Building BIOS Architecture

The Power-On Self-Test, or POST, verifies that the BIOS platform can safely perform its foundational functions.

POST shall evaluate, as applicable:

processor operation;

volatile memory;

persistent storage availability;

storage integrity;

hardware security module;

cryptographic functions;

real-time clock;

watchdog;

local display or service interface;

network interfaces;

backup power;

environmental sensors;

redundant BIOS communication;

recovery image availability.

POST shall distinguish among:

passed;

passed with advisory;

degraded but bootable;

recovery required;

boot prohibited.

A failed optional communication interface may permit degraded operation if an alternative authorized path exists. Failure of the root of trust, authoritative configuration storage, or required integrity checks shall prevent normal boot.

POST shall not claim to test the complete physical building. It verifies the BIOS platform and only those connected building functions for which defined startup tests exist.

Extended self-tests may be scheduled after essential BIOS availability is established. These may include:

network reachability;

Cartridge communication;

redundant-path tests;

storage consistency;

backup verification;

selected sensor validation;

safety-system status exchange.

Self-test results shall include:

test identity;

tested component;

method;

result;

measured values;

applicable threshold;

timestamp;

BIOS version;