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Jeffrey
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[hard drive] gsmartcontrol data interpretation needed

I'm trying to repair the laptop of a friend of mine. It's an HP Pavillion dm4 running Windows 7 64-bit, 4GB of RAM i5 @ 2.53Ghz. The laptop is slow as molasses. I worked on it remotely; antivirus, malware and TDSSKiller showed no infections. Laptop remains slow. Asked friend to ship it to me, she did. Upon receiving, same symptoms continued. Ran gsmartcontrol and found some errors (see below). My friend said this unit worked well once, but at some point in the past, it started going south to the point where it is now. I have backed up her essential files, and while the unit works speedily in safe mode, something may be causing the slowdown during a normal boot to Windows. That said, I never know how to properly read these hard drive testing output data when errors are shown.

Recommendations? I obviously don't want to incur any extra price on her or work for me for that matter, if not necessary. "Warnings" and "failures" always scare me.

(FWIW, I did google gsmartcontrol data interpretation with little success, unless I missed something, which is entirely possible.)


smartctl 5.43 2012-06-30 r3573 [i686-w64-mingw32-win7(64)-sp1] (sf-5.43-1)
Copyright (C) 2002-12 by Bruce Allen, »smartmontools.sourceforge.net

=== START OF INFORMATION SECTION ===
Model Family: Toshiba 2.5" HDD MK..65GSX
Device Model: TOSHIBA MK6465GSX
Serial Number: Y0DBF100S
LU WWN Device Id: 5 000039 2e6c81dcf
Firmware Version: GJ002C
User Capacity: 640,135,028,736 bytes [640 GB]
Sector Size: 512 bytes logical/physical
Device is: In smartctl database [for details use: -P show]
ATA Version is: 8
ATA Standard is: Exact ATA specification draft version not indicated
Local Time is: Tue Aug 21 19:38:41 2012 EDT
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
See vendor-specific Attribute list for marginal Attributes.

General SMART Values:
Offline data collection status: (0x00) Offline data collection activity
was never started.
Auto Offline Data Collection: Disabled.
Self-test execution status: ( 121) The previous self-test completed having
the read element of the test failed.
Total time to complete Offline
data collection: ( 120) seconds.
Offline data collection
capabilities: (0x51) SMART execute Offline immediate.
No Auto Offline data collection support.
Suspend Offline collection upon new
command.
No Offline surface scan supported.
Self-test supported.
No Conveyance Self-test supported.
Selective Self-test supported.
SMART capabilities: (0x0003) Saves SMART data before entering
power-saving mode.
Supports SMART auto save timer.
Error logging capability: (0x01) Error logging supported.
General Purpose Logging supported.
Short self-test routine
recommended polling time: ( 2) minutes.
Extended self-test routine
recommended polling time: ( 164) minutes.
SCT capabilities: (0x003f) SCT Status supported.
SCT Error Recovery Control supported.
SCT Feature Control supported.
SCT Data Table supported.

SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW _VALUE
1 Raw_Read_Error_Rate 0x000f 100 100 015 Pre-fail Always - 0
2 Throughput_Performance 0x0007 100 100 007 Pre-fail Always - 0
3 Spin_Up_Time 0x0003 100 100 003 Pre-fail Always - 197 4
4 Start_Stop_Count 0x0032 100 100 050 Old_age Always - 871
5 Reallocated_Sector_Ct 0x0033 028 028 051 Pre-fail Always FAILING_NOW 148 4
7 Seek_Error_Rate 0x000f 100 100 015 Pre-fail Always - 0
8 Seek_Time_Performance 0x0005 100 100 005 Pre-fail Offline - 0
9 Power_On_Hours 0x0032 099 099 050 Old_age Always - 644
10 Spin_Retry_Count 0x0013 117 100 019 Pre-fail Always - 0
12 Power_Cycle_Count 0x0032 100 100 050 Old_age Always - 856
183 Runtime_Bad_Block 0x0022 100 100 034 Old_age Always - 1
184 End-to-End_Error 0x0033 100 100 051 Pre-fail Always - 0
185 Unknown_Attribute 0x0032 100 100 050 Old_age Always - 655 35
187 Reported_Uncorrect 0x0032 001 001 050 Old_age Always FAILING_NOW 470 1
188 Command_Timeout 0x0032 100 097 050 Old_age Always - 5
189 High_Fly_Writes 0x003a 100 100 058 Old_age Always - 0
190 Airflow_Temperature_Cel 0x0022 067 058 034 Old_age Always - 33 (Min/Max 33/42)
191 G-Sense_Error_Rate 0x0032 100 100 050 Old_age Always - 61
192 Power-Off_Retract_Count 0x0032 100 100 050 Old_age Always - 104 8592
193 Load_Cycle_Count 0x0032 100 100 050 Old_age Always - 280 8
196 Reallocated_Event_Count 0x0032 100 100 050 Old_age Always - 361
197 Current_Pending_Sector 0x0012 100 100 018 Old_age Always - 2
199 UDMA_CRC_Error_Count 0x003e 200 200 062 Old_age Always - 0

