S.M.A.R.T. attribute description

The following table was taken from Wikipedia. For the most up to date information you can go and check out the original resource. The rows marked with red background color representing the critical S.M.A.R.T. attributes. To the information provided on this page applies the Creative Commons Attribution/Share-Alike License.

ID Hex Attribute name Better Description
01 01 Read Error Rate
Indicates the rate of hardware read errors that occurred when reading data from a disk surface. A non-zero value indicates a problem with either the disk surface or read/write heads. Note that Seagate drives often report a raw value that is very high even on new drives, and does not thereby indicate a failure.
02 02 Throughput Performance
Overall (general) throughput performance of a hard disk drive. If the value of this attribute is decreasing there is a high probability that there is a problem with the disk.
03 03 Spin-Up Time
Average time of spindle spin up (from zero RPM to fully operational [millisecs]).
04 04 Start/Stop Count A tally of spindle start/stop cycles. The spindle turns on, and hence the count is increased, both when the hard disk is turned on after having before been turned entirely off (disconnected from power source) and when the hard disk returns from having previously been put to sleep mode.
05 05 Reallocated Sectors Count
Count of reallocated sectors. When the hard drive finds a read/write/verification error, it marks this sector as “reallocated” and transfers data to a special reserved area (spare area). This process is also known as remapping, and “reallocated” sectors are called remaps. This is why, on modern hard disks, “bad blocks” cannot be found while testing the surface – all bad blocks are hidden in reallocated sectors. However, as the number of reallocated sectors increases, the read/write speed tends to decrease. The raw value normally represents a count of the number of bad sectors that have been found and remapped. Thus, the higher the attribute value, the more sectors the drive has had to reallocate.
06 06 Read Channel Margin Margin of a channel while reading data. The function of this attribute is not specified.
07 07 Seek Error Rate
Rate of seek errors of the magnetic heads. If there is a partial failure in the mechanical positioning system, then seek errors will arise. Such a failure may be due to numerous factors, such as damage to a servo, or thermal widening of the hard disk. More seek errors indicates a worsening condition of a disk’s surface or the mechanical subsystem, or both. Note that Seagate drives often report a raw value that is very high, even on new drives, and this does not normally indicate a failure.
08 08 Seek Time Performance
Average performance of seek operations of the magnetic heads. If this attribute is decreasing, it is a sign of problems in the mechanical subsystem.
09 09 Power-On Hours (POH)
Count of hours in power-on state. The raw value of this attribute shows total count of hours (or minutes, or seconds, depending on manufacturer) in power-on state.
10 0A Spin Retry Count
Count of retry of spin start attempts. This attribute stores a total count of the spin start attempts to reach the fully operational speed (under the condition that the first attempt was unsuccessful). An increase of this attribute value is a sign of problems in the hard disk mechanical subsystem.
11 0B Recalibration Retries
This attribute indicates the number of times recalibration was requested (under the condition that the first attempt was unsuccessful). An increase of this attribute value is a sign of problems in the hard disk mechanical subsystem.
12 0C Power Cycle Count This attribute indicates the count of full hard disk power on/off cycles.
13 0D Soft Read Error Rate
Uncorrected read errors reported to the operating system.
184 B8 End-to-End error
This attribute is a part of HPs SMART IV technology and it means that after transferring through the cache RAM data buffer the parity data between the host and the hard drive did not match.
187 BB Reported Uncorrectable Errors
A number of errors that could not be recovered using hardware ECC (see attribute 195).
188 BC Command Timeout
A number of aborted operations due to HDD timeout. Normally this attribute value should be equal to zero and if you have values far above zero, then most likely you have some serious problems with your power supply or you have an oxidized data cable.
189 BD High Fly Writes
HDD producers implement a Fly Height Monitor that attempts to provide additional protections for write operations by detecting when a recording head is flying outside its normal operating range. If an unsafe fly height condition is encountered, the write process is stopped, and the information is rewritten or reallocated to a safe region of the hard drive. This attribute indicates the count of these errors detected over the lifetime of the drive.This feature is implemented in most modern Seagate drives and some of Western Digital’s drives, beginning with the WD Enterprise WDE18300 and WDE9180 Ultra2 SCSI hard drives, and will be included on all future WD Enterprise products.
