NAME | DESCRIPTION | FILES | SEE ALSO | COLOPHON
MEM(4) Linux Programmer's Manual MEM(4)
mem, kmem, port - system memory, kernel memory and system ports
mem is a character device file that is an image of the main memory of the
computer. It may be used, for example, to examine (and even patch) the
system.
Byte addresses in mem are interpreted as physical memory addresses.
References to nonexistent locations cause errors to be returned.
Examining and patching is likely to lead to unexpected results when read-only
or write-only bits are present.
It is typically created by:
mknod -m 660 /dev/mem c 1 1
chown root:kmem /dev/mem
The file kmem is the same as mem, except that the kernel virtual memory rather
than physical memory is accessed.
It is typically created by:
mknod -m 640 /dev/kmem c 1 2
chown root:kmem /dev/kmem
port is similar to mem, but the I/O ports are accessed.
It is typically created by:
mknod -m 660 /dev/port c 1 4
chown root:mem /dev/port
/dev/mem
/dev/kmem
/dev/port
chown(1), mknod(1), ioperm(2)
This page is part of release 3.23 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
Linux 1992-11-21 MEM(4)