S.M.A.R.T.

funktion som övervakar, diagnosticerar och indikerar eventuella tekniska fel på hårddiskar och SSD-enheter

S.M.A.R.T. (akronym för Self-Monitoring Analysis and Reporting Technology) är en funktion i vissa hårddiskar som gör det möjligt uppskatta tillståndet på dessa. Diagnostiken som görs varierar mellan olika hårddiskar, men innefattar ofta saker som att söktid och andel felläsningar ligger inom ett acceptabelt intervall. Antalet timmar hårddisken varit påslagen, antalet gånger den startat upp, och den högsta temperatur den blivit utsatt för är andra vanliga parametrar som kan läsas ut.

Vissa datorer visar en varning vid uppstart om dessa parametrar indikerar att något verkar fel. I sådana fall bör en backup omedelbart göras och hårddisken bytas ut då den har en klart ökad risk för att inom kort helt gå sönder och bli oläsbar.

TräffsäkerhetRedigera

En fältstudie på Google[1] som täckte över 100 000 enheter för konsumentklass från december 2005 till augusti 2006 hittade följande samband mellan viss SMART-information och årliga hårddiskhaverier:

  • Under 60 dagar efter det första okorrigerbara felet på en enhet (SMART-data 198/0xC6) som upptäcktes genom en offline-skanning, var enheten 39 gånger i genomsnitt mer benägen att haverera, än en felfri enhet.
  • Första registreringen av SMART-data för omlokalisering (5/0x05 och 196/0xC5) samt väntad omlokalisering (SMART-data 197/0xC5) var också starkt korrelerad med högre sannolikhet för haveri.
  • Små samband för ökad temperatur och inget samband för användningsnivå.
  • 56% av de havererade enheterna hade inget registrerat i något av de "fyra starka S.M.A.R.T.-varningarna" (läsfel eller olika typer av omlokaliseringsräknare).
  • 36% av de havererade enheterna hade inga S.M.A.R.T.-fel alls, utom temperaturen, vilket innebär att S.M.A.R.T.-data ensamt bara ger begränsad möjlighet att förutse haveri.[2]

ATA S.M.A.R.T.-attributRedigera

Varje tillverkare definierar en uppsättning attribut[3][4], och sätter olika tröskelvärden för attribut som inte ska passera under normal drift. Varje attribut har ett råvärde(RAW) i decimal- eller hexadecimal form vars betydelse bestäms av drivenhetstillverkaren. Dessa råvärden står för antal gånger något har är inträffat, drifttimmar, uppstarter, temperatur, söktider, time-outer, läsfel, överförda datamängder, etc. Viktigare är att avläsa aktuellt attributvärde i förhållande till sämsta uppmätta värde och tröskelvärde, ofta uttryckt i skalor 252->0, 200->0 eller 100->0, där högt aktuellt värde är bäst.[5]

Tillverkare som har implementerat minst ett S.M.A.R.T.-attribut i olika produkter inkluderar Samsung, Seagate, IBM (Hitachi), Fujitsu, Maxtor, Toshiba, Intel, sTec, Inc., Western Digital och ExcelStor Technology.

Kända ATA S.M.A.R.T.-attributRedigera

Följande diagram visar några S.M.A.R.T.-attribut och den typiska betydelsen av deras råvärden. Normaliserade värden kartläggs vanligtvis så att de högre värdena är bättre (undantag inkluderar körtemperatur, antal läshuvudbelastningar-/avlastningscykler[6]), men högre RAW-värden kan vara bättre eller sämre beroende på attributet och tillverkaren. Till exempel attributet "Reallocated Sectors Count/Antal omlokaliserade sektorer" aktuella normaliserade värde minskar när antalet omlokaliserade sektorer ökar. I detta fall indikerar attributets "RAW"-värde ofta antalet sektorer som har omfördelats, även om leverantörer inte på något sätt säger sig följa denna konvention.

Eftersom tillverkare inte nödvändigtvis håller med om exakta attributdefinitioner och mätenheter, är följande lista med attribut bara en allmän guide.

Enheter stöder inte alla attributkoder (ibland förkortade "ID", för "identifierare", i tabeller). Vissa koder är specifika för specifika drivenheter (magnetisk tallrik, blixt, SSD). Enheter kan använda olika koder för samma parameter, se till exempel koder 193 och 225.

Legend/Teckenförklaring
ID 193
0xC1
Attribut i decimal och
hexadecimal form
Önskvärt
Hög
Högre RAW-värde är bättre.
Låg
 
Lägre RAW-värde är bättre.
!
(Kritisk)
 
Kritiskt attribut.
Specifika värden kan förutse enhetshaveri.
ID Attribut Önskvärt ! Beskrivning
01
0x01
Read Error Rate
Låg
 
(Vendor specific raw value.) Stores data related to the rate of hardware read errors that occurred when reading data from a disk surface. The raw value has different structure for different vendors and is often not meaningful as a decimal number.
02
0x02
Throughput Performance
Hög
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
0x03
Spin-Up Time
Låg
 
