Considering time scales, there are three that significantly interrelate, and no matter what Perl 6 uses internally, it needs to be able to convert to and from these:
TAI: continuous count of time using SI seconds as measured by atomic clocks, 60 seconds in every minute, 60 minutes in every hour, 24 hours in every day. UTC: TAI with an offset, as corrected for the actual revolution of the Earth: usually 60 seconds in a minute, but occasionally 59 or 61. 60 minutes in every hour (so 3599, 3600, or 3601 seconds), 24 hours in every day (86399, 86400, or 86401 seconds). time_t: the value you get by taking the UTC time since Jan 1, 1970 at midnight and converting to a simple count of seconds, pretending there have been no leap seconds along the way. Right now as I type this it is 17:13:38 UTC. That's 17:14:12 in TAI (which is 34 seconds ahead of UTC until the next leap second). The corresponding time_t value is 1,235,150,018, but there have actually been 1,235,150,042 seconds since the UNIX epoch.
