What is the Ethereum Virtual Machine (EVM), and what is its function?

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What is the Ethereum Virtual Machine (EVM), and what does it do?

Hey, friend! That's a great question, and it's something many people get stuck on when they're first introduced to blockchain. Don't worry, I'll explain it to you in plain language, so you're sure to understand.

Simply put, the Ethereum Virtual Machine (EVM) is the "heart" and "brain" of the entire Ethereum system.

So, what exactly is the EVM?

You can imagine it as a globally shared, perpetually running supercomputer.

But it's not a physical computer; it's "virtual." What does that mean?

Thousands of computers worldwide (which we call "nodes") run the Ethereum software. These computers work together to form this virtual supercomputer—the EVM. It's not located in a data center in a specific country; instead, it's distributed globally and maintained collectively by all participants.

The characteristics of this "computer" are:

Absolute Neutrality: Code is executed exactly as written, and no one can tamper with or stop it.
High Isolation: It operates solely within its own environment, without affecting other programs on your computer.
Global Synchronization: The state of the EVM on all nodes in the network is identical, ensuring consistent results.

What does the EVM do?

Now that we understand what it is, let's look at what it actually does. Its primary function boils down to one core point: running smart contracts.

You can think of a "smart contract" as a piece of pre-written program code that can execute automatically. The EVM is the "environment" responsible for running these codes.

Specifically, its functions can be categorized into the following points:

1. Running and Managing Smart Contracts

This is the EVM's most core function. Things we commonly hear about, like DeFi (Decentralized Finance) and NFTs (Non-Fungible Tokens), are all powered by individual smart contracts.

For example:
- A smart contract might stipulate: "If A transfers 1 Ether to me, I will automatically transfer ownership of an NFT to A."
- When A actually transfers 1 Ether, the EVM will automatically execute this code, transferring the NFT to A.
- The entire process is like a vending machine: you insert coins, and it dispenses the product. It's fully automated and requires no trust in any individual, because the code is law. The EVM is the system that ensures this "vending machine" operates correctly.

2. Ensuring Network Security and Consistency

Because the Ethereum network has thousands of nodes, how do we ensure everyone's ledger is the same and no one cheats?

The answer is the EVM.

When a transaction or a smart contract operation occurs, all nodes in the network will independently run it within their respective EVMs. Then, they compare the results. If the results are all identical, the operation is confirmed and recorded on the blockchain. If a particular node tries to be malicious and calculates a different result, other nodes will detect and reject it.

This is similar to an entire class solving a math problem: only if everyone arrives at the same answer will that answer be accepted by the teacher. The EVM is that unified "calculator" and "rulebook for solving problems."

3. Providing a Standardized Development Platform

The EVM provides a unified, standardized environment for all developers. Developers don't need to worry whether users' computers are Windows or Mac, nor do they need to concern themselves with server configurations.

They simply need to write smart contracts using languages like Solidity and then deploy them onto the Ethereum network. The EVM ensures that this contract will run in exactly the same way on any Ethereum node worldwide.

This significantly lowers the barrier to development, fostering a rich and diverse ecosystem of applications on Ethereum. Many "EVM-compatible chains" we hear about today (like BSC, Polygon) mean they also use a "system" similar to Ethereum's EVM, allowing applications from Ethereum to be easily ported over.

A Simple Analogy to Summarize

If Ethereum is like an Apple iOS system, then:

The EVM is comparable to the runtime environment and rules Apple provides for all App developers (App Store review guidelines, development kits, etc.).
Smart contracts (or DApps) are the various Apps we run on our phones (like WeChat, TikTok).

As long as developers adhere to the EVM's rules when writing code (developing Apps), they can ensure their programs (Apps) will run smoothly and securely on Ethereum (the iOS system) and be used by users worldwide.

I hope this explanation makes it clear to you! The EVM is key to understanding Ethereum and smart contracts, laying the foundation for the entire decentralized application world.