craig@NNSC.NSF.NET (Craig Partridge) (05/26/88)
Hi folks,
I recall seeing a message on either tcp-ip or header-people a few
months back to the effect that the military timezones specified in
RFC 822 were wrong. I am now unable to find the message. A note to
header-people failed to shake it loose. Perhaps some kind soul on TCP-IP
could describe the problem to me again?
Thanks,
Craigwales@valeria.cs.ucla.edu (Rich Wales) (05/27/88)
In article <8805260153.AA13746@ucbvax.Berkeley.EDU> craig@NNSC.NSF.NET (Craig Partridge) writes: I recall seeing a message on either tcp-ip or header-people a few months back to the effect that the military timezones specified in RFC 822 were wrong. I am now unable to find the message. A note to header-people failed to shake it loose. Perhaps some kind soul on TCP-IP could describe the problem to me again? With pleasure. On page 26 of RFC822 (Section 5.1), the single-letter military time zone designations are defined with the wrong sign. For example, "A" is said to be "-1" (i.e., 1 hour west of UT/GMT), while "N" is said to be "+1" (i.e., 1 hour east of UT/GMT). The *correct* definition is as follows: East of UT/GMT: A = +1; B = +2; ...; M = +12 (note that "J" is not used) West of UT/GMT: N = -1; O = -2; ...; Y = -12 UT/GMT itself: Z = 0 Thus, for example, Pacific Daylight Time in North America can be repre- sented in RFC822 as "PDT", "-0700", or "T" (*not* "G"). -- Rich Wales // UCLA CS Dept // wales@CS.UCLA.EDU // +1 (213) 825-5683 3531 Boelter Hall // Los Angeles, California 90024-1596 // USA ...!(ucbvax,rutgers)!ucla-cs!wales ...!uunet!cs.ucla.edu!wales "Zounds! A Gorkon death station appears! Evasive action!"
Mills@UDEL.EDU (05/27/88)
Craig, There is only one time zone in the cosmos and that is UT (nee GMT). There is only one clock in the cosmos and it speaketh UT. All other timezones are false gods and have meaning only to local holy men. In Saudi Arabia it is said that midnight occurs at local sundown. In Bombay and parts of Australia the time zones are on the half-hour and in at least one spot they are on the quarter hour. And then we get to talk about summer/winter time. Those of you who know me have heard this view on a few prior occasions. Oh yes, the Supreme Clock speaks time in 24-hour format and adds a 61st second 14 times in the last 16 years. If I set my clock back 1431 days, what time is it in Sydney? What day? Ponder before answering. If I write a contract on Blenheim Reef to expire precisely on 1 January 2000 how long, precisely, is it in force? Let's assume a leap-second is inserted on the previous day. Assume the contract expires based on local London time. Your answer? Yeah, I remember a very old message that complained an RFC-822 time zone was bogus, one of the European zones, I believe. There are at least a couple of Navy chaps watching these frequencies that should have the answer. Dave
stjohns@BEAST.DDN.MIL (Mike St. Johns) (05/27/88)
In practice, I've never seen anything except time zone Z "ZULU" used by the military. Mike
Mills@UDEL.EDU (05/28/88)
Mike, Yup, "Z" is used by aviation, maritime and weather radio and wire as well. Actually, I'm bent much less by what you call it than by where the Sun is when you holler "lunchtime!" To be really picky, the real standard time told by the fuzzballs is UT-0 (corrected for mean solar rotation in steps of one second). It is possible to correct this time to 100-ms steps by listening to the radio broadcasts more carefully (these corrections are included in the broadcasts as vernier adjustments). If there is a huge groundswell of anguish that these adjustments are not included in the existing primary time server chimes, I would be glad to reconsider the issue. Then you could navigate your yachts by NTP down to the second or so in longitude. Happy day. Dave
Mills@UDEL.EDU (05/28/88)
Rich, Aha! Another greasemonkey! The International Telecommunication Union (UIT), of which the CCITT and CCIR are parts, recommends the use of "J" to mean "daylight hours" and "N" to mean "nightime hours" and "X" to mean both, which should add another zest of grease to this discussion. We should point out that ISO has already standardized the time representation, of course. Now, let's talk about Antartica... Dave
budden@tetra.NOSC.MIL (Rex A. Buddenberg) (05/30/88)
"Now lets talk about Antarctica..." Time there gets interesting, simply because you can cross so many zones in a small linear distance... but the interesting problem is this: When you are at the Pole, every direction is north, or 000 (recall the color-of-the-bear riddle about the other Pole). So how do you fly out? If you pick any of the 'norths' at random, all but one of them lead somewhere other than McMurdo -- and not places you want to go. The conventional fix to the problem is to superimpose a grid over the true geography -- graft a piece of the equator over the pole, so to speak. Grid north is generally aligned along the Prime Meridian, so grid south runs along 180, grid east up the 090 meridian, etc. Rex Buddenberg
Mills@UDEL.EDU (05/31/88)
Rex, Geeze, last I ran phone patches with the KC4 folk at the various US bases in Antarctica they were keeping Greenwich time but living US Eastern Time and working radio between 0300 UT and 0900 UT on whatever frequencies got through. Such hours resulted in some sleepy wives when I patched them through to their old man stuck at Palmer Station, which turns out to be, at 64 west longitude, pretty close to US Eastern Time). Now, I have two QSL cards from Navy Seebee batallions listing their coordinates as 0W, 90S, which suggests they salute Greenwich instead. Who cares when you'r humping theodolites with a SnoCat at 60 below. By the by, the boys there tell me about the 100-degree club, not so well known and sort of an initiation haze. The victim takes the 100-degree plus shower, then is thrown out the door in the 100-degree minus snowdrift. All temperatures are F and the victim is presumably rescued before his parts start falling off his nude bod. Dave