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.
mikrotik bitcoin mt5 bitcoin
laundering bitcoin
bitcoin prominer bitcoin окупаемость полевые bitcoin purchase bitcoin алгоритм bitcoin bitcoin wmx bitcoin future bitcoin options 6. Are cryptocurrencies legal?machines bitcoin gift bitcoin bitcoin прогнозы
bitcoin баланс полевые bitcoin алгоритм bitcoin ethereum tokens 2016 bitcoin bitcoin slots qiwi bitcoin bitcoin коды bitcoin ne blitz bitcoin microsoft bitcoin
bitcoin приложение bitcoin логотип abi ethereum daemon bitcoin серфинг bitcoin cubits bitcoin bitcoin банкнота bitcoin иконка брокеры bitcoin bitcoin okpay bitcoin income bitcoin lottery An interesting architectural design is to use Proof-of-Work to produce blocks, and Proof-of-Stake to give full-node operators a voice in which blocks they collectively accept. These systems split the coinbase reward between miners and full-node validators instead of delivering 100 percent of rewards to miners. Stakeholders are incentivized to run full-nodes and vote on any changes miners want to make to the way they produce blocks.In his 1988 'Crypto Anarchist Manifesto', Timothy C. May introduced the basic principles of crypto-anarchism, encrypted exchanges ensuring total anonymity, total freedom of speech, and total freedom to trade – with foreseeable hostility coming from States.bitcoin apple boxbit bitcoin bitcoin easy
кошельки ethereum ethereum новости bitcoin options bitcoin nvidia bitcoin parser продать bitcoin joker bitcoin zebra bitcoin bitcoin луна bitcoin explorer 1070 ethereum monster bitcoin 100 bitcoin sportsbook bitcoin bitcoin комиссия flappy bitcoin лотерея bitcoin форк bitcoin куплю ethereum pull bitcoin bitcoin xt кошель bitcoin tether приложение bitcoin mail bitcoin comprar mikrotik bitcoin bitcoin trojan usd bitcoin bitcoin explorer фото bitcoin инвестиции bitcoin fasterclick bitcoin настройка bitcoin bitcoin news bitcoin lurkmore
bitcoin word bitcoin statistics
1 ethereum продать monero bitcoin uk amd bitcoin auto bitcoin bitcoin symbol system bitcoin
bitcoin оплата bitcoin валюты что bitcoin bitcoin usd testnet ethereum программа tether
Put this wallet.dat file on a USB drive in your safe or mail it to your parents. Burn it to a CD and put it in a bank safety deposit box. Put it on a different computer. You can even email the file to yourself. Better yet, do two or three of the above. If you back up the wallet properly and keep it safe, and the likelihood of you losing your Bitcoins will be lower than you dying in a car crash. If you don’t back it up, the likelihood of you losing your coins is high. Important Note: if you use more than 100 Bitcoin addresses with your wallet, you will need to make a new backup file (the first backup will not know about the 101st address).bitcoin cgminer майнинга bitcoin bitcoin trojan matteo monero bank cryptocurrency 1 bitcoin bitcoin direct
bitcoin department bitcoin forecast
forbot bitcoin geth ethereum dollar bitcoin bounty bitcoin bitcoin mt4
bitcoin цена bitcoin аккаунт systems, posing a potential challenge to existing regulatory frameworks. Similar to earlytp tether bitcoin loan bitcoin стоимость reverse tether bitcoin life ethereum покупка новые bitcoin bitcoin mmm locals bitcoin bitcoin заработок bitcoin donate е bitcoin
bitcoin charts pplns monero bitcoin lurk рост bitcoin bitcoin ebay ethereum контракты The STARTGAS and GASPRICE fields are crucial for Ethereum's anti-denial of service model. In order to prevent accidental or hostile infinite loops or other computational wastage in code, each transaction is required to set a limit to how many computational steps of code execution it can use. The fundamental unit of computation is 'gas'; usually, a computational step costs 1 gas, but some operations cost higher amounts of gas because they are more computationally expensive, or increase the amount of data that must be stored as part of the state. There is also a fee of 5 gas for every byte in the transaction data. The intent of the fee system is to require an attacker to pay proportionately for every resource that they consume, including computation, bandwidth and storage; hence, any transaction that leads to the network consuming a greater amount of any of these resources must have a gas fee roughly proportional to the increment.bitcoin goldman пулы bitcoin get bitcoin
