How To Get Hardware Information On Linux Using dmidecode Command

dmidecode command reads the system DMI table to display hardware and BIOS information of the server. Apart from getting current configuration of the system, you can also get information about maximum supported configuration of the system using dmidecode. For example, dmidecode gives both the current RAM on the system and the maximum RAM supported by the system.

This article provides an overview of the dmidecode and few practical examples on how to use dmidecode command.

1. Overview of dmidecode

Distributed Management Task Force maintains the DMI specification and SMBIOS specification. The output of the dmidecode contains several records from the DMI (Desktop Management interface) table.

Following is the record format of the dmidecode output of the DMI table.

Record Header: Handle {record id}, DMI type {dmi type id}, {record size} bytes
Record Value: {multi line record value}

• record id: Unique identifier for every record in the DMI table.
• dmi type id: Type of the record. i.e BIOS, Memory etc.,
• record size: Size of the record in the DMI table.
• multi line record values: Multi line record value for that specific DMI type.

Sample output of dmidecode command:

# dmidecode | head -15

# dmidecode 2.9
SMBIOS 2.3 present.
56 structures occupying 1977 bytes.
Table at 0x000FB320.

Handle 0xDA00, DMI type 218, 11 bytes
OEM-specific Type
        Header and Data:
                DA 0B 00 DA B0 00 17 03 08 28 00

Handle 0x0000, DMI type 0, 20 bytes
BIOS Information
        Vendor: Dell Computer Corporation
        Version: A07
        Release Date: 01/13/2004

Get the total number of records in the DMI table as shown below:

# dmidecode | grep ^Handle | wc -l
56

(or)

# dmidecode | grep structures
56 structures occupying 1977 bytes.

2. DMI Types

DMI Type id will give information about a particular hardware component of your system. Following command with type id 4 will get the information about CPU of the system.

# dmidecode -t 4
# dmidecode 2.9
SMBIOS 2.3 present.

Handle 0x0400, DMI type 4, 35 bytes
Processor Information
        Socket Designation: Processor 1
        Type: Central Processor
        Family: Xeon
        Manufacturer: Intel
        ID: 29 0F 00 00 FF FB EB BF
        Signature: Type 0, Family 15, Model 2, Stepping 9
        Flags:
                FPU (Floating-point unit on-chip)
                VME (Virtual mode extension)
                DE (Debugging extension)
                PSE (Page size extension)
                TSC (Time stamp counter)
                MSR (Model specific registers)

Following are the different DMI types available.

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 type_id, you can also pass the keyword to the -t option of the dmidecode command. Following are the available keywords.