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
35 DMI type 2, 8 bytes.
36 Base Board Information
37 Manufacturer: Intel
38 Product Name: C440GX+
39 Version: 727281-001
40 Serial Number: INCY92700942
41 Each record has:
43 · 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.
47 · 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".
51 · 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 · 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.
61
64 -d, --dev-mem FILE
65 Read memory from device FILE (default: /dev/mem)
66 -q, --quiet
68 Be less verbose. Unknown, inactive and OEM-specific entries are
69 not displayed. Meta-data and handle references are hidden. Mutu‐
70 ally exclusive with --dump.
71 -s, --string KEYWORD
73 Only display the value of the DMI string identified by KEYWORD.
74 KEYWORD must be a keyword from the following list: bios-vendor,
75 bios-version, bios-release-date, system-manufacturer, system-
76 product-name, system-version, system-serial-number, baseboard-
77 manufacturer, baseboard-product-name, baseboard-version, base‐
78 board-serial-number, baseboard-asset-tag, chassis-manufacturer,
79 chassis-version, chassis-serial-number, chassis-asset-tag, pro‐
80 cessor-manufacturer, processor-version. Each keyword corre‐
81 sponds to a given DMI type and a given offset within this entry
82 type. Not all strings may be meaningful or even defined on all
83 systems. Some keywords may return more than one result on some
84 systems (e.g. processor-version on a multi-processor system).
85 If KEYWORD is not provided or not valid, a list of all valid
86 keywords is printed and dmidecode exits with an error. This
87 option cannot be used more than once, and implies --quiet.
88 Mutually exclusive with --type and --dump.
89 -t, --type TYPE
91 Only display the entries of type TYPE. TYPE can be either a DMI
92 type number, or a comma-separated list of type numbers, or a
93 keyword from the following list: bios, system, baseboard, chas‐
94 sis, processor, memory, cache, connector, slot. Refer to the DMI
95 TYPES section below for details. If this option is used more
96 than once, the set of displayed entries will be the union of all
97 the given types. If TYPE is not provided or not valid, a list
98 of all valid keywords is printed and dmidecode exits with an
99 error. Mutually exclusive with --string.
100 -u, --dump
102 Do not decode the entries, dump their contents as hexadecimal
103 instead. Note that this is still a text output, no binary data
104 will be thrown upon you. The strings attached to each entry are
105 displayed as both hexadecimal and ASCII. This option is mainly
106 useful for debugging. Mutually exclusive with --quiet and
107 --string.
108 -h, --help
110 Display usage information and exit
111 -V, --version
113 Display the version and exit
114
117 The SMBIOS specification defines the following DMI types:
118 Type Information
121 ────────────────────────────────────────
122 0 BIOS
123 1 System
124 2 Base Board
125 3 Chassis
126 4 Processor
127 5 Memory Controller
128 6 Memory Module
129 7 Cache
130 8 Port Connector
131 9 System Slots
132 10 On Board Devices
134 11 OEM Strings
135 12 System Configuration Options
136 13 BIOS Language
137 14 Group Associations
138 15 System Event Log
139 16 Physical Memory Array
140 17 Memory Device
141 18 32-bit Memory Error
142 19 Memory Array Mapped Address
143 20 Memory Device Mapped Address
144 21 Built-in Pointing Device
145 22 Portable Battery
146 23 System Reset
147 24 Hardware Security
148 25 System Power Controls
149 26 Voltage Probe
150 27 Cooling Device
151 28 Temperature Probe
152 29 Electrical Current Probe
153 30 Out-of-band Remote Access
154 31 Boot Integrity Services
155 32 System Boot
156 33 64-bit Memory Error
157 34 Management Device
158 35 Management Device Component
159 36 Management Device Threshold Data
160 37 Memory Channel
161 38 IPMI Device
162 39 Power Supply
163 Additionally, type 126 is used for disabled entries, type 127 is an
165 end-of-table marker, and types 128 to 255 are for OEM-specific data.
166 dmidecode will display these entries by default, but cannot decode
167 them.
168 Keywords can be used instead of type numbers with --type. Each keyword
170 is equivalent to a list of type numbers:
171 Keyword Types
174 ──────────────────────────────
175 bios 0, 13
176 system 1, 12, 15, 23, 32
177 baseboard 2, 10
178 chassis 3
179 processor 4
180 memory 5, 6, 16, 17
181 cache 7
182 connector 8
183 slot 9
184 Keywords are matched case-insensitively. The following command lines
186 are equivalent:
187 · dmidecode --type 0 --type 13
189 · dmidecode --type 0,13
191 · dmidecode --type bios
193 · dmidecode --type BIOS
195
198 /dev/mem
199
201 More often than not, information contained in the DMI tables is inaccu‐
202 rate, incomplete or simply wrong.
203
205 Alan Cox, Jean Delvare
206
208 biosdecode(8), mem(4), ownership(8), vpddecode(8)
209dmidecode August 2005 DMIDECODE(8)