1DMIDECODE(8)                System Manager's Manual               DMIDECODE(8)
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NAME

6       dmidecode - DMI table decoder
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SYNOPSIS

9       dmidecode [OPTIONS]
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11

DESCRIPTION

13       dmidecode  is a tool for dumping a computer's DMI (some say SMBIOS) ta‐
14       ble contents in a human-readable format. This table contains a descrip‐
15       tion  of  the  system's  hardware  components,  as well as other useful
16       pieces of information such as serial numbers and BIOS revision.  Thanks
17       to  this  table,  you  can  retrieve this information without having to
18       probe for the actual hardware.  While this is a good point in terms  of
19       report  speed  and  safeness, this also makes the presented information
20       possibly unreliable.
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22       The DMI table doesn't only describe what the system is  currently  made
23       of,  it  also  can  report the possible evolutions (such as the fastest
24       supported CPU or the maximal amount of memory supported).
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26       SMBIOS stands for System Management BIOS, while DMI stands for  Desktop
27       Management  Interface. Both standards are tightly related and developed
28       by the DMTF (Desktop Management Task Force).
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30       As you run it, dmidecode will try to locate  the  DMI  table.  It  will
31       first  try  to  read  the  DMI  table  from sysfs, and next try reading
32       directly from memory if sysfs access failed.  If dmidecode succeeds  in
33       locating a valid DMI table, it will then parse this table and display a
34       list of records like this one:
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36       Handle 0x0002, DMI type 2, 8 bytes.  Base Board Information
37               Manufacturer: Intel
38               Product Name: C440GX+
39               Version: 727281-001
40               Serial Number: INCY92700942
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42       Each record has:
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44       · A handle. This is a unique identifier, which allows records to refer‐
45         ence  each  other.  For  example, processor records usually reference
46         cache memory records using their handles.
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48       · A type. The SMBIOS specification defines different types of  elements
49         a  computer  can  be  made  of. In this example, the type is 2, which
50         means that the record contains "Base Board Information".
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52       · A size. Each record has a 4-byte header (2 for the handle, 1 for  the
53         type,  1  for  the  size),  the rest is used by the record data. This
54         value doesn't take text strings into account (these are placed at the
55         end of the record), so the actual length of the record may be (and is
56         often) greater than the displayed value.
57
58       · Decoded values. The information presented of course  depends  on  the
59         type of record. Here, we learn about the board's manufacturer, model,
60         version and serial number.
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62

OPTIONS

64       -d, --dev-mem FILE
65              Read memory from device FILE (default: /dev/mem)
66
67       -q, --quiet
68              Be less verbose. Unknown, inactive and OEM-specific entries  are
69              not displayed. Meta-data and handle references are hidden.
70
71       -s, --string KEYWORD
72              Only  display the value of the DMI string identified by KEYWORD.
73              KEYWORD must be a keyword from the following list:  bios-vendor,
74              bios-version,  bios-release-date,  system-manufacturer,  system-
75              product-name, system-version, system-serial-number, system-uuid,
76              system-family,  baseboard-manufacturer,  baseboard-product-name,
77              baseboard-version, baseboard-serial-number, baseboard-asset-tag,
78              chassis-manufacturer,  chassis-type,  chassis-version,  chassis-
79              serial-number, chassis-asset-tag,  processor-family,  processor-
80              manufacturer, processor-version, processor-frequency.  Each key‐
81              word corresponds to a given DMI type and a given  offset  within
82              this  entry  type.   Not  all  strings may be meaningful or even
83              defined on all systems. Some keywords may return more  than  one
84              result  on some systems (e.g.  processor-version on a multi-pro‐
85              cessor system).  If KEYWORD is not provided or not valid, a list
86              of  all  valid  keywords  is printed and dmidecode exits with an
87              error.  This option cannot be used more than once.
88
89              Note: on Linux, most of these strings can alternatively be  read
90              directly    from    sysfs,    typically    from    files   under
91              /sys/devices/virtual/dmi/id.  Most of these files are even read‐
92              able by regular users.
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94       -t, --type TYPE
95              Only  display the entries of type TYPE. TYPE can be either a DMI
96              type number, or a comma-separated list of  type  numbers,  or  a
97              keyword  from the following list: bios, system, baseboard, chas‐
98              sis, processor, memory, cache, connector, slot. Refer to the DMI
99              TYPES  section  below  for details.  If this option is used more
100              than once, the set of displayed entries will be the union of all
101              the  given  types.  If TYPE is not provided or not valid, a list
102              of all valid keywords is printed and  dmidecode  exits  with  an
103              error.
104
105       -H, --handle HANDLE
106              Only display the entry whose handle matches HANDLE.  HANDLE is a
107              16-bit integer.
108
109       -u, --dump
110              Do not decode the entries, dump their  contents  as  hexadecimal
111              instead.   Note that this is still a text output, no binary data
112              will be thrown upon you. The strings attached to each entry  are
113              displayed  as  both hexadecimal and ASCII. This option is mainly
114              useful for debugging.
115
116           --dump-bin FILE
117              Do not decode the entries, instead dump the DMI data to  a  file
118              in  binary  form.  The  generated  file  is  suitable to pass to
119              --from-dump later.
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121           --from-dump FILE
122              Read the DMI data from a binary file previously generated  using
123              --dump-bin.
124
125           --no-sysfs
126              Do not attempt to read DMI data from sysfs files. This is mainly
127              useful for debugging.
128
129           --oem-string N
130              Only display the value of the OEM string number N. The first OEM
131              string has number 1. With special value "count", return the num‐
132              ber of OEM strings instead.
133
134       -h, --help
135              Display usage information and exit
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137       -V, --version
138              Display the version and exit
139
140       Options --string, --type, --dump-bin  and  --oem-string  determine  the
141       output format and are mutually exclusive.
142
143       Please  note  in  case  of  dmidecode is run on a system with BIOS that
144       boasts new SMBIOS specification, which is not  supported  by  the  tool
145       yet,  it  will print out relevant message in addition to requested data
146       on the very top of the output. Thus informs  the  output  data  is  not
147       reliable.
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149

