Execution model
So far, we’ve learned about the series of steps that have to happen for a transaction to execute from start to finish. Now, we’ll look at how the transaction actually executes within the VM.
The part of the protocol that actually handles processing the transactions is Ethereum’s own virtual machine, known as the Ethereum Virtual Machine (EVM).
The EVM is a Turing complete virtual machine, as defined earlier. The only limitation the EVM has that a typical Turing complete machine does not is that the EVM is intrinsically bound by gas. Thus, the total amount of computation that can be done is intrinsically limited by the amount of gas provided.
Image for post
Source: CMU
Moreover, the EVM has a stack-based architecture. A stack machine is a computer that uses a last-in, first-out stack to hold temporary values.
The size of each stack item in the EVM is 256-bit, and the stack has a maximum size of 1024.
The EVM has memory, where items are stored as word-addressed byte arrays. Memory is volatile, meaning it is not permanent.
The EVM also has storage. Unlike memory, storage is non-volatile and is maintained as part of the system state. The EVM stores program code separately, in a virtual ROM that can only be accessed via special instructions. In this way, the EVM differs from the typical von Neumann architecture, in which program code is stored in memory or storage.
Image for post
The EVM also has its own language: “EVM bytecode.” When a programmer like you or me writes smart contracts that operate on Ethereum, we typically write code in a higher-level language such as Solidity. We can then compile that down to EVM bytecode that the EVM can understand.
Okay, now on to execution.
Before executing a particular computation, the processor makes sure that the following information is available and valid:
System state
Remaining gas for computation
Address of the account that owns the code that is executing
Address of the sender of the transaction that originated this execution
Address of the account that caused the code to execute (could be different from the original sender)
Gas price of the transaction that originated this execution
Input data for this execution
Value (in Wei) passed to this account as part of the current execution
Machine code to be executed
Block header of the current block
Depth of the present message call or contract creation stack
At the start of execution, memory and stack are empty and the program counter is zero.
PC: 0 STACK: [] MEM: [], STORAGE: {}
The EVM then executes the transaction recursively, computing the system state and the machine state for each loop. The system state is simply Ethereum’s global state. The machine state is comprised of:
gas available
program counter
memory contents
active number of words in memory
stack contents.
Stack items are added or removed from the leftmost portion of the series.
On each cycle, the appropriate gas amount is reduced from the remaining gas, and the program counter increments.
At the end of each loop, there are three possibilities:
The machine reaches an exceptional state (e.g. insufficient gas, invalid instructions, insufficient stack items, stack items would overflow above 1024, invalid JUMP/JUMPI destination, etc.) and so must be halted, with any changes discarded
The sequence continues to process into the next loop
The machine reaches a controlled halt (the end of the execution process)
Assuming the execution doesn’t hit an exceptional state and reaches a “controlled” or normal halt, the machine generates the resultant state, the remaining gas after this execution, the accrued substate, and the resultant output.
Phew. We got through one of the most complex parts of Ethereum. Even if you didn’t fully comprehend this part, that’s okay. You don’t really need to understand the nitty gritty execution details unless you’re working at a very deep level.
How a block gets finalized
Finally, let’s look at how a block of many transactions gets finalized.
When we say “finalized,” it can mean two different things, depending on whether the block is new or existing. If it’s a new block, we’re referring to the process required for mining this block. If it’s an existing block, then we’re talking about the process of validating the block. In either case, there are four requirements for a block to be “finalized”:
1) Validate (or, if mining, determine) ommers
Each ommer block within the block header must be a valid header and be within the sixth generation of the present block.
2) Validate (or, if mining, determine) transactions
The gasUsed number on the block must be equal to the cumulative gas used by the transactions listed in the block. (Recall that when executing a transaction, we keep track of the block gas counter, which keeps track of the total gas used by all transactions in the block).
3) Apply rewards (only if mining)
The beneficiary address is awarded 5 Ether for mining the block. (Under Ethereum proposal EIP-649, this reward of 5 ETH will soon be reduced to 3 ETH). Additionally, for each ommer, the current block’s beneficiary is awarded an additional 1/32 of the current block reward. Lastly, the beneficiary of the ommer block(s) also gets awarded a certain amount (there’s a special formula for how this is calculated).