190 BE Airflow Temperature
Airflow temperature on Western Digital HDs
190 BE Temperature Difference
from 100
Value is equal to (100 – temp. °C), allowing manufacturer to set a minimum threshold which corresponds to a maximum temperature.
191 BF G-sense error rate
Frequency of mistakes as a result of impact loads
192 C0 Power-off Retract Count
Number of times the heads are loaded off the media. Heads can be unloaded without actually powering off. (or Emergency Retract Cycle count – Fujitsu)
193 C1 Load Cycle Count
Load/Unload Cycle Count
Count of load/unload cycles into head landing zone position.The typical lifetime rating for laptop (2.5-in) hard drives is 200,000 to 600,000 load cycles. Some laptop drives are programmed to unload the heads whenever there has not been any activity for about five seconds. Many Linux installations write to the filesystem a few times a minute in the background. As a result, there may be 100 or more load cycles per hour, and the load cycle rating may be exceeded in less than a year.
194 C2 Temperature
Current internal temperature.
195 C3 Hardware ECC Recovered
Time between ECC-corrected errors or number of ECC on-the-fly errors. Sources differ on this point.
196 C4 Reallocation Event Count
Count of remap operations. The raw value of this attribute shows the total number of attempts to transfer data from reallocated sectors to a spare area. Both successful & unsuccessful attempts are counted.
197 C5 Current Pending Sector Count
Number of “unstable” sectors (waiting to be remapped). If the unstable sector is subsequently written or read successfully, this value is decreased and the sector is not remapped. Read errors on the sector will not remap the sector, it will only be remapped on a failed write attempt.
198 C6 Uncorrectable Sector Count
The total number of uncorrectable errors when reading/writing a sector. A rise in the value of this attribute indicates defects of the disk surface and/or problems in the mechanical subsystem. (or Off-Line Scan Uncorrectable Sector Count – Fujitsu)
199 C7 UltraDMA CRC Error Count
The number of errors in data transfer via the interface cable as determined by ICRC (Interface Cyclic Redundancy Check).
200 C8 Write Error Rate /
Multi-Zone Error Rate
The total number of errors when writing a sector.
201 C9 Soft Read Error Rate
Number of off-track errors.
202 CA Data Address Mark errors
Number of Data Address Mark errors (or vendor-specific).
203 CB Run Out Cancel
Number of ECC errors
204 CC Soft ECC Correction
Number of errors corrected by software ECC
205 CD Thermal Asperity Rate (TAR)
Number of errors due to high temperaure.
206 CE Flying Height Height of heads above the disk surface. A flying height that’s too low increases the chances of a head crash while a flying height that’s too high increases the chances of a read/write error.
207 CF Spin High Current
Amount of surge current used to spin up the drive.
208 D0 Spin Buzz Number of buzz routines needed to spin up the drive due to insufficient power.
209 D1 Offline Seek Performance Drive’s seek performance during its internal tests.
211 D3 Vibration During Write Vibration During Write
212 D4 Shock During Write Shock During Write
220 DC Disk Shift
Distance the disk has shifted relative to the spindle (usually due to shock or temperature). Unit of measure is unknown.
221 DD G-Sense Error Rate
The number of errors resulting from externally-induced shock & vibration.
222 DE Loaded Hours Time spent operating under data load (movement of magnetic head armature)
223 DF Load/Unload Retry Count Number of times head changes position.
224 E0 Load Friction
Resistance caused by friction in mechanical parts while operating.
225 E1 Load/Unload Cycle Count
Total number of load cycles
226 E2 Load ‘In’-time Total time of loading on the magnetic heads actuator (time not spent in parking area).
227 E3 Torque Amplification Count
Number of attempts to compensate for platter speed variations
228 E4 Power-Off Retract Cycle
The number of times the magnetic armature was retracted automatically as a result of cutting power.
230 E6 GMR Head Amplitude Amplitude of “thrashing” (distance of repetitive forward/reverse head motion)
231 E7 Temperature
Drive Temperature
240 F0 Head Flying Hours Time while head is positioning
250 FA Read Error Retry Rate
Number of errors while reading from a disk
254 FE Free Fall Protection
Number of “Free Fall Events” detected