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
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