Hard fork meaning is a backward-incompatible software update. Typically, these occur when nodes add new rules in a way that conflicts with the rules of old nodes. New nodes can only communicate with others that operate the new version. As a result, the blockchain splits, creating two separate networks: one with the old rules, and one with the new rules. In this article we will be talking about forks, as well as the difference between hard forks and soft forks.
Who marks decisions in a blockchain network?
In Bitcoin, you could broadly make the distinction between three subsets of participants – developers, miners, and full node users. These are the parties that actually contribute to the network, and make decisions for how the network is run.
What is a fork?
A software fork occurs at a point where software is copied and modified. The original project lives on, but it is now distinct from the new one, which takes a different direction. Suppose that the team of your favourite cryptocurrency content website had a major disagreement with how to proceed. One part of the team might replicate the site on a different domain. But going forward, they would post different types of content than the original.
The projects build off a common ground and share a history. Just like a single road that later splits into two, there’s now a permanent divergence in their paths. In blockchain, there are two types of forks: hard forks and soft forks.
Hard forks
Hard fork meaning, as mentioned, is backward-incompatible software updates. When the network splits, there are now two networks running in parallel. They’ll both continue to propagate blocks and transactions, but they’re no longer working on the same blockchain. All nodes had an identical blockchain until the point of the fork (and that history remains), but they’ll have different blocks and transactions afterward.
An example of a hard fork was the 2017 fork that saw Bitcoin fragmented into two separate chains – the original one, Bitcoin (BTC), and a new one, Bitcoin Cash (BCH). The fork occurred after a lot of arguing over the best approach to scaling. Bitcoin Cash proponents wanted to increase the block size, while Bitcoin proponents opposed the change.
Soft Forks
Contrary to hard forks, a soft fork is a backward-compatible upgrade, meaning that the upgraded nodes can still communicate with the non-upgraded ones. What you typically see in a soft fork is the addition of a new rule that doesn’t clash with the older rules.
A good real-life example of a soft fork was the aforementioned Segregated Witness (SegWit) fork, which occurred shortly after the Bitcoin/Bitcoin Cash split. SegWit was an update that changed the format of blocks and transactions, but it was cleverly crafted. Old nodes could still validate blocks and transactions (the formatting didn’t break the rules), but they just wouldn’t understand them. Some fields are only readable when nodes switch to the newer software, which allows them to parse additional data.
In Conclusion
Hard fork meaning is a backward-incompatible software update that happens when nodes add new rules in a way that conflicts with the rules of the old nodes.
