Ethereum Client

Ethereum Client

⭐ 1. What Is an “Ethereum Client”?

Think of Ethereum not as “one software,” but as a protocol specification.

✔ Ethereum protocol = rules

• block format

• transaction format

• gas rules

• EVM instructions

• state trie

• consensus rules

• networking rules

• JSON-RPC

• log format

• storage model

The protocol is written in documents (Yellow Paper, EIP specs).

It is NOT code.

✔ A client = a real software implementation of those rules.

Clients are software programs that implement the Ethereum protocol.

Examples:

Client	Language
Geth	Go (most popular)
Nethermind	C#
Erigon	Go + Rust optimized
Besu	Java
Reth	Rust

Every Ethereum node you run is one of these clients.

---

⭐ 2. What Is GETH?

GETH = Go-Ethereum

• Written in Golang

• Developed by Ethereum Foundation

• Most widely used Ethereum client (~70% of nodes)

• Runs full EVM

• Executes tx, mines/verifies blocks

• Stores blockchain state

• Provides JSON-RPC endpoints

When you run:

geth --syncmode=full

You are running the Ethereum blockchain, fully syncing the chain.

---

⭐ 3. What Does It Mean “BSC Forked Geth”?

This is VERY important.

“Fork” here means:

Binance downloaded the source code of Geth →
Modified the code →
Launched their own blockchain using that codebase.

They DID NOT modify Ethereum protocol by proposing a fork.
They simply copied Ethereum’s node software and changed parts of it.

Exactly like:

• You fork a GitHub repo

• You modify the code

• You deploy your own version

That’s what BSC is.

---

⭐ 4. WHAT EXACTLY DID BSC CHANGE IN GETH?

They changed:

✔ A. Consensus architecture

Ethereum (now) uses Proof of Stake
Ethereum (before 2022) used Proof of Work

BSC introduced Proof-of-Staked-Authority (PoSA)

Meaning:

• Only 21 validators

• Validators selected through staking

• Faster block times

• Partially centralized

To implement PoSA, they modified:

• validator selection logic

• block sealing logic

• difficulty rules

• gossip rules

• block signature rules

• slashing rules

---

✔ B. Block time

Ethereum block time: 12–15 seconds
BSC block time: 3 seconds

They changed parameters:

params.BlockInterval = 3 * time.Second

---

✔ C. Gas limits

Ethereum gas limit ~30M gas
BSC increased throughput so block gas limit ~100M+

Modified:

params.GasLimitBoundDivisor
params.BlockGasLimit

---

✔ D. Reward mechanism

Ethereum PoW or PoS reward structure
BSC pays validator rewards using BNB
Implemented in code in:

consensus/posavoting/...

---

✔ E. Genesis File

They created their own genesis block:

• new chain ID

• new initial accounts

• pre-mined BNB

• network ID

• initial validators

Example (simplified):

{
  "config": {
    "chainId": 56,
    "homesteadBlock": 0,
    "eip150Block": 0,
    ...
  },
  "alloc": {
    "0xvalidator1...": { "balance": "1000000000000000" },
    ...
  }
}

---

⭐ 5. WHAT DID BSC NOT CHANGE?

They did NOT change:

• EVM bytecode

• Solidity language

• ABI format

• Logs/events format

• Transaction format

• Address format

• JSON-RPC API

Meaning:

💡 A contract compiled for Ethereum runs 100% same on BSC
💡 Tools like Hardhat, MetaMask, ethers.js work identically
💡 A smart contract port requires zero code changes

This is why BSC became huge so fast — no new ecosystem learning required.

---

⭐ 6. Why Forking Geth Makes BSC “Ethereum-Compatible”

Because:

✔ Geth includes the entire EVM
✔ Geth includes the JSON-RPC API
✔ Geth includes the transaction and block validation logic
✔ Geth includes storage trie logic
✔ Geth includes gas rules

So BSC inherited:

• Deploy contract in Solidity

• Call contract with Web3/ethers.js

• Logs decoded by same ABI

• Transactions signed in same way

• Same address format (0x...)

All Ethereum tools work without modification.

---

⭐ 7. HOW BLOCK PRODUCTION WORKS ON BSC (Compared to Ethereum)

Ethereum (PoS):

• Thousands of validators

• Random leader selection

• High decentralization

• Slower finality (~12 sec)

BSC (PoSA):

• 21 validators only

• Selected by Binance stakers

• Very centralized

• Very fast (3 sec)

Because they rewrote consensus inside Geth.

---

⭐ 8. So What Is BSC Technically?

BSC is:

Ethereum Go client (Geth)

• Modified consensus (PoSA)

• Modified block parameters (faster, cheaper)

• Different validator set

• Different genesis state
  = “Ethereum-compatible blockchain optimized for speed & low fees”

It is a fork, meaning:

• Same codebase

• Modified behavior

• Different network

• Same developer interface

---

⭐ 9. Why Developers Love BSC?

Because they can:

✔ Deploy same Solidity smart contracts

✔ Use same libraries (OpenZeppelin)

✔ Use same tools (Hardhat, Remix, Truffle)

✔ Use MetaMask directly

✔ Pay cheap gas fees

And it works exactly like Ethereum.

---

⭐ FINAL SUMMARY (SUPER CLEAR)

✔ Ethereum = protocol + many clients (Geth, Besu, Nethermind, Erigon)

✔ Geth = Go client implementing EVM + RPC + state + consensus

✔ BSC forked Geth:

• copied its code

• swapped Ethereum consensus → PoSA

• changed parameters

• created new chain ID

• kept EVM exactly same

✔ Result:

BSC is a cheap, fast, centralized Ethereum copy
with full EVM compatibility.

This is why people say:

“BSC is an Ethereum fork.”

It literally is.