Replace the obsolete update(4) manual page with syncer(4). I was

not abble to solicit review from <freebsd-hackers>.

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

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 .