answerpointe.cctec.com/maillists/ietf/msg11662.html
The original request asked for a response by January 15, but we are extending that so as to reach a larger constituency, such as the IETF. I am anticipating that this will be distributed via an email exploder, and would appreciate a response by anyone interested by February 15. Although all responses will be tabulated, we are most interested in finding verifiable specific practical show-stoppers such as "system X would require Y million dollars to be reprogrammed, and you have our permission to identify it publicly". I also would prefer to receive responses in ascii, as opposed to attachments. Demetrios Matsakis ************************************************************************* Dear Project Manager or Scientist, It is being proposed to change the definition of Coordinated Universal Time (UTC) regarding the insertion of leap-seconds, possibly even eliminating their use. The issue has been discussed in several timekeeping forums, and published in the Innovations Section of the November, 1999 issue of GPS World. Should no new leap seconds be inserted, solar time will diverge from atomic time at the rate of about 2 seconds every 3 years, and after about a century |UT1-UTC| would exceed 1 minute. Although no fundamental problems are anticipated, it is very likely that Y2K-like problems may result in software that assumes UT1=UTC, or |UT1-UTC|< some value, or whose input/output records use a field size that can only accommodate |UT1-UTC| values up to one second. To gather information, an URSI Commission J Working Group was formed, consisting of Don Backer, Wim. We would like to ask you to consult with the members of your institute who currently deal with UT1-UTC, and give us a considered response to the following two questions: A. If the appropriate international bodies decide to eliminate the insertion of new leap seconds, would you foresee any practical problems for your institution/instrument/observations? This questionnaire was first sent to the URSII national representatives, a list of 931 astronomical institutions maintained by the American Astronomical Society, and 125 prominent scientists. It has since sent sent to several mailing lists associated with Earth rotation. I would like to apologize to anyone contacted twice, but also appreciate it if you would forward this email to anyone we may have missed. We will tabulate all responses, and are particularly interested in quantitative estimates from people whose systems can not easily accommodate the change. Unix technology permitting, I will also email the report to all who have responded. Matsakis Director, Time Service Department (202) 762-1587 DSN 762-1587 U. It seems more appropriate to provide it in advance: Thank you for your response, which will be tabulated. Unix-technology willing, we also plan to send a copy of our report all responders. Many people have asked me why there is a move to rethink the leap seconds, with solutions such as (but not limited to) adding no new leap seconds. I unfortunately edited out some of the reasons from early drafts of the questionnaire, because I was afraid that people would not read a long email. GLONASS, the Russian equivalent to GPS, goes off-line for leap second adjustments. Also, problems can occur in interfacing between systems that handle leap seconds differently. There is also the practical problem of inserting a second every year and half - people often do it the wrong way. The response one person sent me is below, and it concerns Network Time Protocol (NTP), which uses the internet to transfer time. Leap secs introduce a manual discontinuity in the NTP time scale. Leap seconds > are a tremendous headache in the NTP world because they cannot be predicted. I think it is a very > true statement that all GPS users would vote against continuing leap seconds, > not just NTP users. Many telecommunications circuits use GPS or atomic clocks > to keep cellular phones in operation, and leap seconds are a nuisance to them > as well. Note that we are talking about a minute in the next century. Society routinely handles a one-hour switch with every daily savings time, and a half-hour offset if they live at the edge of a time zone. By the time leap seconds add up to an hour, the world will be very different. If we have settled the solar system, a whole new scheme will probably have evolved. Even if we have not changed our system, society has enough slop in its timekeeping that people will slowly shift without even knowing it. More people will start showing up to work at 9:00 AM, and less at 8:30 AM, etc. These are inserting larger discontinuities less frequently, inserting integer leap seconds at predefined times, simply using TAI, and redefining the length of the second.
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