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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.
	      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 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.

	      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.	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 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.

       -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	number
	      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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