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DMIDECODE(8)		    System Manager's Manual		  DMIDECODE(8)

NAME
       dmidecode - DMI table decoder

SYNOPSIS
       dmidecode [OPTIONS]

DESCRIPTION
       dmidecode  is a tool for	dumping	a computer's DMI (some say SMBIOS) ta-
       ble contents in a human-readable	format.	This table contains a descrip-
       tion  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 di-
       rectly 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:

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

       o 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".

       o 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.

       o 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.

OPTIONS
       -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,	 bios-revision,	firmware-revi-
	      sion, system-manufacturer, system-product-name,  system-version,
	      system-serial-number,  system-uuid,  system-sku-number,  system-
	      family,  baseboard-manufacturer,	baseboard-product-name,	 base-
	      board-version,   baseboard-serial-number,	  baseboard-asset-tag,
	      chassis-manufacturer, chassis-type, chassis-version, chassis-se-
	      rial-number, chassis-asset-tag, processor-family,	processor-man-
	      ufacturer, 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  sys-
	      tem).   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/de-
	      vices/virtual/dmi/id.   Most of these files are even readable by
	      regular users.

       -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,	 chas-
	      sis, 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 er-
	      ror.

       -H, --handle HANDLE
	      Only display the entry whose handle matches HANDLE.  HANDLE is a
	      16-bit integer.

       -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
	      --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 num-
	      ber of OEM strings instead.

       -h, --help
	      Display usage information	and exit

       -V, --version
	      Display the version and exit

       Options	--string,  --type,  --dump-bin	and --oem-string 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 re-
       liable.

DMI TYPES
       The SMBIOS specification	defines	the following DMI types:

       Type   Information
       --------------------------------------------
	  0   BIOS
	  1   System
	  2   Baseboard
	  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 Devices Extended Information
	 42   Management Controller Host Interface

       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:

       o dmidecode --type 0 --type 13

       o dmidecode --type 0,13

       o dmidecode --type bios

       o dmidecode --type BIOS

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

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

       o The DMI table is located at offset 0x20.

UUID FORMAT
       There is	some ambiguity about how to interpret the UUID fields prior to
       SMBIOS specification version 2.6. There was no mention  of  byte	 swap-
       ping,  and RFC 4122 says	that no	byte swapping should be	applied	by de-
       fault. However, SMBIOS specification version 2.6	(and later) explicitly
       states that the first 3 fields of the UUID should be read as little-en-
       dian numbers (byte-swapped).  Furthermore, it implies that the same was
       already	true  for  older versions of the specification,	even though it
       was not mentioned. In practice, many hardware vendors  were  not	 byte-
       swapping	 the  UUID. So,	in order to preserve compatibility, it was de-
       cided to	interpret the UUID fields according to RFC 4122	(no byte swap-
       ping)  when  the	SMBIOS version is older	than 2.6, and to interpret the
       first 3 fields as little-endian (byte-swapped) when the SMBIOS  version
       is 2.6 or later.	The Linux kernel follows the same logic.

FILES
       /dev/mem
       /sys/firmware/dmi/tables/smbios_entry_point (Linux only)
       /sys/firmware/dmi/tables/DMI (Linux only)

BUGS
       More often than not, information	contained in the DMI tables is inaccu-
       rate, incomplete	or simply wrong.

AUTHORS
       Alan Cox, Jean Delvare

SEE ALSO
       biosdecode(8), mem(4), ownership(8), vpddecode(8)

dmidecode			 January 2019			  DMIDECODE(8)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | DMI TYPES | BINARY DUMP FILE FORMAT | UUID FORMAT | FILES | BUGS | AUTHORS | SEE ALSO

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