Clarify between decimal bytes and binary bytes

Alvin Cox alvin.cox at seagate.com
Thu Jul 8 13:13:16 PDT 2010


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1007081_f.htm">HTML-formatted message</a>

If the capacity is stated per the IDEMA formula (which is used by the
storage device manufacturers), then it is not exactly decimal, but close.
That item should probably be clarified.
Part of the confusion exists because JEDEC defines MB and GB as a binary
values. A component or	RAM module or will have a binary capacity with what
virtualy every other standards organization considers as a decimal
descriptor. This is not a T10 or T13 problem
On Wed, Jul 7, 2010 at 3:43 PM, Paul Stone <Paul.Stone at quantum.com> wrote:
>  SSC-4 uses the terms “megabytes written”, “megabytes read”, “megabytes
> transferred”, and “capacity in megabytes” in a number of fields.  These are
> all decimal values.
>
>
>
> *___________________________________*
>
> *Paul Stone* | Firmware Engineer |* **Quantum Corporation* |
*Office**:*949.725.1874 |
> paul.stone at quantum.com
>
>
>
>
>  ------------------------------
>
> *From:* owner-t10 at t10.org [mailto:owner-t10 at t10.org] *On Behalf Of
*Penokie,
> George
> *Sent:* Wednesday, July 07, 2010 12:34 PM
> *To:* T10 Reflector
> *Subject:* RE: Clarify between decimal bytes and binary bytes
>
>
>
> I agree with Gerry’s comment. I also looked in several of the most common
> T10 standards (SPL, SPC, SAM, SBC) and there is no instance of MB, MiB, or
> the four letters “mega” in any of those standards. So unless you can show
> specific instances of its use, I don’t see why we have to deal with
> something that is not used in our standards.
>
>
>
> Bye for now,
> George Penokie
>
> LSI Corporation
> 3033 41st St. NW
> Suite 100
> Rochester, MN 55901
>
> 507-328-9017
> george.penokie at lsi.com
>
> *From:* owner-t10 at t10.org [mailto:owner-t10 at t10.org] *On Behalf Of *Gerry
> Houlder
> *Sent:* Wednesday, July 07, 2010 1:44 PM
> *To:* T10 Reflector
> *Subject:* Re: Clarify between decimal bytes and binary bytes
>
>
>
> I agree with your description of the use of MB versus MiB, but a quick
> search of the most common T10 standards show no instance of the use of
> either acronym. I'm not sure we should be specifying use of terms that are
> not present in T10 standards, but are used in product data sheets.
>
> SAS-2 does use MBps (for Megabytes per second) and correctly defines it as
> a decimal entity.
>
> On Wed, Jul 7, 2010 at 11:37 AM, Kevin D Butt <kdbutt at us.ibm.com> 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:
> http://physics.nist.gov/cuu/Units/binary.html
> http://en.wikipedia.org/wiki/Binary_prefix
>
> 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
> standards?
> What is the preferred manner in which we should proceed to make sure this
> clarification is added to each standard?
>
> Thanks,
>
> Kevin D. Butt
> SCSI & Fibre Channel Architect, Tape Firmware
> MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
> Tel: 520-799-5280
> Fax: 520-799-2723 (T/L:321)
> Email address: kdbutt at us.ibm.com
> http://www-03.ibm.com/servers/storage/
>
>
>
-- 
Alvin Cox
Seagate Technology, LLC
Cell 405-206-4809
Office 405-392-3738
E-Mail	alvin.cox at seagate.com



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