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.
ethereum programming комиссия bitcoin blacktrail bitcoin flex bitcoin bitcoin biz развод bitcoin bitcoin биткоин bitcoin alpari ubuntu ethereum polkadot su car bitcoin bitcoin video адрес bitcoin ethereum игра bitcoin проблемы monero hardware 100 bitcoin mastering bitcoin asrock bitcoin bitcoin тинькофф падение ethereum purchase bitcoin программа ethereum
ethereum создатель
сервисы bitcoin bitcoin billionaire ethereum claymore tether перевод stellar cryptocurrency cryptocurrency calendar акции ethereum cardano cryptocurrency tether майнинг ethereum рубль
ethereum code magic bitcoin tether перевод
bitcoin cny ethereum icon mindgate bitcoin bitcoin proxy ethereum cryptocurrency p2pool bitcoin monero fork bitcoin nodes oil bitcoin
ethereum прогнозы Ethereum is relatively new in the cryptocurrency world, having launched in 2015. It operates in a similar way to the bitcoin network, allowing people to send and receive tokens representing value via an open network. The tokens are called ether, and this is what is used as payment on the network. Ethereum’s primary use, however, is to operate as smart contracts rather than as a form of payment. Smart contracts are scripts of code which can be deployed in the ethereum blockchain. The limit on ether also works slightly differently to bitcoin. Issuance is capped at 18 million ether per year which equals 25% of the initial supply. So, while the absolute issuance is fixed, relative inflation decreases every year. Learn more about ethereumказахстан bitcoin платформу ethereum теханализ bitcoin love bitcoin vector bitcoin bitcoin block bitcoin network ethereum txid nanopool ethereum bitcoin сигналы bitcoin goldmine cryptocurrency bitcoin
mastering bitcoin adc bitcoin bitcoin server excel bitcoin bitcoin алгоритм monero 1070 win bitcoin алгоритм bitcoin all bitcoin ethereum gas online bitcoin monero algorithm платформы ethereum
love bitcoin ethereum покупка bitcoin ann by bitcoin асик ethereum bitcoin antminer проект ethereum bitcoin coin forbot bitcoin android tether bitcoin roulette сайт bitcoin bitcoin сервера widget bitcoin кликер bitcoin best cryptocurrency 50 bitcoin bitcoin flapper bitcoin 2048 blockstream bitcoin bitcoin путин blitz bitcoin mikrotik bitcoin ферма bitcoin pool bitcoin
ethereum mine bitcoin rotator bitcoin tm
bitcoin кошелек новости bitcoin bitcoin fields bitcoin earning gif bitcoin 1070 ethereum coinmarketcap bitcoin ethereum видеокарты bitcoin dark joker bitcoin
rx560 monero purchase bitcoin transaction bitcoin bitcoin hyip metal bitcoin algorithm bitcoin bitcoin блоки 2016 bitcoin bitcoin froggy bitcoin account
masternode bitcoin bitcoin capitalization ethereum faucets
bitcoin vip
bitcoin ledger bitcoin wordpress bitcoin скачать rpg bitcoin avto bitcoin
se*****256k1 ethereum zebra bitcoin
торги bitcoin bitcoin unlimited super bitcoin bitcoin оборудование solo bitcoin ethereum метрополис ethereum статистика форки ethereum
ethereum цена greenaddress bitcoin bitcoin etherium
programming bitcoin скачать tether принимаем bitcoin bitcoin sberbank bitcoin сатоши bitcoin loan bitcoin рейтинг bitcoin frog Monero is based on the CryptoNote protocol, which deploys one-time ring signatures as the core cryptographic primitive to provide anonymity. Ring Confidential Transactions (RingCTs), a variant of linkable ring signatures, were implemented on 10 January 2017. RingCTs have two components. The first is Multilayered Linkable Spontaneous Anonymous Group (MLSAG) ring signatures, which obfuscate the sender of a transaction. The second is Confidential Transactions (CTs), which use the Pedersen commitment to hide transaction amounts.bitcoin symbol tether перевод Anyone who wants to make a profit through cryptocurrency mining has the choice to either go solo with their own dedicated devices or to join a mining pool where multiple miners and their devices combine to enhance their hashing output. For example, attaching six mining devices that each offers 335 megahashes per second (MH/s) can generate a cumulative 2 gigahashes of mining power, thereby leading to faster processing of the hash function.bitcoin картинки ● Durability: Bitcoins are durable and do not degrade over time.Malaysiafreeman bitcoin tor bitcoin bitcoin traffic bitcoin flapper node bitcoin ethereum casino платформе ethereum bitcoin фильм bitcoin currency cryptocurrency trading bitcoin mining тинькофф bitcoin bitcoin monkey ethereum покупка bitcoin greenaddress фонд ethereum fork ethereum invest bitcoin
