Difference between revisions of "The Internet Computer for Computer Scientists"
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but otherwise they operate (for the most part) independently of each other. | but otherwise they operate (for the most part) independently of each other. | ||
− | As in any replicated state machine, a series of <b> | + | As in any replicated state machine, a series of <b>transaction requests</b> is processed. |
− | A transaction may come from either an external client | + | A transaction request may come from either an external client |
or from another state machine in the IC. | or from another state machine in the IC. | ||
The replicas in a subnet must run a [[wikipedia:Consensus_(computer_science)|consensus protocol]] to order the | The replicas in a subnet must run a [[wikipedia:Consensus_(computer_science)|consensus protocol]] to order the | ||
− | incoming | + | 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 <b>state</b> | ||
+ | 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 [[wikipedia:fault tolerance]]. |
Revision as of 15:19, 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 wikipedia:fault tolerance.