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  • Imagine trying to use words to describe every scene in a film,

  • every note in your favorite song,

  • or every street in your town.

  • Now imagine trying to do it using only the numbers 1 and 0.

  • Every time you use the Internet to watch a movie,

  • listen to music,

  • or check directions,

  • that’s exactly what your device is doing,

  • using the language of binary code.

  • Computers use binary because it's a reliable way of storing data.

  • For example, a computer's main memory is made of transistors

  • that switch between either high or low voltage levels,

  • such as 5 volts and 0 volts.

  • Voltages sometimes oscillate, but since there are only two options,

  • a value of 1 volt would still be read as "low."

  • That reading is done by the computer’s processor,

  • which uses the transistorsstates to control other computer devices

  • according to software instructions.

  • The genius of this system is that a given binary sequence

  • doesn't have a pre-determined meaning on its own.

  • Instead, each type of data is encoded in binary

  • according to a separate set of rules.

  • Let’s take numbers.

  • In normal decimal notation,

  • each digit is multiplied by 10 raised to the value of its position,

  • starting from zero on the right.

  • So 84 in decimal form is 4x10⁰ + 8x10¹.

  • Binary number notation works similarly,

  • but with each position based on 2 raised to some power.

  • So 84 would be written as follows:

  • Meanwhile, letters are interpreted based on standard rules like UTF-8,

  • which assigns each character to a specific group of 8-digit binary strings.

  • In this case, 01010100 corresponds to the letter T.

  • So, how can you know whether a given instance of this sequence

  • is supposed to mean T or 84?

  • Well, you can’t from seeing the string alone

  • just as you can’t tell what the sound "da" means from hearing it in isolation.

  • You need context to tell whether you're hearing Russian, Spanish, or English.

  • And you need similar context

  • to tell whether youre looking at binary numbers or binary text.

  • Binary code is also used for far more complex types of data.

  • Each frame of this video, for instance,

  • is made of hundreds of thousands of pixels.

  • In color images,

  • every pixel is represented by three binary sequences

  • that correspond to the primary colors.

  • Each sequence encodes a number

  • that determines the intensity of that particular color.

  • Then, a video driver program transmits this information

  • to the millions of liquid crystals in your screen

  • to make all the different hues you see now.

  • The sound in this video is also stored in binary,

  • with the help of a technique called pulse code modulation.

  • Continuous sound waves are digitized

  • by taking "snapshots" of their amplitudes every few milliseconds.

  • These are recorded as numbers in the form of binary strings,

  • with as many as 44,000 for every second of sound.

  • When theyre read by your computer’s audio software,

  • the numbers determine how quickly the coils in your speakers should vibrate

  • to create sounds of different frequencies.

  • All of this requires billions and billions of bits.

  • But that amount can be reduced through clever compression formats.

  • For example, if a picture has 30 adjacent pixels of green space,

  • they can be recorded as "30 green" instead of coding each pixel separately -

  • a process known as run-length encoding.

  • These compressed formats are themselves written in binary code.

  • So is binary the end-all-be-all of computing?

  • Not necessarily.

  • There’s been research into ternary computers,

  • with circuits in three possible states,

  • and even quantum computers,

  • whose circuits can be in multiple states simultaneously.

  • But so far, none of these has provided

  • as much physical stability for data storage and transmission.

  • So for now, everything you see,

  • hear,

  • and read through your screen

  • comes to you as the result of a simple "true" or "false" choice,

  • made billions of times over.

Imagine trying to use words to describe every scene in a film,


動画の操作 ここで「動画」の調整と「字幕」の表示を設定することができます

B2 中上級

バイナリコードは正確にはどのように動作しますか?- ホセ・アメリコ・N・L・F・デ・フレイタス (How exactly does binary code work? - José Américo N L F de Freitas)

  • 21 3
    林宜悉 に公開 2021 年 01 月 14 日