SMART Error Log Version: 1
ATA Error Count: 5063 (device log contains only the most recent five errors)
CR = Command Register [HEX]
FR = Features Register [HEX]
SC = Sector Count Register [HEX]
SN = Sector Number Register [HEX]
CL = Cylinder Low Register [HEX]
CH = Cylinder High Register [HEX]
DH = Device/Head Register [HEX]
DC = Device Command Register [HEX]
ER = Error register [HEX]
ST = Status register [HEX]
Powered_Up_Time is measured from power on, and printed as
DDd+hh:mm:SS.sss where DD=days, hh=hours, mm=minutes,
SS=sec, and sss=millisec. It "wraps" after 49.710 days.

Error 5063 occurred at disk power-on lifetime: 641 hours (26 days + 17 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 41 5a 78 df 6a 60 Error: UNC at LBA = 0x006adf78 = 7004024

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name
-- -- -- -- -- -- -- -- ---------------- --------------------
60 20 68 81 ed 23 40 00 01:03:31.684 READ FPDMA QUEUED
60 10 60 a7 3a 4b 40 00 01:03:31.681 READ FPDMA QUEUED
60 08 58 78 df 6a 40 00 01:03:31.662 READ FPDMA QUEUED
60 20 50 87 3a 4b 40 00 01:03:31.662 READ FPDMA QUEUED
2f 00 01 10 00 00 40 00 01:03:31.662 READ LOG EXT

Error 5062 occurred at disk power-on lifetime: 641 hours (26 days + 17 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 41 b2 78 df 6a 60 Error: WP at LBA = 0x006adf78 = 7004024

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name
-- -- -- -- -- -- -- -- ---------------- --------------------
61 08 40 f8 2c 62 40 00 01:03:28.171 WRITE FPDMA QUEUED
61 08 38 00 2d 62 40 00 01:03:28.171 WRITE FPDMA QUEUED
61 08 30 90 27 63 40 00 01:03:28.171 WRITE FPDMA QUEUED
61 01 28 c8 c3 07 40 00 01:03:25.582 WRITE FPDMA QUEUED
61 08 20 c0 d9 b9 40 00 01:03:24.911 WRITE FPDMA QUEUED

Error 5061 occurred at disk power-on lifetime: 641 hours (26 days + 17 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 41 82 78 df 6a 60 Error: UNC at LBA = 0x006adf78 = 7004024

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name
-- -- -- -- -- -- -- -- ---------------- --------------------
60 06 88 80 f3 64 40 00 01:03:15.931 READ FPDMA QUEUED
60 08 80 78 df 6a 40 00 01:03:15.917 READ FPDMA QUEUED
60 08 78 30 10 68 40 00 01:03:15.917 READ FPDMA QUEUED
2f 00 01 10 00 00 40 00 01:03:15.917 READ LOG EXT
61 08 68 38 4d 66 40 00 01:03:14.912 WRITE FPDMA QUEUED

Error 5060 occurred at disk power-on lifetime: 641 hours (26 days + 17 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 41 4a 78 df 6a 60 Error: WP at LBA = 0x006adf78 = 7004024

