BA-03 · LESSON 07

Fork history

A fork occurs when participants follow different histories or rule sets. Past disputes show how software rules, mining work, businesses, and individual validation interact.

55 min Difficulty 1/5 Not started

VISUAL MODEL

See the whole mechanism before going step by step

Use the diagrams to orient yourself. Then the guided explanation below teaches every part in depth.

4 explanatory views

CONCEPT-SPECIFIC MAP · state machineOne valid action transforms a known stateSelect any state to inspect its exact role.

RELATIONSHIP MAPOrdered mechanism flow

01
BEFOREKnown state
Identify the facts and objects that exist before the action.
02
ACTIONFork history
The Fork history lesson isolates the event that proposes a change.
03
RULEDeterministic check
The enforcing rule accepts or rejects the proposed transition.
04
AFTERSuccessor state
Accepted work creates a new state without silently changing the prior facts.
05
FAILUREState unchanged
A failed condition must not produce a partially accepted successor.

Rule shown: A valid transition names the prior state, action, enforcing rule, and successor state.

STAGE 1 OF 5BEFORE: Known state

Identify the facts and objects that exist before the action.

Governing relationship: A valid transition names the prior state, action, enforcing rule, and successor state. Complete path: 1. BEFORE, Known state. Identify the facts and objects that exist before the action. 2. ACTION, Fork history. The Fork history lesson isolates the event that proposes a change. 3. RULE, Deterministic check. The enforcing rule accepts or rejects the proposed transition. 4. AFTER, Successor state. Accepted work creates a new state without silently changing the prior facts. 5. FAILURE, State unchanged. A failed condition must not produce a partially accepted successor.

1. State transitionWhat exists, what changes, and what results

BEFORE

Old rules allow blocks up to condition set O. New rules accept only a strict subset N of O.

MECHANISM

Ask whether old and new nodes accept the same candidate blocks. Compatibility is defined by validation behavior, not by a project's chosen name.

AFTER

Compatibility classification describes rule sets; deployment outcome depends on participants and produced blocks.

Text equivalent: Starting from Old rules allow blocks up to condition set O. New rules accept only a strict subset N of O. The mechanism begins when Ask whether old and new nodes accept the same candidate blocks. Compatibility is defined by validation behavior, not by a project's chosen name. The resulting lesson is Compatibility classification describes rule sets; deployment outcome depends on participants and produced blocks.

2. Mechanism pathSelect a stage to inspect its job

STAGE 1 OF 5

Identify the rule difference

Ask whether old and new nodes accept the same candidate blocks. Compatibility is defined by validation behavior, not by a project's chosen name.

Complete path: 1. Identify the rule difference: Ask whether old and new nodes accept the same candidate blocks. Compatibility is defined by validation behavior, not by a project's chosen name. 2. Map deployment choices: Users and businesses choose software, miners choose templates and signaling, and exchanges choose market labels and settlement policies. 3. Observe chain production: Hash power affects which valid branch accumulates work, but each node first filters branches through its own rules. 4. Track economic coordination: Assets on divergent rule sets can trade separately. Wallets, exchanges, and replay protections affect whether users can safely control both. 5. Distinguish outcomes: A proposal may activate, fail, remain optional, or create a persistent split. Technical activation does not by itself determine long-run economic value.

3. Rule and failure boundaryWhat accepts the result and where it can stop

ACCEPTED PATH

Compatibility follows the old-node and upgraded-node validity sets; accumulated work is considered only after each node applies its own rules.

CHANGED CONDITION

Old nodes reject an expanded-validity block regardless of hash power, while equal-work competing blocks under identical rules are only a temporary chain fork.

Important distinction: A majority of hash power can force every node to accept any hard-fork rule. Miners can build a high-work chain, but nodes running incompatible rules reject its invalid blocks. Economic users decide which software and asset they value.

Text equivalent: The accepted path is enforced by Compatibility follows the old-node and upgraded-node validity sets; accumulated work is considered only after each node applies its own rules. If the required condition changes, Old nodes reject an expanded-validity block regardless of hash power, while equal-work competing blocks under identical rules are only a temporary chain fork.

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Learn the idea

A fork is a divergence in rules or block history. A soft fork tightens validity rules so upgraded nodes reject some blocks older nodes might accept. A hard fork permits blocks that old nodes reject. Chain splits can also occur temporarily when miners find competing blocks under the same rules. Replay means copying a transaction from one persistent branch to another where the same signatures and inputs are also valid; replay protection changes the rules or signed data so that copied transaction is not valid on both.

GUIDED EXPLANATION1/5 ideas inspected

Identify the rule difference

Ask whether old and new nodes accept the same candidate blocks. Compatibility is defined by validation behavior, not by a project's chosen name.

The worked example follows the explanation

Inspect every idea above to open it.

Important distinction“A majority of hash power can force every node to accept any hard-fork rule.”

Miners can build a high-work chain, but nodes running incompatible rules reject its invalid blocks. Economic users decide which software and asset they value.

FINISH LEARNING FIRST

The questions unlock after every required learning activity

Inspect every guided idea, open the worked example, rebuild its mechanism, and complete the deterministic lesson tool. Your progress is saved automatically.