Date: Fri, 15 Jan 1999 17:30:53 +1030 From: Greg Lehey <grog@lemis.com> To: Warner Losh <imp@village.org> Cc: cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/usr.sbin/tcpdump/tcpslice tcpslice.c Message-ID: <19990115173053.N55525@freebie.lemis.com> In-Reply-To: <199901150649.XAA21928@harmony.village.org>; from Warner Losh on Thu, Jan 14, 1999 at 11:49:43PM -0700 References: <19990115170933.L55525@freebie.lemis.com> <199901150546.VAA17426@freefall.freebsd.org> <19990115170933.L55525@freebie.lemis.com> <199901150649.XAA21928@harmony.village.org>
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On Thursday, 14 January 1999 at 23:49:43 -0700, Warner Losh wrote: > In message <19990115170933.L55525@freebie.lemis.com> Greg Lehey writes: > : I thought there was some guideline that small 2-digit years represent > : 20xx, and large 2-digit years represent 19xx. > > The short answer is that it depends. I think that w/o reading the > file that tcpslice is looking at it would be hard to know for sure > which year to use. So I made an arbitrary choice that made the > behavior well defined. > > Two digit dates generally have been interpreted as meaning in the > century that context says they are in. I suppose that I could have > figured out what year it was and made that year the "pivot" year. For > example, right now 1999 is the pivot year. 1999 + 50 is 2049 and 1999 > - 49 is 1950, so any number >= 50 means 19xx, while any number < 50 > means 20xx. In 2001 the pivot is 52, 2009 the pivot is 60, etc. You > can quibble over the edge cases I'm sure. > > Some have proposed that single digits < 38 mean 20xx and > 38 mean > 19xx, but that isn't a good long term solution.... > > If you have a better suggestion, please let me know, or commit better > patches. :-) Given the mass hysteria that seems to be building up to the turn of the century, I'm quite happy to let you do it :-) If you look at http://www.eunet.pt/ano2000/sun/sup_sun5.htm, you'll see that Sun uses a pivot date of 68 (i.e. two-digit years range between 1969 and 2068). I'm assuming that they have some reason to choose this particular number, and that others will do the same. There's also more stuff at http://www.sun.com/y2000/index.html, but I haven't looked at it much. There is, however, a guide at http://www.sun.com/y2000/devguide.html, which looks well worth reading. You might be interested in this: If a two-digit year representation is necessary, define 00-68 as 2000-2068 and 69-99 as 1969-1999. Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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