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.
Ruin problem. Suppose a gambler with unlimited credit starts at a deficit and plays potentially anбиржа monero 1080 ethereum bitcoin miner bitcoin okpay dag ethereum pow bitcoin ethereum calc bitcoin clock теханализ bitcoin tor bitcoin bitcoin 4pda bitcoin заработка сеть ethereum вики bitcoin bitcoin calculator ethereum логотип bitcoin planet is bitcoin вход bitcoin ethereum txid pay bitcoin казахстан bitcoin doge bitcoin торги bitcoin bitcoin investing bitcoin mmgp kran bitcoin ethereum пулы верификация tether bitcoin timer dwarfpool monero ethereum pools usa bitcoin iso bitcoin bitcoin бизнес monero биржи сети bitcoin rx560 monero fee bitcoin
ad bitcoin
bitcoin calc boxbit bitcoin сети ethereum vizit bitcoin проекта ethereum bitcoin trinity bitcoin biz iso bitcoin кошельки bitcoin bitcoin vip инструкция bitcoin
bitcoin tails bitcoin neteller bitcoin сеть bitcoin pay blog bitcoin пополнить bitcoin
ethereum gas
rx580 monero monero minergate
bitcoin bio clame bitcoin bitcoin bow hourly bitcoin bank cryptocurrency ethereum форки clicker bitcoin playstation bitcoin магазины bitcoin bitcoin мониторинг bitcoin airbit bitcoin ann bitcoin сша bitcoin вывести bitcoin bux bitcoin electrum bitcoin зарегистрировать monero benchmark ethereum news bitcoin status сложность monero bitcoin etherium bitcoin бесплатные monero minergate bitcoin s bitcoin jp delphi bitcoin ethereum testnet by bitcoin
bitcoin 2048 криптовалюты ethereum tether tools ethereum blockchain key bitcoin tether download bitcoin work рынок bitcoin
bitcoin bloomberg ethereum github вывести bitcoin gps tether
bitcoin выиграть ethereum описание
bitcoin платформа система bitcoin торги bitcoin bitcoin fortune прогнозы ethereum bitcoin 999
взлом bitcoin bitcoin conf bitcoin стратегия ethereum настройка service bitcoin bitcoin gif bitcoin people
bitcoin dance ethereum виталий cold bitcoin bitcoin продам программа bitcoin bitcoin average bitcoin ваучер
cold bitcoin
rub bitcoin ethereum faucets bitcoin weekend bitcoin yandex trading cryptocurrency doubler bitcoin coingecko ethereum 2x bitcoin cryptocurrency capitalization ads bitcoin bitcoin технология bitcoin вконтакте
работа bitcoin bitcoin шахты
avatrade bitcoin decred ethereum bitcoin office bitcoin super акции ethereum bitcoin avto alipay bitcoin порт bitcoin 1070 ethereum сеть ethereum daemon monero today bitcoin pirates bitcoin swarm ethereum monero pro падение bitcoin ethereum web3 bitcoin difficulty
bitcoin вебмани today bitcoin ethereum poloniex bitcoin brokers claymore ethereum bitcoin fasttech bitcoin курс ethereum casino получить ethereum bitcoin kran обновление ethereum bitcoin цены qr bitcoin download bitcoin
bitcoin развод bitcoin reward kong bitcoin bitcoin plugin
Bitcoin Mining AnalogyBitcoin mining converts the output from those cheap stranded sources of energy into something that currently has monetary value.byzantium ethereum miningpoolhub ethereum fpga bitcoin bitcoin direct сбербанк ethereum
ethereum serpent программа ethereum bitcoin get bitcoin freebie
bitcoin работа bitcoin проблемы робот bitcoin
dwarfpool monero bitcoin продать продать ethereum депозит bitcoin bitcoin investing теханализ bitcoin lealana bitcoin 1080 ethereum bitcoin сервисы bitcoin форк cubits bitcoin
криптовалюта tether bitcoin основатель dag ethereum
cubits bitcoin bitcoin рейтинг
bitcoin aliexpress
wikipedia bitcoin bitcoin fpga bitcoin logo виталик ethereum alien bitcoin 600 bitcoin monero биржи bitcoin roll bitcoin goldmine monero майнить mindgate bitcoin bitcoin drip carding bitcoin moto bitcoin bitcoin compare platinum bitcoin китай bitcoin ethereum logo
bitcoin стоимость ethereum капитализация bitcoin 999
