Clarify between decimal bytes and binary bytes

Alvin Cox alvin.cox at seagate.com
Fri Jul 9 08:03:08 PDT 2010


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1007091_f.htm">HTML-formatted message</a>

So is the reported capacity the advertised capacity or a pure decimal value?
On Fri, Jul 9, 2010 at 9:05 AM, <Frank_Widjaja at dell.com> wrote:
>  I believe IDEMA formula is about converting (Numbers of LBAs/Sectors) to
> (Advertised Capacity) and vice versa.
>
> It is not about binary of decimal bytes.
>
>
>
> Best Regards,
>
> Frank Widjaja | Storage Device Strategist | Enterprise Disk Advanced
> Engineering | Dell Inc.
>
> 512-728-3877 Office
>
> 512-296-3453 Cell
>
>
>
> *From:* owner-t10 at t10.org [mailto:owner-t10 at t10.org] *On Behalf Of *Alvin
> Cox
> *Sent:* Thursday, July 08, 2010 3:13 PM
> *To:* Paul Stone
> *Cc:* T10 Reflector
>
> *Subject:* Re: Clarify between decimal bytes and binary bytes
>
>
>
> 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
>
-- 
Alvin Cox
Seagate Technology, LLC
Cell 405-206-4809
Office 405-392-3738
E-Mail	alvin.cox at seagate.com



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