Average time of spindle spin up (from zero RPM to fully operational [milliseconds]).
04
0x04
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.[7]
05
0x05
Reallocated Sectors Count
Låg
 

 
Count of reallocated sectors. The raw value represents a count of the bad sectors that have been found and remapped.[11] Thus, the higher the attribute value, the more sectors the drive has had to reallocate. This value is primarily used as a metric of the life expectancy of the drive; a drive which has had any reallocations at all is significantly more likely to fail in the immediate months.[8][12]
06
0x06
Read Channel Margin Margin of a channel while reading data. The function of this attribute is not specified.
07
0x07
Seek Error Rate Mall:Varies (Vendor specific raw value.) 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. The raw value has different structure for different vendors and is often not meaningful as a decimal number.
08
0x08
Seek Time Performance
Hög
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
0x09
Power-On Hours 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.[13]

"By default, the total expected lifetime of a hard disk in perfect condition is defined as 5 years (running every day and night on all days). This is equal to 1825 days in 24/7 mode or 43800 hours."[14]

On some pre-2005 drives, this raw value may advance erratically and/or "wrap around" (reset to zero periodically).[15]

10
0x0A
Spin Retry Count
Låg

 
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
0x0B
Recalibration Retries or Calibration Retry Count
Låg
This attribute indicates the count that 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
0x0C
Power Cycle Count This attribute indicates the count of full hard disk power on/off cycles.
13
0x0D
Soft Read Error Rate
Låg
 
Uncorrected read errors reported to the operating system.
22
0x16
Current Helium Level Specific to He8 drives from HGST. This value measures the helium inside of the drive specific to this manufacturer. It is a pre-fail attribute that trips once the drive detects that the internal environment is out of specification.[17]
170
0xAA
Available Reserved Space See attribute E8.[18]
171
0xAB
SSD Program Fail Count (Kingston) The total number of flash program operation failures since the drive was deployed.[19] Identical to attribute 181.
172
0xAC
SSD Erase Fail Count (Kingston) Counts the number of flash erase failures. This attribute returns the total number of Flash erase operation failures since the drive was deployed. This attribute is identical to attribute 182.
173
0xAD
SSD Wear Leveling Count Counts the maximum worst erase count on any block.
174
0xAE
Unexpected power loss count Also known as "Power-off Retract Count" per conventional HDD terminology. Raw value reports the number of unclean shutdowns, cumulative over the life of an SSD, where an "unclean shutdown" is the removal of power without STANDBY IMMEDIATE as the last command (regardless of PLI activity using capacitor power). Normalized value is always 100.[20]
175
0xAF
Power Loss Protection Failure Last test result as microseconds to discharge cap, saturated at its maximum value. Also logs minutes since last test and lifetime number of tests. Raw value contains the following data:
  • Bytes 0-1: Last test result as microseconds to discharge cap, saturates at max value. Test result expected in range 25 <= result <= 5000000, lower indicates specific error code.
  • Bytes 2-3: Minutes since last test, saturates at max value.
  • Bytes 4-5: Lifetime number of tests, not incremented on power cycle, saturates at max value.

Normalized value is set to one on test failure or 11 if the capacitor has been tested in an excessive temperature condition, otherwise 100.[20]

176
0xB0
Erase Fail Count S.M.A.R.T. parameter indicates a number of flash erase command failures.[21]
177
0xB1
Wear Range Delta Delta between most-worn and least-worn Flash blocks. It describes how good/bad the wearleveling of the SSD works on a more technical way.
179
0xB3
Used Reserved Block Count Total "Pre-Fail" attribute used at least in Samsung devices.
180
0xB4
Unused Reserved Block Count Total "Pre-Fail" attribute used at least in HP devices.
181
0xB5
Program Fail Count Total or Non-4K Aligned Access Count
Låg
 
Total number of Flash program operation failures since the drive was deployed.[22]
Number of user data accesses (both reads and writes) where LBAs are not 4 KiB aligned (LBA % 8 != 0) or where size is not modulus 4 KiB (block count != 8), assuming logical block size (LBS) = 512 B.[23]
182
0xB6
Erase Fail Count "Pre-Fail" Attribute used at least in Samsung devices.
183
0xB7
SATA Downshift Error Count or Runtime Bad Block
Låg
 
Western Digital, Samsung or Seagate attribute: Either the number of downshifts of link speed (e.g. from 6Gbps to 3Gbps) or the total number of data blocks with detected, uncorrectable errors encountered during normal operation.[24] Although degradation of this parameter can be an indicator of drive aging and/or potential electromechanical problems, it does not directly indicate imminent drive failure.[25]
184
0xB8
End-to-End error / IOEDC
Låg
 

 
This attribute is a part of Hewlett-Packard's SMART IV technology, as well as part of other vendors' IO Error Detection and Correction schemas, and it contains a count of parity errors which occur in the data path to the media via the drive's cache RAM.[27]
185
0xB9
Head Stability Western Digital attribute.
186
0xBA
Induced Op-Vibration Detection Western Digital attribute.
187
0xBB
Reported Uncorrectable Errors
Låg

