Deep dive into Ractors in Ruby 3+: Architecture, communication, and thread-safety guarantees.

Ractors (Ruby Actors) provide true parallel execution by establishing completely isolated execution environments with independent GVLs, eliminating shared mutable state vulnerabilities.

Ractors implement an actor-model concurrency primitive. Unlike threads, which share standard object references freely, Ractors isolate memory almost entirely. Each Ractor has its own independent Global VM Lock. To maintain thread-safety without lock overhead, objects cannot be shared between Ractors unless they are deeply immutable (frozen) or passed explicitly via message-passing channels using copy or move semantics. Moving an object strips ownership from the sender Ractor, ensuring a memory address is never modified concurrently.