Hi I need some one explain me how proof of work history I mean what was the problem and what the difference between PoW and RPOW

https://techcrunch.com/2021/05/14/solana-a-blockchain-platform-followed-by-top-crypto-investors-says-its-a-lot-faster-than-ethereum/

No threats detected at https://techcrunch.com/2021/05/14/solana-a-blockchain-platform-followed-by-top-crypto-investors-says-its-a-lot-faster-than-ethereum/‎.

check out solana docs as well