Clarify between decimal bytes and binary bytes

Frank_Widjaja at Dell.com Frank_Widjaja at Dell.com
Fri Jul 9 07:05:25 PDT 2010


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1007090_f.htm">HTML-formatted message</a>

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>
[mailto: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>
[mailto: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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