In many APIs, a failed TAS simply returns false (0). However, the message tells you the test condition failed—not that the set was impossible due to hardware error. This distinction is crucial:
“Correct behavior observed: atomic test-and-set returned false on equality check, meaning the block had been modified since the expected value was read. The operation correctly aborted without updating, preserving consistency.” In many APIs, a failed TAS simply returns false (0)
When the OS asks, "Is this zero?" the drive lies and says "Yes" (because it forgot it wrote something else). Then the atomic compare fails. In many APIs
: Hosts may lose access to shared storage or report it as "offline". preserving consistency.” When the OS asks