In this article we’ll see how we can use Dmidecode command to retrieve hardware information of any Linux system. Suppose if we want to upgrade a system we need to gather information like Memory, BIOS and CPU etc. With help of Dmidecode command we will come to know the details without opening system chasis. Dmidecode command works for RHEL/CentOS/Fedora/Ubuntu Linux.
Dmidecode tool read DMI (some say SMBIOS) table to fetch data and displays useful system informations like hardware details, serial numbers and BIOS version, Processor etc. in human readable format. You may require root priviledge to execute dmidecode command.
1. Basic Output of Demidecode
Below is the Demidecode command sample output.
# dmidecode 2.11
SMBIOS version fixup (2.31 -> 2.3).
SMBIOS 2.3 present.
45 structures occupying 1642 bytes.
Table at 0x000E0010.
Handle 0x0000, DMI type 0, 20 bytes
BIOS Information
Vendor: Phoenix Technologies LTD
Version: 6.00
Release Date: 12/06/2006
Address: 0xE78A0
Runtime Size: 100192 bytes
ROM Size: 64 kB
Characteristics:
ISA is supported
PCI is supported
PC Card (PCMCIA) is supported
PNP is supported
APM is supported
BIOS is upgradeable
BIOS shadowing is allowed
ESCD support is available
USB legacy is supported
Smart battery is supported
BIOS boot specification is supported
2. How to Get DMI Types
DMI Id give us particular hardware information of system. Dmidecode with options ‘-t ‘or ‘–type‘ and ‘Id‘ will provide us the exact infromation. Id 6 will give us Memory Module information.
[root@tecmint ~]# dmidecode -t 6
# dmidecode 2.11
SMBIOS version fixup (2.31 -> 2.3).
SMBIOS 2.3 present.
Handle 0x0009, DMI type 6, 12 bytes
Memory Module Information
Socket Designation: RAM socket #0
Bank Connections: 0 1
Current Speed: Unknown
Type: EDO DIMM
Installed Size: 1024 MB (Single-bank Connection)
Enabled Size: 1024 MB (Single-bank Connection)
Error Status: OK
Handle 0x000A, DMI type 6, 12 bytes
Memory Module Information
Socket Designation: RAM socket #1
Bank Connections: 2 3
Current Speed: Unknown
Type: EDO DIMM
Installed Size: Not Installed
Enabled Size: Not Installed
Error Status: OK
Handle 0x000B, DMI type 6, 12 bytes
Memory Module Information
Socket Designation: RAM socket #2
Bank Connections: 4 5
Current Speed: Unknown
Type: EDO DIMM
Installed Size: Not Installed
Enabled Size: Not Installed
Error Status: OK
Handle 0x000C, DMI type 6, 12 bytes
Memory Module Information
Socket Designation: RAM socket #3
Bank Connections: 6 7
Current Speed: Unknown
Type: EDO DIMM
Installed Size: Not Installed
Enabled Size: Not Installed
Error Status: OK
Following are the DMI types details.
Type Information
----------------------------------------
0 BIOS
1 System
2 Base Board
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
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
Instead of going with ‘type_id‘ you can also use keyword with ‘-t‘ argument to the dmidecode command. Following are the list of available keywords.
Keyword Types
------------------------------
bios 0, 13
system 1, 12, 15, 23, 32
baseboard 2, 10
chassis 3
processor 4
memory 5, 6, 16, 17
cache 7
connector 8
slot 9
For example, to get the Cache information on system, you can execute below command instead of Id 7.
[root@tecmint ~]# dmidecode -t cache
# dmidecode 2.11
SMBIOS version fixup (2.31 -> 2.3).
SMBIOS 2.3 present.
