Chapter 1: The Mystery of Code Interpretation

Have you ever wondered how computers comprehend programming languages?

It's astonishing to think that a simple command can manipulate millions of pixels on a screen with such accuracy.

We often overlook the complexity behind how machines interpret a command like “console.log()” to alter specific pixels on a display. How can these machines communicate seamlessly with others thousands of miles away, all through the power of electricity?

Section 1.1: The Essence of Computers

At their core, computers consist of an extensive network of intricate circuits. The fundamental operation of a computer relies on the continuous flow of electric current through these circuits.

The basic principle of computing involves using electric currents to represent real-world data. In digital computing, there are only two states for current: On (1) and Off (0), akin to a light switch.

#### Subsection 1.1.1: Binary Instructions

These two states allow us to convey messages (instructions) to the processor. Thanks to the ingenious design of circuits, different commands lead the processor to perform various actions, which is a topic worthy of its own discussion.

In a processor that operates with just 1 bit, there are only two potential instructions — 1 or 0 (binary). However, to construct a fully functioning computer, we require a broader range of instructions. Therefore, we work with groups of 1s and 0s to represent the multitude of commands needed.

We can depict these instructions using strings of 1s and 0s, hexadecimal representations, or more user-friendly formats.

An instruction is the most fundamental unit of any action a computer can execute — essentially an atomic action. Individually, they perform simplistic tasks such as adding binary values or transferring current states within the circuit.

The true power of computing arises from processors executing vast numbers of instructions simultaneously (in the millions or billions). Nowadays, household processors can operate at speeds of up to 3 GHz, executing up to 3 billion instructions every second!

Section 1.2: From Code to Action

When we write code, we creatively combine these basic instructions to produce remarkable outcomes.

You could theoretically communicate with the processor by sending electric currents directly as instructions. However, this would require an overwhelming number of commands to achieve even the simplest tasks, such as displaying text on a screen.

Instead, we developed expressive programming languages that can accomplish what would take hundreds of machine instructions in just one line. Compilers convert these high-level languages into Assembly language and, ultimately, into machine instructions.

Unlike natural languages, these programming languages are precise, leaving no room for misinterpretation.

For example, a C++ code snippet like this:

can be transformed into Assembly code:

Eventually, this translates into machine instructions, which are what we refer to as programs or applications. However, the CPU does not execute this machine code directly.

The machine code varies for each operating system, which is why .exe files function exclusively on Windows, and .apk files run only on Android. When a program is executed, the operating system sends the specific low-level instructions to the processor based on the program's content.

When this processor connects to external devices like network adapters, speakers, and monitors, it can send specialized signals to these peripherals, resulting in extraordinary functionalities.

Final Thoughts: The Enchantment of Computing

The true magic of computing lies in the intricate dance of circuits and logic. Each line of code we write initiates a journey from human intention to digital action, as electricity interprets our commands through the binary language.

This complex relationship transforms our abstract concepts into a tangible, interactive digital environment, showcasing the intricate beauty at the heart of computing.

Chapter 2: Videos to Deepen Your Understanding

In the first video, "How does a Computer understand your Program?" we delve into how computers interpret programming languages and execute commands efficiently.

The second video, "How do computers read code?" further explores the mechanisms by which computers decode and execute our written instructions.