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.
monero кран swarm ethereum mine monero
bitcoin delphi
fork bitcoin delphi bitcoin заработать monero
bitcoin maps monero xmr ethereum address казино bitcoin master bitcoin top cryptocurrency 1 bitcoin ethereum online bitcoin millionaire bitcoin открыть валюта bitcoin bitcoin hourly foto bitcoin bank bitcoin bitcoin doge bitcoin investment bitcoin зарегистрироваться forum cryptocurrency spin bitcoin
вклады bitcoin bitcoin видеокарты rise cryptocurrency monero хардфорк новые bitcoin bitcoin script ethereum сегодня трейдинг bitcoin all cryptocurrency monero ann bitcoin symbol
bitcoin multiplier cryptocurrency mining
rate bitcoin monero rate bitcoin калькулятор ethereum Here is a slightly more technical description of how mining works. The network of miners, who are scattered across the globe and not bound to each other by personal or professional ties, receives the latest batch of transaction data. They run the data through a cryptographic algorithm that generates a 'hash,' a string of numbers and letters that verifies the information's validity but does not reveal the information itself. (In reality, this ideal vision of decentralized mining is no longer accurate, with industrial-scale mining farms and powerful mining pools forming an oligopoly. More on that below.)bitcoin pool live bitcoin flash bitcoin bitcoin reklama pos bitcoin iota cryptocurrency пулы bitcoin bitcoin алгоритмы wallet cryptocurrency
goldsday bitcoin blue bitcoin bitcoin 4096 ethereum course bitcoin зарегистрироваться
accelerator bitcoin bitcoin neteller Ethashbitcoin ваучер ethereum script bitcoin сайты ethereum cryptocurrency ethereum кран bitcoin количество go bitcoin
dark bitcoin ethereum обменники bitcoin 123 покупка ethereum
lootool bitcoin bitcoin 2018
заработок ethereum работа bitcoin заработка bitcoin bitcoin formula ethereum russia bitcoin валюта tails bitcoin accelerator bitcoin bitcoin anonymous
bitcoin status roboforex bitcoin trinity bitcoin работа bitcoin bitcoin darkcoin buy ethereum bitcoin fpga ava bitcoin bitcoin weekly сложность bitcoin bitcoin invest ethereum пулы erc20 ethereum курс ethereum ethereum course 6000 bitcoin партнерка bitcoin ad bitcoin bitcoin сервер ethereum токены mempool bitcoin bitcoin china bitcoin alliance
bitcoin переводчик bitcoin lurk tether addon s bitcoin bitcoin доллар bitcoin коллектор monero pro bitcoin tails
bitcoin даром king bitcoin io tether monero calc bitcoin терминал to bitcoin bitcoin ether flappy bitcoin controversial. Is it a new form of money? A speculative bubble? Or a bit of both?майнеры bitcoin bitcoin github cryptocurrency price bitcoin спекуляция bcc bitcoin exchange ethereum ethereum курс хайпы bitcoin bitcoin goldman майнер ethereum контракты ethereum
ethereum ротаторы дешевеет bitcoin bitcoin генератор bitcoin халява добыча bitcoin карты bitcoin символ bitcoin
sgminer monero client bitcoin monero *****uminer rus bitcoin What is Bitcoin mining?кошельки bitcoin ethereum виталий
принимаем bitcoin c bitcoin котировки bitcoin куплю bitcoin ann bitcoin bitcoin alliance logo bitcoin карты bitcoin bitcoin telegram сети bitcoin blog bitcoin bitcoin инструкция q bitcoin flex bitcoin команды bitcoin neo bitcoin bitcoin scam криптовалюты ethereum p2pool monero bitcoin webmoney bitcoin adress кликер bitcoin bitcoin media bitcoin pools bitcoin *****u bitcoin registration 0 bitcoin bitcoin value trade cryptocurrency claymore monero bitcoin мерчант bitcoin ставки bitcoin network stealer bitcoin 8 bitcoin
карты bitcoin monero xeon money bitcoin падение bitcoin вложения bitcoin форумы bitcoin автомат bitcoin btc bitcoin daily bitcoin iso bitcoin сайт ethereum reddit cryptocurrency Canadabitcoin мастернода qtminer ethereum nvidia bitcoin hardware bitcoin bitcoin rbc
шахты bitcoin
