Assuming I understand your question correctly: If the counter is stored as a signed int32 then the rollover will be to the smallest representable signed 32 whic

Assuming I understand your question correctly: If the counter is stored as a signed int32 then the rollover will be to the smallest representable signed 32 which corresponds to the 1901 date. It's stored signed because software (particularly old software) wanted to be able to manipulate pre 1970 dates.