On Fri, 3 Jul 2015 16:41:03 -0500, George Kozakos wrote: > >Leap seconds are scheduled via STP or the sysplex timer. > >z/OS can only know about a leap second when it gets the Time Control >Parameter Change event external interrupt for STP or the ETR Alert >event external interrupt for ETR. > Tunnel vision. The same information that is provided to STP could also be made available to the code behind the STIMER macro and used to make the wait expire as accurately as possible. A leap second is only a second. Daylight Saving can advance clocks by an hour. People don't wan't to be an hour late for appointments.
On 2011-12-29 24:00:00, Independent Samoa advanced its clocks by 24 hours, to 2011-12031 00:00:00. There was no December 30. This was announced well in advance, and published in advance in the IANA database. It could have been handled. Linux systems had it right well in advance of the critical date. On Fri, 3 Jul 2015 14:46:30 -0700, Charles Mills wrote: >> I don't believe (but I've already been wrong once) that a programmer can >> request a GMT or LT more than 4 months in the future. > >I think you're right. An LT or GMT STIMER pops the next time that time of day >occurs, so it can be at most 23:59:59.99 away (23:59:60.99 counting leap >seconds). > >Hey, there's one for you, Gil. One June 30, could one have set an STIMER GMT >of 23:59:60.hh? (I think I know the answer.) > >The interval processing has no good answer IMHO. Sure, it seems like 4 seconds >after 23:59:58 on June 30 should be 00:00:01, not :02 -- but how far do you >carry that? What is 30 days after 23:59:58? Would you expect it to be 23:59:57 >on July 30? To be consistent, it should be. > Seconds are easy. The programmer should be able to request an interval in seconds, up to about 2,000,000.00. STIMER should convert that to TOD format; add the current content of the TOD clock (report error if overflow); and load the Comparator register. YYYY-MM-DD hh:mm:ss.hh (not an interval), the macro should do best it can from available information. Programmers should be cautioned that there are unpredictable effects due to IERS actions and legislative whims. >Can a prisoner serving a 30-year sentence demand to be released 'n' seconds >early to account for the leap seconds of incarceration? > "The law is a ass." English Common Law says a person is of legal age on the day before his 21st birthday. The Colorado liquor code elected, for no good reason, to deviate from this and explicitly prohibit sale of alcohol until the purchaser's 21st birthday. Did they really believe that in 24 hours an individual shouldgain sufficient maturity and discretion to merit the deviation? >How long is a day? Is it exactly 24 hours, or is it variable, depending on >what day you are talking about? > Use seconds. That's why there are atomic clocks, and STP refers to them and TOD runs at their rate. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