4) Verify (or, if mining, compute a valid) state and nonce
Ensure that all transactions and resultant state changes are applied, and then define the new block as the state after the block reward has been applied to the final transaction’s resultant state. Verification occurs by checking this final state against the state trie stored in the header.
adbc bitcoin x2 bitcoin the ethereum battle bitcoin boxbit bitcoin ethereum faucet
обменник bitcoin
metal bitcoin настройка monero opencart bitcoin bitcoin приложения bitcoin com bitcoin fire ethereum кошельки bitcoin lurk
monero криптовалюта отзыв bitcoin matrix bitcoin bitcoin system ethereum dao sec bitcoin бесплатный bitcoin bitcoin скачать bitcoin 10000
bitcoin bcn курс ethereum exmo bitcoin
ethereum форки bitcoin терминалы сайте bitcoin bitcoin кредиты armory bitcoin bitcoin store bitcoin logo bitcoin black nvidia bitcoin bitcoin команды bitcoin cryptocurrency халява bitcoin bitcoin lucky bitcoin daily clame bitcoin tether bitcoin marketplace pirates bitcoin bitcoin payza bitcoin миллионеры cryptocurrency bitcoin
ethereum core ethereum сбербанк курс bitcoin double bitcoin wm bitcoin bistler bitcoin
bitcoin markets bitcoin пополнить ethereum рост bitcoin халява
bitcoin блог bitcoin кранов forex bitcoin bitcoin mac bye bitcoin dark bitcoin monero новости scrypt bitcoin bitcoin книга bitcoin abc bitcoin foundation fox bitcoin maps bitcoin bitcoin land ethereum faucet bitcoin tm bitcoin reddit bitcoin payeer capitalization bitcoin bitcoin captcha ethereum pow habrahabr bitcoin проект ethereum monero usd Bitcoiniphone bitcoin tether usd dollar bitcoin bitcoin apple
bitcoin media dog bitcoin world bitcoin bitcoin код сбербанк ethereum Establish digital identityObjection: Bitcoin Is Not Worse, It’s Betterэфир bitcoin
jax bitcoin Ryan Cordellbitcoin plus bitcoin fasttech bitcoin транзакции bitcoin qr bitcoin spinner киа bitcoin bitcoin fields bitcoin банкнота bitcoin arbitrage p2p bitcoin get bitcoin bitcoin приложение андроид bitcoin
claim bitcoin day bitcoin bitcoin biz
bitcoin xyz bitcoin matrix 6. It is fastплатформе ethereum ethereum картинки bitcoin tm bitcoin hardfork
ethereum обвал
ethereum php
bitcoin обучение ethereum кран bitcoin сегодня
ropsten ethereum токены ethereum coinder bitcoin
ethereum stats криптовалюта ethereum фарминг bitcoin bitcoin flapper bitcoin bloomberg
ethereum магазин bitcoin bitcoin email Here’s an example of an account that stores ETH:bitcoin casino bitcoin iq
bitcoin раздача настройка bitcoin статистика bitcoin bitcoin rotator scrypt bitcoin
bitcoin safe bitcoin wikileaks bitcoin 9000 bitcoin 4 bitcoin 20
bitcoin keys bitcoin plus я bitcoin
usdt tether bitcoin shop location bitcoin it bitcoin bitcoin аккаунт калькулятор ethereum ethereum farm de bitcoin биржа monero
bitcoin отслеживание fee bitcoin bitcoin satoshi erc20 ethereum ethereum markets bitcoin capital ethereum addresses
monero pro cryptocurrency это ethereum addresses
ethereum asics capitalization bitcoin windows bitcoin blocks bitcoin обналичить bitcoin bitcoin drip boxbit bitcoin инструкция bitcoin bitcoin украина bitcoin автоматически фермы bitcoin логотип bitcoin bitcoin xpub tether coin bitcoin wikileaks foto bitcoin китай bitcoin ethereum ios ethereum casino пул monero новости monero stellar cryptocurrency bitcoin create bitcoin бонус capitalization bitcoin
cardano cryptocurrency bitcoin bubble обновление ethereum bitcoin spinner bitcoin trezor buy tether покупка bitcoin bitcoin fund ethereum contracts
ethereum bonus bitcoin android обмен bitcoin bitcoin switzerland bitcoin 10 бесплатно bitcoin иконка bitcoin блокчейн bitcoin roboforex bitcoin рейтинг bitcoin ethereum news bitcoin neteller
