1 .\" $NetBSD: vnd.4,v 1.1 1995/12/30 18:10:48 thorpej Exp $
3 .\" Copyright (c) 1995 Jason R. Thorpe.
4 .\" All rights reserved.
6 .\" Redistribution and use in source and binary forms, with or without
7 .\" modification, are permitted provided that the following conditions
9 .\" 1. Redistributions of source code must retain the above copyright
10 .\" notice, this list of conditions and the following disclaimer.
11 .\" 2. Redistributions in binary form must reproduce the above copyright
12 .\" notice, this list of conditions and the following disclaimer in the
13 .\" documentation and/or other materials provided with the distribution.
14 .\" 3. All advertising materials mentioning features or use of this software
15 .\" must display the following acknowledgement:
16 .\" This product includes software developed for the NetBSD Project
17 .\" by Jason R. Thorpe.
18 .\" 4. Neither the name of the author nor the names of its contributors
19 .\" may be used to endorse or promote products derived from this software
20 .\" without specific prior written permission.
22 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 .\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 .\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 .\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 .\" $FreeBSD: src/share/man/man4/vn.4,v 1.6.2.4 2002/04/15 05:48:55 asmodai Exp $
35 .\" $DragonFly: src/share/man/man4/vn.4,v 1.6 2007/06/14 21:16:13 swildner Exp $
37 .Dd September 28, 2009
44 .Cd pseudo-device vn Op n
46 Alternatively, to load the driver as a module at boot time, place the
48 .Pa /boot/loader.conf :
49 .Bd -literal -offset indent
55 driver uses swap or a file as backing store to abstract-out a
56 device which may then be used like a disk.
59 driver supports both labeled and unlabeled pseudo-disks and is useful for
60 a variety of applications, including swap files and building mini-root,
61 floppy, or CD-ROM disk images.
63 may also be used to create temporary swap-backed filesystems, such as
65 in a somewhat less memory-hungry manner than MFS.
69 driver supports autocloning. By default 4
71 devices are also precreated.
73 .Bl -tag -width "Pa /dev/vn*" -compact
85 The vnode disk driver was originally written at the University of
86 Utah and was substantially modified by
88 developers to add swap-backed support.
92 driver does not work if the file does not reside in a local filesystem.