 
The count of errors that could not be recovered using hardware ECC (see attribute 195).[28]
188
0xBC
Command Timeout
Låg

 
The count of aborted operations due to HDD timeout. Normally this attribute value should be equal to zero.[29]
189
0xBD
High Fly Writes
Låg
 
HDD manufacturers implement a flying height sensor 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[30] 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.[31]

190
0xBE
Temperature Difference or Airflow Temperature Mall:Varies Value is equal to (100-temp. °C), allowing manufacturer to set a minimum threshold which corresponds to a maximum temperature. This also follows the convention of 100 being a best-case value and lower values being undesirable. However, some older drives may instead report raw Temperature (identical to 0xC2) or Temperature minus 50 here.
191
0xBF
G-sense Error Rate
Låg
 
The count of errors resulting from externally induced shock and vibration.
192
0xC0
Power-off Retract Count, Emergency Retract Cycle Count (Fujitsu),[32] or Unsafe Shutdown Count
Låg
 
Number of power-off or emergency retract cycles.[5][33]
193
0xC1
Load Cycle Count or Load/Unload Cycle Count (Fujitsu)
Låg
 
Count of load/unload cycles into head landing zone position.[32] Some drives use 225 (0xE1) for Load Cycle Count instead.

Western Digital rates their VelociRaptor drives for 600,000 load/unload cycles,[34] and WD Green drives for 300,000 cycles;[35] the latter ones are designed to unload heads often to conserve power. On the other hand, the WD3000GLFS (a desktop drive) is specified for only 50,000 load/unload cycles.[36]

Some laptop drives and "green power" desktop drives are programmed to unload the heads whenever there has not been any activity for a short period, to save power.[37][38] Operating systems often access the file system a few times a minute in the background,[39] causing 100 or more load cycles per hour if the heads unload: the load cycle rating may be exceeded in less than a year.[40] There are programs for most operating systems that disable the Advanced Power Management (APM) and Automatic acoustic management (AAM) features causing frequent load cycles.[41][42]

194
0xC2
Temperature or Temperature Celsius
Låg
 
Indicates the device temperature, if the appropriate sensor is fitted. Lowest byte of the raw value contains the exact temperature value (Celsius degrees).[43]
195
0xC3
Hardware ECC Recovered Mall:Varies (Vendor-specific raw value.) The raw value has different structure for different vendors and is often not meaningful as a decimal number.
196
0xC4
Reallocation Event Count[32]
Låg

 
Count of remap operations. The raw value of this attribute shows the total count of attempts to transfer data from reallocated sectors to a spare area. Both successful and unsuccessful attempts are counted.[44]
197
0xC5
Current Pending Sector Count[32]
Låg

 
Count of "unstable" sectors (waiting to be remapped, because of unrecoverable read errors). If an unstable sector is subsequently read successfully, the sector is remapped and this value is decreased. Read errors on a sector will not remap the sector immediately (since the correct value cannot be read and so the value to remap is not known, and also it might become readable later); instead, the drive firmware remembers that the sector needs to be remapped, and will remap it the next time it's written.[45]

However, some drives will not immediately remap such sectors when written; instead the drive will first attempt to write to the problem sector and if the write operation is successful then the sector will be marked good (in this case, the "Reallocation Event Count" (0xC4) will not be increased). This is a serious shortcoming, for if such a drive contains marginal sectors that consistently fail only after some time has passed following a successful write operation, then the drive will never remap these problem sectors.

198
0xC6
(Offline) Uncorrectable Sector Count[32]
Låg
 

 
The total count 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.[1][29][26]
199
0xC7
UltraDMA CRC Error Count
Låg
 
The count of errors in data transfer via the interface cable as determined by ICRC (Interface Cyclic Redundancy Check).
200
0xC8
Multi-Zone Error Rate [46]
Låg
 
The count of errors found when writing a sector. The higher the value, the worse the disk's mechanical condition is.
200
0xC8
Write Error Rate (Fujitsu)
Låg
 
The total count of errors when writing a sector.[47]
201
0xC9
Soft Read Error Rate or
TA Counter Detected
Låg
 

 
Count indicates the number of uncorrectable software read errors.[48]
202
0xCA
Data Address Mark errors or
TA Counter Increased
Låg
 
Count of Data Address Mark errors (or vendor-specific).[5]
203
0xCB
Run Out Cancel
Låg
 
The number of errors caused by incorrect checksum during the error correction.
204
0xCC
Soft ECC Correction
Låg
Count of errors corrected by the internal error correction software.[5]
205
0xCD
Thermal Asperity Rate
Low
Count of errors due to high temperature.[49]
206
0xCE
Flying Height Height of heads above the disk surface. If too low, head crash is more likely; if too high, read/write errors are more likely.[5][50]
207
0xCF
Spin High Current
Låg
Amount of surge current used to spin up the drive.[49]
208
0xD0
Spin Buzz Count of buzz routines needed to spin up the drive due to insufficient power.[49]
209
0xD1
Offline Seek Performance Drive’s seek performance during its internal tests.[49]
210
0xD2
Vibration During Write Found in Maxtor 6B200M0 200GB and Maxtor 2R015H1 15GB disks.
211
0xD3
Vibration During Write A recording of a vibration encountered during write operations.[51]
212
0xD4
Shock During Write A recording of shock encountered during write operations.[19][52]
220
0xDC
Disk Shift
Låg
 
