Unix billennium
The Unix billennium is the point in time represented by a Unix time value of 109: 01:46:40 UTC on September 9, 2001. Some programs which stored timestamps using a text representation encountered sorting errors, as in a text sort times after the turnover, starting with a "1" digit, erroneously sorted before earlier times starting with a "9" digit. Affected programs included the popular usenet reader KNode and e-mail client KMail, part of the KDE desktop environment. Such bugs were generally cosmetic in nature and quickly fixed once problems became apparent.
The problem also affected many 'Filtrix' document-format filters provided with Linux versions of WordPerfect; a patch was created by the user community to solve this problem, since Corel no longer sold or supported that version of the program.[1]
The Unix Billennium is sometimes described as "109 seconds after the Unix epoch". This is not quite correct, because Unix time is not a purely linear count of seconds: "109 non-leap seconds after the Unix epoch" would be a more accurate description[citation needed].
The name is a portmanteau of "billion" and "millennium", recalling the year 2000 bug. The name is not very logical as billennium should rather mean a billion years. "Gigasecond" would be a more apt term.