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 Please note in case of dmidecode is run on a system with BIOS that
124 boasts new SMBIOS specification, which is not supported by the tool
125 yet, it will print out relevant message in addition to requested data
126 on the very top of the output. Thus informs the output data is not
127 reliable.
128
131 The SMBIOS specification defines the following DMI types:
132 Type Information
136 ────────────────────────────────────────────
137 0 BIOS
138 1 System
139 2 Baseboard
140 3 Chassis
141 4 Processor
142 5 Memory Controller
143 6 Memory Module
144 7 Cache
145 8 Port Connector
146 9 System Slots
147 10 On Board Devices
148 11 OEM Strings
149 12 System Configuration Options
150 13 BIOS Language
151 14 Group Associations
152 15 System Event Log
153 16 Physical Memory Array
154 17 Memory Device
155 18 32-bit Memory Error
156 19 Memory Array Mapped Address
157 20 Memory Device Mapped Address
158 21 Built-in Pointing Device
159 22 Portable Battery
160 23 System Reset
161 24 Hardware Security
162 25 System Power Controls
163 26 Voltage Probe
164 27 Cooling Device
165 28 Temperature Probe
166 29 Electrical Current Probe
167 30 Out-of-band Remote Access
168 31 Boot Integrity Services
169 32 System Boot
170 33 64-bit Memory Error
171 34 Management Device
172 35 Management Device Component
173 36 Management Device Threshold Data
174 37 Memory Channel
175 38 IPMI Device
176 39 Power Supply
177 40 Additional Information
178 41 Onboard Devices Extended Information
179 42 Management Controller Host Interface
180 Additionally, type 126 is used for disabled entries and type 127 is an
182 end-of-table marker. Types 128 to 255 are for OEM-specific data.
183 dmidecode will display these entries by default, but it can only decode
184 them when the vendors have contributed documentation or code for them.
185 Keywords can be used instead of type numbers with --type. Each keyword
187 is equivalent to a list of type numbers:
188 Keyword Types
191 ──────────────────────────────
192 bios 0, 13
193 system 1, 12, 15, 23, 32
194 baseboard 2, 10, 41
195 chassis 3
196 processor 4
197 memory 5, 6, 16, 17
198 cache 7
199 connector 8
200 slot 9
201 Keywords are matched case-insensitively. The following command lines
203 are equivalent:
204 · dmidecode --type 0 --type 13
206 · dmidecode --type 0,13
208 · dmidecode --type bios
210 · dmidecode --type BIOS
212
215 The binary dump files generated by --dump-bin and read using --from-
216 dump are formatted as follows:
217 · The SMBIOS or DMI entry point is located at offset 0x00. It is
219 crafted to hard-code the table address at offset 0x20.
220 · The DMI table is located at offset 0x20.
222
225 /dev/mem
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228 More often than not, information contained in the DMI tables is inaccu‐
229 rate, incomplete or simply wrong.
230
232 Alan Cox, Jean Delvare
233
235 biosdecode(8), mem(4), ownership(8), vpddecode(8)
236dmidecode March 2012 DMIDECODE(8)