бесплатно bitcoin bitcoin hacker stats ethereum bitcoin billionaire monero address bitcointalk monero land bitcoin bitcoin doubler bitcoin greenaddress Ripple planned to release a maximum of 1 billion XRP tokens each month as governed by an in-built smart contract; the current circulation is over 50 billion.13 16 Any unused portion of the XRP in a particular month will be shifted back to an escrow account.16On 21 November 2017, the Tether cryptocurrency announced they were hacked, losing $31 million in USDT from their primary wallet. The company has 'tagged' the stolen currency, hoping to 'lock' them in the hacker's wallet (making them unspendable). Tether indicates that it is building a new core for its primary wallet in response to the attack in order to prevent the stolen coins from being used.planet bitcoin This year, Facebook was forced to apologize for selling its users’ personal data.bitcoin 99 cryptocurrency exchanges скачать tether tinkoff bitcoin ethereum supernova удвоитель bitcoin ethereum токены avto bitcoin reddit cryptocurrency bitcoin монеты
bitcoin home cgminer bitcoin bitcoin gif bitcoin конвертер bitcoin weekend
coindesk bitcoin txid bitcoin trade cryptocurrency bitcoin galaxy китай bitcoin
monero ico депозит bitcoin
cryptocurrency charts dog bitcoin
bitcoin vip
opencart bitcoin explorer ethereum
collector bitcoin easy bitcoin bitcoin billionaire ethereum gas CRYPTObitcoin генератор bitcoin central bitcoin брокеры биржа monero jax bitcoin bitcoin map платформы ethereum bitcoin abc bitcoin ne monero fork blogspot bitcoin minergate ethereum segwit2x bitcoin erc20 ethereum collector bitcoin ethereum calc цены bitcoin bitcoin paypal купить monero bitcoin crush monero кошелек bitcoin официальный контракты ethereum chvrches tether bitcoin tor
вывести bitcoin 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.bitcoin gold bitcoin phoenix
bitcoin создать cryptonator ethereum bitcoin earnings genesis bitcoin
bitcoin hesaplama bitcoin games cryptocurrency calendar bitcoin youtube создать bitcoin bitcoin mixer 1070 ethereum bitcoin капитализация робот bitcoin icons bitcoin
bitcoin metatrader bitcoin flapper difficulty monero
bitcoin fund казино ethereum майнинга bitcoin ethereum контракт bitcoin usd tether android форки ethereum проект bitcoin bitcoin book bitcoin бумажник bitcoin надежность bitcoin 99 bitcoin это
bitcoin markets заработать monero блок bitcoin bitcoin rub bitcoin xapo up bitcoin bitcoin зарегистрировать pow bitcoin bitcoin analysis bitcoin индекс bitcoin 33 q bitcoin se*****256k1 bitcoin nxt cryptocurrency bitcoin cranes теханализ bitcoin kurs bitcoin bitcoin 99 mine ethereum tether android monero форум bitcoin покупка ютуб bitcoin bitcoin calculator plus bitcoin и bitcoin bitcoin раздача bitcoin 2020 bitcoin кэш bitcoin pools
bitcoin arbitrage калькулятор bitcoin monero fr bitcoin бесплатно poloniex monero кликер bitcoin bitcoin api your bitcoin bitcoin blocks bitcoin euro bitcoin рубль ethereum blockchain blogspot bitcoin casascius bitcoin chvrches tether bitcoin litecoin loco bitcoin bitcoin farm clicker bitcoin bitcoin apk
bitcoin курс polkadot блог bitcoin qiwi bitcoin vpn
wikipedia ethereum раздача bitcoin dark bitcoin вход bitcoin wallet cryptocurrency fake bitcoin takara bitcoin
ConclusionShareчто bitcoin 'what happens when a blockchain diverges into two potential paths forward'keystore ethereum blitz bitcoin кран ethereum bitcoin config tether coin график ethereum bitcoin indonesia ethereum ubuntu bitcoin bcc monero xmr проект bitcoin Bitcoin created something unique: digital property.bitcoin прогнозы tether coin консультации bitcoin (An infrastructure cost yes, but no transaction cost.) The blockchain is a simple yet ingenious way of passing information from A to B in a fully automated and safe manner. One party to a transaction initiates the process by creating a block. This block is verified by thousands, perhaps millions of computers distributed around the net. The verified block is added to a chain, which is stored across the net, creating not just a unique record, but a unique record with a unique history. Falsifying a single record would mean falsifying the entire chain in millions of instances. That is virtually impossible. Bitcoin uses this model for monetary transactions, but it can be deployed in many other ways.server bitcoin blogspot bitcoin bitcoin box кошель bitcoin
bitcoin center monero free
бесплатный bitcoin
bitcoin sign
торрент bitcoin client bitcoin курс ethereum продам bitcoin bitcoin crane bitcoin описание ethereum contracts pk tether site bitcoin coingecko ethereum bitcoin динамика service bitcoin bitcoin bcc bitcoin обозначение pos bitcoin bitcoin cli location bitcoin падение ethereum bitcoin 10 ethereum bonus payza bitcoin parity ethereum bitcoin asics bitcoin linux trading cryptocurrency
bitcoin journal новости monero карты bitcoin майнер monero bitcoin rt кости bitcoin fasterclick bitcoin bitcoin bio bitcoin card bitcoin чат bitcoin spinner курс ethereum locate bitcoin bitcoin swiss заработай bitcoin bitcoin rotator bitcoin coins bitcoin payment bitcoin телефон bitcoin hacker bitcoin pay bitcoin multisig bitcoin uk ethereum продать monero usd bitcoin timer security bitcoin
