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+.\" Copyright (c) 1980, 1991, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 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
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"     From: @(#)swapon.8	8.1 (Berkeley) 6/5/93
+.\"	$Id: dumpon.8,v 1.2 1996/02/12 01:20:09 mpp Exp $
+.\"
+.Dd May 12, 1995
+.Dt DUMPON 8
+.Os FreeBSD 2.1
+.Sh NAME
+.Nm dumpon
+.Nd "specify a device for crash dumps"
+.Sh SYNOPSIS
+.Nm dumpon
+.Op Fl v
+.Ar special_file
+.Sh DESCRIPTION
+.Nm Dumpon
+is used to specify a device where the kernel can save a crash dump in
+the case of a panic.
+The system begins with no dump area configured for safety, unless a
+.Dq dumps on
+clause was specified in the input to
+.Xr config 8 .
+The dump device must be one of the swap areas
+specified in the configuration file, and it must be at least the size
+of physical memory.
+Calls to
+.Nm dumpon
+normally occur in the system multi-user initialization file
+.Pa /etc/rc ,
+before the
+.Xr savecore 8
+program is run.
+The
+.Fl v
+flag can be specified to cause the
+.Nm
+program to be verbose about its activity.
+.Pp
+The 
+.Nm
+program operates by setting the
+.Xr sysctl 3
+MIB variable
+.Dq kern.dumpdev
+to the device number of the designated 
+.Ar special_file
+or to
+.Dv NODEV
+(meaning that no dumps are to be taken) if
+.Ar special_file
+is the text string
+.Dq Li off .
+.Sh SEE ALSO
+.Xr sysctl 3 ,
+.Xr init 8 ,
+.Xr rc 8 ,
+.Xr savecore 8
+.Sh FILES
+.Bl -tag -width /dev/[ws]d?b -compact
+.It Pa /dev/[ws]d?b
+standard paging devices
+.El
+.Sh BUGS
+Because the filesystem layer is already dead by the time a crash dump
+is taken, it is not possible to send crash dumps directly to a file.
+.Sh HISTORY
+The
+.Nm
+command appeared in
+.Fx 2.1 .