1.\" $NetBSD: drum.4,v 1.5 2003/08/07 10:31:01 agc Exp $ 2.\" 3.\" Copyright (c) 1980, 1991, 1993 4.\" The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)drum.4 8.1 (Berkeley) 6/5/93 31.\" 32.Dd June 5, 1993 33.Dt DRUM 4 34.Os 35.Sh NAME 36.Nm drum 37.Nd paging device 38.Sh DESCRIPTION 39This file refers to the paging device in use by the system. 40This may actually be a subdevice of one of the disk drivers, but in 41a system with paging interleaved across multiple disk drives 42it provides an indirect driver for the multiple drives. 43.Sh FILES 44.Bl -tag -width /dev/drum 45.It Pa /dev/drum 46.El 47.Sh HISTORY 48The 49.Nm 50special file appeared in 51.Bx 3.0 . 52.Sh BUGS 53Reads from the drum are not allowed across the interleaving boundaries. 54Since these only occur every .5Mbytes 55or so, 56and since the system never allocates blocks across the boundary, 57this is usually not a problem. 58