Distance the disk has shifted relative to the spindle (usually due to shock or temperature). Unit of measure is unknown.[19]
221
0xDD
G-Sense Error Rate
Låg
 
The count of errors resulting from externally induced shock and vibration.
222
0xDE
Loaded Hours Time spent operating under data load (movement of magnetic head armature).[19]
223
0xDF
Load/Unload Retry Count Count of times head changes position.[19]
224
0xE0
Load Friction
Låg
Resistance caused by friction in mechanical parts while operating.[19]
225
0xE1
Load/Unload Cycle Count
Låg
 
Total count of load cycles[19] Some drives use 193 (0xC1) for Load Cycle Count instead. See Description for 193 for significance of this number.
226
0xE2
Load 'In'-time Total time of loading on the magnetic heads actuator (time not spent in parking area).[19]
227
0xE3
Torque Amplification Count
Låg
 
Count of attempts to compensate for platter speed variations.[53]
228
0xE4
Power-Off Retract Cycle
Låg
 
The number of power-off cycles which are counted whenever there is a "retract event" and the heads are loaded off of the media such as when the machine is powered down, put to sleep, or is idle.[5][33]
230
0xE6
GMR Head Amplitude (magnetic HDDs), Drive Life Protection Status (SSDs) Amplitude of "thrashing" (repetitive head moving motions between operations).[5][54]

In solid-state drives, indicates whether usage trajectory is outpacing the expected life curve[55]

231
0xE7
Life Left (SSDs) or Temperature Indicates the approximate SSD life left, in terms of program/erase cycles or available reserved blocks.[55] A normalized value of 100 represents a new drive, with a threshold value at 10 indicating a need for replacement. A value of 0 may mean that the drive is operating in read-only mode to allow data recovery.[56]

Previously (pre-2010) occasionally used for Drive Temperature (more typically reported at 0xC2).

232
0xE8
Endurance Remaining or Available Reserved Space Number of physical erase cycles completed on the SSD as a percentage of the maximum physical erase cycles the drive is designed to endure.

Intel SSDs report the available reserved space as a percentage of the initial reserved space.

233
0xE9
Media Wearout Indicator (SSDs) or Power-On Hours Intel SSDs report a normalized value from 100, a new drive, to a minimum of 1. It decreases while the NAND erase cycles increase from 0 to the maximum-rated cycles.

Previously (pre-2010) occasionally used for Power-On Hours (more typically reported in 0x09).

234
0xEA
Average erase count AND Maximum Erase Count Decoded as: byte 0-1-2 = average erase count (big endian) and byte 3-4-5 = max erase count (big endian).[57]
235
0xEB
Good Block Count AND System(Free) Block Count Decoded as: byte 0-1-2 = good block count (big endian) and byte 3-4 = system (free) block count.
240
0xF0
Head Flying Hours or 'Transfer Error Rate' (Fujitsu) Time spent during the positioning of the drive heads.[5][58] Some Fujitsu drives report the count of link resets during a data transfer.[59]
241
0xF1
Total LBAs Written Total count of LBAs written.
242
0xF2
Total LBAs Read Total count of LBAs read.
Some S.M.A.R.T. utilities will report a negative number for the raw value since in reality it has 48 bits rather than 32.
243
0xF3
Total LBAs Written Expanded The upper 5 bytes of the 12-byte total number of LBAs written to the device. The lower 7 byte value is located at attribute 0xF1.[60]
244
0xF4
Total LBAs Read Expanded The upper 5 bytes of the 12-byte total number of LBAs read from the device. The lower 7 byte value is located at attribute 0xF2.[61]
249
0xF9
NAND Writes (1GiB) Total NAND Writes. Raw value reports the number of writes to NAND in 1 GB increments.[62]
250
0xFA
Read Error Retry Rate
Låg
 
Count of errors while reading from a disk.[19]
251
0xFB
Minimum Spares Remaining The Minimum Spares Remaining attribute indicates the number of remaining spare blocks as a percentage of the total number of spare blocks available.[63]
252
0xFC
Newly Added Bad Flash Block The Newly Added Bad Flash Block attribute indicates the total number of bad flash blocks the drive detected since it was first initialized in manufacturing.[63]
254
0xFE
Free Fall Protection
Låg
 
Count of "Free Fall Events" detected.[64]

Tröskelvärdedatum - Threshold Exceeds Condition (TEC)Redigera

Tröskelvärdedatum (TEC) är ett bedömt datum då ett kritiskt enhetsstatistikattribut når sitt tröskelvärde. När "Drive Health"-programvaran rapporterar en "närmaste TEC" bör den betraktas som ett "Failure date", dvs. då enheter havererar. Ibland anges inget datum och enheten kan förväntas fungera utan fel.[65]

För att förutsäga datum följer enheten hastigheten som attributet ändras i. Observera att TEC-datum endast är uppskattningar; hårddiskar kan haverera både mycket tidigare eller mycket senare.[66]

