Longword

A longword is a piece of computer data, 32 bits long, which can count up to 130 years' worth of seconds.

Every Macintosh made includes such a longword. The start of the longword can be seen if the system underwent a serious crash or if the battery dies -- completely -- when the system boots normally once more.

Early Macs had the longword start on January 1, 1904. (1900 was not selected because it was a century year.) More recent Macs have the longword start somewhere in the 1970s.

The last day for Macs using the earlier longword is February 6, 2030; for newer Macs, it is around the switchover to the 22nd century.