1DMIDECODE(8) System Manager's Manual DMIDECODE(8)
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6 dmidecode - DMI table decoder
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9 dmidecode [OPTIONS]
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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.
21 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).
25 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).
29 As you run it, dmidecode will try to locate the DMI table. If it suc‐
31 ceeds, it will then parse this table and display a list of records like
32 this one:
33 Handle 0x0002, DMI type 2, 8 bytes. Base Board Information
35 Manufacturer: Intel
36 Product Name: C440GX+
37 Version: 727281-001
38 Serial Number: INCY92700942
39 Each record has:
41 · A handle. This is a unique identifier, which allows records to refer‐
43 ence each other. For example, processor records usually reference
44 cache memory records using their handles.
45 · A type. The SMBIOS specification defines different types of elements
47 a computer can be made of. In this example, the type is 2, which
48 means that the record contains "Base Board Information".
49 · A size. Each record has a 4-byte header (2 for the handle, 1 for the
51 type, 1 for the size), the rest is used by the record data. This
52 value doesn't take text strings into account (these are placed at the
53 end of the record), so the actual length of the record may be (and is
54 often) greater than the displayed value.
55 · Decoded values. The information presented of course depends on the
57 type of record. Here, we learn about the board's manufacturer, model,
58 version and serial number.
59
62 -d, --dev-mem FILE
63 Read memory from device FILE (default: /dev/mem)
64 -q, --quiet
66 Be less verbose. Unknown, inactive and OEM-specific entries are
67 not displayed. Meta-data and handle references are hidden.
68 -s, --string KEYWORD
70 Only display the value of the DMI string identified by KEYWORD.
71 KEYWORD must be a keyword from the following list: bios-vendor,
72 bios-version, bios-release-date, system-manufacturer, system-
73 product-name, system-version, system-serial-number, system-uuid,
74 baseboard-manufacturer, baseboard-product-name, baseboard-ver‐
75 sion, baseboard-serial-number, baseboard-asset-tag, chassis-man‐
76 ufacturer, chassis-type, chassis-version, chassis-serial-number,
77 chassis-asset-tag, processor-family, processor-manufacturer,
78 processor-version, processor-frequency. Each keyword corre‐
79 sponds to a given DMI type and a given offset within this entry
80 type. Not all strings may be meaningful or even defined on all
81 systems. Some keywords may return more than one result on some
82 systems (e.g. processor-version on a multi-processor system).
83 If KEYWORD is not provided or not valid, a list of all valid
84 keywords is printed and dmidecode exits with an error. This
85 option cannot be used more than once.
86 -t, --type TYPE
88 Only display the entries of type TYPE. TYPE can be either a DMI
89 type number, or a comma-separated list of type numbers, or a
90 keyword from the following list: bios, system, baseboard, chas‐
91 sis, processor, memory, cache, connector, slot. Refer to the DMI
92 TYPES section below for details. If this option is used more
93 than once, the set of displayed entries will be the union of all
94 the given types. If TYPE is not provided or not valid, a list
95 of all valid keywords is printed and dmidecode exits with an
96 error.
97 -u, --dump
99 Do not decode the entries, dump their contents as hexadecimal
100 instead. Note that this is still a text output, no binary data
101 will be thrown upon you. The strings attached to each entry are
102 displayed as both hexadecimal and ASCII. This option is mainly
103 useful for debugging.
104 --dump-bin FILE
106 Do not decode the entries, instead dump the DMI data to a file
107 in binary form. The generated file is suitable to pass to
108 --from-dump later.
109 --from-dump FILE
111 Read the DMI data from a binary file previously generated using
112 --dump-bin.
113 -h, --help
115 Display usage information and exit
116 -V, --version
118 Display the version and exit
119 Options --string, --type and --dump-bin determine the output format and
121 are mutually exclusive.
122
125 The SMBIOS specification defines the following DMI types:
126 Type Information
129 ────────────────────────────────────────
130 0 BIOS
131 1 System
132 2 Base Board
133 3 Chassis
134 4 Processor
136 5 Memory Controller
137 6 Memory Module
138 7 Cache
139 8 Port Connector
140 9 System Slots
141 10 On Board Devices
142 11 OEM Strings
143 12 System Configuration Options
144 13 BIOS Language
145 14 Group Associations
146 15 System Event Log
147 16 Physical Memory Array
148 17 Memory Device
149 18 32-bit Memory Error
150 19 Memory Array Mapped Address
151 20 Memory Device Mapped Address
152 21 Built-in Pointing Device
153 22 Portable Battery
154 23 System Reset
155 24 Hardware Security
156 25 System Power Controls
157 26 Voltage Probe
158 27 Cooling Device
159 28 Temperature Probe
160 29 Electrical Current Probe
161 30 Out-of-band Remote Access
162 31 Boot Integrity Services
163 32 System Boot
164 33 64-bit Memory Error
165 34 Management Device
166 35 Management Device Component
167 36 Management Device Threshold Data
168 37 Memory Channel
169 38 IPMI Device
170 39 Power Supply
171 40 Additional Information
172 41 Onboard Device
173 Additionally, type 126 is used for disabled entries and type 127 is an
175 end-of-table marker. Types 128 to 255 are for OEM-specific data.
176 dmidecode will display these entries by default, but it can only decode
177 them when the vendors have contributed documentation or code for them.
178 Keywords can be used instead of type numbers with --type. Each keyword
180 is equivalent to a list of type numbers:
181 Keyword Types
184 ──────────────────────────────
185 bios 0, 13
186 system 1, 12, 15, 23, 32
187 baseboard 2, 10, 41
188 chassis 3
189 processor 4
190 memory 5, 6, 16, 17
191 cache 7
192 connector 8
193 slot 9
194 Keywords are matched case-insensitively. The following command lines
196 are equivalent:
197 · dmidecode --type 0 --type 13
199 · dmidecode --type 0,13
201 · dmidecode --type bios
203 · dmidecode --type BIOS
205
208 The binary dump files generated by --dump-bin and read using --from-
209 dump are formatted as follows:
210 · The SMBIOS or DMI entry point is located at offset 0x00. It is
212 crafted to hard-code the table address at offset 0x20.
213 · The DMI table is located at offset 0x20.
215
218 /dev/mem
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221 More often than not, information contained in the DMI tables is inaccu‐
222 rate, incomplete or simply wrong.
223
225 Alan Cox, Jean Delvare
226
228 biosdecode(8), mem(4), ownership(8), vpddecode(8)
229dmidecode November 2008 DMIDECODE(8)