DMIDECODE(8)                                                      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 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. If  it  suc
ceeds, it will then parse this table and display a list of records like
this one:

Handle 0×0002, 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 refer
ence  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. Mutu
ally exclusive with –dump.

-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-ver
sion, baseboard-serial-number, baseboard-asset-tag, chassis-man
ufacturer, 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, and implies –quiet.
Mutually exclusive with –type and –dump.

-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
error.  Mutually exclusive with –string.

-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.   Mutually  exclusive  with  –quiet  and

-h, –help
Display usage information and exit

-V, –version
Display the version and exit

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

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
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


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

Alan Cox, Jean Delvare

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

dmidecode                        February 2007                    DMIDECODE(8)