77 lines
2.7 KiB
Groff
77 lines
2.7 KiB
Groff
.\" Copyright (c) 1992, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This software was developed by the Computer Systems Engineering group
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.\" at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
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.\" contributed to Berkeley.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" from: @(#)mem.4 8.1 (Berkeley) 6/5/93
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.\" $NetBSD: mem.4,v 1.2 2003/08/07 10:31:07 agc Exp $
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.\"
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.Dd November 28, 1999
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.Dt MEM 4 mvme68k
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.Os
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.Sh NAME
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.Nm mem ,
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.Nm kmem
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.Nd main memory
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.Sh DESCRIPTION
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The file
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.Nm /dev/mem
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is an interface to the physical memory of the computer.
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Byte offsets in this file are interpreted as physical memory addresses.
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Reading and writing this file is equivalent to reading and writing
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memory itself.
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An error will be returned if an attempt is made to reference
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an offset outside of
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.Nm /dev/mem .
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.Pp
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Kernel virtual memory is accessed via the file
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.Nm /dev/kmem
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in the same manner as
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.Nm /dev/mem .
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Only kernel virtual addresses that are currently mapped to memory are allowed.
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.Pp
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On the
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.Tn Motorola
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MVME series of single board computers,
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physical memory may be discontiguous;
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kernel virtual memory begins at
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.Ad 0x00008000 .
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.Sh FILES
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.Bl -tag -width /dev/kmem -compact
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.It Pa /dev/mem
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.It Pa /dev/kmem
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.El
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.Sh HISTORY
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The files
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.Nm mem
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and
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.Nm kmem
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appeared in
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.At v6 .
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