We’re rewarding the question askers & reputations are being recalculated! Read more.
306

"Gas" is the name for a special unit used in Ethereum. It measures how much "work" an action or set of actions takes to perform: for example, to calculate one Keccak256 cryptographic hash it will take 30 gas each time a hash is calculated, plus a cost of 6 more gas for every 256 bits of data being hashed. Every operation that can be performed by a ...


114

DApp is an abbreviated form for decentralized application. A DApp has its backend code running on a decentralized peer-to-peer network. Contrast this with an app where the backend code is running on centralized servers. A DApp can have frontend code and user interfaces written in any language (just like an app) that can make calls to its backend. ...


49

Short: Gas is the execution fee for every operation made on ethereum. Its price is expressed in ether and it's decided by the miners, which can refuse to process transaction with less than a certain gas price. To get gas you simply need to add ether to your account. Long: Ethereum implements on the blockchain an execution environment called the Ethereum ...


44

The following response is taken from Ethereum, Gas, Fuel & Fees What is Gas? Gas is the metering unit for use of the Ethereum "World Computer". As an analogy, electricity is metered by kilowatt hours. Using more computation and storage in Ethereum means that more gas is used. One fundamental reason for metering is that it provides an incentive for ...


15

Your ideas for the first few fields are correct. The remainder are as follows: 0 Mgas/s - million gas processed/s 13399+ - unverified queue size 0 - verified queue size #2360201 - last imported block number 0/8/25 peers - number of active peers / number of known peers / configured maximum number of peers (this can be configured up to 50) 9 MiB db - ...


15

This is an External Owned Account, so your normal ethereum address, not a wallet contract. In general, there are two types of accounts: externally owned accounts, controlled by private keys, and contract accounts, controlled by their contract code. https://github.com/ethereum/wiki/wiki/White-Paper


14

A good Blog post by Vitalik Buterin goes through and the concept of a Dapp and other related concepts such as smart contract, Decentralised Autonomous Organisation, Decentraclised Corporation ect.. Here is the link with the Blog Post: DAOs, DACs, DAs and More: An Incomplete Terminology Guide


13

I usually avoid copy pasting info from docs, as many here do, but here I think its appropriate: Ethash uses a DAG (directed acyclic graph) for the proof of work algorithm, this is generated for each epoch, i.e every 30000 blocks (100 hours). The DAG takes a long time to generate. If clients only generate it on demand, you may see a long wait at each ...


12

Additional useful content on gas in Ethreum from: http://ethdocs.org/en/latest/ether.html#gas-and-ether Gas and ether Gas is supposed to be the constant cost of network resources/utilisation. You want the real cost of sending a transaction to always be the same, so you can’t really expect Gas to be issued, currencies in general are volatile. So instead, ...


10

Find below a definition of DApp written in this doc called "The General Theory of Decentralized Applications, Dapps". For an application to be considered a Dapp (pronounced Dee-app, similar to Email) it must meet the following criteria: The application must be completely open-source, it must operate autonomously, and with no entity controlling ...


10

The terms "Contract", "Smart Contract", and sometimes "DApp" are all often used interchangeably to describe the same thing. A "Contract" on Ethereum is a piece of code. This code is stored on the blockchain as bytecode and is immutable once created. A Contract has an address similar to the way that normal private key based accounts have a public address....


9

Subjectivity is the idea that there can be multiple potentially correct-looking versions of a particular blockchain ledger, and it's OK if a computer can't automatically choose between them. This is opposed to a blockchain where the correct ledger is knowable by looking at something objective like which chain has the most proof-of-work, or which has the most ...


9

From the Yellow Paper: Transaction: A piece of data, signed by an External Actor. It represents either a Message or a new Autonomous Object. Transactions are recorded into each block of the blockchain. This means that a transaction represents either a Message or a new contract. Message: Data (as a set of bytes) and Value (specified as Ether) that ...


9

It is certainly not a legal document. Put simply it is just a piece of code embedded to a blockchain that has its own address that is being executed every time transactions to this address arrive. You can think of it as a contract that has strict logic defined by a code and there is nothing in existence that could stop this code to be executed if somebody ...