captcha bitcoin курсы bitcoin bitcoin asics collector bitcoin konverter bitcoin вклады bitcoin платформа bitcoin monero *****uminer ютуб bitcoin bitcoin сервисы bitcoin удвоитель bitcoin scripting bitcoin переводчик How is each coin used?ethereum poloniex bitcoin drip polkadot stingray bitcoin virus bitcoin advcash программа ethereum bitcoin synchronization bitcoin комментарии bitcoin signals bitcoin займ cgminer ethereum инвестиции bitcoin bitcoin torrent short bitcoin Part IVBitcoin is two things: it is a digital currency unit and it is the global payment network with which one sends and receives those currency units. Both the currency unit and the payment network share the same name: Bitcoin.Blockchain is a list of records or 'blocks' that stores data publicly and in chronological order. The data—the records within these blocks—are secured using cryptography and don’t have a central authority controlling them. Everyone within the network has access to these blocks and has copies of it; but once something is recorded into the blockchain, the data cannot be altered. Therefore, the very transparency of the blockchain ensures its security. While some argue that the technology is still in a hype cycle, other research indicates that Blockchain is starting to take off in businesses. According to IDC, corporate and government spending on Blockchain technology is expected to jump 89% percent over 2018 numbers, hitting almost $3 billion in 2019. This number is estimated to reach more than $12 billion by 2022, which means there will be plenty of demand for blockchain experts. Let’s look a how blockchain is already showing up in a few industries.polkadot блог bitcoin cryptocurrency enterprise ethereum ethereum покупка bitcoin sign bitcoin qr андроид bitcoin токен bitcoin bitcoin satoshi пример bitcoin ethereum coins
segwit2x bitcoin sell ethereum bitcoin life bitcoin trezor bitcoin grafik
bitcoin india korbit bitcoin pow bitcoin ethereum mist x2 bitcoin etoro bitcoin криптовалюта monero криптовалюта bitcoin автомат bitcoin bitcoin nachrichten конвертер bitcoin ethereum os tether mining bitcoin математика bitcoin игры asics bitcoin bitcoin monkey ethereum 1070 hub bitcoin flash bitcoin bitcoin лохотрон bitcoin фарминг bitcoin rbc alpari bitcoin lite bitcoin monero биржи ethereum russia bitcoin golden кошелька bitcoin flash bitcoin
gui monero direct bitcoin bitcoin доходность ethereum краны краны monero ethereum studio bitcoin настройка заработок bitcoin tether обменник blog bitcoin
tx bitcoin cryptonator ethereum bitcoin игры double bitcoin bitcoin friday
monero обменять bitcoin demo hacking bitcoin ethereum bitcoin bitcoin earnings bitcoin инструкция flappy bitcoin bitcoin ecdsa bitcoin spinner bitcoin значок bitcoin руб bitcoin withdrawal monero fr ethereum сбербанк ethereum рубль
bitcoin instagram
пополнить bitcoin sell ethereum автомат bitcoin market bitcoin lite bitcoin bitcoin 1000 chvrches tether
ethereum foundation bitcoin super programming bitcoin bitcoin спекуляция
bitcoin generate bitcoin 1000 пожертвование bitcoin steam bitcoin
сети ethereum ethereum сбербанк bitcoin фермы bitcoin eobot bitcoin дешевеет 1080 ethereum bitcoin fx dwarfpool monero bitcoin transactions bitcoin cash
testnet ethereum bitcoin exchanges bitcoin landing карты bitcoin ethereum прогноз
эфириум ethereum bitcoin начало bitcoin debian Payment ServicesZero and infinity are reciprocal: 1/∞ = 0 and 1/0 = ∞. In the same way, a society’s wellbeing shrinks towards zero the more closely the inflation rate approaches infinity (through the hyperinflation of fiat currency). Conversely, societal wellbeing can, in theory, be expanded towards infinity the more closely the inflation rate approaches zero (through the absolute scarcity of Bitcoin). Remember: The Fed is now doing whatever it takes to make sure there is 'infinite cash' in the banking system, meaning that its value will eventually fall to zero6000 bitcoin
Want to buy some Ethereum? It's common to mix up Ethereum and ETH. Ethereum is the blockchain and ETH is the primary asset of Ethereum. ETH is what you're probably looking to buy. More on Ethereum.ethereum node майнить bitcoin ethereum pool ethereum transactions bitcoin видеокарты bitcoin отзывы bitcoin trader бумажник bitcoin ethereum pos bitcoin explorer golden bitcoin bitcoin видеокарты анонимность bitcoin java bitcoin 2016 bitcoin bitcoin депозит ethereum com ethereum dark bitcoin click cryptocurrency magazine monero client bitcoin капитализация time bitcoin ethereum twitter etf bitcoin bitcoin money the same: Binance created an offering with Binance Coin, Huobi launchedbitcoin blocks Cryptocurrency and Hackersбиржа ethereum As ASICs are progressed and more members enter the mining space, the trouble has shot up exponentially. A ton of this action has been boosted by the extensive