Serenity has a link to the existing PoW chain
Serenity has a link to the existing PoW chain, said Vitalik Buterin. Serenity would be aware of block hashes of the existing PoW chain, you’d be able to move ETH from the PoW chain to Serenity.
once Serenity is stable, then all of applications on the existing blockchain can be folded into a contract on one shard of an EVM interpreter written in EWASM.
phases are:
0 : beacon chain PoS
1 : shards as data chains
2 : state transitions (EWASM)
features are:
pure PoS consensus
synchronous confirmation : 8–16 seconds
economic finality : 10–20 minutes
VM execution via EWASM
1000x higher scalability
Buterin said:
beacon chain is full Proof of Stake. once that launches, the PoW miners' role will decrease, as will their reward. then the PoW chain is discarded. that will be in very long term.
beacon chain is not holding information. all you have is validators. these validators are running PoS algorithm. one confirmation in Beacon chain involves confirmation from thousands of validators so you’d be able to treat one confirmation as close to final.
beacon chain is a half-way between a testnet and a mainnet. it’s not quite a testnet because you’d be able to actually stake real ETH and earn real rewards on it. it’s not quite a mainnet because it does not have applications.
phase 1 is where sharding part turns on. it’s a simplified version that doesn’t do sharding of state, it does sharding of data. in phase 2, ETH can be moved across shards, enabling state transition and virtual machine.
https://www.trustnodes.com/2018/10/31/soon-serenity-begins-says-vitalik-buterin
https://www.cryptoglobe.com/latest/2018/11/vitalik-buterin-ethereum-2-0-serenity-with-its-promise-of-1000x-scalability-is-really-not-so-far-away/