1.\" Copyright (c) 1992, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This software was developed by the Computer Systems Engineering group 5.\" at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 6.\" contributed to Berkeley. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed by the University of 19.\" California, Berkeley and its contributors. 20.\" 4. Neither the name of the University nor the names of its contributors 21.\" may be used to endorse or promote products derived from this software 22.\" without specific prior written permission. 23.\" 24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34.\" SUCH DAMAGE. 35.\" 36.\" from: @(#)mem.4 8.1 (Berkeley) 6/5/93 37.\" $NetBSD: mem.4,v 1.1 2001/08/17 01:11:11 fredette Exp $ 38.\" 39.Dd June 5, 1993 40.Dt MEM 4 sun2 41.Os 42.Sh NAME 43.Nm mem , 44.Nm kmem 45.Nd main memory 46.Sh DESCRIPTION 47The file 48.Pa /dev/mem 49is an interface to the physical memory of the 50computer. 51Byte offsets in this file are interpreted as physical memory addresses. 52Reading and writing this file is equivalent to reading and writing 53memory itself. 54An error will be returned if an attempt is made to reference 55an offset outside of 56.Pa /dev/mem . 57.Pp 58Kernel virtual memory is accessed via the file 59.Pa /dev/kmem 60in the same manner as 61.Pa /dev/mem . 62Only kernel virtual addresses that are currently mapped to memory are allowed. 63.Pp 64On the 65.Tn Sun2 , 66kernel virtual memory begins at 67.Ad 0x000000 . 68.Sh FILES 69.Bl -tag -width /dev/kmem -compact 70.It Pa /dev/mem 71.It Pa /dev/kmem 72.El 73.Sh HISTORY 74The files 75.Nm mem 76and 77.Nm kmem 78appeared in 79.At v6 . 80