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name
-- -- -- -- -- -- -- -- ---------------- --------------------
61 08 68 38 4d 66 40 00 01:03:14.912 WRITE FPDMA QUEUED
61 08 40 d8 55 07 40 00 01:03:13.729 WRITE FPDMA QUEUED
61 08 38 08 2d 62 40 00 01:03:13.729 WRITE FPDMA QUEUED
61 01 30 d8 29 99 40 00 01:03:13.729 WRITE FPDMA QUEUED
61 08 18 d8 55 07 40 00 01:03:13.729 WRITE FPDMA QUEUED

Error 5059 occurred at disk power-on lifetime: 641 hours (26 days + 17 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 41 fa 78 df 6a 60 Error: WP at LBA = 0x006adf78 = 7004024

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name
-- -- -- -- -- -- -- -- ---------------- --------------------
61 08 30 f0 2c 62 40 00 01:03:07.659 WRITE FPDMA QUEUED
61 08 28 08 2d 62 40 00 01:03:07.658 WRITE FPDMA QUEUED
61 08 20 80 27 63 40 00 01:03:07.658 WRITE FPDMA QUEUED
60 30 18 e2 69 27 40 00 01:03:05.794 READ FPDMA QUEUED
61 08 10 b0 94 24 40 00 01:03:02.916 WRITE FPDMA QUEUED

SMART Self-test log structure revision number 1
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_ error
# 1 Short offline Completed: read failure 90% 641 7004023
# 2 Short offline Completed without error 00% 3 -
# 3 Short offline Completed without error 00% 2 -
# 4 Short offline Completed without error 00% 2 -
# 5 Short offline Completed without error 00% 2 -
# 6 Short offline Completed without error 00% 2 -
# 7 Short offline Completed without error 00% 1 -
# 8 Short offline Completed without error 00% 1 -
# 9 Short offline Completed without error 00% 1 -

SMART Selective self-test log data structure revision number 1
SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS
1 0 0 Not_testing
2 0 0 Not_testing
3 0 0 Not_testing
4 0 0 Not_testing
5 0 0 Not_testing
Selective self-test flags (0x0):
After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.


--
He used to say that soul shine, is better than sunshine, better than moonshine, damn sure better than rain.

Debunking the 2012 hysteria. | Always looking for a new job | Begging the Wilpons to sell the Mets.


koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23

1 edit
This one isn't too hard to decode. Please keep in mind all attributes represent the state of the drive during its entire lifetime (total of 644 hours).

First and foremost, it looks like your copy-paste contains extraneous whitespace in it, which makes parsing this output difficult (I have to make some assumptions). I can tell from this line:


Note the space after RAW and before _VALUE. As such, I'm going assume that any RAW_VALUE attributes with spaces in them SHOULD NOT have spaces in them. Why this matters: yes, some RAW_VALUE attributes are decoded in a way where multiple values are shown in the RAW_VALUE column (very common for Seagate disks), so ensuring proper formatting is very important.

Looking at the FAILING_NOW entries (and I'll explain what that means shortly):

SMART attribute 5 indicates the number of actual reallocated LBAs to sectors (meaning instead of a 1:1 ratio of LBA number to sector number, you now have some LBAs which point to spare sectors). These were LBAs which pointed to sectors which the drive definitely confirmed as bad. Data at those sectors was lost. There were a total of 1484 bad sectors.

SMART attribute 187 indicates the total number of times the drive has tried to read a sector and either failed, or, the number of times a drive has read a sector and could not auto-correct the read data using the associated ECC portion of the physical sector itself. I do not know which is the case on Toshiba drives. There were a total of 4701 events of this type.

Now for the other attributes which are also of concern, and can act as indicators of what lead to the above situation:

SMART attribute 183 indicates something (hehe :D) but I'm not sure what -- it's an attribute I'm not familiar with (don't have much familiarity with Toshiba disks).

SMART attribute 188 indicates the drive has experienced a total of 5 ATA command timeouts during its lifetime; these could have been to the drive itself spending too much time doing ECC, or due to the aforementioned sector problems. In my experience, it's usually the latter, especially when I see a drive in this condition.

SMART attribute 191 indicates this is probably a laptop or 2.5" drive and that it has been jostled about to the point where the shock sensor tripped. Total number of times is 61. This sensor is only in use when the drive is powered on (including sleep/standby mode). It's normal when this drive is used actively in a laptop for this number to increment if the person is walking around with the laptop powered on (I see people doing this all the time), so expect some variance. However, that's 61 times within 644 hours. That's almost once every 10 hours. Is someone spinning their laptop like a pizza pie, doing flips and jigs at the same time? :P This sensor is separate from the sector problems shown on this disk.

