Message Passing and Channel-Based Coordination¶

Instead of sharing memory and synchronizing access, processes communicate by sending messages through channels. This inverts the coordination model: "Don't communicate by sharing memory; share memory by communicating." Synchronization is implicit in message exchange.

Tension Addressed¶

Explicit vs. Implicit Coordination, Isolation vs. Performance

Recognizable As¶

Channels, mailboxes, message queues between concurrent entities. CSP-style: blocking send/receive creates synchronization points. Actor-style: async mailboxes with no shared state. Both avoid locks on shared data.

Canonical Sources¶

Hoare, "Communicating Sequential Processes" (1978, 1985); Hewitt, Bishop, & Steiger, "A Universal Modular ACTOR Formalism" (1973)

Transfers To¶

Distributed systems (network is inherently message-based), microservices, event-driven architecture

Sub-concepts: - CSP (Communicating Sequential Processes): Synchronous channel-based communication where sender and receiver rendezvous. - Actor Model: Asynchronous message passing to isolated actors with private state and a mailbox.