8

Gas is basically the internal pricing for running a transaction or a contract. The gas price per transaction or contract is set up to deal with the Turing Complete nature of Ethereum and its EVM (Ethereum Virtual Machine Code) So, the more complex the transaction or the operation, the more gas it would cost.


8

Latest means the latest block that is already inside your own chain. All transactions contained within can be considered successfully executed. Security wise of course there can be reorgs, but in general they are executed transactions. Pending on the other hand is the collection of transactions that can be executed by the network (that your own node knows ...


7

A full node has the full blockchain downloaded and available. There are multiple pruning methods in clients that store different levels of the blockchain as well. Pruning Mode Differences A light node does not store the blockchain, but gets the parts it cares about from someone it trusts. Light Client Protocol Consensys Light Wallet To be a miner you ...


7

In order, from the most recent. July 20, 2016: Ethereum Classic does not contain the irregular state change in block 1920000 that transferred Ether to a WithdrawDAO recovery contract.


7

PoWhash is the proof-of-work hash. As you have assumed, you can see in the following ethminer log of a successfully mined block that the PoWhash string matches the first 7 characters of the Header-hash of the solution found: miner 04:35:37.957|ethminer Mining on PoWhash #1fe4f34a… : 62291643 H/s = 12582912 hashes / 0.202 s miner 04:35:38.160|ethminer ...


7

I searched the ethminer code for the string "Mining on PoWhash" and found it in libethereum/ethminer/MinerAux.h. Looking there I see this line: minelog << "Mining on PoWhash" << current.headerHash << ": " << mp; And a few lines above it: EthashProofOfWork::WorkPackage current; Based on those lines (and the way current is treated ...


6

https://en.wikipedia.org/wiki/Smart_contract http://szabo.best.vwh.net/smart_contracts_idea.html An Ethereum Contract is programming code (as data stored in the blockchain) that you send money (ether) at, which it can decide (through smart contract logic and blockchain consensus) to delay, send on money, call other contracts, modify it's storage, signal ...


6

There are a couple of differences between Bitcoin scripts and Ethereum smart contracts. USE BITCOIN In bitcoin the transaction have a different format from Ethereum: A transaction typically references previous transaction outputs as new transaction inputs and dedicates all input Bitcoin values to new outputs. So a transaction is formed by one or more ...


5

Dapp abbreviate as Decentralized Application used to Developed Applications using Front-end(HTML+CSS+JS) Web page + Back-end(Solidity Smart contract) Programming code + Server(TestRPC) Private Blockchain/Dummy Network in Ethereum platform


5

In a transaction receipt the fied topics correspond to your event arguments which are indexed in your smart contract. For all events you will find as first argument the hash of the event name, and then the data which are indexed in hexabytes. So in your case, in topics you will find 'topics':[hash_event_name,// w3.sha3(text='myEvent(uint256)').hex() where ...


5

This question is about the verb "to grief" rather than the noun "grief". The latter is presumably what lots of people are currently feeling due to the drop in cryptocurrency prices. The former, which is what you're asking about, is when someone uses a system in an unexpected way to create what other users of the system might call an attack. Such an attack ...


4

It is an Externally Owned Account controled by a public/private key pair. You'll find as well Contract accounts controlled by the inside code written in the contract.


4

The presale ran from 22nd of July 2014 to 2nd September 2014. This was before the general public launch of the network. For the first couple of weeks, 2000 ETH cost 1 BTC. Thereafter, your 1 BTC gradually got you fewer ETH. See: What was the approximate cost of 1 ETH during pre-launch (Aug 2014) The "presale wallet" was the keystore file loaded with the ...


4

Every node runs everything. Think of everything in the EVM, every contract and all their states, running in 1 virtual computer. The blocks don't contain the state, they're just the transactions that cause changes in the state. Every node then must simulate every transaction to generate the current state of the network.


3

The code itself for Ethereum (non-classic) was modified in such a way that at block 1920000 it moved the ether in all the child DAO's created from The DAO to a withdraw contract. The classic code was not modified. This had the effect of changing the affected accounts' balances on the non-classic fork. Resetting, for example, the balance of the Dark DAO to ...


3

Here's a direct description from the online documentation: https://wiki.parity.io/FAQ#what-does-paritys-command-line-output-mean


Only top voted, non community-wiki answers of a minimum length are eligible