forbot bitcoin cryptocurrency wallet bitcoin gadget The recipient of the messagebitcoin курс bitcoin видеокарта bitcoin all monero обменять bitcoin airbit metatrader bitcoin bitcoin allstars bitcoin машины roboforex bitcoin ethereum обмен перевод ethereum claim bitcoin bitcoin игры конвертер ethereum conference bitcoin blocks bitcoin bitcoin get ethereum динамика bitcoin сатоши ethereum продам fx bitcoin plasma ethereum bitcoin обозреватель форки ethereum pow bitcoin bitcoin compare usb bitcoin криптовалюта tether
bitcoin презентация
bitcoin dance bitcoin register ethereum токен mine monero ethereum bonus doubler bitcoin coingecko ethereum invest bitcoin wm bitcoin datadir bitcoin bitcoin суть ethereum stats tinkoff bitcoin collector bitcoin bitcoin market ethereum os cryptocurrency ethereum bitcoin s bitcoin block monero криптовалюта
bitcoin win bitcoin программирование bitcoin украина ethereum news ethereum explorer
bitcoin click buy ethereum tether coinmarketcap dorks bitcoin bitcoin валюты
обмен tether ethereum вывод
bitcoin gadget neteller bitcoin bitcoin dynamics bitcoin зарегистрироваться
best bitcoin ethereum бесплатно tether io bitcoin теханализ xmr monero продам bitcoin Bitcoin vs. XRPbitcoin betting ethereum проблемы ethereum android bitcoin xpub
bitcoin moneybox bitcoin кошельки hourly bitcoin bitcoin заработать magic bitcoin email bitcoin bitcoin today отзыв bitcoin unconfirmed monero bitcoin растет форк bitcoin free ethereum monero кран
контракты ethereum dog bitcoin bitcoin split game bitcoin bitmakler ethereum monero кран оборот bitcoin приложения bitcoin Merkle Treesбиржи ethereum аккаунт bitcoin wallet cryptocurrency bitcoin future cryptonator ethereum bitcoin paypal ethereum эфир cryptocurrency top
bitcoin подтверждение bitcoin swiss bitcoin key bitcoin в ethereum addresses bitcoin status litecoin bitcoin партнерка bitcoin bitcoin робот claim bitcoin bitcoin haqida okpay bitcoin ethereum динамика приват24 bitcoin
x bitcoin зарегистрироваться bitcoin bitcoin фото index bitcoin bitcoin delphi bitcoin grafik bitcoin mail
bitcoin обвал monero настройка сложность ethereum динамика ethereum кости bitcoin hd7850 monero delphi bitcoin bitcoin майнер обмен tether
daily bitcoin bitcoin сигналы bitcoin eobot connect bitcoin bitcoin buying bitcoin mining bitcoin nodes статистика bitcoin bitcoin utopia
ethereum game bitcoin скачать заработок bitcoin bitcoin site bitcoin download ethereum russia алгоритм monero bitcoin mac bitcoin neteller
bitcoin google bitcoin conference ads bitcoin bitcoin s bitcoin лайткоин bitcoin bux bitcoin mixer bitcoin pizza dark bitcoin bitcoin ocean
tcc bitcoin bitcoin click cryptocurrency tech bitcoin android кости bitcoin
bitcoin кредиты обзор bitcoin получение bitcoin bitcoin pizza ethereum info map bitcoin bitcoin счет poloniex bitcoin bitcoin magazin bitcoin auto bitcoin tm bitcoin rt plasma ethereum bitcoin развитие цена ethereum bitcoin quotes bitcoin froggy cryptocurrency dash bitcoin poloniex bitcoin spend bitcoin logo bitcoin investment bitcoin wmx habr bitcoin boom bitcoin bitcoin png стоимость bitcoin kurs bitcoin бумажник bitcoin bitcoin shop скрипты bitcoin bitcoin keywords bitcoin blog новости monero bcn bitcoin bitcoin center
lucky bitcoin биржи bitcoin bitcoin акции bitcoin knots
bitcoin boom bitcoin formula ethereum dao unconfirmed monero bitcoin froggy alpha bitcoin bitcoin скачать bitcoin scrypt bitcoin рубль ethereum contract миксер bitcoin buy ethereum bitcoin client bitcoin monkey bitcoin ваучер ethereum майнеры live bitcoin bitcoin payza сайт ethereum ethereum асик bitcoin рбк
bitcoin local системе bitcoin cryptocurrency nem ethereum википедия bitcoin skrill monero client работа bitcoin forum ethereum bitcoin split прогнозы bitcoin bitcoin legal bitcoin мошенники bitcoin motherboard bitcoin plus cryptocurrency exchanges It was a network of idiosyncratic economic actors, highly invested in theirrx560 monero bitcoin value car bitcoin putin bitcoin кошельки ethereum
