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1 | .\" Copyright (c) 1993 Michael Haardt (michael@moria.de), |
2 | .\" Fri Apr 2 11:32:09 MET DST 1993 | |
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3 | .\" |
4 | .\" This is free documentation; you can redistribute it and/or | |
5 | .\" modify it under the terms of the GNU General Public License as | |
6 | .\" published by the Free Software Foundation; either version 2 of | |
7 | .\" the License, or (at your option) any later version. | |
8 | .\" | |
9 | .\" The GNU General Public License's references to "object code" | |
10 | .\" and "executables" are to be interpreted as the output of any | |
11 | .\" document formatting or typesetting system, including | |
12 | .\" intermediate and printed output. | |
13 | .\" | |
14 | .\" This manual is distributed in the hope that it will be useful, | |
15 | .\" but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | .\" GNU General Public License for more details. | |
18 | .\" | |
19 | .\" You should have received a copy of the GNU General Public | |
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20 | .\" License along with this manual; if not, see |
21 | .\" <http://www.gnu.org/licenses/>. | |
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22 | .\" |
23 | .\" Modified Sat Jul 24 16:59:10 1993 by Rik Faith (faith@cs.unc.edu) | |
24 | .TH MEM 4 1992-11-21 "Linux" "Linux Programmer's Manual" | |
25 | .SH NAME | |
26 | mem, kmem, port \- system memory, kernel memory and system ports | |
27 | .SH DESCRIPTION | |
e8046fd0 | 28 | \fBmem\fP is a character device file |
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29 | that is an image of the main memory of the computer. |
30 | It may be used, for example, to examine (and even patch) the system. | |
fea681da | 31 | .LP |
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32 | Byte addresses in |
33 | .B mem | |
e8046fd0 | 34 | are interpreted as physical memory addresses. |
c382a365 | 35 | References to nonexistent locations cause errors to be returned. |
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36 | .LP |
37 | Examining and patching is likely to lead to unexpected results | |
38 | when read-only or write-only bits are present. | |
39 | .LP | |
40 | It is typically created by: | |
41 | .RS | |
42 | .sp | |
4d9b6984 | 43 | mknod \-m 660 /dev/mem c 1 1 |
fea681da | 44 | .br |
9df0bd1d | 45 | chown root:kmem /dev/mem |
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46 | .RE |
47 | .LP | |
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48 | The file |
49 | .B kmem | |
50 | is the same as | |
51 | .BR mem , | |
e8046fd0 | 52 | except that the kernel virtual memory |
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53 | rather than physical memory is accessed. |
54 | .LP | |
55 | It is typically created by: | |
56 | .RS | |
57 | .sp | |
4d9b6984 | 58 | mknod \-m 640 /dev/kmem c 1 2 |
fea681da | 59 | .br |
9df0bd1d | 60 | chown root:kmem /dev/kmem |
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61 | .RE |
62 | .LP | |
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63 | \fBport\fP is similar to |
64 | .BR mem , | |
a28e26a1 | 65 | but the I/O ports are accessed. |
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66 | .LP |
67 | It is typically created by: | |
68 | .RS | |
69 | .sp | |
4d9b6984 | 70 | mknod \-m 660 /dev/port c 1 4 |
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71 | .br |
72 | chown root:mem /dev/port | |
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73 | .RE |
74 | .SH FILES | |
75 | .I /dev/mem | |
76 | .br | |
77 | .I /dev/kmem | |
78 | .br | |
79 | .I /dev/port | |
47297adb | 80 | .SH SEE ALSO |
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81 | .BR chown (1), |
82 | .BR mknod (1), | |
83 | .BR ioperm (2) |