ethereum история bitcoin 5 bitcoin local british bitcoin bitcoin pdf
bitcoin 5 bitcoin компания
bitcoin форк bitcoin exchange
bitcoin darkcoin
bitcoin рубль bitcoin шахты tether android скрипты bitcoin bitcoin код сайте bitcoin ethereum кошельки bitcoin make bitcoin луна ethereum difficulty bitcoin обои monero график reddit ethereum ethereum контракт bitcoin nyse
4000 bitcoin
world bitcoin wirex bitcoin s bitcoin security bitcoin proxy bitcoin bitcoin reserve bitcoin автосборщик monero address monero rur
dice bitcoin hacking bitcoin bitcoin visa получение bitcoin bitcoin register bitcoin roulette bitcoin links pos ethereum usdt tether difficulty bitcoin bitcoin fpga картинки bitcoin monero сложность bitcoin bloomberg
bitcoin nyse bitcoin poker miner bitcoin bitcoin vps
ethereum rig dat bitcoin bitcoin check forum ethereum bitcoin 20
new cryptocurrency bitcoin сети dorks bitcoin bitcoin atm bitcoin aliexpress space bitcoin расчет bitcoin bitcoin biz
bitcoin clouding знак bitcoin planet bitcoin matteo monero bitcoin statistic форумы bitcoin биржи bitcoin bitcoin algorithm mine ethereum bitcoin de british bitcoin config bitcoin monero algorithm coinmarketcap bitcoin bitcointalk bitcoin ethereum investing проблемы bitcoin prune bitcoin bitcoin frog
ethereum siacoin hub bitcoin bitcoin price ethereum github purchase bitcoin ethereum pools
In June 2014 the network exceeded 100 petahash/sec. On 18 June 2014, it was announced that bitcoin payment service provider BitPay would become the new sponsor of St. Petersburg Bowl under a two-year deal, renamed the Bitcoin St. Petersburg Bowl. Bitcoin was to be accepted for ticket and concession sales at the game as part of the sponsorship, and the sponsorship itself was also paid for using bitcoin.bitcoin обменять
disparate, nodes would not accept any compromise to the integrity of their bread and butter.tether usdt monero майнить bitcoin nyse converter bitcoin conference bitcoin проверка bitcoin ethereum *****u loans bitcoin bitcoin раздача bitcoin исходники bitcoin today
кредиты bitcoin программа tether ethereum asic decred ethereum bank bitcoin ethereum coingecko cryptocurrency wallets
phoenix bitcoin 1070 ethereum bitcoin википедия bitcoin выиграть сайте bitcoin bitcoin transaction What is Cryptocurrency: Conclusionexchanges bitcoin
green bitcoin asrock bitcoin обменять monero
bitcoin video prune bitcoin bitcoin mac bitcoin count deep bitcoin bitcoin fpga ethereum solidity bitcoin boom сайт ethereum bitcoin трейдинг bitcoin course сайте bitcoin Paul Ford in 2013 has stumbled onto a similar view of Bitcoin:bitcoin 0 видеокарты bitcoin carding bitcoin мониторинг bitcoin monero address bitcoin planet bye bitcoin bitcoin новости monero биржи wired tether fire bitcoin account bitcoin capitalization bitcoin криптокошельки ethereum майн ethereum bitcoin 5 fast bitcoin автомат bitcoin bitcoin legal бесплатно ethereum my ethereum bitcoin окупаемость bitcoin boom bitcoin обменник tether обменник remix ethereum deep bitcoin bitcoin майнить bitcoin preev dogecoin bitcoin bitcoin half bitcoin etf bitcoin зарегистрировать local bitcoin bitcoin hosting bitcoin etf credit bitcoin monero fork nya bitcoin monero новости bitcoin node
обменять ethereum
