Ubuntu Wiki

Firmware Test Suite - cmosdump utility

This dumps and annotate the CMOS memory. Unfortunately different firmware vendors utilise CMOS memory differently and hence this tool only annotates fields that seem to be common across most modern BIOSes.

An example output is as follows:

Dump CMOS Memory.
--------------------------------------------------------------------------------
Test 1 of 1: Dump CMOS Memory.
CMOS Memory Dump:
  0000: 11 38 17 17 14 13 03 25 02 13 26 02 50 a5 00 00  .8.....%..&.P...
  0010: 00 00 00 00 0e 76 02 ff ff 00 00 00 00 00 00 00  .....v..........
  0020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 84  ................
  0030: ff ff 20 00 00 ff 01 00 00 00 00 00 00 00 00 00  .. .............
  0040: 00 00 2d 36 00 00 00 00 00 00 00 00 00 00 00 00  ..-6............
  0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  0060: 00 00 00 00 00 00 00 00 00 00 00 30 00 00 00 00  ...........0....
  0070: 00 00 00 01 00 00 00 00 00 5a 00 00 49 53 b2 00  .........Z..IS..

RTC Current Time: (CMOS 0x00..0x09)
  RTC seconds:            11
  RTC minutes:            17
  RTC hours:              14
  RTC day of week:        03
  RTC date day:           25
  RTC date month:         02
  RTC date year:          13

RTC Alarm:
  RTC seconds:            38
  RTC minutes:            17
  RTC hours:              13

Status Register A: (CMOS 0x0a): 0x26
  Rate freq:              6 (976.562 microseconds (default))
  Timer freq divider:     2 (32.768 KHz (default))
  Update in progress:     0

Status Register B: (CMOS 0x0b): 0x02
  Daylight savings:       0 (Disabled)
  24 Hour Clock:          1 (24 Hour)
  Data Mode (DM):         0 (BCD)
  Square Wave:            0 (Disabled)
  Update ended IRQ:       0 (Disabled)
  Alarm IRQ:              0 (Disabled)
  Periodic IRQ:           0 (Disabled)
  Clock update cycle:     0 (Update normally)

Status Register C: (CMOS 0x0c): 0x50
  UF flag:                0x1
  AF flag:                0x0
  PF flag:                0x1
  IRQF flag:              0x0

Status Register D: (CMOS 0x0d): 0xa5
  Valid CMOS RAM flag:    0x1 (Battery Good)

Diagnostic Status: (CMOS 0x0e): 0x00
  CMOS time status:       0x0 (Valid)
  Fixed disk init:        0x0 (Good)
  Memory size check:      0x0 (Good)
  Config info status:     0x0 (Valid)
  CMOS checksum status:   0x0 (Good)
  CMOS power loss:        0x0 (Not lost power)

CMOS Shutdown Status: (CMOS 0x0f): 0x00 (Power on or soft reset)

Floppy Disk Type: (CMOS 0x10): 0x00
  Drive 0: None
  Drive 1: None

Hard Disk Type: (CMOS 0x12, Obsolete): 0x00
  Drive 0: None
  Drive 1: None

Installed H/W: (CMOS 0x14): 0x0e
  Maths Coprocessor:      0x1 (Installed)
  Keyboard:               0x1 (Installed)
  Display Adaptor:        0x1 (Installed)
  Primary Display:        0x0 (BIOS selected)
  Floppy Drives:          None.

Base Mem: (CMOS 0x16):
  0x0276 (630K)

Extended Mem: (CMOS 0x18):
  0xffff (65280K) [untrustworthy]

Hard Disk Extended Types (CMOS 0x19, 0x1a):
  Hard Disk 0:            0x00
  Hard Disk 1:            0x00

CMOS Checksum:(CMOS 0x2e):0x8402

Extended Mem: (CMOS 0x30):0xffff

Century Date: (CMOS 0x32):20

POST Information Flag (CMOS 0x33):
  POST cache test:        0x0 Passed
  BIOS size:              0x0 64KB

Examples:

sudo fwts cmosdump - 

..runs the cmosdump on your machine and dumps the output to stdout.