Background
A system’s BIOS is a treasure trove of a lot of useful info about the capabilities of a computer. BIOS, which stands for Basic Input/Output System, contains information such as:
- motherboard manufacturer
- system’s serial number
- amount of RAM installed
- the CPUs speed & signature
Normally the BIOS is accessible by pressing the delete key or the F1 key while your computer is booting up.
Problem
Occasionally I’ve wanted to check out the BIOS settings of a system without having to go through the hassle of rebooting. With the help of this nifty command line tool, dmidecode, BIOS info can be had, without having to reboot.
Solution
…from the dmidecode man page…
dmidecode is a tool for dumping a computer’s DMI (some say SMBIOS) 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 BIOS 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 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).
SMBIOS stands for System Management BIOS, while DMI stands for Desktop Management Interface. Both standards are tightly related and developed by the DMTF (Desktop Manage- ment Task Force).
Example output from a Thinkpad T42 laptop
When you first run the dmidecode command it tells you a summary of how many structures are present within your system’s BIOS.
1 2 3 4 5 | % dmidecode # dmidecode 2.9 SMBIOS 2.33 present. 61 structures occupying 2126 bytes. Table at 0x000E0010. |
Each structure is represented by a handle ID which is a hex value of the form 0×001F, followed by it’s type and it’s size.
System Info
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | ... Handle 0x0000, DMI type 0, 20 bytes BIOS Information Vendor: IBM Version: 1RETDPWW (3.21 ) Release Date: 06/02/2006 Address: 0xDC000 Runtime Size: 144 kB ROM Size: 1024 kB Characteristics: PCI is supported PC Card (PCMCIA) is supported PNP is supported APM 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"/720 KB floppy services are supported (int 13h) Print screen service is supported (int 5h) 8042 keyboard services are supported (int 9h) Serial services are supported (int 14h) Printer services are supported (int 17h) CGA/mono video services are supported (int 10h) ACPI is supported USB legacy is supported AGP is supported BIOS boot specification is supported Handle 0x0001, DMI type 1, 25 bytes System Information Manufacturer: IBM Product Name: 2373B09 Version: ThinkPad T42 Serial Number: 99N4BVC UUID: 205A7001-46D4-22CB-B51D-FDE5F7FCD3CD Wake-up Type: Power Switch Handle 0x0002, DMI type 2, 8 bytes Base Board Information Manufacturer: IBM Product Name: 2373B09 Version: Not Available Serial Number: J1ZTY5031AP Handle 0x0003, DMI type 3, 17 bytes Chassis Information Manufacturer: IBM Type: Notebook Lock: Not Present Version: Not Available Serial Number: Not Available Asset Tag: No Asset Information Boot-up State: Unknown Power Supply State: Unknown Thermal State: Unknown Security Status: Unknown OEM Information: 0x00000000 |
CPU Info
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 | ... Handle 0x0006, DMI type 4, 35 bytes Processor Information Socket Designation: None Type: Central Processor Family: Pentium M Manufacturer: GenuineIntel ID: D6 06 00 00 BF B3 A3 AF Signature: Type 0, Family 6, Model 13, Stepping 6 Flags: FPU (Floating-point unit on-chip) VME (Virtual mode extension) DE (Debugging extension) PSE (Page size extension) TSC (Time stamp counter) MSR (Model specific registers) MCE (Machine check exception) CX8 (CMPXCHG8 instruction supported) SEP (Fast system call) MTRR (Memory type range registers) PGE (Page global enable) MCA (Machine check architecture) CMOV (Conditional move instruction supported) PAT (Page attribute table) CLFSH (CLFLUSH instruction supported) DS (Debug store) ACPI (ACPI supported) MMX (MMX technology supported) FXSR (Fast floating-point save and restore) SSE (Streaming SIMD extensions) SSE2 (Streaming SIMD extensions 2) SS (Self-snoop) TM (Thermal monitor supported) PBE (Pending break enabled) Version: Intel(R) Pentium(R) M processor Voltage: 1.3 V External Clock: 400 MHz Max Speed: 1600 MHz Current Speed: 1600 MHz Status: Populated, Enabled Upgrade: None L1 Cache Handle: 0x000A L2 Cache Handle: 0x000B L3 Cache Handle: Not Provided Serial Number: Not Specified Asset Tag: Not Specified Part Number: Not Specified ... |
