1.\" $NetBSD: vnd.4,v 1.1 1995/12/30 18:10:48 thorpej Exp $ 2.\" 3.\" Copyright (c) 1995 Jason R. Thorpe. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 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. 21.\" 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 32.\" SUCH DAMAGE. 33.\" 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 1.4 2006/03/26 22:56:57 swildner Exp $ 36.\" 37.Dd December 30, 1995 38.Dt VN 4 39.Os 40.Sh NAME 41.Nm vn 42.Nd vnode disk driver 43.Sh SYNOPSIS 44.Cd "pseudo-device vn" 45.Sh DESCRIPTION 46The 47.Nm 48driver uses swap or a file as backing store to abstract-out a character and 49block device which may then be used like a disk. The 50.Nm 51driver supports both labeled and unlabeled pseudo-disks and is useful for 52a variety of applications, including swap files and building mini-root, 53floppy, or CDRom disk images. 54.Nm 55may also be used to create temporary swap-backed filesystems, such as /tmp, 56in a somewhat less memory-hungry manner than MFS. 57.Pp 58This document assumes that you're familiar with how to generate kernels, 59how to properly configure disks and pseudo-devices in a kernel 60configuration file. 61.Pp 62In order to compile in support for the 63.Nm , 64you must add a line similar 65to the following to your kernel configuration file: 66.Bd -unfilled -offset indent 67pseudo-device vn #Vnode driver 68.Ed 69.Pp 70.Nm 71may also exist as a kernel module to be automatically loaded into the 72system when you run the vnconfig command for the first time. 73.Pp 74There is a run-time utility that is used for configuring 75.Nm Ns 's . 76See 77.Xr vnconfig 8 78for more information. 79.Sh FILES 80/dev/{,r}vn* - vn device special files. 81.Sh SEE ALSO 82.Xr config 8 , 83.Xr fsck 8 , 84.Xr MAKEDEV 8 , 85.Xr mount 8 , 86.Xr newfs 8 , 87.Xr vnconfig 8 88.Sh HISTORY 89The vnode disk driver was originally written at the University of 90Utah and was substantially modified by 91.Fx 92developers to add 93swap-backed support. 94.Sh BUGS 95The 96.Nm 97driver does not work if the file does not reside in a local filesystem. 98