diff options
Diffstat (limited to 'man/dmidecode.8')
| -rw-r--r-- | man/dmidecode.8 | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/man/dmidecode.8 b/man/dmidecode.8 new file mode 100644 index 0000000..ed066b3 --- /dev/null +++ b/man/dmidecode.8 @@ -0,0 +1,325 @@ +.TH DMIDECODE 8 "January 2019" "dmidecode" +.\" +.SH NAME +dmidecode \- \s-1DMI\s0 table decoder +.\" +.SH SYNOPSIS +.B dmidecode +.RI [ OPTIONS ] +.\" +.SH DESCRIPTION +.B dmidecode +is a tool for dumping a computer's \s-1DMI\s0 (some say \s-1SMBIOS\s0) table +contents in a human-readable format. This table contains a description of the +system's hardware components, as well as other useful pieces of information +such as serial numbers and \s-1BIOS\s0 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 \s-1DMI\s0 table doesn't only describe what the system is currently made +of, it also can report the possible evolutions (such as the fastest supported +\s-1CPU\s0 or the maximal amount of memory supported). + +\s-1SMBIOS\s0 stands for System Management \s-1BIOS\s0, while \s-1DMI\s0 +stands for Desktop Management Interface. Both standards are tightly related +and developed by the \s-1DMTF\s0 (Desktop Management Task Force). + +As you run it, +.B dmidecode +will try to locate the \s-1DMI\s0 table. It will first try to read the DMI table +from sysfs, and next try reading directly from memory if sysfs access failed. +If +.B dmidecode +succeeds in locating a valid DMI table, it will then parse this table +and display a list of records like this one: + +Handle 0x0002, DMI type 2, 8 bytes. +Base Board Information + Manufacturer: Intel + Product Name: C440GX+ + Version: 727281-001 + Serial Number: INCY92700942 + +Each record has: +.IP \(bu "\w'\(bu'u+1n" +A handle. This is a unique identifier, which allows records to +reference each other. For example, processor records usually reference +cache memory records using their handles. +.IP \(bu +A type. The \s-1SMBIOS\s0 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". +.IP \(bu +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. +.IP \(bu +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. +.\" +.SH OPTIONS +.TP +.BR "-d" ", " "--dev-mem \fIFILE\fP" +Read memory from device \fIFILE\fP (default: \fI/dev/mem\fP) +.TP +.BR "-q" ", " "--quiet" +Be less verbose. Unknown, inactive and \s-1OEM\s0-specific entries are not +displayed. Meta-data and handle references are hidden. +.TP +.BR "-s" ", " "--string \fIKEYWORD\fP" +Only display the value of the \s-1DMI\s0 string identified by \fIKEYWORD\fP. +It must be a keyword from the following list: +.nh +.BR bios\-vendor , +.BR bios\-version , +.BR bios\-release\-date , +.BR bios\-revision , +.BR firmware\-revision , +.BR system\-manufacturer , +.BR system\-product\-name , +.BR system\-version , +.BR system\-serial\-number , +.BR system\-uuid , +.BR system\-sku\-number , +.BR system\-family , +.BR baseboard\-manufacturer , +.BR baseboard\-product\-name , +.BR baseboard\-version , +.BR baseboard\-serial\-number , +.BR baseboard\-asset\-tag , +.BR chassis\-manufacturer , +.BR chassis\-type , +.BR chassis\-version , +.BR chassis\-serial\-number , +.BR chassis\-asset\-tag , +.BR processor\-family , +.BR processor\-manufacturer , +.BR processor\-version , +.BR processor\-frequency . +.hy +Each keyword corresponds to a given \s-1DMI\s0 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. +.nh +.B processor\-version +.hy +on a multi-processor system). +If \fIKEYWORD\fP is not provided or not valid, a list of all valid +keywords is printed and +.B dmidecode +exits with an error. +This option cannot be used more than once. + +Note: on Linux, most of these strings can alternatively be read directly +from +.BR sysfs , +typically from files under +.IR /sys/devices/virtual/dmi/id . +Most of these files are even readable by regular users. +.TP +.BR "-t" ", " "--type \fITYPE\fP" +Only display the entries of type \fITYPE\fP. It can be either a +\s-1DMI\s0 type number, or a comma-separated list of type numbers, or a +keyword from the following list: +.nh +.BR bios , +.BR system , +.BR baseboard , +.BR chassis , +.BR processor , +.BR memory , +.BR cache , +.BR connector , +.BR slot . +.hy +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 \fITYPE\fP is not provided or not