Date: Sun, 28 Apr 2024 18:29:44 GMT From: Mateusz Piotrowski <0mp@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 5119386711a8 - stable/13 - sync.8: Document that the "sync dance" is not a thing Message-ID: <202404281829.43SITiZF026828@gitrepo.freebsd.org>
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The branch stable/13 has been updated by 0mp: URL: https://cgit.FreeBSD.org/src/commit/?id=5119386711a88f86dfb3ec3eb609d0d2c6a4f050 commit 5119386711a88f86dfb3ec3eb609d0d2c6a4f050 Author: Mateusz Piotrowski <0mp@FreeBSD.org> AuthorDate: 2024-04-23 14:12:45 +0000 Commit: Mateusz Piotrowski <0mp@FreeBSD.org> CommitDate: 2024-04-28 18:29:36 +0000 sync.8: Document that the "sync dance" is not a thing People still believe that it is essential to run sync(8) a couple of times before a reboot/halt. Document that this has not been necessary for a long time now. Reviewed by: imp, bcr, Pau Amma <pauamma@gundo.com> MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D33233 (cherry picked from commit 177ba183076bd6fe6b29b1d657b954cca256506b) --- bin/sync/sync.8 | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/bin/sync/sync.8 b/bin/sync/sync.8 index 732d813880e2..222e9edf59f9 100644 --- a/bin/sync/sync.8 +++ b/bin/sync/sync.8 @@ -28,7 +28,7 @@ .\" .\" @(#)sync.8 8.1 (Berkeley) 5/31/93 .\" -.Dd May 31, 1993 +.Dd April 25, 2024 .Dt SYNC 8 .Os .Sh NAME @@ -71,3 +71,31 @@ A .Nm utility appeared in .At v4 . +.Pp +On systems older than +.Bx 4.0 , +commands like +.Xr reboot 8 +and +.Xr halt 8 +were unavailable. +The shutdown procedure involved running +.Nm , +waiting for the lights to stop, +and turning off the machine. +.Pp +Issuing three separate +.Nm +commands (one line each) was a placebo that would generally suffice in +.At v7 +machines that were otherwise quiesced systems. +It replaced the one-per-line +.Nm +as a substitute for waiting. +.Pp +.Bx 4.0 +introduced +.Xr reboot 2 +and +.Xr sync 2 +which rendered this trick obsolete.
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