{ "mode": "man", "parameter": "dmidecode", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/dmidecode/8/json", "generated": "2026-10-04T16:32:34Z", "synopsis": "dmidecode [OPTIONS]", "sections": { "NAME": { "content": "dmidecode - DMI table decoder\n", "subsections": [] }, "SYNOPSIS": { "content": "dmidecode [OPTIONS]\n", "subsections": [] }, "DESCRIPTION": { "content": "dmidecode is a tool for dumping a computer's DMI (some say SMBIOS) table contents in a human-\nreadable format. This table contains a description of the system's hardware components, as\nwell as other useful pieces of information such as serial numbers and BIOS revision. Thanks\nto this table, you can retrieve this information without having to probe for the actual hard‐\nware. While this is a good point in terms of report speed and safeness, this also makes the\npresented information possibly unreliable.\n\nThe DMI table doesn't only describe what the system is currently made of, it also can report\nthe possible evolutions (such as the fastest supported CPU or the maximal amount of memory\nsupported).\n\nSMBIOS stands for System Management BIOS, while DMI stands for Desktop Management Interface.\nBoth standards are tightly related and developed by the DMTF (Desktop Management Task Force).\n\nAs you run it, dmidecode will try to locate the DMI table. It will first try to read the DMI\ntable from sysfs, and next try reading directly from memory if sysfs access failed. If\ndmidecode succeeds in locating a valid DMI table, it will then parse this table and display a\nlist of records like this one:\n\nHandle 0x0002, DMI type 2, 8 bytes. Base Board Information\nManufacturer: Intel\nProduct Name: C440GX+\nVersion: 727281-001\nSerial Number: INCY92700942\n\nEach record has:\n\n• A handle. This is a unique identifier, which allows records to reference each other. For\nexample, processor records usually reference cache memory records using their handles.\n\n• A type. The SMBIOS specification defines different types of elements a computer can be made\nof. In this example, the type is 2, which means that the record contains \"Base Board Infor‐\nmation\".\n\n• A size. Each record has a 4-byte header (2 for the handle, 1 for the type, 1 for the size),\nthe rest is used by the record data. This value doesn't take text strings into account\n(these are placed at the end of the record), so the actual length of the record may be (and\nis often) greater than the displayed value.\n\n• Decoded values. The information presented of course depends on the type of record. Here, we\nlearn about the board's manufacturer, model, version and serial number.\n", "subsections": [] }, "OPTIONS": { "content": "", "subsections": [ { "name": "-d --dev-mem _", "content": "Read memory from device FILE (default: /dev/mem)\n", "flag": "-d", "long": "--dev-mem" }, { "name": "-q --quiet", "content": "Be less verbose. Unknown, inactive and OEM-specific entries are not displayed. Meta-\ndata and handle references are hidden.\n\n--no-quirks\nDecode everything exactly as it is in the table, without trying to fix up common mis‐\ntakes or hide irrelevant fields. This mode is primarily aimed at firmware developers.\n", "flag": "-q", "long": "--quiet" }, { "name": "-s --string _", "content": "Only display the value of the DMI string identified by KEYWORD. It must be a keyword\nfrom the following list: bios-vendor, bios-version, bios-release-date, bios-revision,\nfirmware-revision, system-manufacturer, system-product-name, system-version,\nsystem-serial-number, system-uuid, system-sku-number, system-family,\nbaseboard-manufacturer, baseboard-product-name, baseboard-version,\nbaseboard-serial-number, baseboard-asset-tag, chassis-manufacturer, chassis-type,\nchassis-version, chassis-serial-number, chassis-asset-tag, processor-family,\nprocessor-manufacturer, processor-version, processor-frequency. Each keyword corre‐\nsponds to a given DMI type and a given offset within this entry type. Not all strings\nmay be meaningful or even defined on all systems. Some keywords may return more than\none result on some systems (e.g. processor-version on a multi-processor system). If\nKEYWORD is not provided or not valid, a list of all valid keywords is printed and\ndmidecode exits with an error. This option cannot be used more than once.\n\nNote: on Linux, most of these strings can alternatively be read directly from sysfs,\ntypically from files under /sys/devices/virtual/dmi/id. Most of these files are even\nreadable by regular users.