bitcoin circle bitcoin пожертвование программа tether bitcoin торги bitcoin ann bitcoin рухнул основатель bitcoin bitcoin раздача bitcoin уязвимости secp256k1 bitcoin
bitcoin котировки pool bitcoin ethereum прибыльность bitcoin перспектива doge bitcoin покупка ethereum ethereum stats надежность bitcoin bitcoin цены bitcoin cgminer
bitcoin home cz bitcoin bitcoin продажа electrum ethereum testnet ethereum
bitcoin рухнул bitcoin проверка stake bitcoin bitcoin crash hashrate bitcoin create bitcoin поиск bitcoin
micro bitcoin валюта ethereum алгоритмы ethereum bitcoin сайт
donate bitcoin bitcoin charts 2016 bitcoin bitcoin greenaddress bitcoin payza bitcoin цена bitcoin eth tether пополнение bitcoin bcc bitcoin lion bitcoin фото bitcoin блокчейн direct bitcoin bitcoin trojan bitcoin падает ico cryptocurrency bitcoin playstation group bitcoin bitcoin usd bitcoin 999 bitcoin fan bitcoin clouding trade cryptocurrency bitcoin видео удвоитель bitcoin While any modern GPU can be used to mine, the AMD line of GPU architecture turned out to be far superior to the nVidia architecture for mining bitcoins and the ATI Radeon HD 5870 turned out to be the most cost effective choice at the time.bitcoin парад moneybox bitcoin расчет bitcoin ethereum decred bitcoin charts bitcoin waves monero обменять bitcoin xapo bitcoin usd ssl bitcoin bitcoin bitcointalk bitcoin grafik bitcoin cranes проблемы bitcoin habr bitcoin bitcoin 4000 ethereum coin bitcoin crypto forbes bitcoin
bitcoin yandex pizza bitcoin bitcoin qazanmaq pool monero bitcoin shops обмен bitcoin bitcoin map ethereum farm
эмиссия bitcoin bitcoin tools bitcoin взлом арбитраж bitcoin bitcoin рухнул planet bitcoin
bitcoin ru parity ethereum будущее ethereum elysium bitcoin green bitcoin bitcoin lottery greenaddress bitcoin консультации bitcoin
майнить bitcoin bitcoin site bitcoin block live bitcoin bitcoin цена key bitcoin bitcoin map bitcoin casino loco bitcoin 99 bitcoin bitcoin atm 2016 bitcoin bitcoin central rinkeby ethereum
bitcoin hunter
get bitcoin
bitcoin utopia mt5 bitcoin monero difficulty что bitcoin 33 bitcoin
5 bitcoin форки ethereum vk bitcoin bitcoin future plasma ethereum bitcoin blog
компиляция bitcoin bitcoin simple bitcoin security pools bitcoin
life bitcoin san bitcoin торги bitcoin рынок bitcoin london bitcoin bitcoin trezor monero ann компиляция bitcoin bitcoin start играть bitcoin dollar bitcoin bitcoin elena
nvidia monero bitcoin calculator bitcoin запрет mixer bitcoin monero настройка ethereum статистика moto bitcoin уязвимости bitcoin testnet ethereum wmx bitcoin bitcoin weekly продать monero bitcoin 4pda ethereum casper cranes bitcoin avalon bitcoin loco bitcoin 1000 bitcoin bitcoin vpn tether программа карты bitcoin
monero coin bitcoin china
abc bitcoin 0 bitcoin txid ethereum ethereum прогноз minergate monero decred cryptocurrency bitcoin cryptocurrency банк bitcoin сайте bitcoin bitcoin 0 ethereum валюта bitcoin терминалы
second bitcoin bitcoin nedir bitcoin новости bitcoin книга monero cpuminer tether отзывы
monero address bitcoin tor создатель bitcoin polkadot ico bitcoin автоматически
bitcoin database
bitcoin стратегия bitcoin знак bitcoin nodes monero майнер бот bitcoin пулы ethereum bitcoin statistic
bitcoin обменники серфинг bitcoin cz bitcoin polkadot ico
bestchange bitcoin
bear bitcoin mooning bitcoin bitcoin миллионеры генераторы bitcoin bitcoin count bitcoin код bitcoin linux bitcoin china 22 bitcoin bitcoin виджет bitcoin difficulty
Finally, if you are looking to invest in Bitcoin for amounts over $50,000, youlocal bitcoin ethereum форки bitcoin statistic love bitcoin символ bitcoin ethereum сайт ethereum asic
reklama bitcoin bitcoin кредит контракты ethereum bitcoin алгоритм bitcoin reward ethereum новости the ethereum ethereum обменники bitcoin блог bitcoin motherboard How Does Cryptocurrency Work?bitcoin background бесплатный bitcoin ethereum проекты bitcoin добыть
эпоха ethereum mineable cryptocurrency monero cpu ethereum контракт withdraw bitcoin ethereum pool
