For your edification.... (Forwarded by permission.) -GAWollman ------- start of forwarded message (RFC 934 encapsulation) ------- Message-ID: <2538.944162601@critter.freebsd.dk> From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: dnm@orion.usno.navy.mil Cc: core@freebsd.org Subject: UTC questionnaire Date: Thu, 02 Dec 1999 20:23:21 +0100 Dear Mr. Matsakis, I am answering your questionaier on behalf of The FreeBSD project, a supplier of a UNIX family Computer Operating System:

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?

* no ____

In fact it would eliminate a few minor inconveniences every time it happens: UNIX computers account for time using the UTC scale with an epoch of 00:00 01/01/1970 UTC, so the computer needs its clock adjusted for a leap-second. Online transactions is a phenomena in sharp increase and the issue of keeping and legally documenting "time of transaction" in the face of leap-seconds is certainly too expensive for the benefit we see from them. UNIX is also a widely used operating system for science and research and the fact that no widely available facilities exist for calculating actual time difference between two events on either side of a leap-second is known to have bitten more than one scientific author over the years. Obviously it would be simple to provide these facilities, but the fact that operating systems are seldomly upgraded would relatively soon render the list of leap-seconds obsolete and the facility thereby useless.

B. Would you be in favor of such a proposal?

yes ____

Absolutely. If it is deemed desirable to keep UTC and UT1 synchronized it would be of tremendous benefit if the leap-seconds could be predicted or even just declared earlier than in the current mode of operation. A rule along the lines of "a leapsecond every 18 months" would go a long way to keep UTC and UT1 tied closely while at the same time providing a predictability for "normal civilization" equivalent to what we know from leap-days. Alternatively, rather than abandon leap-seconds make it leap-minutes. Once in a century we could probably use an extra minute anyway. Poul-Henning Kamp phk@FreeBSD.org In message <199912021444.PAA09602@hpopa.obspm.fr>, iers@hpopa.obspm.fr writes:

*************************************************************************** Gazette IERS Gazette IERS Gazette IERS Gazette IERS Gazette ________________________________________ No 48, 02 December 1999 / _________________________________/ Contact: iers@obspm.fr ftp: hpiers.obspm.fr (145.238.100.28) WWW: http://hpiers.obspm.fr ***************************************************************************

Subject: UTC Questionnaire Author : Demetrios Matsakis

--------------------------------------------------------------------------

Dear Colleague,

It has been proposed to change the definition of Coordinated Universal Time (UTC) regarding the insertion of leap-seconds, possibly even eliminating their use. Leap seconds are introduced so as to keep UTC synchronized (within 0.9 s) to the time scale determined from the Earth's rotation.

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. N. Brouw, Barry Clark, Irwin Shapiro, Ir. E. Van Lil, and myself.

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?

yes ___

* no ____

* possibly ____

(* please explain any known or possible problems)

B. Would you be in favor of such a proposal?

yes ____

no ____

indifferent ___

have better idea ___

(feel free to comment)

C. Is there anyone else you would recommend we contact? (feel free to forward this eamil directly)

I would appreciate your assistance, and a response by January 15 to dnm@orion.usno.navy.mil.

I am attaching a list of institutions and persons contacted, except for 931 institutions whose emails were obtained from the AAS. I would like to apologize to anyone contacted twice, but also appreciate it if you would forward this email to anyone we have missed. Also, if you are an URSI Commission J national chair, we would appreciate your forwarding this email to your complete membership and in particular to the directors of observatories.

Sincerely,

Demetrios Matsakis _____________________________________________________________________ Dr. Demetrios N. Matsakis Director, Time Service Department (202) 762-1587 DSN 762-1587 U. S. Naval Observatory FAX (202) 762-1511 3450 Massachusetts Avenue NW dnm@orion.usno.navy.mil Washington DC, USA 20392-5420 _____________________________________________________________________

- -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." FreeBSD -- It will take a long time before progress goes too far! ------- end -------