Number of ECC bytes

Gerry.Houlder at Gerry.Houlder at
Thu Sep 18 11:57:04 PDT 2008

* From the T10 Reflector (t10 at, posted by:
* Gerry.Houlder at
The READ LONG mechanism is the only standard method that even hints at the
number of ECC bytes per LBA. Its a very good bet that [READ LONG returned
data length] - [logical block length] - [protection information length if
implemented] = [number of ECC bytes]. Even if you know the number of bytes
you still don't know what error correction capability is indicated because
this varies according to the algorithm, interleaving, and other
characteristics of ECC.
	     Bill.Martin at emule													   
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				       Number of ECC bytes		   
	     09/18/2008 12:09						   
I have looked and not found a mechanism for determining the number of ECC
bytes per logical block on an attached device.	Is there any place in any
mode page that this information is available, or any other mechanism to
determine this information?  I know that READ LONG allows reading of this
information, but it is vendor specific where this information is, and there
is no information in the return about what portion of the additional data
is ECC and what portion is WRProtect etc.
Thanks for any input.
Bill Martin
Office of Technology
Industry Standards
916 772-3658
916 765-6875 (Cell)
bill.martin at
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