Difference between Hard fork and Soft fork ?

[maplelake]

Let 's simplify concept of Fork.
1. Forks means new node adopt new protocol and old node does not know it. As a result nodes cannot make a
    agreement/consensus about data chain as before.
2. Hard Fork means, the new protocol is not compatible with old ones. The new node reject old node's txs/block.
    Old node also thinks data from new node is illegal.
3. Soft Fork means, the new protocol is compatible with old ones. New node reject old node's data. But old node
    accepts new node's data.

Whatever Hard or soft forks, during the deployment of new version node, fork happens inevitable. while the difference is that ... during this time, Soft fork looks better as "old node also accepts new-node's data'.

And whatever hard or soft forks, if deployment is finished(might be over half 50% node upgrade it) , the bitcoin network could make consensus again and everything works well.

Is it right ?

[DaCryptoRaccoon]

You are basically correct.

 A simple way to look at hard / soft fork is a Hard fork is a required upgrade users MUST port in the event of a hard fork any clients who do not update would no longer be part of the system.

Soft fork is allows a user to decided to upgrade or not they will still be in participation only with possibly outdated software.

Here is a good read about Hard / Soft forks.

https://medium.com/@lightcoin/the-differences-between-a-hard-fork-a-soft-fork-and-a-chain-split-and-what-they-mean-for-the-769273f358c9

[pooya87]

And whatever hard or soft forks, if deployment is finished(might be over half 50% node upgrade it) , the bitcoin network could make consensus again and everything works well.

consensus must be reached before the fork no matter if it is a hard fork or a soft fork otherwise the fork will lead to a chain split that could severely damage the entire system.
in a soft fork there is no immediate need for nodes to upgrade to new version due to their forward compatibility.

[RHavar]

consensus must be reached before the fork no matter if it is a hard fork or a soft fork otherwise the fork will lead to a chain split that could severely damage the entire system.

You don't really need consensus for a soft-fork, just the majority of the hash power and there won't be a chain split (pretty much by definition).

[pooya87]

consensus must be reached before the fork no matter if it is a hard fork or a soft fork otherwise the fork will lead to a chain split that could severely damage the entire system.

You don't really need consensus for a soft-fork, just the majority of the hash power and there won't be a chain split (pretty much by definition).

that's true but at the same time the main part of reaching consensus involves getting majority of hash power on board since bitcoin is still "proof of work"! so when i said "reach consensus" i mean the case where more than 95% of miners accept the change otherwise a chain split happens. conversely lack of consensus means not having majority of hashrate backing the change.

[charlie137]

More on "soft forks" https://en.bitcoin.it/wiki/BIP_0009 https://en.bitcoin.it/wiki/BIP_0034