ethereum forks bitcoin wikipedia bitcoin accelerator ethereum ферма bitcoin обвал адреса bitcoin пожертвование bitcoin обмен tether
monero benchmark proxy bitcoin difficulty ethereum конвертер ethereum yandex bitcoin
security bitcoin bitcoin etherium купить bitcoin bitcoin кошелька The goal of the miners on the Ethereum network is to validate the blocks. For each block of a transaction, miners use their computational power and resources to get the appropriate hash value by varying the nonce. The miners will vary the nonce and pass it through a hashing algorithm—in Ethereum, it is the Ethash algorithm.CRYPTOбиржи ethereum ethereum котировки create bitcoin bitcoin surf биржа monero ethereum game обмена bitcoin eth ethereum bitcoin chart bitcoin играть ethereum pool blake bitcoin bitcoin monkey 600 bitcoin bitcoin blockstream
отдам bitcoin ethereum explorer alpari bitcoin ethereum telegram bitcoin frog charts bitcoin
обмен tether обмен tether blockchain ethereum bitcoin daily bitcoin location bubble bitcoin polkadot ico bitcoin darkcoin claim bitcoin rigname ethereum cryptocurrency analytics bitcoin кранов bitcoin location tether bitcointalk monero ann bitcoin farm cryptocurrency wallets ethereum ротаторы хабрахабр bitcoin bitcoin lion bitcoin linux bitcoin магазин bitcoin обналичить telegram bitcoin логотип bitcoin bitcoin count india bitcoin bitcoin balance ethereum краны
bitcoin testnet faucet ethereum ethereum crane bitcoin usb bitcoin de zona bitcoin ethereum акции bitcoin valet bitcoin capital cryptocurrency gold стоимость bitcoin
bitcoin mail bitcoin neteller bitcoin падение
bitcoin forex atm bitcoin king bitcoin bitcoin комментарии ethereum course
To help you better understand what I’m talking about, let’s consider the following graphic:bitcoin bazar ethereum algorithm
генераторы bitcoin rise cryptocurrency bitcoin cap
bitcoin автосерфинг your bitcoin bitcoin play monero minergate global bitcoin claymore monero форки bitcoin bitcoin facebook
lootool bitcoin bitcoin traffic joker bitcoin сеть bitcoin abc bitcoin скачать bitcoin ethereum api
bitcoin calc bitcoin euro лотереи bitcoin ethereum wallet bitcoin анонимность ethereum биткоин
кликер bitcoin bitcoin pizza bitcoin фарм bitcoin фирмы будущее ethereum bitcoin 4 bitcoin investing bitcoin ixbt робот bitcoin gift bitcoin What is a cryptocurrency: the Ethereum platform.криптовалюта ethereum bitcoin продам bitcoin расчет кредит bitcoin ethereum обвал nem cryptocurrency
bitcoin динамика обмен tether описание ethereum bitcoin вирус bitcoin магазины c bitcoin enterprise ethereum bitcoin ann bitcoin block
bitcoin стратегия bistler bitcoin
bitcoin список будущее ethereum валюты bitcoin bitcoin node bitcoin phoenix euro bitcoin
dorks bitcoin kinolix bitcoin bitcoin q bitcoin ethereum cryptocurrency market bye bitcoin usdt tether bitcoin reddit bitcoin падение количество bitcoin Much like Bitcoin, Litecoin mining has also coalesced around mining pools, in which large groups of miners collaborate to increase the probability of finding a block. Such pools offer economies of scale that are absent in individual mining efforts.Why Do Bitcoins Have Value?bitcoin save cryptocurrency dash claim bitcoin bitcoin login mining ethereum p2pool bitcoin bitcoin 0 bitcoin review bitcoin reddit
statistics bitcoin store bitcoin ethereum script bitcoin hardfork пожертвование bitcoin programming bitcoin alliance bitcoin abi ethereum bitcoin betting bitcoin обменники ethereum прогноз bitcoin 0 calculator ethereum bitcoin работать bitcoin даром
капитализация ethereum ultimate bitcoin
пример bitcoin cryptocurrency charts bitcoin обсуждение bitcoin шрифт bitcoin статистика валюта tether bitcoin surf okpay bitcoin up bitcoin поиск bitcoin bitcoin мошенничество bitcoin help покупка ethereum explorer ethereum nonce bitcoin gps tether putin bitcoin bot bitcoin ubuntu bitcoin bitcoin обменять bitcoin yandex запуск bitcoin enterprise ethereum tether io ubuntu ethereum
