Running a node is the first real step of independence: the ledger sits on your machine, and from then on what the project says matters less than what you can read.

Three kinds of node, not to be confused — each asks for a different level of trust and carries a different risk.

Kind of node	What it does	Needs	Door status
Full node	Holds and serves the ledger, does not sign	One machine, one command, no keys, no tokens, nobody's permission	AJAR — the guide is public, the configuration bundle is still inside the unopened repository
Archive node	Holds the entire history from the first block	As above, plus disk and sync time	AJAR — the same door as a full node
Validator	Signs blocks, is accountable for consensus	A signing key, a stake, and acceptance into the consensus set	CLOSED — the project has not invited outsiders into the signing set

Diagram

flowchart TB M["Your machine"] --> S["Sync from a public p2p endpoint"] S --> A{"The distinguishing check:<br/>can you read the FIRST block?"} A -->|"yes"| R["A genuine archive copy"] A -.->|"no"| F["Only a copy taken from midway"] R --> Q["Answer any question about the ledger<br/>without asking anyone"]

Figure 27 — A one-question test for whether your node holds the whole history or only its tail.

The most useful test when raising a node. A node that syncs quickly is not necessarily a node holding the full history: some sync methods copy only recent state and continue from there. The cheapest way to tell is to ask it for the first block: if it can be read, and that block's time matches what the network declares, it is a genuine archive copy. If it cannot, you are holding the tail of the ledger rather than the ledger.

Why this page does not copy commands. Commands and parameters change with each release. The original is kept by the technical team at 9chain.org/docs, under Run your own node — that is the correct version, and if it differs from this page, this page is wrong.

Where the door is stuck, stated plainly. The very first command of that guide tells you to copy a configuration directory that lives in a repository that is not public. That means the "run a node" door and the "open the code" door are really one door: however open a guide is, it is no more open than the repository holding what it tells you to copy. So the honest measure of this door is not "has a guide been published" but "can a stranger, with only what is public, actually raise a node".

A full node does not make the network more decentralised. It makes you more independent — a different thing. The network's fault tolerance is decided by its signing set, and its countable threshold is in The 9Chain platform: no machine may hold a third or more of the signers.

In short: your node cannot save the network, but it saves you from having to trust the network — and that is the whole reason open infrastructure must make raising a node boringly easy.