spc3r21c.pdf tupo kib != KiB
dennis at hale-pohaku.com
Fri Jan 21 16:06:21 PST 2005
* From the T10 Reflector (t10 at t10.org), posted by:
* Dennis Painter <dennis at hale-pohaku.com>
Presumably our marketing persons would use plain English, as defined
Webster defines a Gigabyte as
: 1,073,741,824 bytes
Then again, being marketing persons, they probably don't use Webster ;-)
Robert Snively wrote:
> * From the T10 Reflector (t10 at t10.org), posted by:
> * "Robert Snively" <rsnively at Brocade.COM>
> This is all good and constructive (and accurate) information.
> The real key is that the units, whichever they are, should be
> correctly specified in any documentation. It really doesn't
> matter quite so much which you use, but proper specification
> is a key.
> As an example, as a marketing person, it would be in my interest to
> use MegaBytes, because I can specify a number that is bigger
> and because most people are more familiar with decimal arithmetic.
> As a computer person involved in hardware and software design,
> it would be in my interest to use MegaBytesBinary, because that is the
> arithmetic value most convenient to computer implementations.
> In a standard, it is even more key that units be properly specified
> using abbreviations and names that are internationally recognized.
> However, a value or parameter could constructively be of either
> decimal or binary type, depending on whether it is principally
> being made available for human/marketing use or for
> engineering/computation use.
> That aligns with our discussion at the T10 meeting where
> you chose and we agreed to accept familiar decimal percentage
> numbers for health and free-space values, since those values
> were principally focused on supporting human-useable interfaces.
> Of course that may slightly complicate the programming in a
> USB disk chip, since conversions from the actual fractional
> value seen by the hardware, probably a binary fraction, to
> the desired decimal fraction would be required.
> > -----Original Message-----
> > From: owner-t10 at t10.org [mailto:owner-t10 at t10.org]On Behalf Of Pat
> > LaVarre
> > Sent: Thursday, January 20, 2005 1:40 PM
> > To: t10 at t10.org
> > Subject: RE: spc3r21c.pdf tupo kib != KiB
> > * From the T10 Reflector (t10 at t10.org), posted by:
> > * "Pat LaVarre" <plavarre at lexarmedia.com>
> > *
> > "Standard" usage is split.
> > The device folk who actually pay to create the storage build their
> > companies on the physics of recording, be that flash, battery backup,
> > rotating magnetic, whatever.
> > Those physicists, like http://physics.nist.gov/cuu/Units/binary.html
> > now, have consistently defined T G M K defined to mean 10
> > raised to the
> > powers 12 9 6 3 since the metric era dawned, circa Bastille day 1789,
> > drawing its prefixes from Greek teras, Latin gigas, Greek mega, Greek
> > khiloi, etc.
> > Yes the vast majority of people involved are the customers who buy the
> > storage, and many of whom still speak of inches and ounces.
> > Yes the physicists would be unemployed, without the
> > cooperation of those
> > customers.
> > Yes those customers have consistently defined T G M K in computing to
> > mean 2 raised to the powers 40 30 20 10, denoted instead as
> > Ti Gi Mi Ki
> > by the physicists of the U.S. NIST but then also the international IEC
> > in December 1998, together with the pun of "mebibytes" pronounced like
> > "may be bytes".
> > But the physicists since the beginning have noticed that yielding in
> > this dispute would mean they lose 2.4%, compounded with every
> > generation. To let T mean Ti costs 1.024 to the fourth power, i.e.,
> > more than 9.95%, i.e., fuggeddaboutit.
> > Our RAM colleagues could take a share of the blame here: in the
> > beginning, they sold RAM architected to end on boundaries that grew
> > exponentially as a power of two, without leaving room for ECC
> > and other
> > overhead, as if physical storage were reliable.
> > I remember in 2004 some friends & I checked a small
> > indeterminate sample
> > of flash - I can report that least those flash folk had begun trending
> > towards the physicists' T G M K, same as HDD always have.
> > PEL
> > *
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