The Ethereum Virtual Machine (EVM) exists to provide a secure and deterministic environment for executing smart contracts, further enabling decentralized applications (dApps). It ensures that the code within these contracts is executed consistently across all nodes in the [[Ethereum]] network, regardless of the underlying hardware or operating system. This consistency is vital for maintaining trust and enabling interoperability within the decentralized ecosystem. ### System Architecture EVM is a stack-based virtual machine meaning it operates on a stack data structure. It is designed to be a sandboxed environment, isolating the execution of smart contracts from the host machine to enhance security. The EVM is a part of every Ethereum node, ensuring that all participants in the network have access to the same execution environment. ### Smart Contracts and Execution [[Smart Contracts|Smart contracts]] are self-executing agreements written in code that are deployed on the blockchain. The EVM is responsible for executing the bytecode of these smart contracts. When a transaction triggers a smart contract, the EVM processes the code line by line, performing the necessary computations and updating the state of the Ethereum blockchain accordingly. ### Opcodes and Gas EVMs operate using a set of [[opcodes]], which are the sets of operational instructions defining system performance. These opcodes include arithmetic operations, control flow instructions, and data manipulation commands. Each opcode has a specific [[gas]] cost associated with it, representing the computational resources required to execute that operation. Gas acts as a measure of computational effort and is used to allocate resources fairly among participants. ### Gas and Fee Mechanisms To prevent abuse and prioritize resource allocation, Ethereum implements a [[Transaction Fee Mechanisms|fee mechanism]] using [[gas]]. Every operation performed by the EVM consumes a certain amount of gas. Users must pay for the gas consumed by their transactions by attaching an appropriate fee. The fee is calculated based on the gas cost of the operations performed, multiplied by the current gas price. ### EVM Operators In the Ethereum network, every participating node runs an instance of EVM. These nodes can be operated by individuals, organizations, or even mining pools. Each node independently executes the smart contracts and verifies the transactions according to the consensus rules of the Ethereum network. This decentralized approach ensures that the execution of smart contracts is distributed across the network, enhancing security and preventing a single point of failure.