From Wired
Computers have been digital for half a century. Why would anyone want to resurrect the clunkers of yesteryear?
When old tech dies, it usually stays dead. No one expects rotary phones or adding machines to come crawling back from oblivion. Floppy diskettes, VHS tapes, cathode-ray tubes—they shall rest in peace. Likewise, we won’t see old analog computers in data centers anytime soon. They were monstrous beasts: difficult to program, expensive to maintain, and limited in accuracy.
Or so I thought. Then I came across this confounding statement:Bringing back analog computers in much more advanced forms than their historic ancestors will change the world of computing drastically and forever..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 example of how digital has displaced analog, look at photography. In a pre-digital 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 predicting solar and lunar eclipses. Because its mechanical workings simulated real-world celestial events, it is regarded as one of the earliest analog computers..
As the centuries passed, mechanical analog devices were fabricated for earthlier purposes. In the 1800s, an invention called the planimeter consisted of a little wheel, a 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 indispensable item in real-estate offices when buyers wanted to know the acreage of an irregularly shaped piece of land. 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 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 appropriately. Gears, linkages, pulleys, and levers could also predict tides or calculate distances on a map..
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 of fluids, gases, and other phenomena in the physical world. A varying voltage could 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:.
....MUCH MORE
For an idea of just how advanced the Antikythera mechanism was see "Matters of Tolerance"
