Hwinfo32 readings for SMR HD don't make sense

mariolana

New Member
I bought a new Seagate ST2000DM008-2FR102. After formatting, used PC-3000, HDDScan, and HDTune to check the drive, and fould portions where the scan speed fluctuated wildly, although no dud sectors. Moreover, the parts of the drive where this happens seem to move around a bit on successive scans. Put an OS and some files on the drive. .The strange behavior continues.

This is not a CMR/PMR drive. It's an SMR drive, i.e. shingled tracks.

Ran HWINFO32 over it, and get the following :

Number of Cylinders: 16383
Number of Heads: 16
Sectors Per Track: 63
Number of Sectors: 16514064
Total 32-bit LBA Sectors: 268435455
Total 48-bit LBA Sectors: 3907029168
Logical Sector Size: 512 Bytes

The reference to both 32-bit and 48-bit LBA sectors doesn't seem to make sense. Ran this by some people-who-should-know, and they said the same thing.

Can anyone her explain this?
 

Dalai

Well-Known Member
3907029168 sectors * 512 bytes = 2,000,398,934,016 bytes in total which is pretty much 2 TB or 1863 GiB - the capacity of the drive.

I admit that I don't know why the LBA 32-bit sector count is capped at that number although 2^32 is roughly 4.29 billion sectors which should be enough to address 2 TiB (in theory). That being said, I know and remember that LBA 48-bit is required to access disks larger than 137 GB (128 GiB). Windows 2000 and XP didn't support it initially, SP3 and SP1 added support for this for these OS's respectively. Windows (and other systems) without LBA48 support were only able to address the first 128 GiB of the drive, though I'm not sure if they're capped at 28-bit or 32-bit in such cases.

It would make a little more sense to me if HWiNFO would show LBA 28-bit and 48-bit. Does LBA 32-bit even exist? So far I have only found references mentioning the extension from LBA28 to LBA48 in 2003. Maybe @Martin can explain this better than I could.

Regards
Dalai
 

Martin

HWiNFO Author
Staff member
32-bit LBA is a legacy item that should not be used when 48-bit addressing is supported.
 

mariolana

New Member
32-bit LBA is a legacy item that should not be used when 48-bit addressing is supported.
That would have been my assumption, too.

So why is HWInfo32 saying that my new 2TB SMR drive has 268435455 32-bit LBA Sectors, and 3907029168 48-bit LBA Sectors?

Either this data is correct, which begs some questions about the design of the HD, or it is not, in which case it begs some questions about the validity of the data supplied by HWInfo32.

So which is it?
 

Dalai

Well-Known Member
As explained above, the number of sectors for LBA 48-bit is correct. It's only the LBA 32-bit value which I have doubts about, too. My guess is that should be LBA 28-bit instead of LBA 32-bit. Then it would match the maximum value addressable with 28 bits.

BTW: This has nothing to with the drive recording technology. I don't have any SMR drives and HWiNFO (HWiNFO64 in my case) shows 3,907,027,055 sectors for my 2TB drive and 7,814,028,911 sectors for my 4TB drive.

Regards
Dalai
 

Martin

HWiNFO Author
Staff member
32-bit LBA value of 268435455 (0x0FFFFFFF) is a sort of "dummy" value to be reported according to specification when 48-bit addressing is used. Really no need to search for issues here, it should be ignored.
 

mariolana

New Member
32-bit LBA value of 268435455 (0x0FFFFFFF) is a sort of "dummy" value to be reported according to specification when 48-bit addressing is used. Really no need to search for issues here, it should be ignored.
Okay, I'll ignore the 32-bit thing. But dummy value or whatever, it's a bit confusing when one sees that in the output of HWInfo32. Why does it have to show at all?
 
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