SjälvtesterRedigera

SMART-enheter kan erbjuda flera självtester:[67][68][69]

Kortfattad (Short)
Kontrollerar den elektriska och mekaniska prestandan såväl som skivans läsprestanda. Elektriska tester kan inkludera ett test av buffert-RAM, ett test av läs-/skrivkrets eller ett test av läs-/skrivhuvud. Mekaniska tester inkluderar sökning och motorstyrning, genom att skanna delar av enhetens yta. Vidare kontrolleras listan över sektorer som kan ha läsfel. Testet utformas olika av olika tillverkare och det körs under en begränsad tid, vanligtvis under två minuter.
Utförlig (Long/Extended)
En längre och mer grundlig version av det korta självtestet som skannar hela skivytan utan tidsgräns. Detta test tar vanligtvis flera timmar, beroende på läs-/skrivhastighet på enheten och dess storlek.
Kortfattad tillverkaranpassad (Conveyance)
Avsedd som ett snabbtest för att identifiera skador som uppstod vid transport av enheten från enhetens tillverkare till datortillverkaren.[70]

Endast tillgängligt på ATA-enheter och tar vanligtvis flera minuter.

Selektivt (Selective)
Vissa enheter tillåter selektivt självtest på bara en del av ytan.[71]

Självtestloggarna för SCSI- och ATA-enheter är något olika. Det är möjligt för det långa testet att passera även om det korta testet misslyckas.[72]

Diskens självtestlogg kan innehålla upp till 21 skrivskyddade poster. När loggen är fylld tas gamla poster bort.[73]

Se ävenRedigera

ReferenserRedigera

Den här artikeln är helt eller delvis baserad på material från engelskspråkiga Wikipedia, S.M.A.R.T., 31 augusti 2019.