valid, a list of all valid keywords +is printed and +.B dmidecode +exits with an error. +.TP +.BR "-H" ", " "--handle \fIHANDLE\fP" +Only display the entry whose handle matches \fIHANDLE\fP. +\fIHANDLE\fP is a 16-bit integer. +.TP +.BR "-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 \s-1ASCII\s0. This option is mainly useful for debugging. +.TP +.BR " " " " "--dump-bin \fIFILE\fP" +Do not decode the entries, instead dump the DMI data to a file in binary +form. The generated file is suitable to pass to \fB--from-dump\fP +later. +.TP +.BR " " " " "--from-dump \fIFILE\fP" +Read the DMI data from a binary file previously generated using +\fB--dump-bin\fP. +.TP +.BR " " " " "--no-sysfs" +Do not attempt to read DMI data from sysfs files. This is mainly useful for +debugging. +.TP +.BR " " " " "--oem-string \fIN\fP" +Only display the value of the \s-1OEM\s0 string number \fIN\fP. The first +\s-1OEM\s0 string has number \fB1\fP. With special value \fBcount\fP, return the +number of OEM strings instead. +.TP +.BR "-h" ", " "--help" +Display usage information and exit +.TP +.BR "-V" ", " "--version" +Display the version and exit +.P +Options +.BR --string , +.BR --type, +.BR --dump-bin " and " --oem-string +determine the output format and are mutually exclusive. +.P +Please note in case of +.B dmidecode +is run on a system with BIOS that boasts new SMBIOS specification, which +is not supported by the tool yet, it will print out relevant message in +addition to requested data on the very top of the output. Thus informs the +output data is not reliable. +.\" +.SH "DMI TYPES" +The \s-1SMBIOS\s0 specification defines the following \s-1DMI\s0 types: +.TS +r l +__ +r l. +Type Information +0 BIOS +1 System +2 Baseboard +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 +40 Additional Information +41 Onboard Devices Extended Information +42 Management Controller Host Interface +.TE + +Additionally, type 126 is used for disabled entries and type 127 is an +end-of-table marker. Types 128 to 255 are for \s-1OEM\s0-specific data. +.B 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 \fB--type\fP. +Each keyword is equivalent to a list of type numbers: + +.TS +l l +__ +l l. +Keyword Types +bios 0, 13 +system 1, 12, 15, 23, 32 +baseboard 2, 10, 41 +chassis 3 +processor 4 +memory 5, 6, 16, 17 +cache 7 +connector 8 +slot 9 +.TE + +Keywords are matched case-insensitively. The following command lines are equivalent: +.IP \(bu "\w'\(bu'u+1n" +dmidecode --type 0 --type 13 +.IP \(bu +dmidecode --type 0,13 +.IP \(bu +dmidecode --type bios +.IP \(bu +dmidecode --type BIOS +.\" +.SH BINARY DUMP FILE FORMAT +The binary dump files generated by \fB--dump-bin\fP and read using \fB--from-dump\fP +are formatted as follows: +.IP \(bu "\w'\(bu'u+1n" +The SMBIOS or DMI entry point is located at offset 0x00. +It is crafted to hard-code the table address at offset 0x20. +.IP \(bu "\w'\(bu'u+1n" +The DMI table is located at offset 0x20. +.\" +.SH UUID FORMAT +There is some ambiguity about how to interpret the UUID fields prior to SMBIOS +specification version 2.6. There was no mention of byte swapping, and RFC 4122 +says that no byte swapping should be applied by default. However, SMBIOS +specification version 2.6 (and later) explicitly states that the first 3 fields +of the UUID should be read as little-endian numbers (byte-swapped). +Furthermore, it implies that the same was already true for older versions of +the specification, even though it was not mentioned. In practice, many hardware +vendors were not byte-swapping the UUID. So, in order to preserve +compatibility, it was decided to interpret the UUID fields according to RFC +4122 (no byte swapping) when the SMBIOS version is older than 2.6, and to +interpret the first 3 fields as little-endian (byte-swapped) when the SMBIOS +version is 2.6 or later. The Linux kernel follows the same logic. +.\" +.SH FILES +.I /dev/mem +.br +.I /sys/firmware/dmi/tables/smbios_entry_point +(Linux only) +.br +.I /sys/firmware/dmi/tables/DMI +(Linux only) +.\" +.SH BUGS +More often than not, information contained in the \s-1DMI\s0 tables is inaccurate, +incomplete or simply wrong. +.\" +.SH AUTHORS +Alan Cox, Jean Delvare +.\" +.SH "SEE ALSO" +.BR biosdecode (8), +.BR mem (4), +.BR ownership (8), +.BR vpddecode (8) |