Ethereum’s co-founder Vitalik Buterin has revealed the ethereum 2.0 roadmap has changed considerably to the point eth1 will no longer be a shard in the new Proof of Stake (PoS) blockchain.
Instead, eth1 will be merged into the beacon chain itself, something that means effectively base sharding is now out of the picture, and with it base scalability too. Buterin says:
“Eth1 transactions will live directly on the beacon chain instead of being in a shard and… “phase 2″ (native sharded execution) is de-emphasized for the time being.”
That means the new execution engine, eWASM, is out of the picture too, with the ethereum roadmap now basically being staking but without base scaling. Danny Ryan, the ethereum 2.0 coordinator, says:
“If we move forward with just one execution chain (eth1), then a native integration into the beacon chain as a first class citizen provides the highest security, immediately native access to the sharded data commitments, and much reduced consensus complexity. It is a very elegant design, and is being actively prototyped today (might even see a beacon chain merge testnet soon!).”
Basically they couldn’t do parallelization and thus they seem to have given up scaling the base layer, but Buterin says “we are not making any irreversible moves that prevent us adding native sharded execution in the future.”
How to reconcile that statement with putting eth1 in the beacon itself – the coordinator – is not clear, but what seems a bit clear is that ethereum is basically going the way of bitcoin: little substantial changes where base layer is concerned and full reliance on second layer methods.
One difference here may well be that data sharding is being promised in eth, but that appears to be of use for just these second layers.
The problem with second layers is interoperability as they need to be treated like being the base layer itself, something difficult to bootstrap as they generally have their own tradeoffs.