Difference between revisions of "The Internet Computer for Computer Scientists"

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The reason for using a replicated state machine, rather than just a single state machine,
 
The reason for using a replicated state machine, rather than just a single state machine,
is to achieve [[wikipedia:fault tolerance]].
+
is to achieve [[wikipedia:fault tolerance|fault tolerance]].

Revision as of 15:20, 5 October 2021

To a first approximation, the IC (Internet Computer) is a network of replicated state machines.

Each replicated state machine comprises a subnet of replicas. Subnets may communicate with one another, but otherwise they operate (for the most part) independently of each other.

As in any replicated state machine, a series of transaction requests is processed. A transaction request may come from either an external client or from another state machine in the IC. The replicas in a subnet must run a consensus protocol to order the incoming transaction requests, so that each replica processes the transaction requests in the same order. Each replica processes the transaction requests in the agreed-upon order. In processing a transaction request, each replica will update its internal state according to a deterministic function that maps the pair (current state, transaction request) to a new state. Because all replicas in a subnet process transaction requests in the same order, their internal states will evolve over time in exactly the same way. In response to processing a transaction, a subnet may also generate an outgoing message, which can be sent to either an external client or to another state machine in the IC.

The reason for using a replicated state machine, rather than just a single state machine, is to achieve fault tolerance.