From owner-freebsd-stable@freebsd.org Fri Nov 20 00:51:02 2020 Return-Path: Delivered-To: freebsd-stable@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id AD391478F85 for ; Fri, 20 Nov 2020 00:51:02 +0000 (UTC) (envelope-from dmagda+stable@ee.ryerson.ca) Received: from eccles.ee.ryerson.ca (eccles.ee.ryerson.ca [141.117.1.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4CcdJj4xmKz3rqj for ; Fri, 20 Nov 2020 00:51:01 +0000 (UTC) (envelope-from dmagda+stable@ee.ryerson.ca) Received: from [192.168.10.101] (216-154-8-25.cpe.teksavvy.com [216.154.8.25] (may be forged)) (authenticated bits=0) by eccles.ee.ryerson.ca (8.16.1/8.15.2) with ESMTPSA id 0AK0ouUk021408 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Thu, 19 Nov 2020 19:50:58 -0500 (EST) (envelope-from dmagda+stable@ee.ryerson.ca) X-Authentication-Warning: eccles.ee.ryerson.ca: Host 216-154-8-25.cpe.teksavvy.com [216.154.8.25] (may be forged) claimed to be [192.168.10.101] From: David Magda Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.15\)) Subject: NTP, UTC, and (negative) leap seconds Message-Id: <64E52A56-4C8F-4B9E-A4D3-33117C270D43@ee.ryerson.ca> Date: Thu, 19 Nov 2020 19:50:52 -0500 To: freebsd-stable X-Mailer: Apple Mail (2.3445.104.15) X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.2 (eccles.ee.ryerson.ca [141.117.1.2]); Thu, 19 Nov 2020 19:50:58 -0500 (EST) X-Rspamd-Queue-Id: 4CcdJj4xmKz3rqj X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of dmagda@ee.ryerson.ca designates 141.117.1.2 as permitted sender) smtp.mailfrom=dmagda@ee.ryerson.ca X-Spamd-Result: default: False [-2.90 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; MV_CASE(0.50)[]; R_SPF_ALLOW(-0.20)[+mx]; HAS_XAW(0.00)[]; TO_DN_ALL(0.00)[]; NEURAL_HAM_SHORT(-1.00)[-1.000]; RCVD_IN_DNSWL_LOW(-0.10)[141.117.1.2:from]; MIME_TRACE(0.00)[0:+]; RBL_DBL_DONT_QUERY_IPS(0.00)[141.117.1.2:from]; ASN(0.00)[asn:26996, ipnet:141.117.0.0/17, country:CA]; MID_RHS_MATCH_FROM(0.00)[]; TAGGED_FROM(0.00)[stable]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-stable@freebsd.org]; DMARC_NA(0.00)[ryerson.ca]; RCPT_COUNT_ONE(0.00)[1]; SPAMHAUS_ZRD(0.00)[141.117.1.2:from:127.0.2.255]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; MAILMAN_DEST(0.00)[freebsd-stable] X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Nov 2020 00:51:02 -0000 Hello, So there was a recent weblog post on a timekeeping observation: https://fanf.dreamwidth.org/133823.html https://news.ycombinator.com/item?id=3D25145870 (via) https://en.wikipedia.org/wiki/Leap_second In all circumstances in the past, leap seconds were added: 23:59:57Z 23:59:58 23:59:59 23:59:60 00:00:00 00:00:01 The post brings up the possibility of a =E2=80=9Cnegative=E2=80=9D leap = second, i.e., a skip: 23:59:57Z 23:59:58 00:00:00 00:00:01 Has anyone tested this scenario on FreeBSD? Thanks for any info. -- David Magda=