John and Gil, Wow you sound very similar , very impressive knowledge ....
Sent from my iPad Scott Ford Senior Systems Engineer www.identityforge.com On Feb 29, 2012, at 3:43 PM, John Gilmore <johnwgilmore0...@gmail.com> wrote: > Paul Gilmartin writes: > > <begin extract> > STCKE is notionally closer to TAI than to UTC in that TAI and STCKE > are continuous timescales and UTC is discontinous. TAI and STCKE both > embody the notion of (micro)seconds since an epoch; UTC is specified > in terms of yyyy mm dd hh mm ss.fraction with minutes varying in > length as leap seconds occur. > </end extract> > > Note quite. This formulation is plausible by analogy with the notion > that the Gregorian Month of February, normally comprised of 28 days, > is comprised of 29 days in leap years. > > Leap seconds, however, are inserted into UTC by the BIPM upon the > recommendation of the IERS (Earth Rotation and Reference Systems > Service); and they are conceptually and by definition > extracalendrical. Neither 1) the last minute in June or the first > minute in July nor 2) the last minute in December or the first minute > in the subsequent January is lengthened when a leap second is inserted > between them. [This decision was taken advisedly. There are a number > of calendars---The Hebrew religious one is the obvious example---that > make no use of minutes and/or seconds.] > > I am not sure how seriously Mr Gilmartin's means his distinction of > units is to be taken; cgs [centimeter-gram-second] units and fsf > [furlong-stone-fortnight] units are, I suppose, more and less > perspicuous; but as long as they are unambiguously interconvertible > the choice between them poses only issues of taste not substance. > > John Gilmore, Ashland, MA 01721 - USA > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN
