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,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,9fbc059a74d74032 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-05-30 03:13:56 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!canoe.uoregon.edu!hammer.uoregon.edu!enews.sgi.com!news.xtra.co.nz!not-for-mail From: "AG" Newsgroups: comp.lang.ada References: <9elpii$30i$1@nh.pace.co.uk> <3B0ED67B.E40A4E06@averstar.com> <9f0ciq$itb$1@nh.pace.co.uk> Subject: Re: Leap Seconds X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Message-ID: Date: Wed, 30 May 2001 22:14:12 +1200 NNTP-Posting-Host: 210.55.151.112 X-Complaints-To: newsadmin@xtra.co.nz X-Trace: news.xtra.co.nz 991217635 210.55.151.112 (Wed, 30 May 2001 22:13:55 NZST) NNTP-Posting-Date: Wed, 30 May 2001 22:13:55 NZST Organization: Xtra Xref: archiver1.google.com comp.lang.ada:7864 Date: 2001-05-30T22:14:12+12:00 List-Id: "Arthur Evans Jr" wrote in message news:ev_remove_this_ans-2905012042430001@192.168.1.254... > I expect that an Ada program that communicates with an unmanned > (unpersoned?) space ship might care very much indeed. Suppose the > ship sends a message from somewhere near Saturn or some such, the > message including a time stamp. ... > > Here the problem is not one Ada can solve. You would need a clock > at the receiving station that either was never corrected for leap > seconds, or you would need a table of corrections. To put it > differently, you need some sort of clock at the receiving station > that tells you how much time has elapsed since the vessal was > launched. Given that, an Ada program is easy, providing you have a > big enough field to store all those seconds. Well, considering we're talking about multi-year time spans and speeds which, while still very low compared to the speed of light are not totally negligible, does that mean that you need a clock which can account for the relativity effects? Without any programming support? And what does power that clock? I would suggest that it should be the other way round - highly unlikely any language could provide that sort of timer facility. Rather, it's the language itself that should power the clock if it comes to such extreme cases.