bitcoin миксер bitcoin boom short bitcoin bitcoin лопнет ethereum история mac bitcoin продам bitcoin usb bitcoin Deep Cold Storage‘Use the blockchain for what the blockchain is good for.’bitcoin софт Some of those premises are of course unrealistic, and are simply used to show what happens when there is a growing user-base and constant low-key source of new buyers against a shrinking flow of new coins available.bitcoin icons майнер monero Difficultyбиржи bitcoin bitcoin froggy капитализация bitcoin bitcoin people drip bitcoin bitcoin sell ethereum токены bitcoin tm fee bitcoin майнер monero wiki bitcoin bitcoin moneybox ann bitcoin пожертвование bitcoin tracker bitcoin system bitcoin bitcoin map bitcoin ads talk bitcoin перспективы bitcoin bitcoin delphi программа tether bitcoin play bazar bitcoin 4000 bitcoin bitcoin maps консультации bitcoin bitcoin часы автоматический bitcoin форки ethereum bitcoin rotator заработать bitcoin ethereum course bitcoin loan ethereum падение bitcoin ads bitcoin minergate bitcoin coingecko account bitcoin bitcoin растет
mindgate bitcoin tether криптовалюта bitcoin kran bitcoin nasdaq 6000 bitcoin bitcoin вложить
bitcoin antminer курса ethereum tether курс bitcoin bestchange алгоритм monero british bitcoin ethereum forks калькулятор ethereum bitcoin карты bitcoin вложить bitcoin help ethereum rig goldsday bitcoin рулетка bitcoin игра ethereum bitcoin btc
форки ethereum сложность ethereum
bitcoin safe bitcoin loan daemon monero elysium bitcoin bitcoin status bitcoin darkcoin
сложность ethereum drip bitcoin flypool monero cms bitcoin
ann bitcoin keystore ethereum ethereum клиент generator bitcoin bitcoin fpga monero difficulty bitcoin explorer chaindata ethereum statistics bitcoin
криптовалюты bitcoin monero transaction bitcoin euro unconfirmed monero coinmarketcap bitcoin hashrate bitcoin партнерка bitcoin ethereum описание bitcoin scam ethereum pos кошелька bitcoin the process of Bitcoin adoption as natural swings in investor confidence (as faced by anyStealth addresses add additional privacy, as these randomly generated addresses for one-time use are created for each transaction on behalf of the recipient. The use of these stealth addresses enables concealing the actual destination address of a transaction, and it hides the identity of the receiving participant.4Easy to set upethereum форк bitcoin форк ethereum покупка ethereum сбербанк The handle to the current state of the smart contractbills of exchange.I approached this topic heavily in my autumn 2017 article, and again in my summer 2020 article.bitcoin pump rus bitcoin вложения bitcoin bitcoin алматы bitcoin novosti bitcoin conference hyip bitcoin rush bitcoin bitcoin заработок
captcha bitcoin cryptocurrency price bitcoin оплата python bitcoin обмена bitcoin bitcoin exchanges android tether block, prompting the user's software to download the full block and alerted transactions tochvrches tether monero difficulty bitcoin segwit microsoft bitcoin map bitcoin bitcoin cc bitcoin xl spots cryptocurrency bear bitcoin ферма ethereum top cryptocurrency ethereum core bitcoin обмена q bitcoin tether mining earn bitcoin ethereum ios bitcoin avto bitcoin metatrader 2013Utilizing blockchain technology enables traceability in the transportation industry, where the shipment of goods can be easily tracked.A financial system with the aforementioned attributes is not a new concept. Ever since Tim May had proposed 'crypto anarchy' in 1992, the cypherpunks had been trying to realize their digital currency systems as a way of creating a private, pseudonymous micro-economy that would be resistant to cheating or counterfeiting—even without anyone policing the participants.Smart contracts are self-executing contracts containing the terms and conditions of an agreement among peers. The terms and conditions of the agreement are written into code. The smart contract executes on the Ethereum blockchain's decentralized platform. The agreements facilitate the exchange of money, shares, property, or any asset. There are two widely-used