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Western-Digital Devices

Interpretation of S.M.A.R.T. Attributes

Device Model	Attributes ID#	Attributes Name	Special	Description
	1	Raw Read Error Rate		Frequency of errors while reading raw data from a disk.
	2	Throughput Performance		Average efficiency of a hard disk.
	3	Spin Up Time		Time needed by spindle to spin-up.
	4	Start/Stop Count		Number of start/stop cycles of spindle.
	5	Reallocated Sector Count		Quantity of remapped sectors.
	6	Start/Stop Count		Number of start/stop cycles of spindle.
	?	Read Channel Margin		Margin of a channel while reading data. The function of this attribute is not specified.
	7	Seek Error Rate		Frequency of errors appearance while positioning.
	8	Seek Time Performance		The average efficiency of operations while positioning.
	9	Power-On Hours Count		Quantity of elapsed hours in the switched-on state.
	10	Spin-up Retry Count		Number of retry attempts, that were needed to reach the operational speed of the spindle.
				Western Digital firmware initializes SMART Attribute 10 after either 120 spin-ups or 8 power-on hours. Until that time, they have the uninitialized value 253.
	11	Calibration Retry Count		Number of attempts to calibrate a drive.
				Western Digital firmware initializes SMART Attribute 11 after either 120 spin-ups or 8 power-on hours. Until that time, they have the uninitialized value 253.
	12	Power Cycle Count		Number of complete power on/off cycles of hard disk.
	13	Soft Read Error Rate		Frequency of program errors appearance while reading data from a disk.
	184	End to End Error Count		This attribute is a part of HP's 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.
	185 (?)	Head Stability
	186 (?)	Induced Op-Vibration Detection
	187	Reported Uncorrectable Errors		A number of errors that could not be recovered using hardware ECC (see attribute 195).
	188	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.
WDE18300, WDE9180 Ultra2 SCSI hard drives and future WD Enterprise products 1	189	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.
	190	Airflow Temperature		Airflow temperature (Same as temp. [C2], but current value is 50 less for some models. Marked as obsolete.)
	191	G-sense error rate		The number of errors resulting from externally-induced shock & vibration. (See also attribute ID 221)
	192	Emergency Retract Count		Number of times the heads are loaded off the media.
	193	Load/Unload Cycle Count		Number of cycles into Landing Zone position.
not all (which?)	194	HDA Temperature		Temperature of a Hard Disk Assembly.
<unknown>	195	Hardware ECC Recovered		Frequency of the on the fly errors.
not all (which?)	196	Relocation Event Count		Number of remap operations. That means replacing a bad sector by one from the spare area.
	197	Current Pending Sector Count		Current number of unstable sectors (waiting for remapping).
<unknown>	198	Offline Uncorrectable Sector Count		Number of uncorrected errors.
not all (which?)	199	UltraDMA CRC Error Rate		Total number of errors CRC during UltraDMA mode.
				Western Digital firmware initializes SMART Attribute 199 after either 120 spin-ups or 8 power-on hours. Until that time, they have the uninitialized value 253.
	200	Multi Zone Error Rate		Multi Zone Error Rate.
	201	Soft Read Error Rate		Frequency of program errors appearance while reading data from a disk.
<unknown>	202	Data Address Mark Errors		Number of Data Address Mark (DAM) errors (or) vendor-specific.
<unknown>	203	Run Out Cancel		Number of the ECC errors (Maxtor: ECC Errors).
<unknown>	204	Soft ECC Correction		Quantity of errors corrected by software ECC.
<unknown>	205	Thermal Asperity Rate (TAR)		Frequency of the thermal asperity errors.
<unknown>	206	Flying Height		The height of the disk heads above the disk surface.
<unknown>	207	Spin High Current		Amount of high current used to spin up the drive.
<unknown>	208	Spin Buzz		Number of buzz routines to spin up the drive.
<unknown>	209	Offline Seek Performance		Drive's seek performance during offline operations. (Relation to Seek Time Performance? => ID 8)
<unknown>	220	Disk Shift		Shift of disk is possible as a result of strong shock loading in the store, as a result of it's falling or for other reasons (sometimes: Temperature)
<unknown>	221	G-Sense Error Rate		Frequency of mistakes as a result of impact loads as detected by a shock sensor. (See also attribute ID 191)
<unknown>	222	Loaded Hours		Number of hours in general operational state.
<unknown>	223	Load/Unload Retry Count		Loading on drive caused by numerous recurrences of operations, like reading, recording, positioning of heads, etc.
<unknown>	224	Load Friction		Load on drive caused by friction in mechanical parts of the store.
<unknown>	225	Load/Unload Cycle Count		Number of cycles into Landing Zone position.
<unknown>	226	Load-in Time		General time of loading for drive.
<unknown>	227	Torque Amplification Count		Quantity efforts of the rotating moment of a drive.
<unknown>	228	Power-Off Retract Count		Number of power-off cycles.
<unknown>	230	GMR Head Amp		Amplitude of heads trembling (GMR-head) in running mode.
<unknown>	231	Temperature		Temperature of a drive.
<unknown>	240	Head Flying Hours		Time while head is positioning.
<unknown>	250	Read Error Retry Rate		Number of errors while reading from a disk.

Footnotes:

1. Fly Height Monitor Improves Hard Drive Reliability, Western Digital, April 1999, 79-850123-000

References:

​http://www.ariolic.com/activesmart/smart-attributes/

​http://en.wikipedia.org/wiki/S.M.A.R.T.

​http://en.wikipedia.org/wiki/Talk:S.M.A.R.T.#Attributes_185_.26_186_.28WDC.29

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