\n", "flag": "-s", "long": "--string" }, { "name": "-t --type _", "content": "Only display the entries of type TYPE. It can be either a DMI type number, or a comma-\nseparated list of type numbers, or a keyword from the following list: bios, system,\nbaseboard, chassis, processor, memory, cache, connector, slot. Refer to the DMI TYPES\nsection below for details. If this option is used more than once, the set of dis‐\nplayed entries will be the union of all the given types. If TYPE is not provided or\nnot valid, a list of all valid keywords is printed and dmidecode exits with an error.\n", "flag": "-t", "long": "--type" }, { "name": "-H --handle _", "content": "Only display the entry whose handle matches HANDLE. HANDLE is a 16-bit integer.\n", "flag": "-H", "long": "--handle" }, { "name": "-u --dump", "content": "Do not decode the entries, dump their contents as hexadecimal instead. Note that this\nis still a text output, no binary data will be thrown upon you. The strings attached\nto each entry are displayed as both hexadecimal and ASCII. This option is mainly use‐\nful for debugging.\n\n--dump-bin FILE\nDo not decode the entries, instead dump the DMI data to a file in binary form. The\ngenerated file is suitable to pass to --from-dump later. FILE must not exist.\n\n--from-dump FILE\nRead the DMI data from a binary file previously generated using --dump-bin.\n\n--no-sysfs\nDo not attempt to read DMI data from sysfs files. This is mainly useful for debugging.\n\n--oem-string N\nOnly display the value of the OEM string number N. The first OEM string has number 1.\nWith special value count, return the number of OEM strings instead.\n", "flag": "-u", "long": "--dump" }, { "name": "-h --help", "content": "Display usage information and exit\n", "flag": "-h", "long": "--help" }, { "name": "-V --version", "content": "Display the version and exit\n\nOptions --string, --type, --dump-bin and --oem-string determine the output format and are mu‐\ntually exclusive.\n\nPlease note in case of dmidecode is run on a system with BIOS that boasts new SMBIOS specifi‐\ncation, which is not supported by the tool yet, it will print out relevant message in addi‐\ntion to requested data on the very top of the output. Thus informs the output data is not re‐\nliable.\n", "flag": "-V", "long": "--version" } ] }, "DMI TYPES": { "content": "The SMBIOS specification defines the following DMI types:\nType Information\n────────────────────────────────────────────\n0 BIOS\n1 System\n2 Baseboard\n3 Chassis\n4 Processor\n5 Memory Controller\n6 Memory Module\n7 Cache\n8 Port Connector\n9 System Slots\n10 On Board Devices\n11 OEM Strings\n12 System Configuration Options\n13 BIOS Language\n14 Group Associations\n15 System Event Log\n16 Physical Memory Array\n17 Memory Device\n18 32-bit Memory Error\n19 Memory Array Mapped Address\n20 Memory Device Mapped Address\n21 Built-in Pointing Device\n22 Portable Battery\n23 System Reset\n24 Hardware Security\n25 System Power Controls\n26 Voltage Probe\n27 Cooling Device\n28 Temperature Probe\n29 Electrical Current Probe\n30 Out-of-band Remote Access\n31 Boot Integrity Services\n32 System Boot\n33 64-bit Memory Error\n34 Management Device\n35 Management Device Component\n36 Management Device Threshold Data\n37 Memory Channel\n38 IPMI Device\n39 Power Supply\n40 Additional Information\n41 Onboard Devices Extended Information\n42 Management Controller Host Interface\n\nAdditionally, type 126 is used for disabled entries and type 127 is an end-of-table marker.\nTypes 128 to 255 are for OEM-specific data. dmidecode will display these entries by default,\nbut it can only decode them when the vendors have contributed documentation or code for them.\n\nKeywords can be used instead of type numbers with --type. Each keyword is equivalent to a\nlist of type numbers:\n\nKeyword Types\n──────────────────────────────\nbios 0, 13\nsystem 1, 12, 15, 23, 32\nbaseboard 2, 10, 41\nchassis 3\nprocessor 4\nmemory 5, 6, 16, 17\ncache 7\nconnector 8\nslot 9\n\nKeywords are matched case-insensitively. The following command lines are equivalent:\n\n• dmidecode --type 0 --type 13\n\n• dmidecode --type 0,13\n\n• dmidecode --type bios\n\n• dmidecode --type BIOS\n", "subsections": [] }, "BINARY DUMP FILE FORMAT": { "content": "The binary dump files generated by --dump-bin and read using --from-dump are formatted as\nfollows:\n\n• The SMBIOS or DMI entry point is located at offset 0x00. It is crafted to hard-code the\ntable address at offset 0x20.\n\n• The DMI table is located at offset 0x20.