SMART attribute 196 indicates the total number of reallocation events (either successful or unsuccessful). 361 seems a bit small, however I HAVE seen drives which decrement this attribute as things happen (e.g. it's at 361, then 4 sectors get reallocated, so the number becomes 357).

SMART attribute 197 indicates you have 2 LBAs which the drive considers "suspect" thus cannot be read (you'll receive I/O errors when trying to read them). They can only be re-analysed by issuing a write to them.

Now for the SMART error log:

I can see that there's been a total number of 5063 error events in the log. The log is a limited size, so it's hard to determine what all the errors are, but given the above SMART attributes I can assure you it's a combination of what's been seen above. Some may be the ATA timeouts, some may be the reads which couldn't be auto-corrected by ECC, some may be those 2 "suspect" LBAs which can't be read, others are (obviously) writes. You get the idea.

For those reading the thread and wondering what READ FPDMA QUEUED and WRITE FPDMA QUEUED mean (vs. a "standard read" or a "standard write") -- these are the underlying ATA commands used for NCQ. So from this, I can tell the underlying OS and/or controller is using NCQ. :-)

Now for the SMART self-test log:

Something (not sure if the drive did this internally, or if you did this using smartmontools) induced some SMART short tests. That's fine -- however, at the 641 hour mark, the drive's very quick internal analysis showed LBA 7004023 as unreadable. This could be one of the 2 "suspect" LBAs, but it's impossible for me to tell. In fact, I wouldn't bother trying to figure it out either -- the drive is in too bad shape for me to really care.

Back to the FAILING_NOW stuff:

These are labelled FAILING_NOW because the internal (vendor-chosen) SMART thresholds have been tripped for those normalised attributes. For example, attribute 5 shows a VALUE of 28, a WORST of 28, and a THRESH of 51. VALUE (28) is less than WORST (51), thus the trip.

Final point:

This drive appears to have a firmware bug. You have 2 SMART attributes which are labelled FAILING_NOW yet I see:

SMART overall-health self-assessment test result: PASSED

The health of this drive SHOULD NOT be passed; it should be in FAILED state. You can blame Toshiba for this one. Downright, absolute firmware bug.

Recommendation:

Replace the drive immediately. This drive is in bad shape and should not be used going forward. Copy off all of your data (do not do a disk-to-disk copy or a "disk image" copy that copies all sectors/data -- instead just copy off your individual files that are important to you) to a flash drive or other hard disk and then replace the drive.

If this is a laptop from a vendor like Dell, who keeps the Windows/OS installation on a partition on the hard disk yourself, you should contact the vendor. DO NOT try and copy off the Windows/OS partition (specifically the Factory.wim file) and re-do it yourself; given how many sectors are wonky on this drive I would not trust this. Make this the vendor's problem. This is why you go with vendors in the first place -- to get support.

If this is a laptop from a vendor (Dell, HP, etc.), contact the vendor and have them replace the hard disk. Do not let them tell you "just reinstall Windows" -- NO. The drive is in horrible shape and will get worse.

If this is a self-built laptop or self-maintained, no problem -- replace the drive and reinstall the OS from source material.

That's about all I can say on this matter. Heed my advice. :-)

P.S. -- In the future, please post monospace text into the forum using [code]
blocks, not <pre> blocks. Note that I did not say <code> (ther e is a difference; former is for large blocks of text, latter is for inline monospace text ). :-)
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.


Jeffrey
Connoisseur of leisurely things
Premium
join:2002-12-24
Long Island
kudos:3
Reviews:
·voip.ms
said by koitsu:

This one isn't too hard to decode.

