Skip site navigation (1)Skip section navigation (2)

FreeBSD Man Pages

Man Page or Keyword Search:
Man Architecture
Apropos Keyword Search (all sections) Output format
home | help
DMIDECODE(8)            FreeBSD System Manager's Manual           DMIDECODE(8)

       dmidecode - DMI table decoder

       dmidecode [OPTIONS]

       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. If it
       succeeds, 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:

        A handle. This is a unique identifier, which allows records to
        reference each other. For example, processor records usually reference
        cache memory records using their handles.

        A type. The SMBIOS specification defines different types of elements a
        computer can be made of. In this example, the type is 2, which means
        that the record contains "Base Board Information".

        A size. Each record has a 4-byte header (2 for the handle, 1 for the
        type, 1 for the size), the rest is used by the record data. This value
        doesn't take text strings into account (these are placed at the end of
        the record), so the actual length of the record may be (and is often)
        greater than the displayed value.

        Decoded values. The information presented of course depends on the
        type of record. Here, we learn about the board's manufacturer, model,
        version and serial number.

       -d, --dev-mem FILE
              Read memory from device FILE (default: /dev/mem)

       -q, --quiet
              Be less verbose. Unknown, inactive and OEM-specific entries are
              not displayed. Meta-data and handle references are hidden.

       -s, --string KEYWORD
              Only display the value of the DMI string identified by KEYWORD.
              KEYWORD must be a keyword from the following list: bios-vendor,
              bios-version, bios-release-date, system-manufacturer, system-
              product-name, system-version, system-serial-number, system-uuid,
              baseboard-manufacturer, baseboard-product-name, baseboard-
              version, baseboard-serial-number, baseboard-asset-tag, chassis-
              manufacturer, chassis-type, chassis-version, chassis-serial-
              number, chassis-asset-tag, processor-family, processor-
              manufacturer, processor-version, processor-frequency.  Each
              keyword corresponds to a given DMI type and a given offset
              within this entry type.  Not all strings may be meaningful or
              even defined on all systems. Some keywords may return more than
              one result on some systems (e.g.  processor-version on a multi-
              processor system).  If KEYWORD is not provided or not valid, a
              list of all valid keywords is printed and dmidecode exits with
              an error.  This option cannot be used more than once.

       -t, --type TYPE
              Only display the entries of type TYPE. TYPE can be either a DMI
              type number, or a comma-separated list of type numbers, or a
              keyword from the following list: bios, system, baseboard,
              chassis, processor, memory, cache, connector, slot. Refer to the
              DMI TYPES section below for details.  If this option is used
              more than once, the set of displayed entries will be the union
              of all the given types.  If TYPE is not provided or not valid, a
              list of all valid keywords is printed and dmidecode exits with
              an error.

       -u, --dump
              Do not decode the entries, dump their contents as hexadecimal
              instead.  Note that this is still a text output, no binary data
              will be thrown upon you. The strings attached to each entry are
              displayed as both hexadecimal and ASCII. This option is mainly
              useful for debugging.

           --dump-bin FILE
              Do not decode the entries, instead dump the DMI data to a file
              in binary form. The generated file is suitable to pass to
              --from-dump later.

           --from-dump FILE
              Read the DMI data from a binary file previously generated using

       -h, --help
              Display usage information and exit

       -V, --version
              Display the version and exit

       Options --string, --type and --dump-bin determine the output format and
       are mutually exclusive.

       The SMBIOS specification defines the following DMI types:

       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
         40   Additional Information
         41   Onboard Device

       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:

       Keyword     Types
       bios        0, 13
       system      1, 12, 15, 23, 32
       baseboard   2, 10, 41
       chassis     3
       processor   4
       memory      5, 6, 16, 17
       cache       7
       connector   8
       slot        9

       Keywords are matched case-insensitively. The following command lines
       are equivalent:

        dmidecode --type 0 --type 13

        dmidecode --type 0,13

        dmidecode --type bios

        dmidecode --type BIOS

       The binary dump files generated by --dump-bin and read using --from-
       dump are formatted as follows:

        The SMBIOS or DMI entry point is located at offset 0x00.  It is
        crafted to hard-code the table address at offset 0x20.

        The DMI table is located at offset 0x20.


       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)

dmidecode                        November 2008                    DMIDECODE(8)


Want to link to this manual page? Use this URL:

home | help