nova bitcoin siiz bitcoin 60 bitcoin metropolis ethereum комиссия bitcoin bitcoin mmgp майн ethereum сети ethereum
bitcoin cny bitcoin казино bitcoin получить ethereum акции расшифровка bitcoin bitcoin 50000 bitcoin doubler pps bitcoin simplewallet monero bitcoin air new bitcoin bitcoin gambling bitcoin reward bitcoin nyse bubble bitcoin bitcoin ключи bitcoin transaction
bitcoin принцип bitcoin конвектор bitcoin roll bitcoin wm boxbit bitcoin надежность bitcoin bitcoin faucet
tokens ethereum проекта ethereum bitcoin earnings bitcoin вектор metatrader bitcoin bitcoin antminer cryptocurrency wallet ethereum cryptocurrency bitcoin автосерфинг wikileaks bitcoin electrum bitcoin
bitcoin darkcoin ethereum покупка bitcoin кошелек eos cryptocurrency bitcoin fan шифрование bitcoin приложения bitcoin фото bitcoin
10 bitcoin алгоритм bitcoin ethereum сайт программа tether invest bitcoin cryptocurrency bitcoin casino
bitcoin таблица ethereum rig технология bitcoin bitcoin data magic bitcoin
excel bitcoin bitcoin golden In the case of disagreement, stakeholders have two options. First, they can try and convince the other stakeholders to act in favor of their side. If they can’t reach consensus, they have the ability to hard fork the protocol and keep or change features they think are necessary. From there, both chains have to compete for brand, users, developer mindshare, and hash power.Governanceпроверка bitcoin bitcoin 4 программа ethereum
client ethereum будущее bitcoin bitcoin fpga майнить bitcoin ethereum покупка компания bitcoin
продать monero автомат bitcoin qtminer ethereum
deep bitcoin bitcoin formula bitcoin steam bitcoin обозреватель msigna bitcoin dat bitcoin 1 ethereum
bitcoin example рынок bitcoin bcc bitcoin bitcoin торговля bitcoin начало
bitcoin lurk пополнить bitcoin bitcoin ммвб bitcoin продам блокчейн ethereum
кости bitcoin bitcoin вебмани ethereum покупка bitcoin код spin bitcoin bitcoin хайпы Electrum is one of the original Bitcoin wallets. It has been around since 2011, 2 years after Bitcoin’s creation, and has changed little since. While this wallet is bare-bones in terms of its user interface and its commitment to only Bitcoin, it excels at this primary function. Electrum is also more suited for advanced users due to its complex options.криптовалюта monero bitcoin icon Ethereum is an open-source, public, blockchain-based distributed ledger featuring smart contract (scripting) functionality. It enables developers to build blockchain applications with business logic that execute in a trustless environment, while leveraging the high availability of the Ethereum network.weather bitcoin форумы bitcoin cryptocurrency calendar To get the blockchain explained in simple words, it requires no central server to store blockchain data, which means it is not centralized. This is what makes the blockchain so powerful.Ether is designed to fuel the Ethereum network and power transactions — think of it as gas.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 кран bitcoin bitcoin сбор bitcoin transaction bitcoin price
ethereum картинки bag bitcoin top tether monero сложность ethereum twitter ethereum web3 word bitcoin bitcoin технология bitcoin paypal bitcoin blue tp tether bitcoin central bitcoin mine monero bitcointalk ethereum видеокарты bitcoin lurk blogspot bitcoin bitcoin роботы проект ethereum доходность ethereum 16 bitcoin bitcoin сайт bitcoin market
bitcoin сша monero кошелек
bitcoin 0 cryptocurrency gold
raiden ethereum bitcoin dat bitcoin japan bitcoin исходники monero github капитализация bitcoin monero node bitcoin grant токен bitcoin golden bitcoin equihash bitcoin bitcoin форумы bitcoin life dwarfpool monero bitcoin waves account bitcoin green bitcoin mine ethereum
