Ethereum hard forks

Ethereum, like Bitcoin, has undergone several hard forks, both planned and contentious, since its inception. Here’s an overview of some significant Ethereum hard forks:

DAO Hard Fork (July 2016):

Reason: Following the DAO (Decentralized Autonomous Organization) hack, where around 3.6 million ETH was stolen, the Ethereum community decided to revert the transactions that led to the theft through a hard fork.

Outcome: This resulted in two chains:

Ethereum (ETH): The new chain where the DAO funds were returned, and the protocol was updated.

Ethereum Classic (ETC): The original chain, which did not revert the hack, advocating for the principle of “code is law.”

 

Byzantium (October 2017):

Part of Metropolis: This was part of the Metropolis upgrade, introducing several Ethereum Improvement Proposals (EIPs) like EIP-140 for REVERT opcode, EIP-658 for reducing gas costs, and EIP-196 for precompiled contracts for modular exponentiation.

Purpose: Aimed at improving privacy, efficiency, and preparing the network for future scalability solutions.

 

Constantinople (February 2019):

Delay: Initially planned for late 2018 but delayed due to security concerns regarding one of the EIPs.

Changes: Included five EIPs focusing on reducing block reward from 3 ETH to 2 ETH, making the network more efficient and preparing for sharding.

 

Istanbul (December 2019):

EIPs: Implemented six EIPs, with a focus on improving privacy (like EIP-152 for BLAKE2 compression function) and preparing for Ethereum 2.0.

 

Muir Glacier (January 2020):

Purpose: A minor hard fork to delay the difficulty bomb (also known as the ice age) that would increase mining difficulty, which was initially set to encourage the transition to Proof of Stake.

 

Berlin (April 2021):

EIPs: Focused on gas cost optimizations and included EIP-2929 for reducing gas costs for certain operations, aiming to improve the efficiency of the network.

 

London (August 2021):

EIP-1559: Introduced a new fee market mechanism where a base fee is burned rather than given to miners, aiming to make transaction fees more predictable and potentially deflationary for ETH supply.

 

Arrow Glacier (December 2021):

Purpose: Similar to Muir Glacier, it further delayed the difficulty bomb to give more time for the Ethereum community to transition to Proof of Stake with Ethereum 2.0.

 

The Merge (September 2022):

Merge: Not a hard fork in the traditional sense, but the event where Ethereum transitioned from Proof of Work to Proof of Stake, effectively merging the Ethereum 1.0 chain with the Beacon Chain.

 

Ethereum’s hard forks have generally been about improving network performance, security, and preparing for scalability solutions. They reflect Ethereum’s ongoing development towards Ethereum 2.0, which promises significant upgrades in terms of scalability, security, and sustainability. Each hard fork has had its implications on the Ethereum ecosystem, from community consensus to changes in network economics.