Ethereum is a general purpose blockchain
Blockchains can be taught of as distributed state machine
Along with currency ownership keeps track of general purpose data storage
Ethereum can store code and data and the blockchain keeps track of how his data changes over time
The state changes are governed by the rules of consensus and is distributed
Ethereum runs on port 30303 and uses the DevP2P protocol
The state transitions are processed by the Ethereum Virtual Machine (EVM)
The transactions and system state is stored locally in Merkle Patricia Tree
Ethereum PoW algorithm is called Ethash
ETH and Gas Fees
Halting Problem: The path of a program cannot be determined without running it
Ethereum is Turing complete i.e. can run emulate other Turing Machines
Can create Smart Contracts that never terminate (infinite loop)
Ethereum uses a metering mechanism called gas
Gas determines the amount of computational work that has to be performed by a smart contract/ transaction
When creating the contract we specify the max gas that can be used
Gas is purchased using Ether (ETH) the currency used on Ethereum
Decentralized App (DApp)
DApp is an web application that uses the blockchain as its underlying infrastructure
Consists of smart contracts and web frontend interface
Can also contain P2P storage and P2P message protocols
Development Culture
Ethereum uses the “move fast and break things” philosophy
Because of this approach Ethereum evolves at a very fast rate
Backwards compatibility is not always preserved and could break out apps
Ethereum does not have a reference implement but has a reference specification
All Ethereum clients have to follow the specification