1.\" $NetBSD: mem.4,v 1.5 1999/12/17 16:23:25 abs Exp $ 2.\" 3.\" Copyright (c) 1992, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" This software was developed by the Computer Systems Engineering group 7.\" at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 8.\" contributed to Berkeley. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. All advertising materials mentioning features or use of this software 19.\" must display the following acknowledgement: 20.\" This product includes software developed by the University of 21.\" California, Berkeley and its contributors. 22.\" 4. Neither the name of the University nor the names of its contributors 23.\" may be used to endorse or promote products derived from this software 24.\" without specific prior written permission. 25.\" 26.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36.\" SUCH DAMAGE. 37.\" 38.\" from: @(#)mem.4 8.1 (Berkeley) 6/5/93 39.\" 40.Dd June 5, 1993 41.Dt MEM 4 sparc 42.Os 43.Sh NAME 44.Nm mem , 45.Nm kmem 46.Nd Sun main memory access driver 47.Sh DESCRIPTION 48The file 49.Pa /dev/mem 50is an interface to the physical memory of the computer. 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.Sh SPARC 64On the 65.Tn SPARC , 66physical memory may be discontiguous; 67kernel virtual memory begins at 68.Li 0xf0000000 . 69.Sh FILES 70.Bl -tag -width /dev/kmem -compact 71.It Pa /dev/mem 72.It Pa /dev/kmem 73.El 74.Sh HISTORY 75The files 76.Nm mem 77and 78.Nm kmem 79appeared in 80.At v6 . 81