The development team at Cardano (ADA), a major DLT network for building decentralized applications or dApps, notes that the platform’s development has been conceived as “a journey involving five overlapping development themes, each of which is underpinned by a consensus protocol – Ouroboros.”
Kevin Hammond, a Scotland based Haskell programmer, states that as Cardano continues to evolve, the protocol needs to change as additional functionality and utility are added onto the platform. Updates will have to be made in a gradual manner, Hammond explains.
In the crypto-assets space, any major change made to the blockchain protocol is known as a hard fork (or backwards incompatible upgrade). On most blockchain or distributed ledger tech (DLT) networks, a hard fork is considered a “traumatic” event that “causes a – hopefully short – break in block production,” Hammond writes.
He adds that “in contrast, Cardano handles hard forks automatically, without stopping block production.” This allows for a “uniquely smooth” upgrade process that enables additional features – which are added “easily” and “evolve the platform’s capabilities,” Hammond claims.
Hammond explains that traditionally, whenever there’s a hard fork update, the existing protocol stops working or operating. All block producers (or transaction validators) upgrade to a newer version of the software which implements the updated block production rules and/or various other changes. After completing this step, the (block) chain history is deleted and block production starts up again, Hammond notes. He explains that “this means that a hard-forked chain will be different from the previous version, which can raise concerns over the integrity of the blockchain, or even lead to splits in the chain.”
Hammond points out:
“The way that Cardano implements protocol changes is completely different from the way other blockchains handle hard forks. Our goal has always been to make these changes as seamless as possible. To enable a smooth transition, Cardano automatically preserves the history of previous blocks. This allows the protocol to be upgraded without radical interference to the chain. The previous state does not vanish. Rather, it is extended to include new capabilities. Instead of splitting into two different chains, Cardano combines the original blocks that comply with the current block production rules with new blocks that comply with the new block production rules.”
Hammond claims that the Cardano team has “christened” the mechanism that performs this the hard-fork combinator “since it combines protocols without triggering interruptions or forcing a restart to Cardano.” He adds that the Byron to Shelley transition used this particular technique for the very first time. However, the main point here is that Byron’s (block) chain history didn’t just “disappear,” Hammond clarifies.
He goes on to note that Byron and Shelley chains “appear ‘as one’, where the Shelley blocks extend the chain that was produced in the Byron era.” He also mentioned that “shifting from Byron’s Byzantine Fault Tolerance consensus protocol (OBFT) to Shelley’s Ouroboros Praos did not require block production to be stopped or all the nodes to update simultaneously.” Nodes could “update independently,” Hammond explains.
As Cardano and Ouroboros continue to evolve, the hard fork combinator approach aims to ensure that Goguen, Basho, and Voltaire blocks will all reside in a single chain, Hammond added. He also mentioned that the features will be “added at each stage in successive hard forks.” He further noted that certain features might not require a hard fork (where the blockchain consensus protocol doesn’t change).
According to Hammond:
“IOHK’s … hard fork combinator has given Cardano a secure, smooth path to regular protocol updates – each bringing fresh value and utility to the network while minimizing disruption and risk.”
He confirmed that the team at IOHK is currently in the final stages of performing quality testing and will begin the testnet deployment process at some point this month, with “an expectation of moving to the mainnet around the middle of December.” During 2021, there will be more updates using the combinator (multi-asset support will be added) as the Cardano platform continues to focus on achieving its full potential, Hammond noted.
(Note: for more details on this update, check here.)