1 .\" Copyright (c) 1993 Michael Haardt (michael@moria.de),
2 .\" Fri Apr 2 11:32:09 MET DST 1993
4 .\" %%%LICENSE_START(GPLv2+_DOC_FULL)
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25 .\" Modified Sat Jul 24 16:59:10 1993 by Rik Faith (faith@cs.unc.edu)
26 .TH MEM 4 1992-11-21 "Linux" "Linux Programmer's Manual"
28 mem, kmem, port \- system memory, kernel memory and system ports
31 is a character device file
32 that is an image of the main memory of the computer.
33 It may be used, for example, to examine (and even patch) the system.
37 are interpreted as physical memory addresses.
38 References to nonexistent locations cause errors to be returned.
40 Examining and patching is likely to lead to unexpected results
41 when read-only or write-only bits are present.
43 It is typically created by:
46 mknod \-m 660 /dev/mem c 1 1
48 chown root:kmem /dev/mem
55 except that the kernel virtual memory
56 rather than physical memory is accessed.
58 It is typically created by:
61 mknod \-m 640 /dev/kmem c 1 2
63 chown root:kmem /dev/kmem
69 but the I/O ports are accessed.
71 It is typically created by:
74 mknod \-m 660 /dev/port c 1 4
76 chown root:mem /dev/port
89 This page is part of release 3.67 of the Linux
92 A description of the project,
93 information about reporting bugs,
94 and the latest version of this page,
96 \%http://www.kernel.org/doc/man\-pages/.