1 .\" Copyright (c) 1993 Michael Haardt (michael@moria.de),
2 .\" Fri Apr 2 11:32:09 MET DST 1993
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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
30 \fBmem\fP is a character device file
31 that is an image of the main memory of the computer.
32 It may be used, for example, to examine (and even patch) the system.
36 are interpreted as physical memory addresses.
37 References to nonexistent locations cause errors to be returned.
39 Examining and patching is likely to lead to unexpected results
40 when read-only or write-only bits are present.
42 It is typically created by:
45 mknod \-m 660 /dev/mem c 1 1
47 chown root:kmem /dev/mem
54 except that the kernel virtual memory
55 rather than physical memory is accessed.
57 It is typically created by:
60 mknod \-m 640 /dev/kmem c 1 2
62 chown root:kmem /dev/kmem
65 \fBport\fP is similar to
67 but the I/O ports are accessed.
69 It is typically created by:
72 mknod \-m 660 /dev/port c 1 4
74 chown root:mem /dev/port