On Jul 5, 2012, at 10:49 48AM, Peter Lothberg wrote:
>>> On one of my BSD boxes. /usr/src/share/zoneinfo/leapseconds, I see no
>>> "-"
>> No, but they're allowed; see Figure 9 of RFC 5905:
>
> Steve,
>
> I commented that it was stated that we where doing both positive and
> negative corrections. Only positive corrections have been made, and
> yes, negative are possible.
>
> I pointed out in a previous post that we can count 57, 58, 00
> or 57, 58, 59, 00 or 57, 58, 59, 60, 00. And actually, this is the
> only thing operating-systems and applications need to be capable to
> handle to make it a non_issue.
Fair enough.
>
>
>> LI Leap Indicator (leap): 2-bit integer warning of an impending leap
>> second to be inserted or deleted in the last minute of the current
>> month with values defined in Figure 9.
>>
>> +-------+----------------------------------------+
>> | Value | Meaning |
>> +-------+----------------------------------------+
>> | 0 | no warning |
>> | 1 | last minute of the day has 61 seconds |
>> | 2 | last minute of the day has 59 seconds |
>> | 3 | unknown (clock unsynchronized) |
>> +-------+----------------------------------------+
>
> That's NTP packet format, used to implemment NTP's represenation of
> UTC, but not the definition of UTC... (What do I do if I receive a
> packet with "3".) Or better, all the UTC(k) are free-running and the
> (old) recomenadtion was to try to keep them within 1us, is that
> unsyncronized -:)
>
> And ooops, I did not catch that before, should it not say "last minute
> of the month"?
The text as I copied it is certainly not consistent...
>
> If I remember right the posix standard don't allow "60" in seconds...
>
> -Peter
>
--Steve Bellovin, https://www.cs.columbia.edu/~smb
