Parlando di BIOS, il DMI non è altro che la serie di informazioni contenute nel CMOS per rappresentare la configurazione hardware attuale della nostra macchina. In condizioni normali non è possibile leggere direttamente il DMI del bios, se non accedendo al bios stesso e facendo capolino sulla voce che riguarda la configurazione hardware.
Linux, però , fornisce un aiuto anche per questo : direttamente da terminale possiamo accedere al DMI e leggerlo. Come? Ve lo spiego subito.

Sappiamo che in linux qualsiasi periferica viene mappata in un file (i dischi rigidi solitamente sono /dev/sdX , gli schermi virtuali sono i /dev/tty:SX , il mouse è /dev/mouse e così via), e di conseguenza anche la memoria viene mappata in un file ( /dev/mem ) . Il CMOS risiede in una parte di memoria, ed è quindi anch’esso accessibile tramite /dev/mem. C’è un comando da dare, con i privilegi di root (quindi utilizzando sudo, su, o qualsiasi altra cosa che vi permetta di ottenerli, in quanto /dev/mem è leggibile solo da root) che ci permette di accedere al DMI della macchina e di “rendere umanamente comprensibile” ciò che c’è scritto, e questo comando è

dmidecode

L’output è qualcosa di simile a questo:

malefika:~$ sudo dmidecode
# dmidecode 2.9
SMBIOS 2.3 present.
17 structures occupying 652 bytes.
Table at 0x000D8010.

Handle 0×0000, DMI type 0, 20 bytes
BIOS Information
Vendor: Phoenix Technologies LTD
Version: R0041G0
Release Date: 02/05/2003
Address: 0xE5700
Runtime Size: 108800 bytes
ROM Size: 1024 kB
Characteristics:
PCI is supported
PC Card (PCMCIA) 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
8042 keyboard services are supported (int 9h)
CGA/mono video services are supported (int 10h)
ACPI is supported
USB legacy is supported
AGP is supported
Smart battery is supported
BIOS boot specification is supported
Function key-initiated network boot is supported

Handle 0×0001, DMI type 1, 25 bytes
System Information
Manufacturer: Sony Corporation
Product Name: PCG-Z1SP(IT)
Version: 01
Serial Number: 28112065-5190151
UUID: CF5D4740-4B65-11C6-8895-080046A2D067
Wake-up Type: Power Switch

Handle 0×0002, DMI type 3, 17 bytes
Chassis Information
Manufacturer: Sony Corporation
Type: Notebook
Lock: Not Present
Version: N/A
Serial Number: 01
Asset Tag: 571M1478e14e0640000000000000
Boot-up State: Safe
Power Supply State: Safe
Thermal State: Safe
Security Status: None
OEM Information: 0×00000005

Handle 0×0003, DMI type 4, 35 bytes
Processor Information
Socket Designation: N/A
Type: Central Processor
Family: Itanium 2
Manufacturer: GenuineIntel
ID: 95 06 00 00 BF F9 E9 A7
Version: Intel(R) Pentium(R) M processor 1500MHz
Voltage: 1.5 V
External Clock: 100 MHz
Max Speed: 1500 MHz
Current Speed: 1500 MHz
Status: Unpopulated
Upgrade: None
L1 Cache Handle: 0×0004
L2 Cache Handle: 0×0005
L3 Cache Handle: 0×0006
Serial Number: N/A
Asset Tag: N/A
Part Number: N/A

Handle 0×0004, DMI type 7, 19 bytes
Cache Information
Socket Designation: L1 Cache
Configuration: Enabled, Socketed, Level 1
Operational Mode: Write Back
Location: Internal
Installed Size: 32 KB
Maximum Size: 32 KB
Supported SRAM Types:
Burst
Pipeline Burst
Asynchronous
Installed SRAM Type: Asynchronous
Speed: Unknown
Error Correction Type: None
System Type: Other
Associativity: 8-way Set-associative

Handle 0×0005, DMI type 7, 19 bytes
Cache Information
Socket Designation: L2 Cache
Configuration: Enabled, Socketed, Level 2
Operational Mode: Write Back
Location: Internal
Installed Size: 1024 KB
Maximum Size: 1024 KB
Supported SRAM Types:
Burst
Pipeline Burst
Asynchronous
Installed SRAM Type: Burst
Speed: Unknown
Error Correction Type: None
System Type: Data
Associativity: 8-way Set-associative

