From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,f3f07e9e53bcc4f6
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2001-12-21 00:51:12 PST
Path: 
 archiver1.google.com!news1.google.com!sn-xit-02!supernews.com!news.tele.dk!small.news.tele.dk!130.133.1.3!fu-berlin.de!uni-berlin.de!tar-alcarin.cbb-automation.DE!not-for-mail
From: dmitry@elros.cbb-automation.de (Dmitry A. Kazakov)
Newsgroups: comp.lang.ada
Subject: Re: FILETIME <-> Ada.Real_Time.Time conversions
Date: Fri, 21 Dec 2001 08:51:09 GMT
Message-ID: <3c22f147.173527453@News.CIS.DFN.DE>
References: <3c21f386.108560406@News.CIS.DFN.DE>
 <NtAU7.17459$Ah.627789@rwcrnsc52>
NNTP-Posting-Host: tar-alcarin.cbb-automation.de (212.79.194.111)
X-Trace: fu-berlin.de 1008924671 18911957 212.79.194.111 (16 [77047])
X-Newsreader: Forte Free Agent 1.21/32.243
Xref: archiver1.google.com comp.lang.ada:18192
Date: 2001-12-21T08:51:09+00:00
List-Id: <comp.lang.ada>

On Fri, 21 Dec 2001 06:17:17 GMT, tmoran@acm.org wrote:

>> The real problem is that there is no correlation between epoch
>> of Ada.Real_Time.Split and UTC.
>  As I understand it, Ada.Real_Time basically tells you the
>state of an increasing counter in your computer's hardware,
>while UTC has to do with the position of the earth relative to
>the sun.  A computer in a rocket passing Pluto cares about the
>former, but not the latter, while a computer controlling
>dropping the Times Square ball at New Year's Midnight cares
>about UTC but not about its hardware counters.  Consider it
>amazing that they correlate as highly as they do.

Well, provided that the rocket has not yet reached sublight speed
(:-)) both UTC and hardware counter ticks are well correlated.

The problem is that. There are many computers (on Earth, which
relative velocities are near to zero (:-)), exchanging time-stamped
data. Any computer may have its own time synchronization source
(atomic clock, GPS etc). It is clear that the time stamps shall be in
UTC. Which time type in Ada 95 should represent the time stamps?

Ada.Calendar.Time is of no use, because it might be a political time.
Ada.Real_Time.Time is well correlated with UTC, but there is no way to
convert one to other.

Regards,
Dmitry Kazakov