For you, no. For me, yes. :) I have run gsmartcontrol a few times in the past,. and I have been able to diagnose it somewhat, but not nearly to the depth I'd like.

said by koitsu:

First and foremost, it looks like your copy-paste contains extraneous whitespace in it, which makes parsing this output difficult (I have to make some assumptions). I can tell from this line:

I wasn't exactly sure how to do it - believe it or not, the output I posted was the cleanest I could get it. You should have seen it before I tried to make it look half decent. :)

said by koitsu:

SMART attribute 191 indicates this is probably a laptop or 2.5" drive and that it has been jostled about to the point where the shock sensor tripped. Total number of times is 61. This sensor is only in use when the drive is powered on (including sleep/standby mode). It's normal when this drive is used actively in a laptop for this number to increment if the person is walking around with the laptop powered on (I see people doing this all the time), so expect some variance. However, that's 61 times within 644 hours. That's almost once every 10 hours. Is someone spinning their laptop like a pizza pie, doing flips and jigs at the same time? :P This sensor is separate from the sector problems shown on this disk.

My friend said she didn't use it too much, and I asked her if it was ever dropped or tossed around, and she said no. After your explanation, I'm going to call her in a few and ask her once again.

said by koitsu:

Now for the SMART error log:

Something (not sure if the drive did this internally, or if you did this using smartmontools) induced some SMART short tests. That's fine -- however, at the 641 hour mark, the drive's very quick internal analysis showed LBA 7004023 as unreadable. This could be one of the 2 "suspect" LBAs, but it's impossible for me to tell. In fact, I wouldn't bother trying to figure it out either -- the drive is in too bad shape for me to really care.

I ran those short tests. Drive hung early on during extended tests.

said by koitsu:

Final point:

This drive appears to have a firmware bug. You have 2 SMART attributes which are labelled FAILING_NOW yet I see:

SMART overall-health self-assessment test result: PASSED

The health of this drive SHOULD NOT be passed; it should be in FAILED state. You can blame Toshiba for this one. Downright, absolute firmware bug.

Good to know. This is the main part that confused me today; I asked myself how could I have all of these errors, and the drive still passed?

said by koitsu:

Recommendation:

Replace the drive immediately.

Done. I actually ordered a drive early this AM as I realized that even with better gsmartcontrol results in the past with other drives, they needed to be replaced. So I didnt waste any time and I just ordered a new drive.

I was going to go the vendor route (HP), but she needs this laptop back as soon as possible and I unfortunately don't have a ton of time this week. We're doing the exchange of dinner one day for a repaired PC. (She had actually brought this to a local computer store in her area, and they told her nothing was wrong.)

Before I started anything, two days ago I copied all of her photos/music/docs to a USB thumb drive I told her to buy and ship to me in the laptop box. I wanted to get all of the data safe before I started any repair. Of course one of the HDD partitions contains the OS for repair, but since that will be useless, I ordered the recovery discs from HP. She's up to dinner and 2 beers now. :)

Thanks for your help. Where can I read more about the knowledge needed to interpret gsmartcontrol data so I can interpret the results better?

said by koitsu:

P.S. -- In the future, please post monospace text into the forum using [ c o d e]
blocks, not <pre> blocks. Note that I did not say (th er e is a difference; former is for large blocks of text, latter is for inline monospace t ext ). :-)


Thanks, I will. I did not know that would help/be better.

Again, I appreciate everything.

--
He used to say that soul shine, is better than sunshine, better than moonshine, damn sure better than rain.

Debunking the 2012 hysteria. | Always looking for a new job | Begging the Wilpons to sell the Mets.


koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23
said by Jeffrey:

I wasn't exactly sure how to do it - believe it or not, the output I posted was the cleanest I could get it. You should have seen it before I tried to make it look half decent. :)

Easiest way is this:

1. Open up a Command Prompt (if on Vista/7, make sure you launch this as Administrator else some SMART functions on some setups won't get passed through to the disk)
2. smartctl -a X: > C:\smart.txt where X: is a filesystem/partition on the drive which you want stats for
3. Open C:\smart.txt in Notepad
4. Copy-paste contents into post here on the forum, within a code block (not <code> but the other one :-) )
5. Delete file when done

said by Jeffrey:

My friend said she didn't use it too much, and I asked her if it was ever dropped or tossed around, and she said no. After your explanation, I'm going to call her in a few and ask her once again.

No need to hound her. The G-shock sensors are sensitive and their sensitivity varies a bit from disk to disk. Simply putting the laptop down on a desk, while in operation, could increment this number. This is one of the major reasons why SSDs are better-suited for laptops.

