THEMI-OS Formal Architecture & State Control

As brain–machine interfaces (BMIs) evolve from laboratory systems into wearable, semi-autonomous platforms supported by general-purpose computing devices, the absence of operating-system–level formalisms introduces critical safety and security risks. Conventional operating systems assume reproducible inputs, recoverable faults, and symmetrical trust between peripherals and hosts—assumptions that fail when neural signals are the primary input source. This paper presents THEMI-OS Formal Architecture & State Control, a formal operating system model governed by a deterministic finite-state machine (FSM) designed specifically for secure, non-invasive, energy-constrained BMI systems. The architecture enforces brain sovereignty, intent abstraction, asymmetric trust, and fail-silent behavior through explicit state transitions and irreversible terminal states. We define the system states, transition rules, safety invariants, and anomaly responses, and analyze the benefits and limitations of such a conservative design. This work contributes a verifiable, OS-level control framework intended for research, assistive, and ethically sensitive BMI deployments.