This document provides a usage guide for the dmidecode command to dump a computer's DMI table contents. It describes retrieving BIOS, chassis, and system information without probing hardware, references the different DMI type tables, and troubleshoots errors accessing /dev/mem.

1. dmidecode Usage Guide
Contents
Overview.......................................................................................................................................................1
Applies To......................................................................................................................................................1
RPM Package.................................................................................................................................................1
DMI Type Table.............................................................................................................................................1
Retrieve BIOS Information............................................................................................................................2
Retrieve Chassis Information........................................................................................................................3
Retrieve System Information........................................................................................................................3
Troubleshooting............................................................................................................................................4
Blogpost URL.................................................................................................................................................4

2. dmidecode Usage Guide
1 | P a g e
Overview
dmidecode is a tool for dumping a computer's DMI (some say SMBIOS) table contents in a human-
readable format. This table contains a description of the system's hardware components, as well as other
useful pieces of information such as serial numbers and BIOS revision. You can retrieve system information
without having to probe for the actual hardware.
Applies To
CentOS version 6.x, 7.x; RHEL version 6.x, 7.x, it would work on version below also, which is not be tested.
RPM Package
rpm -qa | grep dmidecode
dmidecode-2.12-5.el7.x86_64
DMI Type Table
Below table can used as reference for different type of information that can be collected from system.
Type Information
0 BIOS
1 System
2 Baseboard
3 Chassis
4 Processor
5 Memory Controller
6 Memory Module
7 Cache
8 Port Connector
9 System Slots
10 On Board Devices
11 OEM Strings
12 System Configuration Options
13 BIOS Language
14 Group Associations
15 System Event Log
16 Physical Memory Array
17 Memory Device
18 32-bit Memory Error
19 Memory Array Mapped Address
20 Memory Device Mapped Address
21 Built-in Pointing Device
22 Portable Battery

3. dmidecode Usage Guide
2 | P a g e
23 System Reset
24 Hardware Security
25 System Power Controls
26 Voltage Probe
27 Cooling Device
28 Temperature Probe
29 Electrical Current Probe
30 Out-of-band Remote Access
31 Boot Integrity Services
32 System Boot
33 64-bit Memory Error
34 Management Device
35 Management Device Component
36 Management Device Threshold Data
37 Memory Channel
38 IPMI Device
39 Power Supply
40 Additional Information
41 Onboard Devices Extended Information
42 Management Controller Host Interface
Retrieve BIOS Information
dmidecode -t 0
Output:

4. dmidecode Usage Guide
3 | P a g e
Retrieve Chassis Information
dmidecode -t 3
Output:
Retrieve System Information
dmidecode -t 1
Output:

5. dmidecode Usage Guide
4 | P a g e
Troubleshooting
Error message when executing dmidecode command
/dev/mem: No such file or directory
To resolve this issue, run the below commands and you should be retrieve the system information.
mknod -m 660 /dev/mem c 1 1 # make block or character special files
chmod root:kmem /dev/mem # change group and owner of the file
Blogpost URL
http://mvcp007.blogspot.in/2015/04/dmidecode-how-to-guide.html