> It stores these commands BEFORE any changes are made. Once the change is committed, the record is marked, indicating to the system that the change was already made. If the system fails, it can read the commands sequentially within the logs, starting from the one it left off on.

What happens if power is lost AFTER the change is made, but BEFORE the record is marked?

Interesting post but the format is broken on mobile devices. It cuts off sentences on the right.