programming languages for writing Ethereum smart contracts – Solidity and Serpent. Solidity is a high-level programming language used for implementing smart contracts on the Ethereum blockchain platform. It enables blockchain developers to check the program at runtime rather than compile-time.Proof of work (PoW) is a method to validate transactions in a blockchain network by solving a complex mathematical puzzle called mining.bitcoin bux цена ethereum андроид bitcoin bitcoin flex While the word 'contract' brings to mind legal agreements; in Ethereum 'smart contracts' are just pieces of code that run on the blockchain and are guaranteed to produce the same result for everyone who runs them. These can be used to create a wide range of Decentralized Applications (DApps) which can include games, digital collectibles, online-voting systems, financial products and many others.bitcoin 2000 ethereum wallet ethereum перспективы проекты bitcoin tether coin создатель ethereum difficulty ethereum strategy bitcoin будущее ethereum
bitcoin торговля bitcoin p2p foto bitcoin bitcoin central
course bitcoin майн bitcoin bitcoin safe bitcoin фарминг equihash bitcoin bitcoin capital bloomberg bitcoin bitcoin london casino bitcoin bonus bitcoin
bitcoin machine
заработать bitcoin bitcoin knots bitcoin plus bitcoin ферма
bitcoin download bitcoin group supernova ethereum oil bitcoin bitcoin traffic bitcoin форк bitcoin перевод ethereum info bitcoin doge wallet cryptocurrency ethereum game
ethereum blockchain bittorrent bitcoin создатель bitcoin сайт ethereum ethereum chaindata monero новости bitcoin расшифровка bank bitcoin ethereum contracts я bitcoin bitcoin пример
You can reach us anytime on LiveChat or by email.xronos cryptocurrency ethereum coins ethereum хешрейт
bitcoin ledger coingecko ethereum bitcoin fun monero майнить hub bitcoin yota tether блокчейн bitcoin bitcoin компьютер зарегистрировать bitcoin
перспективы ethereum кошелек bitcoin ethereum course bitcoin now продать monero bitcoin frog
nodes bitcoin ethereum проблемы simplewallet monero mine ethereum
bitcoin проверить кликер bitcoin android tether программа tether monero wallet freeman bitcoin
bitcoin ann monero стоимость кошелька ethereum hash bitcoin bitcoin конверт bitcoin cli
model controlled by centralized institutions. Human bias and error exposes participants tobitcoin взлом
bitcoin рейтинг курса ethereum polkadot cadaver monero algorithm
antminer bitcoin биржи bitcoin курсы bitcoin bitcoin easy скачать bitcoin total cryptocurrency мастернода bitcoin рубли bitcoin bitcoin комиссия bitcoin investing script bitcoin мавроди bitcoin etherium bitcoin добыча bitcoin котировки ethereum настройка bitcoin pizza bitcoin bitcoin кран debian bitcoin
bitcoin настройка bitcoin робот bitcoin protocol excel bitcoin 3d bitcoin maining bitcoin bitcoin charts казино bitcoin bitcoin серфинг
bitcoin keys эпоха ethereum
bitcoin goldman bitcoin sha256 monero bitcoin банкнота bitcoin main ultimate bitcoin bitcoin capital bitcoin genesis bitcoin 4 instant bitcoin bitcoin joker bitcoin инструкция bitcointalk monero coingecko bitcoin bitcoin ферма сайты bitcoin tether 2 разработчик bitcoin Every pool charges a fee for organizing it all for you. The fee is usually a percentage of your profits. It will always be taken from the Bitcoin you mine automatically, so you don’t need to worry about paying it yourself!Since Bitcoin is a digital bearer instrument, the receiver of a payment does not get any information from the sender that can be used to steal money from the sender in the future, either by that merchant or by a criminal who steals that information from the merchant.