RAM Info
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 | ... Handle 0x0007, DMI type 5, 20 bytes Memory Controller Information Error Detecting Method: None Error Correcting Capabilities: None Supported Interleave: One-way Interleave Current Interleave: One-way Interleave Maximum Memory Module Size: 1024 MB Maximum Total Memory Size: 2048 MB Supported Speeds: Other Supported Memory Types: DIMM SDRAM Memory Module Voltage: 2.9 V Associated Memory Slots: 2 0x0008 0x0009 Enabled Error Correcting Capabilities: None Handle 0x0008, DMI type 6, 12 bytes Memory Module Information Socket Designation: DIMM Slot 1 Bank Connections: 0 1 Current Speed: Unknown Type: DIMM SDRAM Installed Size: 1024 MB (Double-bank Connection) Enabled Size: 1024 MB (Double-bank Connection) Error Status: OK Handle 0x0009, DMI type 6, 12 bytes Memory Module Information Socket Designation: DIMM Slot 2 Bank Connections: 2 3 Current Speed: Unknown Type: DIMM SDRAM Installed Size: 1024 MB (Double-bank Connection) Enabled Size: 1024 MB (Double-bank Connection) Error Status: OK ... |
Cache Info
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | ... Handle 0x000A, DMI type 7, 19 bytes Cache Information Socket Designation: Internal L1 Cache Configuration: Enabled, Socketed, Level 1 Operational Mode: Write Back Location: Internal Installed Size: 32 KB Maximum Size: 32 KB Supported SRAM Types: Synchronous Installed SRAM Type: Synchronous Speed: Unknown Error Correction Type: Unknown System Type: Other Associativity: 8-way Set-associative Handle 0x000B, DMI type 7, 19 bytes Cache Information Socket Designation: Internal L2 Cache Configuration: Enabled, Socketed, Level 2 Operational Mode: Write Back Location: Internal Installed Size: 2048 KB Maximum Size: 2048 KB Supported SRAM Types: Burst Installed SRAM Type: Burst Speed: Unknown Error Correction Type: Multi-bit ECC System Type: Unified Associativity: 8-way Set-associative ... |
Port Info (USB, Infrared, Parallel, etc.)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 | ... Handle 0x000D, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: Not Available Internal Connector Type: None External Reference Designator: Infrared External Connector Type: Infrared Port Type: Other Handle 0x000E, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: Not Available Internal Connector Type: None External Reference Designator: Parallel External Connector Type: DB-25 female Port Type: Parallel Port ECP/EPP Handle 0x000F, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: Not Available Internal Connector Type: None External Reference Designator: External Monitor External Connector Type: DB-15 female Port Type: Video Port Handle 0x0015, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: Not Available Internal Connector Type: None External Reference Designator: Microphone Jack External Connector Type: Mini Jack (headphones) Port Type: Audio Port Handle 0x0016, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: Not Available Internal Connector Type: None External Reference Designator: Headphone Jack External Connector Type: Mini Jack (headphones) Port Type: Audio Port Handle 0x0017, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: Not Available Internal Connector Type: None External Reference Designator: S-Video-Out External Connector Type: Other Port Type: Video Port Handle 0x0019, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: Not Available Internal Connector Type: None External Reference Designator: Modem External Connector Type: RJ-11 Port Type: Modem Port Handle 0x001A, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: Not Available Internal Connector Type: None External Reference Designator: Ethernet External Connector Type: RJ-45 Port Type: Network Port Handle 0x001B, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: Not Available Internal Connector Type: None External Reference Designator: USB 1 External Connector Type: Access Bus (USB) Port Type: USB Handle 0x001C, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: Not Available Internal Connector Type: None External Reference Designator: USB 2 External Connector Type: Access Bus (USB) Port Type: USB ... |
