# Summary
Ethereum is a universal blockchain. It achieves this by having a different bookkeeping model and relying on a
distributed state machine called the *EVM*.
* Ethereum is an implementation on top of *BADS*, also true of Bitcoin. 
* Ethereum works on a State model in comparison to Bitcoin’s *UTXO*
* Ethereum runs on EVMs which are state machines run by every node
* Smart Contracts are accounts controlled by code that execute when predetermined conditions are met
* Smart contracts, often coded in languages like Solidity, are broken down into bytecode which the EVM can actually understand.
* Ethereum Gas was introduced to prevent the halting problem and to measure and incentivize EVM processing
* Ethereum’s drawbacks have lead to the much anticipated update Ethereum 2.0 which promises large scalability and PoS