On Mon, 26 Oct 2009 10:24:05 -0600, Howard Brazee wrote: >On 26 Oct 09 08:41:40 -0800, "Charlie Gibbs" wrote: > >>> No, on the contrary. The internals keep representing the same point >>> in time, as utc, but you have it presented as a time in the format >>> of your choosing. >> >>Exactly. UTC has been the standard in aviation for decades for this >>very reason. > Did a few plies of this thread get lost in the newsgroup void?
>With 20-20 hindsight, all computers should have started off marking >files that way. It's not easy changing, but it would really be worth >it. > Regrettably, it rarely works right. MVS and UNIX early realized the benefit of UTC (but MVS only partly -- how are ISPF PDS members marked? What about tape labels?) But new systems must reinvent. MS DOS and Macintosh OS both well after started running the primary clock on civil time. Mac is better now; Windows is still ailing. I suspect the mechanism is that engineers eager to get to power-on test start their test beds with the clock on civil time. They procrastinate implementing the conversion routine. Then the shipment deadline looms, and the transition is deferred to a future release, then the conversion effort is unacceptable. (When will ISPF start using UTC?) And z/OS and Unix System Services still don't do it right for US timestamps prior to 2007. What fraction of z/OS installations (away from the UK meridian) still run the [E]TOD on civil time? >Especially for those sites that gradually change the time to make sure >transactions get stored in order as the clock bumps back because of >daylight savings time - but also for any multi-time zone database. > Gulp! And the ETR will only slew a couple seconds a day. It wouldn't finish before time to change back. I understand that during leap seconds, z/OS dispatches no jobs. The designers likely considered but eschewed making even the leap second correction gradually, over a few hours. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
