Clarify between decimal bytes and binary bytes

Tim Jones tjmac at
Wed Jul 7 11:27:21 PDT 2010

* From the T10 Reflector (t10 at, posted by:
* Tim Jones <tjmac at>
On Jul 7, 2010, at 9:37 AM, Kevin D Butt wrote:
> I believe that the time has come to clear up confusion in the industry
about the units used in T10 standards.	There should be a clause added in
each of the standards describing the difference between decimal bytes (e.g.,
MB = 10^6) and binary bytes (e.g., MiB = 2^20).  There has been this
definition in IEC for since Dec 1998. 
> References: 
> I hesitate to bring in a solo proposal to modify SSC-4 or even SPC-4 when
this issue should apply to all standards. 
> Does anybody disagree that T10 should clarify the units being used in our
> What is the preferred manner in which we should proceed to make sure this
clarification is added to each standard? 
Kevin and all,
While I see a lot of work for ISV's (my team included) over such a change, I
agree that the standards need clarification and updating.  There are many
instances where vendors are getting into trouble over capacity claims for
everything from rotating disc to tape to optical media because of the
difference in the numeric representation of capacities.
I would also go one step further and recommend a standardization for devices
that support any form of compression to be labeled by the media's native,
uncompressed capacity rather that the presumed compressed capacity.  That is
another realm where vendors and getting called to task by consumers.
Tim Jones					tjmac at
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