biosdecode is a command line utility to parses the BIOS memory and prints information about all structures (or entry points) it knows of. You can find out more information about your hardware such as:
=> IPMI Device
=> Type of memory and speed
=> Chassis Information
=> Temperature Probe
=> Cooling Device
=> Electrical Current Probe
=> Processor and Memory Information
=> Serial numbers
=> BIOS version
=> PCI / PCIe Slots and Speed
=> Much more

biosdecode parses the BIOS memory and prints the following information about all structures :
=> SMBIOS (System Management BIOS)
=> DMI (Desktop Management Interface, a legacy version of SMBIOS)
=> SYSID
=> PNP (Plug and Play)
=> ACPI (Advanced Configuration and Power Interface)
=> BIOS32 (BIOS32 Service Directory)
=> PIR (PCI IRQ Routing)
=> 32OS (BIOS32 Extension, Compaq-specific)
=> VPD (Vital Product Data, IBM-specific)
=> FJKEYINF (Application Panel, Fujitsu-specific)

In this tip you will learn about decoding BIOS data (dumping a computer’s DMI ) and getting all information about computer hardware without rebooting the server.

More about the DMI tables

The DMI table doesn’t only describe what the system is currently made of, it also can report the possible evolutions such as the fastest supported CPU or the maximal amount of memory supported.

dmidecode – Read biosdecode data in a human-readable format

Data provided by biosdecode is not in a human-readable format. You need to use dmidecode command for dumping a computer’s DMI (SMBIOS) table contents on screen. This table contains a description of the system’s hardware components, as well as other useful pieces of information such as serial numbers and BIOS revision. Thanks to this table, you can retrieve this information without having to probe for the actual hardware.

Task: Display information about IPMI Device

# dmidecode --type 38
Output:

# dmidecode 2.7
SMBIOS 2.4 present.

Handle 0x0029, DMI type 38, 18 bytes.
IPMI Device Information
        Interface Type: KCS (Keyboard Control Style)
        Specification Version: 2.0
        I2C Slave Address: 0x10
        NV Storage Device: Not Present
        Base Address: 0x0000000000000CA2 (I/O)
        Register Spacing: Successive Byte Boundaries

Task: Display information about PCI / PCIe Slots

# dmidecode --type 9

# dmidecode 2.7
SMBIOS 2.4 present.

Handle 0x000E, DMI type 9, 13 bytes.
System Slot Information
        Designation: PCIX#1-133MHz
        Type: 64-bit PCI-X
        Current Usage: Available
        Length: Long
        ID: 1
        Characteristics:
                3.3 V is provided

Handle 0x000F, DMI type 9, 13 bytes.
System Slot Information
        Designation: PCIX#2-100MHz
        Type: 64-bit PCI-X
        Current Usage: Available
        Length: Long
        ID: 2
        Characteristics:
                3.3 V is provided

Handle 0x0010, DMI type 9, 13 bytes.
System Slot Information
        Designation: PCIE#3-x8
        Type: Other
        Current Usage: Available
        Length: Other
        Characteristics:
                3.3 V is provided

Handle 0x0011, DMI type 9, 13 bytes.
System Slot Information
        Designation: PCIE#4-x8
        Type: Other
        Current Usage: Available
        Length: Other
        Characteristics:
                3.3 V is provided

Handle 0x0012, DMI type 9, 13 bytes.
System Slot Information
        Designation: PCIE#5-x8
        Type: Other
        Current Usage: Available
        Length: Other
        Characteristics:
                3.3 V is provided

Task: Find out Information about BIOS

# dmidecode --type 0
Output:

# dmidecode 2.7
SMBIOS 2.4 present.
Handle 0x0000, DMI type 0, 24 bytes.
BIOS Information
        Vendor: Phoenix Technologies LTD
        Version: 6.00
        Release Date: 01/26/2007
        Address: 0xE56C0
        Runtime Size: 108864 bytes
        ROM Size: 1024 kB
        Characteristics:
                PCI is supported
                PNP is supported
                BIOS is upgradeable
                BIOS shadowing is allowed
                ESCD support is available
                Boot from CD is supported
                Selectable boot is supported
                EDD is supported
                3.5"/2.88 MB floppy services are supported (int 13h)
                ACPI is supported
                USB legacy is supported
                LS-120 boot is supported
                ATAPI Zip drive boot is supported
                BIOS boot specification is supported
                Targeted content distribution is supported

Understanding BIOS keywords

dmidecode --type {KEYWORD / Number }

You need to pass dmidecode following keywords:

• bios
• system
• baseboard
• chassis
• processor
• memory
• cache
• connector
• slot

All DMI types you need to use with dmidecode –type {Number}:

Display Power supply information, enter:
# dmidecode --type 39
Display CPU information, enter:
# dmidecode --type processor
Read man page for more information:
$ man dmidecode

Other tools and commands to gather hardware information

• Linux list hardware information with lshw command
• dconf – Linux command to gather hardware and software snapshot for troubleshooting
• Linux display system hardware status information gathered from /proc filesystem in easy format
• Linux display information about installed hardware
• Linux command to gathers up information about a Linux system

Updated for accuracy.