проверить bitcoin партнерка bitcoin asus bitcoin ccminer monero вывод monero bitcoin me
вложения bitcoin
мастернода ethereum
monero client платформ ethereum carding bitcoin оплатить bitcoin equihash bitcoin golang bitcoin cudaminer bitcoin
wikipedia ethereum миксер bitcoin 22 bitcoin ethereum ios daemon monero bitcoin kran 600 bitcoin обмен ethereum conference bitcoin bitcoin obmen kinolix bitcoin ethereum swarm зарабатывать bitcoin сервисы bitcoin up bitcoin bitcoin продажа bitcoin icons rate bitcoin bitcoin goldman bitcoin 2048 daemon bitcoin konvert bitcoin monero обменять bitcoin бесплатно ann ethereum инвестирование bitcoin программа tether прогноз bitcoin bitcoin cgminer stock bitcoin технология bitcoin bitcoin 123 bitcoin captcha token bitcoin
foto bitcoin bitcoin get
bitcoin unlimited abi ethereum trading bitcoin bitcoin buying keys bitcoin bitcoin пирамиды добыча bitcoin bitcoin значок bitcoin changer ethereum web3 bitcoin cryptocurrency bitcoin miner bitcoin перевод продам bitcoin cold bitcoin получение bitcoin global bitcoin bit bitcoin tether пополнение bitcoin автосерфинг maps bitcoin mac bitcoin отдам bitcoin bitcoin png bitcoin capital bitcoin store майнить bitcoin bitcoin farm 2016 bitcoin wallets cryptocurrency bitcoin airbit total cryptocurrency bitcoin bit chvrches tether local ethereum bitcoin heist ethereum course carding bitcoin ethereum buy bitcoin пополнить payoneer bitcoin
monero pools bitcoin calc
bitcoin sberbank bitcoin fan rocket bitcoin bitcoin asic bitcoin icon bitcoin boxbit ethereum котировки ethereum кран etoro bitcoin monero криптовалюта win bitcoin monero rur daemon monero bitcoin биткоин monero client
bitcoin котировка ethereum investing topfan bitcoin
bitcoin check antminer bitcoin ethereum dark bitcoin like
ethereum btc отследить bitcoin bitcoin free total cryptocurrency geth ethereum баланс bitcoin currency bitcoin group bitcoin bitcoin cards
auction bitcoin email bitcoin развод bitcoin nem cryptocurrency
super bitcoin криптовалюту bitcoin bitcoin кошелька bitcoin безопасность bitcoin получить fire bitcoin
ethereum упал bitcoin автомат bitcoin paw magic bitcoin bitcoin scanner roulette bitcoin bitcoin map ethereum wallet автокран bitcoin ютуб bitcoin fx bitcoin monero difficulty bitcoin скачать ethereum core Because bitcoin mining is essentially guesswork, arriving at the right answer before another miner has almost everything to do with how fast your computer can produce hashes. Just a decade ago, bitcoin mining could be performed competitively on normal desktop computers. Over time, however, miners realized that graphics cards commonly used for video games were more effective and they began to dominate the game. In 2013, bitcoin miners started to use computers designed specifically for mining cryptocurrency as efficiently as possible, called Application-Specific Integrated Circuits (ASIC). These can run from several hundred dollars to tens of thousands but their efficiency in mining Bitcoin is superior.99 bitcoin Often, bitcoin’s transaction ledger is thought of as a public blockchain that lives somewhere in the cloud like a digital public square where all transactions are aggregated. However, there is no central source of truth; there are no oracles and there is no central public blockchain to which everyone independently commits transactions. Instead, every participant within the network constructs and maintains its own independent version of the blockchain based on a common set of rules; no one trusts anyone and everyone validates everything. Everyone is able to come to the same version of the truth without having to trust any other party. This is core to how bitcoin solves the problem of removing third-party intermediaries from a digital cash system.monero кошелек
карты bitcoin ACCESS TO CAPITAL IN A DEFLATIONARY WORLDasic ethereum bitcoin withdraw настройка monero bitcoin страна партнерка bitcoin jax bitcoin raspberry bitcoin
bitcoin mmgp antminer bitcoin
global bitcoin bitcoin mail keystore ethereum куплю ethereum bitcoin sportsbook lealana bitcoin скачать bitcoin monero gpu
bitcoin etf ethereum core зарегистрировать bitcoin блок bitcoin ethereum exchange розыгрыш bitcoin decred ethereum bitcoin обучение autobot bitcoin local bitcoin bitcoin daily bitcoin автоматически cudaminer bitcoin bitcoin fund bitcoin минфин
master bitcoin bonus bitcoin bitcoin wmx вклады bitcoin ethereum эфириум монета ethereum bitcoin обучение bitcointalk ethereum получить bitcoin mainer bitcoin daemon monero bitcoin вирус bitcoin кэш wifi tether динамика ethereum georgia bitcoin bitcoin review bitcoin 2x bitcoin talk reddit cryptocurrency
