The Ethereum virtual machine(EVM) in simple terms is an environment where all Ethereum accounts and smart contracts live.
The EVM is an important part of the Ethereum blockchain as it enables the creation and execution of smart contracts and decentralized applications.
Additionally, the EVM is designed to be Turing complete. This means that it is capable of executing any computation that can be expressed in code. This allows developers to build a wide range of applications on top of the Ethereum blockchain including decentralized applications(dApps) and decentralized autonomous organizations(DAOs).
The EVM as a State Machine
A state machine is a computer program that can operate in different states. When a transaction triggers a smart contract to execute, the Ethereum Virtual Machine (EVM) changes the state of the Ethereum blockchain to meet the requirements of the contract.
At any given moment in time, Ethereum has a single, globally recognized "state," which is determined by the Ethereum Virtual Machine (EVM). The EVM is responsible for defining the rules that are used to compute and update the state of Ethereum from one block to the next.
It works like a machine that has a current state and changes to a new state based on certain rules and input.
In the context of Ethereum, the state refers to the current information about all accounts, contract storage, and the blockchain's variables (such as the block number and block hash). The EVM changes the state by running smart contracts and modifying the information in accounts, contract storage, and the blockchain's variables.
The EVM is designed to always produce the same results for a given input and initial state. This helps all the computers on the Ethereum network agree on the state of the blockchain and the results of executing smart contracts.
How does the Ethereum Virtual Machine work?
The Ethereum Virtual Machine (EVM) is a tool that helps developers create and run special programs called smart contracts on the Ethereum blockchain. These programs are written in programming languages like Solidity and Vyper, and they are turned into a code called bytecode that the EVM can understand. The bytecode is stored on the blockchain and is used by the EVM to carry out actions.
When someone makes a transaction on the Ethereum blockchain and it triggers a smart contract, the EVM is loaded with information about the transaction, including how much resources, or "gas," are available to complete the contract. If the gas runs out during the contract, the transaction is stopped and the changes to the blockchain are not made. However, the person who provided the resources for the contract is still paid for the resources used up until that point.
Smart contracts can also start their transactions and call other contracts, and the EVM is loaded with new information for each of these calls. If there isn't enough gas to complete the execution, the process is reset to the previous EVM. The EVM uses a 256-bit word size and a stack-based architecture to support various operations, including ones that help protect the funds in the blockchain.
In summary, the EVM is a tool that enables developers to create and run decentralized applications (DApps) and smart contracts on the Ethereum blockchain. It ensures that the same code is used on all nodes participating in the network and stores data in a way that is shared by all nodes.