Building BIOS Architecture

25. Building Boot Philosophy

Building Boot is the controlled process through which the Building BIOS establishes a trusted, verified, and operational representation of the building after initial installation, shutdown, power restoration, software restart, hardware replacement, or recovery.

A building does not boot in the same manner as a single computer. Many physical systems may remain mechanically, structurally, hydraulically, electrically, or locally operational while the BIOS is unavailable. The boot process shall therefore determine which physical conditions already exist before it authorizes digital coordination or higher-level control.

The BIOS shall never assume that the physical building remained unchanged during its downtime. It shall compare the last approved configuration with the currently observed configuration.

Building Boot shall proceed from the lowest-trust condition toward progressively higher levels of authorization:

BIOS hardware integrity;

BIOS software integrity;

persistent storage integrity;

essential service availability;

network and communication availability;

component and Interface discovery;

identity verification;

topology reconstruction;

configuration validation;

state reconciliation;

service commissioning;

operational authorization.

The boot process shall distinguish between:

first boot of a new building;

normal restart;

restart after power failure;

restart after configuration change;

restart after BIOS update;

restart after hardware migration;

recovery boot;

emergency restart;

partial zone restart.

Boot completion shall not require every optional component to be available. It shall require all components and services necessary for the selected building operating mode.

The BIOS shall support partial and degraded operation when noncritical systems are unavailable, provided that dependencies, restrictions, and safety requirements are satisfied.