Hi Smartmontools:

I've spent the last few days (newbie) downloading and installing smartmontools on my G4PB OS X (Darwin) and then scouring the Net for anything and everything about how to set it up and then how to interpret the meaning (attributes) of the reports generated. I discovered the fantastic article written by Bruce Allen some time ago in Linux Magazine - next to the description written by SpeedFan it's the best and clearest yet (that I've come across). I have one question. When I run: /usr/local/sbin/smartctl -l error /dev/disk0

I get the following (abstracted) and indications in the report and log that this error occurs again and again (I'm motivated to do this because my performance with Tiger 10.4.2 is treacly slow and it seems to be associated with disk accesses).  In particular EVERY error points to (or has the same signature) i.e. 40 51 01 7f f8 04 e0  Error: UNC 1 sectors at LBA = 0x0004f87f = 325759. Please, any ideas about what this means? At the bottom of this note are my overall disk scores from smartmontools.

Thanks for a fantastic tool and really cool and clear explanations in your articles and on sourceforge!

Cheers (and hope to hear from you),

Ken David

Error 1102 occurred at disk power-on lifetime: 3368 hours (140 days + 8 hours)
  When the command that caused the error occurred, the device was active or idle.

  After command completion occurred, registers were:
  ER ST SC SN CL CH DH
  -- -- -- -- -- -- --
  40 51 01 7f f8 04 e0  Error: UNC 1 sectors at LBA = 0x0004f87f = 325759

  Commands leading to the command that caused the error were:
  CR FR SC SN CL CH DH DC   Powered_Up_Time  Command/Feature_Name
  -- -- -- -- -- -- -- --  ----------------  --------------------
  25 00 01 7f f8 04 e0 00      00:14:46.300  READ DMA EXT
  25 00 01 7e f8 04 e0 00      00:14:46.200  READ DMA EXT
  25 00 01 7d f8 04 e0 00      00:14:46.100  READ DMA EXT
  25 00 01 7c f8 04 e0 00      00:14:46.100  READ DMA EXT
  25 00 01 7b f8 04 e0 00      00:14:46.000  READ DMA EXT


OVERALL SCORES

=== START OF INFORMATION SECTION ===
Device Model:     HTS548080M9AT00
Serial Number:    MRL421L4GB1NHB
Firmware Version: MG4OA53A
User Capacity:    80,026,361,856 bytes
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   6
ATA Standard is:  ATA/ATAPI-6 T13 1410D revision 3a
Local Time is:    Sun Dec  4 14:03:13 2005 GMT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME              FLAG        VAL   WRS THR    TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate         0x000b   090   090   062    Pre-fail  Always       -       2359323
  2 Throughput_Performance      0x0005   100   100   040    Pre-fail  Offline      -       0
  3 Spin_Up_Time                    0x0007   154   154   033    Pre-fail  Always       -       2
  4 Start_Stop_Count                0x0012   100   100   000    Old_age   Always       -       1513
  5 Reallocated_Sector_Ct       0x0033   054   054   005    Pre-fail  Always       -       0
  7 Seek_Error_Rate                 0x000b   100   100   067    Pre-fail  Always       -       0
  8 Seek_Time_Performance       0x0005   100   100   040    Pre-fail  Offline      -       0
  9 Power_On_Hours                  0x0012   093   093   000    Old_age   Always       -       3407
 10 Spin_Retry_Count            0x0013   100   100   060    Pre-fail  Always       -       0
 12 Power_Cycle_Count           0x0032   100   100   000    Old_age   Always       -       1233
191 G-Sense_Error_Rate          0x000a   100   100   000    Old_age   Always       -       0
192 Power-Off_Retract_Count     0x0032   100   100   000    Old_age   Always       -       165
193 Load_Cycle_Count            0x0012   090   090   000    Old_age   Always       -       108543
194 Temperature_Celsius         0x0002   152   152   000    Old_age   Always       -       36 (Lifetime Min/Max 18/55)
196 Reallocated_Event_Count     0x0032   067   067   000    Old_age   Always       -       1498
197 Current_Pending_Sector      0x0022   100   100   000    Old_age   Always       -       2
198 Offline_Uncorrectable       0x0008   100   100   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count   0x000a   200   200   000    Old_age   Always       -       0