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authorsheldonh <sheldonh@FreeBSD.org>2000-07-19 07:15:32 +0000
committersheldonh <sheldonh@FreeBSD.org>2000-07-19 07:15:32 +0000
commit672d736d95bbfe684bbc2e8ebac515121cf3b061 (patch)
treed83941040233272d5a823ee6446eb5d694ae2a03
parent42caeca20380dce4c19fdac6ca8db56e9e5ce276 (diff)
downloadFreeBSD-src-672d736d95bbfe684bbc2e8ebac515121cf3b061.zip
FreeBSD-src-672d736d95bbfe684bbc2e8ebac515121cf3b061.tar.gz
Replace the obsolete update(4) manual page with syncer(4). I was
not abble to solicit review from <freebsd-hackers>.
-rw-r--r--share/man/man4/Makefile6
-rw-r--r--share/man/man4/syncer.4 (renamed from share/man/man4/update.4)76
2 files changed, 39 insertions, 43 deletions
diff --git a/share/man/man4/Makefile b/share/man/man4/Makefile
index 42439d4..8650d5e 100644
--- a/share/man/man4/Makefile
+++ b/share/man/man4/Makefile
@@ -13,9 +13,9 @@ MAN4= adv.4 adw.4 aha.4 ahb.4 ahc.4 amd.4 amr.4 an.4 ata.4 atkbd.4 \
ppbus.4 ppc.4 ppi.4 ppp.4 psm.4 pt.4 pty.4 rl.4 \
route.4 sa.4 sbc.4 screen.4 scsi.4 \
sd.4 ses.4 sf.4 si.4 sio.4 sis.4 sk.4 sl.4 smb.4 smbus.4 smp.4 snp.4 \
- splash.4 sppp.4 st.4 ste.4 stf.4 sym.4 syscons.4 sysmouse.4 tcp.4 \
- termios.4 ti.4 tl.4 ttcp.4 tty.4 tun.4 twe.4 udp.4 udbp.4 uhci.4 \
- ukbd.4 umass.4 ums.4 unix.4 update.4 urio.4 usb.4 vga.4 vinum.4 vn.4 \
+ splash.4 sppp.4 st.4 ste.4 stf.4 sym.4 syncer.4 syscons.4 sysmouse.4 \
+ tcp.4 termios.4 ti.4 tl.4 ttcp.4 tty.4 tun.4 twe.4 udp.4 udbp.4 uhci.4 \
+ ukbd.4 umass.4 ums.4 unix.4 urio.4 usb.4 vga.4 vinum.4 vn.4 \
vpo.4 vr.4 wb.4 wi.4 wx.4 worm.4 xl.4 xpt.4 yp.4 zero.4
MLINKS= ata.4 acd.4 ata.4 ad.4 ata.4 afd.4 ata.4 ast.4
diff --git a/share/man/man4/update.4 b/share/man/man4/syncer.4
index 8a16a24..0d8a84f 100644
--- a/share/man/man4/update.4
+++ b/share/man/man4/syncer.4
@@ -1,8 +1,5 @@
-.\" Copyright (c) 1996
-.\" Mike Pritchard <mpp@FreeBSD.org>. All rights reserved.
-.\"
-.\" Copyright (c) 1991, 1993
-.\" The Regents of the University of California. All rights reserved.
+.\" Copyright (c) 2000 Sheldon Hearn <sheldonh@FreeBSD.org>
+.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
@@ -12,13 +9,6 @@
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
-.\" 3. All advertising materials mentioning features or use of this software
-.\" must display the following acknowledgement:
-.\" This product includes software developed by the University of
-.\" California, Berkeley and its contributors.
-.\" 4. Neither the name of the University nor the names of its contributors
-.\" may be used to endorse or promote products derived from this software
-.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
@@ -34,38 +24,42 @@
.\"
.\" $FreeBSD$
.\"
-.Dd February 11, 1996
-.Dt UPDATE 4
-.Os FreeBSD
+.Dd July 14, 2000
+.Dt SYNCER 4
+.Os
.Sh NAME
-.Nm update
-.Nd flush internal filesystem caches to disk periodically
+.Nm syncer
+.Nd filesystem synchronizer kernel process
.Sh SYNOPSIS
-.Nm update
+.Nm syncer
.Sh DESCRIPTION
The
-.Nm update
+.Nm
kernel process helps protect the integrity of disk volumes
-by flushing
-volatile cached filesystem data
-to disk. This is done at thirty second intervals by default.
-The time period may be changed by using
-.Xr sysctl 8
-to modify the
-.Va kern.update
-variable.
-The
-.Nm update
-process does the equivalent of the
-.Xr sync 2
-function call to do the task.
+by flushing volatile cached filesystem data to disk.
+This is done at thirty second
+.Pq actually Dv SYNCER_MAXDELAY - 2
+intervals by default.
+.Pp
+The kernel places all
+.Xr vnode 9 Ns 's
+in a number of queues equal to
+.Dv SYNCER_MAXDELAY .
+The
+.Nm
+process works through the queues
+in a round-robin fashion,
+usually processing one queue per second.
+For each
+.Xr vnode 9
+on the queue,
+the
+.Nm
+process forces a write out to disk of its dirty buffers.
.Sh SEE ALSO
.Xr sync 2 ,
.Xr fsck 8 ,
-.Xr init 8 ,
-.Xr rc 8 ,
-.Xr sync 8 ,
-.Xr sysctl 8
+.Xr sync 8
.Sh BUGS
It is possible on some systems that a
.Xr sync 2
@@ -73,14 +67,16 @@ occurring simultaneously with a crash may cause
file system damage. See
.Xr fsck 8 .
.Sh HISTORY
-An
-.Nm update
-command appeared in
+The
+.Nm
+process is a descendant of the
+.Sq update
+command, which apeared in
.At v6 ,
and was usually started by
.Pa /etc/rc
when the system went multi-user.
A kernel initiated
-.Nm update
+update
process first appeared in
.Fx 2.0 .
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