NoterRedigera

  1. ^ [a b c d e] https://ai.google/research/pubs/pub32774
  2. ^ Pinheiro, Eduardo; Weber, Wolf-Dietrich; Barroso, Luís André, Failure Trends in a Large Disk Drive Population, 1600 Amphitheatre Pkwy Mountain View, CA 94043, http://research.google.com/archive/disk_failures.pdf 
  3. ^ Stephens 2006, s. 207Of the 512 octets listed in table 42 on page 207: "Device SMART data structure" a total of 489 are marked as "Vendor specific".
  4. ^ Ottem, Eric; Plummer, Judy (1995), Playing it S.M.A.R.T.: The emergence of reliability prediction technology., Seagate Technology Paper, ”"Though attributes are drive-specific, a variety of typical characteristics can be identified: [...] The attributes listed above illustrate typical kinds of reliability indicators. Ultimately, the disc drive design determines which attributes the manufacturer will choose. Attributes are therefore considered proprietary, since they depend on drive design."” 
  5. ^ [a b c d e f g h] Hatfield, Jim (30 September 2005). ”SMART Attribute Annex” (på engelska). Technical Committee T13. Seagate Technology. 1–5. http://www.t13.org/documents/uploadeddocuments/docs2005/e05148r0-acs-smartattributesannex.pdf. Läst 12 juli 2016. 
  6. ^ ”FAQ”, Smartmontools, Source forge, https://www.smartmontools.org/wiki/FAQ#Attribute194TemperatureCelsiusbehavesstrangelyonmySeagatedisk, ”Attribute 194 (Temperature Celsius) behaves strangely on my Seagate disk” 
  7. ^ ”Self-Monitoring, Analysis and Reporting Technology (SMART)”, Smart Linux, Source forge, 2009-03-10, http://smartlinux.sourceforge.net/smart/article.php 
  8. ^ [a b c] Failure Trends in a Large Disk Drive Population” (PDF). Proceedings of the 5th USENIX Conference on File and Storage Technologies (FAST’07). 2007. https://static.googleusercontent.com/media/research.google.com/en//archive/disk_failures.pdf. ”We find that the group of drives with scan errors are ten times more likely to fail than the group with no errors. This effect is also noticed when we further break down the groups by disk model. From Figure 8 we see a drastic and quick decrease in survival probability after the first scan error (left graph). A little over 70% of the drives survive the first 8 months after their first scan error.”. 
  9. ^ What SMART Hard Disk Errors Actually Tell Us” (på amerikansk engelska). Backblaze Blog | Cloud Storage & Cloud Backup. 2016-10-06. https://www.backblaze.com/blog/what-smart-stats-indicate-hard-drive-failures/. 
  10. ^ ”S.M.A.R.T. Attribute: Reallocated Sectors Count | Knowledge Base” (på engelska). kb.acronis.com. https://kb.acronis.com/content/9105. 
  11. ^ ”ATA Command Set 4 (ACS-4) - Working Draft”. October 14, 2016. http://www.t13.org/Documents/UploadedDocuments/docs2016/di529r14-ATAATAPI_Command_Set_-_4.pdf. 
  12. ^ ”What SMART Stats Tell Us About Hard Drives”. Comment by "Mark". https://www.backblaze.com/blog/what-smart-stats-indicate-hard-drive-failures/#comment-2938093635. ”There was a direct link between Reallocated Sectors Count and how quickly the drive would fail [...] Even one Uncorrectable sector count would lead to most drives being unusable within 3months” 
  13. ^ ”9109: S.M.A.R.T. Attribute: Power-On Hours (POH)”, Knowledge Base, Acronis, http://kb.acronis.com/content/9109 
  14. ^ ”Power on time”. hdsentinel.com. http://www.hdsentinel.com/help/en/54_pot.html. Läst 14 juli 2014. 
  15. ^ ”FAQ”. Smartmontools. Sourceforge. Arkiverad från originalet den 2013-02-20. https://web.archive.org/web/20130220063242/http://sourceforge.net/apps/trac/smartmontools/wiki/FAQ#Thepower-ontimerAttribute9rawvalueonmyMaxtordiskactsstrange. Läst 15 januari 2013. 
  16. ^ ”S.M.A.R.T. Attribute: Spin Retry Count Knowledge Base” (på engelska). kb.acronis.com. https://kb.acronis.com/content/9110. 
  17. ^ ”SMART Hard Drive Attributes: SMART 22 is a Gas Gas Gas”. Backblaze Blog - The Life of a Cloud Backup Company. https://www.backblaze.com/blog/smart-22-is-a-gas-gas-gas/. 
  18. ^ (PDF) Intel Solid-state Drive DC S3700 Series Product Specification, Intel, March 2014, http://www.intel.com/content/dam/www/public/us/en/documents/product-specifications/ssd-dc-s3700-spec.pdf 
  19. ^ [a b c d e f g h i] ”S.M.A.R.T.”. Acronis. 9 March 2010. https://kb.acronis.com/es/taxonomy/term/1644?page=3. Läst 1 april 2016.  Samsung, Seagate, IBM (Hitachi), Fujitsu (not all models), Maxtor, Western Digital (not all models)
  20. ^ [a b] (PDF) Intel Solid-state Drive DC S3700 Series Product Specification, Intel, March 2014, http://www.intel.com/content/dam/www/public/us/en/documents/product-specifications/ssd-dc-s3700-spec.pdf 
  21. ^ ”9184: S.M.A.R.T. Attribute: Erase Fail Count (chip)”. March 9, 2010. https://kb.acronis.com/content/9184. 
  22. ^ ”SMART Attribute Details”. SMART Attribute Details. Kingston Technology Corporation. 2013. 4. Arkiverad från originalet den 2013-05-07. https://web.archive.org/web/20130507072056/http://media.kingston.com/support/downloads/MKP_306_SMART_attribute.pdf. Läst 3 augusti 2013. 