CardBus Slot Info
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | ... Handle 0x0022, DMI type 9, 13 bytes System Slot Information Designation: CardBus Slot 1 Type: 32-bit PC Card (PCMCIA) Current Usage: Available Length: Other ID: Adapter 0, Socket 0 Characteristics: 5.0 V is provided 3.3 V is provided PC Card-16 is supported Cardbus is supported Zoom Video is supported Modem ring resume is supported PME signal is supported Hot-plug devices are supported Handle 0x0023, DMI type 9, 13 bytes System Slot Information Designation: CardBus Slot 2 Type: 32-bit PC Card (PCMCIA) Current Usage: Available Length: Other ID: Adapter 1, Socket 0 Characteristics: 5.0 V is provided 3.3 V is provided PC Card-16 is supported Cardbus is supported Zoom Video is supported Modem ring resume is supported PME signal is supported Hot-plug devices are supported ... |
RAM Modules Info
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 | ... Handle 0x002C, DMI type 16, 15 bytes Physical Memory Array Location: System Board Or Motherboard Use: System Memory Error Correction Type: None Maximum Capacity: 1 GB Error Information Handle: Not Provided Number Of Devices: 2 Handle 0x002D, DMI type 17, 27 bytes Memory Device Array Handle: 0x002C Error Information Handle: No Error Total Width: 64 bits Data Width: 64 bits Size: 1024 MB Form Factor: SODIMM Set: None Locator: DIMM 1 Bank Locator: Bank 0/1 Type: DDR Type Detail: Synchronous Speed: Unknown Manufacturer: Not Specified Serial Number: Not Specified Asset Tag: Not Specified Part Number: Not Specified Handle 0x002E, DMI type 17, 27 bytes Memory Device Array Handle: 0x002C Error Information Handle: No Error Total Width: 64 bits Data Width: 64 bits Size: 1024 MB Form Factor: SODIMM Set: None Locator: DIMM 2 Bank Locator: Bank 2/3 Type: DDR Type Detail: Synchronous Speed: Unknown Manufacturer: Not Specified Serial Number: Not Specified Asset Tag: Not Specified Part Number: Not Specified Handle 0x002F, DMI type 18, 23 bytes 32-bit Memory Error Information Type: OK Granularity: Unknown Operation: Unknown Vendor Syndrome: Unknown Memory Array Address: Unknown Device Address: Unknown Resolution: Unknown Handle 0x0030, DMI type 19, 15 bytes Memory Array Mapped Address Starting Address: 0x00000000000 Ending Address: 0x0007FFFFFFF Range Size: 2 GB Physical Array Handle: 0x002C Partition Width: 0 Handle 0x0031, DMI type 20, 19 bytes Memory Device Mapped Address Starting Address: 0x00000000000 Ending Address: 0x0003FFFFFFF Range Size: 1 GB Physical Device Handle: 0x002D Memory Array Mapped Address Handle: 0x0030 Partition Row Position: 1 Handle 0x0032, DMI type 20, 19 bytes Memory Device Mapped Address Starting Address: 0x00040000000 Ending Address: 0x0007FFFFFFF Range Size: 1 GB Physical Device Handle: 0x002E Memory Array Mapped Address Handle: 0x0030 Partition Row Position: 1 ... |
Pointing Device Info
1 2 3 4 5 6 7 8 9 10 11 12 13 | ... Handle 0x0033, DMI type 21, 7 bytes Built-in Pointing Device Type: Track Point Interface: PS/2 Buttons: 3 Handle 0x0034, DMI type 21, 7 bytes Built-in Pointing Device Type: Touch Pad Interface: PS/2 Buttons: 0 ... |
The End
1 2 | ... End Of Table |
There are some additional handles related to system logging, hardware security, and OEM information that I omitted to keep this post from just becoming a complete dump of the output but needless to say dmidecode is a pretty exhaustive and sweet command.
Useful Links
Check out the dmidecode website or the man page for more information.
NOTE: For further details regarding my one-liner blog posts, check out my one-liner style guide primer.
March 12th, 2010, @ 11:10 am |
Tags: 
Category: 
