103 lines
3.5 KiB
Groff
103 lines
3.5 KiB
Groff
.\" $NetBSD: vnd.4,v 1.1 1995/12/30 18:10:48 thorpej Exp $
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.\"
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.\" Copyright (c) 1995 Jason R. Thorpe.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed for the NetBSD Project
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.\" by Jason R. Thorpe.
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.\" 4. Neither the name of the author nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd December 30, 1995
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.Dt VN 4
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.Os
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.Sh NAME
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.Nm vn
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.Nd vnode disk driver
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.Sh SYNOPSIS
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.Cd "pseudo-device vn" Op Ar count
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.Sh DESCRIPTION
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The
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.Nm
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driver uses swap or a file as backing store to abstract-out a character and
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block device which may then be used like a disk. The
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.Nm
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driver supports both labeled and unlabeled pseudo-disks and is useful for
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a variety of applications, including swap files and building mini-root,
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floppy, or CDRom disk images.
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.Nm
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may also be used to create temporary swap-backed filesystems, such as /tmp,
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in a somewhat less memory-hungry manner then MFS.
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.Pp
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This document assumes that you're familiar with how to generate kernels,
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how to properly configure disks and pseudo-devices in a kernel
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configuration file.
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.Pp
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In order to compile in support for the
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.Nm vn ,
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you must add a line similar
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to the following to your kernel configuration file:
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.Bd -unfilled -offset indent
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pseudo-device vn 4 #Vnode driver
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.Ed
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.Pp
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The
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.Ar count
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argument is how many
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.Nm vn Ns 's
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memory is allocated for a boot time. In this example, no more than 4
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.Nm vn Ns 's
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may be configured.
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.Nm
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may also exist as a kernel module to be automatically loaded into the
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system when you run the vnconfig command for the first time.
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.Pp
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There is a run-time utility that is used for configuring
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.Nm vn Ns 's .
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See
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.Xr vnconfig 8
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for more information.
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.Sh BUGS
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The
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.Nm
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driver does not work if the file does not reside in a local filesystem.
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.Sh FILES
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/dev/{,r}vn* - vn device special files.
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.Pp
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.Sh HISTORY
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The vnode disk driver was originally written at the University of
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Utah and was substantially modified by FreeBSD developers to add
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swap-backed support.
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.Sh SEE ALSO
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.Xr config 8 ,
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.Xr fsck 8 ,
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.Xr MAKEDEV 8 ,
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.Xr mount 8 ,
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.Xr newfs 8 ,
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.Xr vnconfig 8 .
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