  23. ^ ”The SMART Command Feature Set”. The SMART Command Feature Set. Micron Technology, Inc. August 2010. 11. Arkiverad från originalet den 2013-02-01. https://web.archive.org/web/20130201025337/http://www.micron.com/~/media/Documents/Products/Technical%20Note/Solid%20State%20Storage/tnfd03.pdf. Läst 3 augusti 2013.  Arkiverad 1 februari 2013 hämtat från the Wayback Machine.
  24. ^ ”HDD Guardian”. CodePlex. https://hddguardian.codeplex.com/wikipage?title=STEC. Läst 21 januari 2015. 
  25. ^ ”S.M.A.R.T. Attribute: SATA Downshift Error Count | Knowledge Base” (på engelska). kb.acronis.com. https://kb.acronis.com/content/9118. 
  26. ^ [a b c] ”Acronis Drive Monitor: Disk Health Calculation Knowledge Base” (på engelska). kb.acronis.com. https://kb.acronis.com/content/9264. 
  27. ^ ”SMART IV Technology on HP Business Desktop Hard Drives” (PDF). SMART IV Technology on HP Business Desktop Hard Drives. Hewlett-Packard. Arkiverad från originalet den 23 mars 2012. https://web.archive.org/web/20120323084450/http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01159621/c01159621.pdf. Läst 8 september 2011.  Arkiverad 23 mars 2012 hämtat från the Wayback Machine.
  28. ^ [a b] ”BackBlaze SMART blog”. BackBlaze SMART blog. https://www.backblaze.com/blog/hard-drive-smart-stats/. Läst 20 juli 2015. 
  29. ^ [a b c d] What SMART Hard Disk Errors Actually Tell Us” (på amerikansk engelska). Backblaze Blog | Cloud Storage & Cloud Backup. 2016-10-06. https://www.backblaze.com/blog/what-smart-stats-indicate-hard-drive-failures/#comment-2938093635. 
  30. ^ (PDF) Enhanced Smart attributes, Seagate, arkiverad från ursprungsadressen den 2006-03-28, https://web.archive.org/web/20060328023033/http://seagate.com/docs/pdf/whitepaper/enhanced_smart.pdf 
  31. ^ (PDF) Fly Height Monitor Improves Hard Drive Reliability, Western Digital, April 1999, 79-850123-000, http://www.wdc.com/wdproducts/library/other/2579-850123.pdf 
  32. ^ [a b c d e] (PDF) MHT2080AT, MHT2060AT, MHT2040AT, MHT2030AT, MHG2020AT Disk Drives, Fujitsu, 2003-07-04, C141-E192-02EN, http://www.fujitsu.com/downloads/COMP/fcpa/hdd/discontinued/mht20xxat_prod-manual.pdf 
  33. ^ [a b] ”9127: S.M.A.R.T. Attribute: Power-off Retract Count”. Acronis Knowledge Base. Acronis International. https://kb.acronis.com/content/9127. Läst 12 juli 2016. 
  34. ^ WD VelociRaptor Spec Sheet, WD, http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-701282.pdf 
  35. ^ WD Green Spec Sheet, WD, http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771438.pdf 
  36. ^ ”WD VelociRaptor SATA Hard Drives” (PDF). WD VelociRaptor SATA Hard Drives. wdc.com. 2008. http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-701260.pdf. Läst 31 mars 2014. 
  37. ^ ”Problem with hard drive clicking”, Think, http://www.thinkwiki.org/wiki/Problem_with_hard_drive_clicking 
  38. ^ ”hdparm(8) - Linux manual page”. hdparm(8) - Linux manual page. man7.org. November 2012. http://man7.org/linux/man-pages/man8/hdparm.8.html. Läst 31 mars 2014. ”Get/set the Western Digital (WD) Green Drive's "idle3" timeout value. This timeout controls how often the drive parks its heads and enters a low power consumption state. The factory default is eight (8) seconds, which is a very poor choice for use with Linux. Leaving it at the default will result in hundreds of thousands of head load/unload cycles in a very short period of time.” 
  39. ^ discussion list, Arch Linux, http://bbs.archlinux.org/viewtopic.php?id=66706, ”If linux tends to write to /var/log/* every 30s, then the heads can park/unpark every 30s.” 
  40. ^ ”Hard drives”, How to Reduce Power Consumption, Think, http://www.thinkwiki.org/wiki/How_to_reduce_power_consumption#Hard_Drives, ”The files access time update, while mandated by POSIX, is causing lots of disks access; even accessing files on disk cache may wake the ATA or USB bus.” 
  41. ^ ”Mac OS X is beating your hard drives to death. Here's the fix.”. Kg4cyx.net. 11 November 2014. http://www.kg4cyx.net/mac-os-x-is-beating-your-hard-drives-to-death-heres-the-fix/. Läst 3 april 2016. 
  42. ^ ”quietHDD”. quiethdd. 13 December 2009. https://sites.google.com/site/quiethdd/. Läst 3 april 2016. 
  43. ^ ”S.M.A.R.T. basics”. S.M.A.R.T. basics. http://www.z-a-recovery.com/manual/smart.aspx. 
  44. ^ ”S.M.A.R.T.-Attribute: Reallocation Event Count”, Knowledge Base, Acronis, http://kb.acronis.com/content/9132 
  45. ^ ”S.M.A.R.T. Attribute: Current Pending Sector Count”, Knowledge Base, Acronis, http://kb.acronis.com/content/9133 
  46. ^ Cabla, Lubomir (2009-08-06). ”HDAT2 v4.6 User's Manual” (PDF). HDAT2 v4.6 User's Manual. http://www.hdat2.com/files/hdat2en_v11.pdf. 
  47. ^ ”Attributes”. SMART Linux project. Source forge. http://smartlinux.sourceforge.net/smart/attributes.php. 
  48. ^ [a b] ”S.M.A.R.T. Attribute: Soft Read Error Rate / Off Track Errors (Maxtor) | Knowledge Base” (på engelska). kb.acronis.com. https://kb.acronis.com/content/9137. 
  49. ^ [a b c d] S.M.A.R.T. attribute list (ATA), HD sentinel, http://www.hdsentinel.com/help/en/56_attrib.html 