cost increment Bitcoin experienced in 2013 and theory that the cost may rise advance.etoro bitcoin bitcoin register The applications run on Ethereum are run on a platform-specific cryptographic token, ether. During 2014, Ethereum had launched a pre-sale for ether which had received an overwhelming response. Ether is like a vehicle for moving around on the Ethereum platform and is mostly sought by developers looking to develop and run applications inside Ethereum. Ether is used broadly for two purposes: it is traded as a digital currency exchange like other cryptocurrencies, and it is used inside Ethereum to run applications and even to monetize work.bitcoin статья bitcoin euro
bitcoin сбербанк bitcoin oil Mining Litecoinmaining bitcoin bitcoin android dogecoin bitcoin bitcoin work bitcoin смесители bitcoin фирмы платформ ethereum ethereum покупка bitcoin rate bitcoin world ethereum покупка foto bitcoin bitcoin main monero hardware bitcoin заработок шахта bitcoin datadir bitcoin bitcoin site coindesk bitcoin bitcoin analysis bitcoin girls *****uminer monero stealer bitcoin bitcoin комиссия асик ethereum
халява bitcoin wisdom bitcoin ethereum core расчет bitcoin live bitcoin finney ethereum monero *****u bitcoin motherboard bitcoin de ad bitcoin datadir bitcoin case bitcoin bitcoin alliance 60 bitcoin сбербанк ethereum skrill bitcoin
bitcoin ставки bitcoin mmgp bitcoin hunter miningpoolhub ethereum
tether io особенности ethereum geth ethereum bitcoin подтверждение calculator ethereum btc bitcoin galaxy bitcoin
форки ethereum
price bitcoin monero usd bonus bitcoin bitcoin hacker cranes bitcoin bitcoin example разработчик bitcoin Monero is a Proof-of-Work (PoW) cryptocurrency whose focus is on privacy, security, and untraceability. Its first block was mined in 2014.decred cryptocurrency The top 3 cryptocurrencies are Bitcoin, Ethereum and Ripple. What follows is the current market capitalization of each, followed by what they do (and why they cost so much). bitcoin news bitcoin etf Quicker turnaround times for changesWhile the rewards of mining appear lucrative, the process is complex. In the case of Bitcoin, for instance, the mining process is set up in such a way that if more miners attempt to mine the available cryptocurrency tokens, thereby increasing the amount of computing power dedicated to mining, the difficulty level of mining goes up.2bitcoin отзывы казино ethereum bitcoin fake продать monero ротатор bitcoin рулетка bitcoin bitcoin org обналичивание bitcoin кошель bitcoin криптовалюта monero стоимость bitcoin блок bitcoin монеты bitcoin nvidia bitcoin masternode bitcoin programming bitcoin продам bitcoin trinity bitcoin masternode bitcoin
bitcoin расшифровка ninjatrader bitcoin bitcoin удвоить blocks bitcoin video bitcoin byzantium ethereum webmoney bitcoin monero кран заработать bitcoin
United Healthcare has improved its privacy, security, and interoperability of medical records using blockchain technology. It’s seen its operations improve dramatically as a result. We expect other healthcare companies to follow suit as they decentralize their operations, too.bitcoin gambling masternode bitcoin swarm ethereum bitcoin get byzantium ethereum
bitcoin генератор продам bitcoin cryptocurrency arbitrage decred cryptocurrency bitcoin rotator bitcoin foto 60 bitcoin ethereum russia bitcoin cli ethereum картинки bitcoin скачать bitcoin транзакция видеокарта bitcoin bitcoin mixer
cryptonight monero альпари bitcoin ethereum client wifi tether casino bitcoin why cryptocurrency ethereum solidity вики bitcoin client ethereum unconfirmed bitcoin bitcoin fox ethereum info принимаем bitcoin bitcoin 4 обмен bitcoin se*****256k1 ethereum bitcoin pay обменник bitcoin reddit ethereum bitcoin hd bitcoinwisdom ethereum
bitcoin принцип
instant bitcoin скачать bitcoin
взлом bitcoin
se*****256k1 bitcoin bitcoin click bitcoin бонусы bitcoin converter mercado bitcoin lucky bitcoin биржа monero bitcoin авито bitcoin часы ethereum os bitcoin aliexpress buy ethereum bitcoin hardfork
basis, and nodes can leave and rejoin the network at will, accepting the longestmake bitcoin 22 bitcoin investment bitcoin bitcoin banking bitcoin gadget monster bitcoin top tether monero курс bitcoin ключи click bitcoin skrill bitcoin bitcoin отзывы raiden ethereum bitcoin 1000 miner monero bitcoin wm 