89 lines
2.9 KiB
Groff
89 lines
2.9 KiB
Groff
.\" $NetBSD: mem.4,v 1.4 1997/10/19 12:57:21 mrg Exp $
|
|
.\"
|
|
.\" Copyright (c) 1990, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" from: @(#)mem.4 8.1 (Berkeley) 6/5/93
|
|
.\"
|
|
.Dd June 5, 1993
|
|
.Dt MEM 4 hp300
|
|
.Os
|
|
.Sh NAME
|
|
.Nm mem ,
|
|
.Nm kmem
|
|
.Nd main memory
|
|
.Sh DESCRIPTION
|
|
The file
|
|
.Nm /dev/mem
|
|
is an interface to the physical memory of the
|
|
computer.
|
|
Byte offsets in this file are interpreted as physical memory addresses.
|
|
Reading and writing this file is equivalent to reading and writing
|
|
memory itself.
|
|
An error will be returned if an attempt is made to reference
|
|
an offset outside of
|
|
.Nm /dev/mem .
|
|
.Pp
|
|
Kernel virtual memory is accessed via the file
|
|
.Nm /dev/kmem
|
|
in the same manner as
|
|
.Nm /dev/mem .
|
|
Only kernel virtual addresses that are currently mapped to memory are allowed.
|
|
.Sh HP300
|
|
On the
|
|
.Tn HP300 ,
|
|
the last byte of physical memory is always
|
|
.Li 0xFFFFFFFF .
|
|
Therefore, on an
|
|
.Tn HP300
|
|
with
|
|
8Mb of memory, physical memory would start
|
|
at
|
|
.Li 0xFF800000 .
|
|
On the
|
|
.Tn HP300 ,
|
|
kernel virtual memory runs from
|
|
.Li 0
|
|
to about
|
|
.Li 0x2400000 .
|
|
.Sh FILES
|
|
.Bl -tag -width /dev/kmem -compact
|
|
.It Pa /dev/mem
|
|
.It Pa /dev/kmem
|
|
.El
|
|
.Sh HISTORY
|
|
The files
|
|
.Nm mem
|
|
and
|
|
.Nm kmem
|
|
appeared in
|
|
.At v6 .
|