  50. ^ ”9142: S.M.A.R.T. Attribute: Flying Height”. Acronis Knowledge Base. Acronis International. https://kb.acronis.com/content/9142. Läst 12 juli 2016. 
  51. ^ ”9146: S.M.A.R.T. Attribute: Vibration During Write”. Acronis Knowledge Base. Acronis International. https://kb.acronis.com/content/9146. Läst 12 juli 2016. 
  52. ^ ”9147: S.M.A.R.T. Attribute: Shock During Write”. Acronis Knowledge Base. Acronis International. https://kb.acronis.com/content/9147. Läst 12 juli 2016. 
  53. ^ ”9154: S.M.A.R.T. Attribute: Torque Amplification Count”. Acronis Knowledge Base. Acronis International. https://kb.acronis.com/content/9154. Läst 12 juli 2016. 
  54. ^ ”9156: S.M.A.R.T. Attribute: GMR Head Amplitude”. Acronis Knowledge Base. Acronis International. https://kb.acronis.com/content/9156. 
  55. ^ [a b] SMART Attribute Details, Kingston, http://media.kingston.com/support/downloads/MKP_306_SMART_attribute.pdf 
  56. ^ ”S.M.A.R.T. Monitoring Tools / Mailing Lists” (på engelska). sourceforge.net. https://sourceforge.net/p/smartmontools/mailman/message/32246334/. 
  57. ^ ”Ticket 171”. Smartmontools. Source forge. Arkiverad från originalet den 2013-05-18. https://web.archive.org/web/20130518042824/http://sourceforge.net/apps/trac/smartmontools/ticket/171. Läst 1 augusti 2019. 
  58. ^ ”9157: S.M.A.R.T. Attribute: Head Flying Hours / Transfer Error Rate (Fujitsu)”. Acronis Knowledge Base. Acronis International. https://kb.acronis.com/content/9157. 
  59. ^ ”MHY2250BH, MHY2200BH, MHY2160BH, MHY2120BH, MHY2100BH, MHY2080BH, MHY2060BH, MHY2040BH Disk Drives, Product/Maintenance Manual”. MHY2250BH, MHY2200BH, MHY2160BH, MHY2120BH, MHY2100BH, MHY2080BH, MHY2060BH, MHY2040BH Disk Drives, Product/Maintenance Manual. Fujitsu Limited. http://pdfstream.manualsonline.com/2/20e501aa-595c-46fe-bbac-2088887ceffe.pdf. 
  60. ^ (PDF) SlimSATA SSD Mini-SATA Embedded Flash Module, Delkin Devices, 2013, arkiverad från ursprungsadressen den 2015-11-17, https://web.archive.org/web/20151117020835/http://delkinoem.com/oem-engineering-specs-product-docs/Industrial-SlimSATA-solid-state-drive-specification.pdf, läst 1 augusti 2019  Arkiverad 17 november 2015 hämtat från the Wayback Machine.
  61. ^ (PDF) SlimSATA SSD Mini-SATA Embedded Flash Module, Delkin Devices, 2013, arkiverad från ursprungsadressen den 2015-11-17, https://web.archive.org/web/20151117020835/http://delkinoem.com/oem-engineering-specs-product-docs/Industrial-SlimSATA-solid-state-drive-specification.pdf, läst 1 augusti 2019  Arkiverad 17 november 2015 hämtat från the Wayback Machine.
  62. ^ (PDF) Intel Solid-state Drive 520 Series Product Specification, Intel, February 2012, http://download.intel.com/newsroom/kits/ssd/pdfs/intel_ssd_520_product_spec_325968.pdf 
  63. ^ [a b] ”SMART Modular Technologies S.M.A.R.T. attributes - A new Windows interface for smartctl”. google.com. https://code.google.com/p/hddguardian/wiki/Smart_Modular_SMART_attributes. 
  64. ^ (PDF) Momentus 7200.2 SATA (D), Seagate, September 2007, Hitachi Document Part Number S13K-1055-20, http://www.seagate.com/staticfiles/support/disc/manuals/notebook/momentus/7200.2/100451238d.pdf 
  65. ^ ”FAQ”, Drive health, http://www.drivehealth.com/faq.html, läst 4 oktober 2011 
  66. ^ The interpretation of the TEC and the SMART, Altrix soft, http://www.altrixsoft.com/en/support/help/hddinsp/tec%20and%20smart.php, läst 4 oktober 2011 
  67. ^ (manpage), arkiverad från ursprungsadressen . Du måste ange datum då sidan arkiverades genom parametern |archivedate=., https://web.archive.org/web/20090715005747/http://smartmontools.sourceforge.net/man/smartctl.8.html  Arkiverad 15 juli 2009 hämtat från the Wayback Machine.
  68. ^ HDDScan, http://hddscan.com/  - gratis HDD-testverktyg med USB-blixt och RAID-stöd.
  69. ^ Evans (PDF), Självtester på hårddisken, Milpitas, CA USA, http://www.t10.org/ftp/t10/document.99/99-179r0.pdf 
  70. ^ Bulik, Darrin (Sep 24, 2001) (PDF), Proposal for Extensions To Drive Self Test, Lake Forest, CA: T10, arkiverad från ursprungsadressen den 2011-09-28, https://web.archive.org/web/20110928091120/http://www.t10.org/t13/technical/e01137r0.pdf  Arkiverad 28 september 2011 hämtat från the Wayback Machine.
  71. ^ McLean, Pete (23 October 2001) (PDF), Proposal for a Selective Self-test, Longmont, CO: T10, arkiverad från ursprungsadressen den 28 September 2011, https://web.archive.org/web/20110928091148/http://www.t10.org/t13/technical/e01139r0.pdf  Arkiverad 28 september 2011 hämtat från the Wayback Machine.
  72. ^ ”HDD fails S.M.A.R.T. short test, but passes long test?”. HDD fails S.M.A.R.T. short test, but passes long test?. Hardware Canucks. Arkiverad från originalet den 2013-01-02. https://web.archive.org/web/20130102165628/http://www.hardwarecanucks.com/forum/storage/23040-hdd-fails-s-m-r-t-short-test-but-passes-long-test.html. Läst 15 januari 2013.  Arkiverad 2 januari 2013 hämtat från the Wayback Machine.
  73. ^ [1], Smartmontools mailing lists

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