I learned about this from my Macintosh back in The Day™, when a dead Parameter RAM battery would reset the system date to January 1st, 1904 at every boot:
- https://spinsidemacintosh.neocities.org/im202#im033-001
> “The date and time setting is also copied at system startup from the clock chip into its own low-memory location. It’s stored as a number of seconds since midnight, January 1, 1904, and is updated every second. The maximum value, $FFFFFFFF, corresponds to 6:28:15 AM, February 6, 2040; after that, it wraps around to midnight, January 1, 1904.”
- https://archive.org/details/mac_Macworld_Mac_Secrets_5th_Edi...
- http://preserve.mactech.com/articles/develop/issue_26/minow....