mem - Online Linux Manual PageSection : 4
Updated : 2022-10-30
Source : Linux man-pages 6.03

---

NAMEmem, kmem, port − system memory, kernel memory and system ports

---

DESCRIPTION/dev/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 /dev/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. Since Linux 2.6.26, and depending on the architecture, the CONFIG_STRICT_DEVMEM kernel configuration option limits the areas which can be accessed through this file. For example: on x86, RAM access is not allowed but accessing memory-mapped PCI regions is. It is typically created by: mknod −m 660 /dev/mem c 1 1 chown root:kmem /dev/memThe file /dev/kmem is the same as /dev/mem, except that the kernel virtual memory rather than physical memory is accessed. Since Linux 2.6.26, this file is available only if the CONFIG_DEVKMEM kernel configuration option is enabled. It is typically created by: mknod −m 640 /dev/kmem c 1 2 chown root:kmem /dev/kmem/dev/port is similar to /dev/mem, but the I/O ports are accessed. It is typically created by: mknod −m 660 /dev/port c 1 4 chown root:kmem /dev/port

---

FILES/dev/mem
/dev/kmem
/dev/port

---

SEE ALSOchown(1), mknod(1), ioperm(2) 0

---

Johanes Gumabo

---

Data Size   :   4,980 byte
man-mem.4Build   :   2024-12-05, 20:55   :  
Visitor Screen   :   x
Visitor Counter ( page / site )   :   2 / 236,709
Visitor ID   :     :  
Visitor IP   :   3.142.172.250   :  
Visitor Provider   :   AMAZON-02   :  
Provider Position ( lat x lon )   :   39.962500 x -83.006100   :   x
Provider Accuracy Radius ( km )   :   1000   :  
Provider City   :   Columbus   :  
Provider Province   :   Ohio ,   :   ,
Provider Country   :   United States   :  
Provider Continent   :   North America   :  
Visitor Recorder   :   Version   :  
Visitor Recorder   :   Library   :  
Online Linux Manual Page   :   Version   :   Online Linux Manual Page - Fedora.40 - march=x86-64 - mtune=generic - 24.12.05
Online Linux Manual Page   :   Library   :   lib_c - 24.10.03 - march=x86-64 - mtune=generic - Fedora.40
Online Linux Manual Page   :   Library   :   lib_m - 24.10.03 - march=x86-64 - mtune=generic - Fedora.40
Data Base   :   Version   :   Online Linux Manual Page Database - 24.04.13 - march=x86-64 - mtune=generic - fedora-38
Data Base   :   Library   :   lib_c - 23.02.07 - march=x86-64 - mtune=generic - fedora.36

---

Very long time ago, I have the best tutor, Wenzel Svojanovsky . If someone knows the email address of Wenzel Svojanovsky , please send an email to johanes_gumabo@yahoo.co.id .

---

If error, please print screen and send to johanes_gumabo@yahoo.co.id
Under development. Support me via PayPal.

---