\n", "subsections": [] }, "UUID FORMAT": { "content": "There is some ambiguity about how to interpret the UUID fields prior to SMBIOS specification\nversion 2.6. There was no mention of byte swapping, and RFC 4122 says that no byte swapping\nshould be applied by default. However, SMBIOS specification version 2.6 (and later) explicit‐\nly states that the first 3 fields of the UUID should be read as little-endian numbers (byte-\nswapped). Furthermore, it implies that the same was already true for older versions of the\nspecification, even though it was not mentioned. In practice, many hardware vendors were not\nbyte-swapping the UUID. So, in order to preserve compatibility, it was decided to interpret\nthe UUID fields according to RFC 4122 (no byte swapping) when the SMBIOS version is older\nthan 2.6, and to interpret the first 3 fields as little-endian (byte-swapped) when the SMBIOS\nversion is 2.6 or later. The Linux kernel follows the same logic.\n", "subsections": [] }, "FILES": { "content": "/dev/mem\n/sys/firmware/dmi/tables/smbiosentrypoint (Linux only)\n/sys/firmware/dmi/tables/DMI (Linux only)\n", "subsections": [] }, "BUGS": { "content": "More often than not, information contained in the DMI tables is inaccurate, incomplete or\nsimply wrong.\n", "subsections": [] }, "AUTHORS": { "content": "Alan Cox, Jean Delvare\n", "subsections": [] }, "SEE ALSO": { "content": "biosdecode(8), mem(4), ownership(8), vpddecode(8)\n\ndmidecode February 2023 DMIDECODE(8)", "subsections": [] } }, "summary": "dmidecode - DMI table decoder", "flags": [ { "flag": "-d", "long": "--dev-mem", "arg": null, "description": "Read memory from device FILE (default: /dev/mem)" }, { "flag": "-q", "long": "--quiet", "arg": null, "description": "Be less verbose. Unknown, inactive and OEM-specific entries are not displayed. Meta- data and handle references are hidden. --no-quirks Decode everything exactly as it is in the table, without trying to fix up common mis‐ takes or hide irrelevant fields. This mode is primarily aimed at firmware developers." }, { "flag": "-s", "long": "--string", "arg": null, "description": "Only display the value of the DMI string identified by KEYWORD. It must be a keyword from the following list: bios-vendor, bios-version, bios-release-date, bios-revision, firmware-revision, system-manufacturer, system-product-name, system-version, system-serial-number, system-uuid, system-sku-number, system-family, 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 corre‐ sponds 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. 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." }, { "flag": "-t", "long": "--type", "arg": null, "description": "Only display the entries of type TYPE. It 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 dis‐ played 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." }, { "flag": "-H", "long": "--handle", "arg": null, "description": "Only display the entry whose handle matches HANDLE. HANDLE is a 16-bit integer." }, { "flag": "-u", "long": "--dump", "arg": null, "description": "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 use‐ ful 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. FILE must not exist. --from-dump FILE Read the DMI data from a binary file previously generated using --dump-bin. --no-sysfs Do not attempt to read DMI data from sysfs files. This is mainly useful for debugging. --oem-string N Only display the value of the OEM string number N. The first OEM string has number 1. With special value count, return the number of OEM strings instead." }, { "flag": "-h", "long": "--help", "arg": null, "description": "Display usage information and exit" }, { "flag": "-V", "long": "--version", "arg": null, "description": "Display the version and exit Options --string, --type, --dump-bin and --oem-string determine the output format and are mu‐ tually exclusive. Please note in case of dmidecode is run on a system with BIOS that boasts new SMBIOS specifi‐ cation, which is not supported by the tool yet, it will print out relevant message in addi‐ tion to requested data on the very top of the output. Thus informs the output data is not re‐ liable." } ], "examples": [], "see_also": [ { "name": "biosdecode", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/biosdecode/8/json" }, { "name": "mem", "section": "4", "url": "https://www.chedong.com/phpMan.php/man/mem/4/json" }, { "name": "ownership", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/ownership/8/json" }, { "name": "vpddecode", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vpddecode/8/json" } ] }