SMART invalid values Total Host Writes/Reads

dan8

Member
Hello,
SMART values Total Host Writes/Reads are wrong for my HDD.
For example for Total Host Reads it shows 2,644,386,408 GB. It is impossible to read that much data, at 150 MB/s (it is not SSD) it would take more than 500 years.
First problem is, that the value 2,644,386,408 is not complete. It is 9D9E2268 in hexadecimal.
But CrystalDiskInfo show 79D9E2268. So HWiNFO64 reads value as 32bit number, but it is 48bit number in reality.
9D9E2268 vs
79D9E2268

From wikipedia:
"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."
https://en.wikipedia.org/wiki/Self-Monitoring,_Analysis_and_Reporting_Technology
Second problem is, that LBA is not GB :)
LBA is 512 bytes (at least in my case).
So the value should be multiplied by 512 and divided by 2^30 if you want to show it in GB.
Thanks for your work, the HWiNFO is amazing otherwise.
 

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I also did test
first I had value 2642291803 then I computed hash on file with 1072433625 bytes. Then I got number 2644386408.
2644386408 - 2642291803 = 2094605
2094605 * 512 = 1072437760 bytes
So the result is quite precise, something else probably read some bytes, maybe for creating the file with hash or reading file structure in total commander.
 
Problem here is that this value is using vendor-specific encoding and it can be different not only between vendors but models too.
And since there's no standard enforcing a certain encoding, it's impossible to report this universally.
Does that drive perhaps also report "Device Statistics" section? Look in the main window for that.
 
I can not find any "Device Statistics" section in main window for the drive. And even CrystalDiskInfo does not show it, so it is probably not supported. My source for value interpretation was the table in link on wikipedia. And it match with my measurements. They also say that it is vendor specific. So maybe you know a HDD with different interpretation. I saw also western digital hdd with such big values, so it seams that at least two big vendors seagate and western digital use it (for at least for one model). :)
 
CrystalDiskInfo doesn't support "Device Statistics", it's the only standardized method.
Problem here is that some Seagate drives seem to be encoding the value in GBytes while some others in sectors (512 Bytes).
 
I see. And what about the 32bit vs 48bit number problem? I can interpret the value myself, but it would be nice to see complete number.
 
That's also a problem :D When it's in GBytes then only 32-bit value is utilized, when in 512B then 48-bit :D
I will add a workaround for your drive based on the model.
 
SMART is a curse...
I discussed this with guys from the t13 committee (responsible for various ATA standards including SMART) and they said it was never standardized and we should use Drive Statistics instead.. But if their own drives don't support that, what choice we have...
 
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