On Unified Actor-Data Systems

Unified Actor-Data Systems (UADS) introduce a computational model where all entities are message-responsive elements that constitute a recursive composition structure. This framework dissolves the artificial boundary between computation and information, creating a unified foundation for reasoning about distributed systems. While the actor model (Hewitt, 1973) provides a theory of concurrent computation and capability-based security (Miller, 2006) offers access control principles, UADS synthesizes these approaches into a coherent system with explicit data relationships and structural consistency.

A UADS is formally defined as a tuple (E, M, C) where E represents the set of message-responsive elements, M defines the message protocols, and C captures the compositional relationships. The system maintains two fundamental invariants: message-response coherence (∀e∈E, ∀m∈M, R(e,m) is well-defined) and compositional consistency (∀c∈C, the composed behavior preserves the individual element behaviors).

The framework integrates four fundamental principles:

Universal Message Interface: Every element in the system—whether traditionally viewed as computation or data—presents a uniform interface for message handling. This eliminates the conceptual duplication inherent in treating information and computation as fundamentally different entities. Data becomes active rather than passive, mediating its own access patterns through message responses.

Recursive Composition: Elements may contain internal systems of elements, creating a fractal structure where complexity is managed through encapsulation rather than through new primitives. This reflects the mathematical principle that recursive composition of simple elements can express arbitrary complexity without introducing fundamental new constructs.

Explicit Reference: Relationships between elements are expressed as message channels with capability-based access control. This ensures that dependency relationships are explicit and analyzable, while preserving the essential flexibility of dynamic reconfiguration through capability transfer.

Asymmetric Protocol Definition: Message protocol ownership follows from communication pattern—in one-to-many relationships, senders define the protocol; in other relationships, protocols emerge through the order of expected operation. This natural asymmetry mirrors information flow in physical systems, where broadcasters typically define protocols rather than receivers.

The UADS model provides several key advantages over traditional actor systems:

  1. Static analyzability of data dependencies while preserving dynamic reconfiguration capabilities
  2. Elimination of conceptual duplication between data and computation
  3. Consistent physics of computation across all system levels
  4. Natural expression of recursive compositional patterns

Current limitations include the computational complexity of static analysis in highly interconnected UADS graphs and the challenge of defining appropriate abstractions for commonly used message patterns.

Future work will focus on developing algebraic laws for UADS transformation, formal verification methodologies for system properties, and efficient implementation strategies that preserve the theoretical guarantees while providing practical performance.

Keywords: actor model, information theory, process calculus, capability-based security, recursive composition, distributed systems, message-passing semantics

Notes:

  • Verification methods: Static dependency analysis, capability flow tracking, compositional correctness proofs
  • Implementation considerations: Message dispatch optimization, capability representation, recursive containment efficiency
  • Primary applications: Distributed systems with explicit information flow requirements, formally verifiable evolving architectures