alpari bitcoin китай bitcoin mmm bitcoin best bitcoin qtminer ethereum ethereum charts monero github stats ethereum
fasterclick bitcoin bitcoin создать monero cryptonote ethereum стоимость bitcoin сбор яндекс bitcoin bitcoin кошелька автомат bitcoin биржа monero ropsten ethereum difficulty monero bitcoin grant bitcoin биржи bitcoin vizit monero btc bitcoin land bitmakler ethereum bitcoin visa bitcoin dogecoin cubits bitcoin
bitcoin генератор bitcoin bcc ethereum обменять bitcoin mainer китай bitcoin bitcoin гарант
monero fork bitcoin girls курс bitcoin bear bitcoin ethereum install bitcoin иконка проверить bitcoin бутерин ethereum
dark bitcoin bitcoin node wmz bitcoin генераторы bitcoin x bitcoin сигналы bitcoin Tokens, cryptocurrencies, and other types of digital assets that are not bitcoin are collectively known as alternative cryptocurrencies, typically shortened to 'altcoins' or 'alt coins'. Paul Vigna of The Wall Street Journal also described altcoins as 'alternative versions of bitcoin' given its role as the model protocol for altcoin designers. The term is commonly used to describe coins and tokens created after bitcoin. The list of such cryptocurrencies can be found in the List of cryptocurrencies article.bitcoin antminer qtminer ethereum 5Anonymous tradingThe goods cannot be transported easily, unlike our modern currency, which fits in a wallet or is stored on a mobile phone.The assumption is that bitcoins must be sold immediately to cover operating expenses. If the shopkeeper's back-end expenses were transacted in bitcoins as well, then the exchange rate would be irrelevant. Larger adoption of Bitcoin would make prices sticky. Future volatility is expected to decrease, as the size and depth of the market grows.king bitcoin котировка bitcoin up bitcoin бесплатные bitcoin bitcoin миллионеры ethereum calc bitcoin список ethereum usd sec bitcoin
bitcoin compare bitcoin математика ethereum картинки windows bitcoin bitcoin register аналитика ethereum monero github
monero cpu store bitcoin
kupit bitcoin видеокарта bitcoin рулетка bitcoin
bitcoin protocol avatrade bitcoin electrum bitcoin bitcoin review polkadot su
bitcoin dice dogecoin bitcoin форк bitcoin clicker bitcoin часы bitcoin ethereum ios ethereum картинки bitcoin paper ethereum капитализация
заработка bitcoin bitcoin tor bitcoin evolution падение ethereum ethereum ann system bitcoin ethereum block bear bitcoin курс bitcoin bitcoin steam
The Ledger Nano S is the first generation hardware wallet introduced by Ledger. One of the first hardware wallets ever made, it followed shortly after the first generation of the Trezor. Like its successor, the Nano S is compatible with thousands of cryptocurrencies. The Nano S does not come with a USB type-C cable, so users with more modern smartphones may have trouble connecting to their devices.bitcoin icon surf bitcoin 1080 ethereum auto bitcoin ethereum course up bitcoin bitcoin split bitcoin reindex
tether кошелек bitcoin mempool bitcoin стратегия проекта ethereum ethereum russia прогнозы ethereum надежность bitcoin bitcoin серфинг escrow bitcoin moon ethereum ads bitcoin icon bitcoin ethereum краны
reverse tether email bitcoin neo cryptocurrency пул ethereum bitcoin криптовалюта bitcoin like bitcoin alliance bitcoin xt monero пулы bitcoin значок bitcoin рубли
ethereum api bitcoin автосерфинг bitcoin онлайн cold bitcoin кошелька bitcoin bitcoin converter боты bitcoin зарабатывать bitcoin cryptocurrency calendar 2016 bitcoin casper ethereum bitcoin scripting waves cryptocurrency bitcoin stealer amazon bitcoin For hundreds of years, gold has dominated the safe-haven asset arena, while bitcoin was launched just over a decade ago and has only achieved widespread recognition in the last few years. Below, we'll compare these two investment options head-to-head:луна bitcoin bitcoinwisdom ethereum
