Most unix kernels measure time in seconds since
TheEpoch, usually the first moment of 1970 in GMT
As a
DateStamp, that is 19700101.000000000000000000000000000000000
Most Unix systems on the internet synchronize to the millisecond, although they may count many more subintervals -- a Gigahertz machine should know which nanosecond some interrupt happened.
ThirtytwoBitTime when treated as a
SignedInteger counting seconds since 19700101.000000 rolls over and becomes negative at 20380119.031408 resulting in a date early in the
TwentiethCentury 19011213.204552
Apparently Eight
LeapSeconds intervened between those two dates -- as far as Unix Knows Today