Handle 0x000D, DMI type 7, 19 bytes
Cache Information
Socket Designation: L1 Cache
Configuration: Enabled, Socketed, Level 1
Operational Mode: Write Back
Location: Internal
Installed Size: 16 kB
Maximum Size: 16 kB
Supported SRAM Types:
Burst
Pipeline Burst
Asynchronous
Installed SRAM Type: Asynchronous
Speed: Unknown
Error Correction Type: Unknown
System Type: Unknown
Associativity: Unknown
Handle 0x000E, DMI type 7, 19 bytes
Cache Information
Socket Designation: L2 Cache
Configuration: Enabled, Socketed, Level 2
Operational Mode: Write Back
Location: External
Installed Size: 0 kB
Maximum Size: 512 kB
Supported SRAM Types:
Burst
Pipeline Burst
Asynchronous
Installed SRAM Type: None
Speed: Unknown
Error Correction Type: Unknown
System Type: Unknown
Associativity: Unknown
3. How to Get Memory Information
How do i get Memory information on system and how much memory is supported by system? The following command shows that the system can support maximum 4GB of RAM.
[root@tecmint ~]# dmidecode -t 16
# dmidecode 2.11
SMBIOS version fixup (2.31 -> 2.3).
SMBIOS 2.3 present.
Handle 0x001D, DMI type 16, 15 bytes
Physical Memory Array
Location: System Board Or Motherboard
Use: System Memory
Error Correction Type: None
Maximum Capacity: 4 GB
Error Information Handle: Not Provided
Number Of Devices: 4
Note: From the keyword list the memory related information IDs are 5, 6, 16 and 17.
4. How Do I Get BIOS information?
To get the BIOS information of the system, run the following command with ‘-t’ option.
[root@tecmint ~]# dmidecode -t bios
# dmidecode 2.11
SMBIOS version fixup (2.31 -> 2.3).
SMBIOS 2.3 present.
Handle 0x0000, DMI type 0, 20 bytes
BIOS Information
Vendor: Phoenix Technologies LTD
Version: 6.00
Release Date: 12/06/2006
Address: 0xE78A0
Runtime Size: 100192 bytes
ROM Size: 64 kB
Characteristics:
ISA is supported
PCI is supported
PC Card (PCMCIA) is supported
PNP is supported
APM is supported
BIOS is upgradeable
BIOS shadowing is allowed
ESCD support is available
USB legacy is supported
Smart battery is supported
BIOS boot specification is supported
5. How Do I Get the Manufacturer, Model and Serial Number?
To get the information about Manufacturer, Model and Serial Number of system, use the following command as shown below.
[root@tecmint ~]# dmidecode -t system
# dmidecode 2.11
SMBIOS 2.4 present.
Handle 0x0001, DMI type 1, 27 bytes
System Information
Manufacturer: LENOVO
Product Name: 9637C76
Version: ThinkCentre M55e
Serial Number: L9BT188
UUID: 8015D37A-2F82-DC11-A3FB-8C6E4EBAD5CE
Wake-up Type: AC Power Restored
SKU Number: Not Specified
Family: Not Specified
Handle 0x000F, DMI type 12, 5 bytes
System Configuration Options
Option 1: Jumper settings can be described here.
Handle 0x0010, DMI type 15, 29 bytes
System Event Log
Area Length: 432 bytes
Header Start Offset: 0x0000
Header Length: 16 bytes
Data Start Offset: 0x0010
Access Method: General-purpose non-volatile data functions
Access Address: 0x0000
Status: Valid, Not Full
Change Token: 0x0000001A
Header Format: Type 1
Supported Log Type Descriptors: 3
Descriptor 1: POST error
Data Format 1: POST results bitmap
Descriptor 2: Single-bit ECC memory error
Data Format 2: Multiple-event
Descriptor 3: Multi-bit ECC memory error
Data Format 3: Multiple-event
Handle 0x0017, DMI type 23, 13 bytes
System Reset
Status: Enabled
Watchdog Timer: Present
Boot Option: Do Not Reboot
Boot Option On Limit: Do Not Reboot
Reset Count: Unknown
Reset Limit: Unknown
Timer Interval: Unknown
Timeout: Unknown
Handle 0x001F, DMI type 32, 20 bytes
System Boot Information
Status:
Please run ‘man dmidecode‘ from terminal or command prompt to know more about dmidecode.
Read Also: 10 Command Line Tools to Get Linux Hardware Information
Very very useful …
Very useful to have known about dmidecode. Thanks
Good article Ravi. Plenty of times that I’ve needed to locate information about my system and knowing how to use dmidecode would have saved a bunch of time searching through technical documentation!
@Rob,
Thanks for liking my article..:)