DMI TYPES

151       The SMBIOS specification defines the following DMI types:
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153
154       Type   Information
155       ────────────────────────────────────────────
156          0   BIOS
157          1   System
158          2   Baseboard
159          3   Chassis
160          4   Processor
161          5   Memory Controller
162          6   Memory Module
163          7   Cache
164          8   Port Connector
165          9   System Slots
166         10   On Board Devices
167         11   OEM Strings
168         12   System Configuration Options
169         13   BIOS Language
170         14   Group Associations
171         15   System Event Log
172         16   Physical Memory Array
173         17   Memory Device
174         18   32-bit Memory Error
175         19   Memory Array Mapped Address
176         20   Memory Device Mapped Address
177         21   Built-in Pointing Device
178         22   Portable Battery
179         23   System Reset
180         24   Hardware Security
181         25   System Power Controls
182         26   Voltage Probe
183         27   Cooling Device
184         28   Temperature Probe
185         29   Electrical Current Probe
186         30   Out-of-band Remote Access
187         31   Boot Integrity Services
188         32   System Boot
189         33   64-bit Memory Error
190         34   Management Device
191         35   Management Device Component
192         36   Management Device Threshold Data
193         37   Memory Channel
194         38   IPMI Device
195         39   Power Supply
196         40   Additional Information
197         41   Onboard Devices Extended Information
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199         42   Management Controller Host Interface
200
201       Additionally,  type 126 is used for disabled entries and type 127 is an
202       end-of-table marker. Types  128  to  255  are  for  OEM-specific  data.
203       dmidecode will display these entries by default, but it can only decode
204       them when the vendors have contributed documentation or code for them.
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206       Keywords can be used instead of type numbers with --type.  Each keyword
207       is equivalent to a list of type numbers:
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209
210       Keyword     Types
211       ──────────────────────────────
212       bios        0, 13
213       system      1, 12, 15, 23, 32
214       baseboard   2, 10, 41
215       chassis     3
216       processor   4
217       memory      5, 6, 16, 17
218       cache       7
219       connector   8
220       slot        9
221
222       Keywords  are  matched  case-insensitively. The following command lines
223       are equivalent:
224
225       · dmidecode --type 0 --type 13
226
227       · dmidecode --type 0,13
228
229       · dmidecode --type bios
230
231       · dmidecode --type BIOS
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233

BINARY DUMP FILE FORMAT

235       The binary dump files generated by --dump-bin and  read  using  --from-
236       dump are formatted as follows:
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238       · The  SMBIOS  or  DMI  entry  point  is located at offset 0x00.  It is
239         crafted to hard-code the table address at offset 0x20.
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241       · The DMI table is located at offset 0x20.
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FILES

245       /dev/mem   /sys/firmware/dmi/tables/smbios_entry_point   (Linux   only)
246       /sys/firmware/dmi/tables/DMI (Linux only)
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BUGS

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

253       Alan Cox, Jean Delvare
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SEE ALSO

256       biosdecode(8), mem(4), ownership(8), vpddecode(8)
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260dmidecode                         March 2012                      DMIDECODE(8)
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