I wouldn't worry too much about this number, honestly. If the user says she didn't do anything naughty with the laptop then I'd believe her. It's not like you have cameras or some other way to prove she's lying, and unless she tossed the laptop from 10 feet in the air onto a desk, I doubt she could cause these kinds of errors.

said by Jeffrey:

I ran those short tests. Drive hung early on during extended tests.

I'm not sure what "extended tests" means (I'm not familiar with gsmartcontrol, only standard smartmontools). The term "extended" here is too vague -- there are many internal SMART tests which run for extended periods of time: long, select, and (on some drives) conveyance.

I have a feeling you mean "long" (gsmartcontrol may call it "an extended test" -- that's not your fault, but the fault of the author of that program :-) ). Regardless, those tests never actually got submit to the drive. Tests which fail right off the bat for internal reasons, fail at LBA 0, as well as tests which are run *while* another test is running (this interrupts the current test and starts a new one), get logged in the SMART self-test log. There's no evidence of these tests being run, so the timeouts you experienced could be an indicator of something more complex. I do not have a way to debug how/why this happened without being there in person + using a protocol analyser between the disk and the controller.

said by Jeffrey:

Where can I read more about the knowledge needed to interpret gsmartcontrol data so I can interpret the results better?

You can find documentation for SMART all over the place, but the problem is that a lot of what's online is written by people who really don't know what it is they're doing (i.e. "enthusiasts" and "my mom bought me a $9000 PC and I know how to hook up cables" types). A good source of information is the official documentation that's on the smartmontools website, and Wikipedia's "known SMART attributes" section is fairly good (but not always 100% accurate).

Learning how to interpret the data is something that comes with experience. I have been asked 3 times in the past few years to write a book on the subject, and I was asked repeatedly at my previous job to write a very long Wiki page on how to go about diagnosing disk problems.

The complexity is in the fact that every situation is different and/or unique and thus must be handled as such. Even if a situation turns out to be the exact same thing as a situation you saw a week ago, you can't assume that from the get-go. Next, writing a book would take me years, and by the time I got done with it it would either be outdated/wrong or some other nonsense.

Furthermore, there is a lot about hard disks (and SMART for that matter, despite how much I do know) that I do not understand. For years I've been trying to find an actual engineer at places like Western Digital and Seagate, solely so I can learn about the underlying mechanical and physical aspects of the drives, as well as how the underlying firmware behaves (not "works", but "behaves"). I imagine the problem is that these guys are under very strict NDA and could lose their jobs disclosing such, especially since I wouldn't be able to quote them as actual references in a book/online material. Then you'd have people going "so, uh, how exactly are you so sure that Thing X is true?" and I'd just have to say "trust me?" Nobody is going to believe that.

And let's not forget the whole SSD thing. It's important to remember that SMART attributes are not part of the ATA standard; the SMART data structure itself is the only thing that's defined as part of the ATA8-ACS specification from T13 (see section 7.53.6.2, table 49). What each attribute is for, how the 6 bytes of data per attribute is stored / what it means is defined by the vendor. I'm pretty certain T13 did this intentionally (politics and vendors really piss me off sometimes :P). SMART threshold values are entirely undocumented; to learn how ATA command 0xd1 worked I had to look at the smartmontools source code. I've written my own polling interface for FreeBSD before, so as stated previously I do have familiarity with the protocol.

So how does smartmontools solve this? It has a very large database of disks (called drivedb.h) which is part of the program. It keys off model number and firmware revision/number. It's the only way to do it, and it's not always reliable/accurate. Plus it's always out of date (e.g. Corsair releases a new SSD which isn't in the DB, and smartmontools may show the wrong attribute names/data depending on what Corsair changed). You get the idea.

This can't really be fixed either, because it's too late in the game for T13 to batten down the hatches and say "okay, attribute 1 will be this, ALWAYS, per spec". It's ~14 years too late. Sure, one could add a new "extended" SMART ATA command to the CDB list, but we're already running out of feature/command space (they're a single byte, so values 0 to 255). You gotta remember ATA was invented a long time ago, and doesn't "scale" (protocol-wise) in the same way SCSI does.

So the bottom line is that there's really no official resource for people to read and go "oh I get it". It comes with experience and repeated, constant exposure.

--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.