projects / thirdparty / man-pages.git / blame
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1 | .\" Copyright (c) 1993 Michael Haardt (michael@moria.de), |
| 2 | .\" Fri Apr 2 11:32:09 MET DST 1993 | |
| fea681da | 3 | .\" |
| 1dd72f9c | 4 | .\" %%%LICENSE_START(GPLv2+_DOC_FULL) |
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5 | .\" This is free documentation; you can redistribute it and/or |
| 6 | .\" modify it under the terms of the GNU General Public License as | |
| 7 | .\" published by the Free Software Foundation; either version 2 of | |
| 8 | .\" the License, or (at your option) any later version. | |
| 9 | .\" | |
| 10 | .\" The GNU General Public License's references to "object code" | |
| 11 | .\" and "executables" are to be interpreted as the output of any | |
| 12 | .\" document formatting or typesetting system, including | |
| 13 | .\" intermediate and printed output. | |
| 14 | .\" | |
| 15 | .\" This manual is distributed in the hope that it will be useful, | |
| 16 | .\" but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 17 | .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 18 | .\" GNU General Public License for more details. | |
| 19 | .\" | |
| 20 | .\" You should have received a copy of the GNU General Public | |
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21 | .\" License along with this manual; if not, see |
| 22 | .\" <http://www.gnu.org/licenses/>. | |
| 6a8d8745 | 23 | .\" %%%LICENSE_END |
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24 | .\" |
| 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" | |
| 27 | .SH NAME | |
| 28 | mem, kmem, port \- system memory, kernel memory and system ports | |
| 29 | .SH DESCRIPTION | |
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30 | .B mem |
| 31 | is a character device file | |
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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. | |
| fea681da | 34 | .LP |
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35 | Byte addresses in |
| 36 | .B mem | |
| e8046fd0 | 37 | are interpreted as physical memory addresses. |
| c382a365 | 38 | References to nonexistent locations cause errors to be returned. |
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39 | .LP |
| 40 | Examining and patching is likely to lead to unexpected results | |
| 41 | when read-only or write-only bits are present. | |
| 42 | .LP | |
| 43 | It is typically created by: | |
| 44 | .RS | |
| 45 | .sp | |
| 4d9b6984 | 46 | mknod \-m 660 /dev/mem c 1 1 |
| fea681da | 47 | .br |
| 9df0bd1d | 48 | chown root:kmem /dev/mem |
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49 | .RE |
| 50 | .LP | |
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51 | The file |
| 52 | .B kmem | |
| 53 | is the same as | |
| 54 | .BR mem , | |
| e8046fd0 | 55 | except that the kernel virtual memory |
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56 | rather than physical memory is accessed. |
| 57 | .LP | |
| 58 | It is typically created by: | |
| 59 | .RS | |
| 60 | .sp | |
| 4d9b6984 | 61 | mknod \-m 640 /dev/kmem c 1 2 |
| fea681da | 62 | .br |
| 9df0bd1d | 63 | chown root:kmem /dev/kmem |
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64 | .RE |
| 65 | .LP | |
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66 | .B port |
| 67 | is similar to | |
| c13182ef | 68 | .BR mem , |
| a28e26a1 | 69 | but the I/O ports are accessed. |
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70 | .LP |
| 71 | It is typically created by: | |
| 72 | .RS | |
| 73 | .sp | |
| 4d9b6984 | 74 | mknod \-m 660 /dev/port c 1 4 |
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75 | .br |
| 76 | chown root:mem /dev/port | |
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77 | .RE |
| 78 | .SH FILES | |
| 79 | .I /dev/mem | |
| 80 | .br | |
| 81 | .I /dev/kmem | |
| 82 | .br | |
| 83 | .I /dev/port | |
| 47297adb | 84 | .SH SEE ALSO |
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85 | .BR chown (1), |
| 86 | .BR mknod (1), | |
| 87 | .BR ioperm (2) |