What is an Ethereum Virtual Machine (EVM) and how does it work?
Ether (ETH), which is the second largest cryptocurrency in terms of market capitalization, is popular among cryptocurrency investors due to its native ETH token. However, its native Solidity programming language and Ethereum Virtual Machine (EVM) are instrumental in the acclaim it receives from the developer community. In fact, the Ethereum blockchain continues to attract decentralized application (DApp) developers due to its flexibility, the wide variety of developer tools available, and the platform’s large user base.
The EVM forms the core of the blockchain’s architecture, and is the program that executes the application code or smart contracts, as they are called, and provides a runtime environment for them to run on top of the Ethereum network. Also, EVM is Turing-complete and thus can run any program coded in any programming language, allowing developers to easily create custom smart contracts and DApps for the burgeoning Web3 space.
In addition to these important functions, EVM has access to all nodes in the network, handles smart contract execution and efficiently handles all transactions on the Ethereum blockchain, making it one of the most powerful virtual machines in existence today.
What is the Ethereum Virtual Machine (EVM) and how does it work?
Conceptualized in 2013 by programmer Vitalik Buterin, the Ethereum network owes its phenomenal success as the blockchain of choice for DApp developers to the Ethereum Virtual Machine (EVM) that was designed by Gavin Wood during his tenure at Ethereum. Written in C++ and using the LLVM Project compiler, the EVM is a special state machine that operates continuously and whose immutable operations determine the state of each block in the Ethereum blockchain.
The EVM not only governs what nodes can or cannot do with the distributed ledger maintained by the Ethereum blockchain, but also defines the specific rules for changing state from block to block. The latter functionality is what enables the smart contract functionality that Ethereum has become known for.
To understand what an Ethereum Virtual Machine does, one must look at each of the different functions it serves to ensure the smooth operation of the Ethereum network. For each input that it receives, the EVM produces an output that is deterministic in nature and follows a mathematical function in the simplest sense.
The EVM acts as a stack machine that pushes transient values onto and off a pushdown stack, and has a depth of 1024 elements, each of which is a 256-bit word. It also maintains a temporary memory in the form of a byte array, which alternates between two transactions on the Ethereum blockchain. Smart contract codes that are compiled are executed by the EVM in the form of a collection of 140 standard opcodes, while other blockchain-specific stack operations are also implemented by it.
Thus, the EVM has a machine state that is volatile in nature during the processing of any transaction and a global or world state that contains information about the various accounts maintained on the Ethereum blockchain. All actions are governed by the EVM code, which itself has gone through several iterations since the launch of the Ethereum network in 2015, leading to the existence of various implementations of EVM currently in use.
In fact, EVM is responsible for maintaining a level of abstraction between thousands of Ethereum nodes and the executing code, acting as a function that delivers consistent results without revealing many details to clients or nodes.
What is the purpose of the Ethereum Virtual Machine (EVM)?
EVM has reliably operated all applications running on the Ethereum network with no major downtime reported. For developers, EVM acts as the parent program that runs smaller executable programs known as smart contracts in Ethereum, while giving them the freedom to write these smart contracts in a variety of programming languages, including Solidity, Vyper, Python, and Yul, among others .
Because of this flexibility offered by EVM, the Ethereum blockchain has spawned thousands of DApps in the decentralized finance (DeFi) and nonfungible token (NFT) space. Each of these DApps and the smart contracts they are created from are converted into bytecode that is fed into the EVM and distributed among all nodes in the Ethereum network. Once a smart contract is deployed, the EVM is responsible for communicating with all nodes and performing state changes once a consensus is reached.
It can be said that the EVM is inserted into each Ethereum node to execute smart contracts using bytecode instead of the base programming language, thus isolating the physical host computer from the machine code that Ethereum runs on.
Advantages of Ethereum Virtual Machine (EVM)
Because of the way EVM works, developers can run code without worrying about its impact on the rest of the network or the possibility of it messing with data or personal files residing on any of the node computers.
In addition, they can run complex smart contracts on different computing environments with distributed consensus. This ensures that the failure of a single node has no negative impact on the operation of the DApp or smart contract, as the EVM code remains the same across all nodes. Also, since account data is maintained at a global level in the EVM, developers find it perfect for writing custom smart contract code and creating distinct DApps that can access this global data set and produce reliable output.
The sanctity of the result is what makes EVM, in particular, and the Ethereum blockchain in general well-suited for the sustainable expansion of DApps and the smart contract Ethereum ecosystem. Add to this the library of default code available for developers to choose from, a growing number of EVM-compatible layer-2 blockchains, and a large number of possible EVM use cases, and it’s easy to see why EVM is the platform of choice for Web3 development.
Disadvantages of Ethereum Virtual Machine (EVM)
Despite the many advantages offered by EVM, there are certain disadvantages that must be considered by developers and entrepreneurs who build on Ethereum. Chief among these are the high transaction fees or gas costs associated with running a smart contract on the Ethereum network.
These fees, paid in ETH, vary depending on the complexity of the contract and the network load at the time of execution, making it crucial for developers and entrepreneurs to price their services accordingly. Additionally, since Solidity is the most preferred language for coding on EVM, it implies that developers must have sufficient experience with it and have a minimum of technical expertise to create effective smart contracts using it.
The latter is important as any additional computational requirement will lead to higher gas costs and ultimately prove detrimental to the project’s success. If developers choose to code with other languages, they must be careful to resolve any inherent repetitions in the code since EVM will continue to compile them anyway. Although upgrading smart contracts is possible at a later date, creating an intermediate smart contract that references the address of the original smart contract comes with security risks.
The future of EVMs
Despite the revolutionary changes caused by EVM in the blockchain ecosystem, this technology for reading and executing code is being improved by a number of blockchain projects.
With cross-chain interoperability as the most important aspect for developers, many EVM-compatible blockchains have been built, and most offer lower throttling and faster transaction speeds than the Ethereum protocol. As a result, these blockchains are now able to interact with Ethereum users seamlessly and facilitate money transfers to their own networks using blockchain bridges.
But with the Ethereum protocol having completed its merger in September 2022, the next goal is to shift from EVM to Ethereum WebAssembly (eWASM). Designed to be highly modular and platform independent, eWASM is being touted as the next game-changer for the Ethereum protocol and could motivate other blockchains to use this smart contract runtime environment as well. However, whether eWASMs will replace EVMs as the most reliable mechanism for smart contracts is a question only time will tell.
