- Show all DMI table contents:sudo dmidecode- Show the BIOS version:sudo dmidecode -s bios-version- Show the system's serial number:sudo dmidecode -s system-serial-number- Show BIOS information:sudo dmidecode -t bios- Show CPU information:sudo dmidecode -t processor- Show memory information:sudo dmidecode -t memory
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. Thanks to this table, you can retrieve this information without having to probe for the actual hardware. While this is a good point in terms of report speed and safeness, this also makes the presented information possibly unreliable.
The DMI table doesn't only describe what the system is currently made of, it also can report the possible evolutions (such as the fastest supported CPU or the maximal amount of memory supported).
SMBIOS stands for System Management BIOS, while DMI stands for Desktop Management Interface. Both standards are tightly related and developed by the DMTF (Desktop Management Task Force).
As you run it, dmidecode will try to locate the DMI table. It will first try to read the DMI table from sysfs, and next try reading directly from memory if sysfs access failed. If dmidecode succeeds in locating a valid DMI table, it will then parse this table and display a list of records like this one:
Handle 0x0002, DMI type 2, 8 bytes. Base Board Information Manufacturer: Intel Product Name: C440GX+ Version: 727281-001 Serial Number: INCY92700942
Each record has:
Note: on Linux, most of these strings can alternatively be read directly from sysfs, typically from files under /sys/devices/virtual/dmi/id. Most of these files are even readable by regular users.
Options --string, --type and --dump-bin determine the output format and are mutually exclusive.
Please note in case of dmidecode is run on a system with BIOS that boasts new SMBIOS specification, which is not supported by the tool yet, it will print out relevant message in addition to requested data on the very top of the output. Thus informs the output data is not reliable.
The SMBIOS specification defines the following DMI types:
Additionally, type 126 is used for disabled entries and type 127 is an end-of-table marker. Types 128 to 255 are for OEM-specific data. dmidecode will display these entries by default, but it can only decode them when the vendors have contributed documentation or code for them.
Keywords can be used instead of type numbers with --type. Each keyword is equivalent to a list of type numbers:
Keywords are matched case-insensitively. The following command lines are equivalent:
The binary dump files generated by --dump-bin and read using --from-dump are formatted as follows:
/dev/mem /sys/firmware/dmi/tables/smbios_entry_point (Linux only) /sys/firmware/dmi/tables/DMI (Linux only)
More often than not, information contained in the DMI tables is inaccurate, incomplete or simply wrong.
Alan Cox, Jean Delvare
biosdecode(8), mem(4), ownership(8), vpddecode(8)