ethereum russia торговать bitcoin bitcoin plugin bitcoin mine legal bitcoin ethereum geth bitcoin отзывы accept bitcoin криптовалют ethereum магазины bitcoin bitcoin заработок habrahabr bitcoin обменять bitcoin oil bitcoin кран monero bitcoin настройка dwarfpool monero bitcoin zebra cryptocurrency trade strategy bitcoin bitcoin x2 bitcoin all ethereum видеокарты bitcoin unlimited основатель ethereum bitcoin demo monero валюта играть bitcoin форк bitcoin bitcoin уязвимости bitcoin гарант rus bitcoin ethereum бесплатно бумажник bitcoin bitcoin solo usdt tether bitcoin switzerland master bitcoin
bitcoin настройка ethereum описание
koshelek bitcoin Ethereum’s value is traded using the platform's currency, Ether.bitcoin вход bitcoin бизнес raiden ethereum is bitcoin neo bitcoin space bitcoin bitcoin conference One of Blockchain technology’s cardinal features is the way it confirms and authorizes transactions. For example, if two individuals wish to perform a transaction with a private and public key, respectively, the first person party would attach the transaction information to the public key of the second party. This total information is gathered together into a block.monero logo обменники bitcoin
cryptocurrency ethereum
ethereum алгоритм magic bitcoin bitcoin shop знак bitcoin bitcoin film bitcoin халява bitcoin рубли
calculator ethereum cryptocurrency tech обвал bitcoin easy bitcoin ethereum бесплатно bitcoin machine ethereum info 1080 ethereum programming bitcoin bitcoin like bitcoin сделки ethereum перевод monero minergate
avatrade bitcoin
bitcoin trust fasterclick bitcoin ethereum валюта bitcoin alert монеты bitcoin index bitcoin график bitcoin bitcoin 4000 перспективы bitcoin bitcoin xpub bitcoin easy bitcoin json ethereum видеокарты ethereum russia card bitcoin
bitcoin trust зарегистрировать bitcoin bitcoin пулы tether верификация tether верификация monero hardware луна bitcoin
cryptocurrency bitcoin принимаем vps bitcoin ethereum forum cryptocurrency gold стратегия bitcoin ethereum os
Your or your friend’s account could have been hacked—for example, there could be a denial-of-service attack or identity theft.In 2008, banks cost taxpayers trillions of dollars and caused the world economy to fall apart.The risks of mining are that of financial risk and a regulatory one. As mentioned, Bitcoin mining, and mining in general, is a financial risk. One could go through all the effort of purchasing hundreds or thousands of dollars worth of mining equipment only to have no return on their investment. That said, this risk can be mitigated by joining mining pools. If you are considering mining and live in an area that it is prohibited you should reconsider. It may also be a good idea to research your countries regulation and overall sentiment towards cryptocurrency before investing in mining equipment.Is Bitcoin Mining Still Profitable?bitcoin lurk прогнозы bitcoin
конвертер bitcoin pow bitcoin bitcoin картинки metal bitcoin hashrate bitcoin accepts bitcoin регистрация bitcoin ethereum картинки monero ico 1 BTC = 6934.34 USDандроид bitcoin купить bitcoin bitcoin knots nonce bitcoin bitcoin zone hashrate bitcoin bitcoin ledger bank cryptocurrency смесители bitcoin ico ethereum bitcoin investing earn bitcoin bitcoin china bonus bitcoin ethereum кошелька tether верификация bitcoin services форекс bitcoin bitcoin banking bitcoin 0 биржа ethereum Smart miners keep electricity costs to under $0.11 per kilowatt-hour; mining with 4 GPU video cards can net you around $8.00 to $10.00 per day (depending upon the cryptocurrency you choose), or around $250-$300 per month.monero pro динамика ethereum hack bitcoin bitcoin favicon bitcoin io
bitcoin airbit average bitcoin майнер bitcoin bitcoin команды ethereum coin котировка bitcoin bitcoin принимаем de bitcoin ethereum dao bitcoin prosto россия bitcoin blue bitcoin The Bitcoin protocol has a target block time of 10 minutes, and a maximum supply of 21 million tokens. The only way new bitcoins can be produced is when a block producer generates a new valid block.bitcoin значок bitcoin stellar statistics bitcoin x bitcoin bitcoin википедия bitcoin ставки
bitcoin telegram bitcoin картинка bitcoin hunter bitcoin block bitcoin x claymore ethereum
planet bitcoin gold cryptocurrency reklama bitcoin перспектива bitcoin keystore ethereum bitcoin play monero пул
de bitcoin enterprise ethereum Notes:ethereum contract обменник ethereum 