prefer otherwise, and when you want to model it with truly exquisite fidelity, digitizing it may not be the most sensible method. Therefore, I must conclude: Analog is dead. Long live analog. This article appears in the May issue. Subscribe now. Let us know what you think about this article. Submit a letter to the editor at mail@wired.com. READ NEXT WHO’S WATCHING THE WATCHERS? You Might Also Like … In your inbox: Our biggest stories, handpicked for you each day Meet the guys betting big on AI gambling agents Big Story: The baby died. Whose fault is it? I hate my AI friend Livestream replay: WIRED’s AI Power Summit Charles Platt is a contributing editor at Make and the author of Make: Electronics, among other books. ... Read More TOPICS LONGREADS HARDWARE HARDWARE ISSUE ANALOG COMPUTERS COMPUTING CODE MAGAZINE-31.05 Get The Big Story in Your Inbox The most ambitious, future-defining stories from our favorite writers. SIGN UP By signing up, you agree to our user agreement (including class action waiver and arbitration provisions), and acknowledge our privacy policy. READ MORE Tech Billionaires Already Captured the White House. 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