Handle 0×0006, DMI type 7, 19 bytes
Cache Information
Socket Designation: L3 Cache
Configuration: Disabled, Not Socketed, Level 3
Operational Mode: Unknown
Location: Unknown
Installed Size: 0 KB
Maximum Size: 0 KB
Supported SRAM Types:
Burst
Pipeline Burst
Asynchronous
Installed SRAM Type: Burst
Speed: Unknown
Error Correction Type: None
System Type: Data
Associativity: 4-way Set-associative

Handle 0×0007, DMI type 9, 13 bytes
System Slot Information
Designation: PCCARD1
Type: 32-bit PC Card (PCMCIA)
Current Usage: Available
Length: Other
ID: Adapter 0, Socket 1
Characteristics:
5.0 V is provided
3.3 V is provided
PC Card-16 is supported
Cardbus is supported
Modem ring resume is supported
PME signal is supported
Hot-plug devices are supported

Handle 0×0008, DMI type 11, 5 bytes
OEM Strings
String 1: EU4361

Handle 0×0009, DMI type 16, 15 bytes
Physical Memory Array
Location: System Board Or Motherboard
Use: System Memory
Error Correction Type: Unknown
Maximum Capacity: 2048 GB
Error Information Handle: Not Provided
Number Of Devices: 2

Handle 0x000A, DMI type 17, 27 bytes
Memory Device
Array Handle: 0×0009
Error Information Handle: Not Provided
Total Width: 32 bits
Data Width: 32 bits
Size: 512 MB
Form Factor: SODIMM
Set: None
Locator: SODIMM1
Bank Locator: Bank 0
Type: DDR
Type Detail: Unknown
Speed: 100 MHz (10.0 ns)
Manufacturer: N/A
Serial Number: N/A
Asset Tag: N/A
Part Number: N/A

Handle 0x000B, DMI type 17, 27 bytes
Memory Device
Array Handle: 0×0009
Error Information Handle: Not Provided
Total Width: 32 bits
Data Width: 32 bits
Size: 512 MB
Form Factor: SODIMM
Set: None
Locator: SODIMM2
Bank Locator: Bank 1
Type: DDR
Type Detail: Unknown
Speed: 100 MHz (10.0 ns)
Manufacturer: N/A
Serial Number: N/A
Asset Tag: N/A
Part Number: N/A

Handle 0x000C, DMI type 19, 15 bytes
Memory Array Mapped Address
Starting Address: 0×00000000000
Ending Address: 0x0003FFFFFFF
Range Size: 1 GB
Physical Array Handle: 0×0009
Partition Width: 0

Handle 0x000D, DMI type 20, 19 bytes
Memory Device Mapped Address
Starting Address: 0×00000000000
Ending Address: 0x0001FFFFFFF
Range Size: 512 MB
Physical Device Handle: 0x000A
Memory Array Mapped Address Handle: 0x000C
Partition Row Position: Unknown
Interleave Position: Unknown
Interleaved Data Depth: Unknown

Handle 0x000E, DMI type 20, 19 bytes
Memory Device Mapped Address
Starting Address: 0×00020000000
Ending Address: 0x0003FFFFFFF
Range Size: 512 MB
Physical Device Handle: 0x000B
Memory Array Mapped Address Handle: 0x000C
Partition Row Position: Unknown
Interleave Position: Unknown
Interleaved Data Depth: Unknown

Handle 0x000F, DMI type 32, 11 bytes
System Boot Information
Status: No errors detected

Handle 0×0010, DMI type 127, 4 bytes
End Of Table

Come potrete notare l’entry relativa ad ogni periferica inizia con la parola handle (il codice che la segue è l’identificatore univoco dell’entry), e immediatamente sotto vi è specificato di che periferica si tratta. Dalla linea successiva, poi, avremo le informazioni specifiche. In grassetto vi ho mostrato tutte le informazioni relative al bios della mia macchina. Comodo,no?