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From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Matt Fleming <matt@codeblueprint.co.uk>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
	linux-efi@vger.kernel.org,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Andrew Morton <akpm@linux-foundation.org>,
	"linux-kernel @ vger . kernel . org"
	<linux-kernel@vger.kernel.org>, Robert Elliott <elliott@hpe.com>
Subject: Re: [PATCH v3 3/4] x86/efi: print size in binary units in efi_print_memmap
Date: Sat, 23 Jan 2016 10:12:55 -0800	[thread overview]
Message-ID: <1453572775.2470.56.camel@HansenPartnership.com> (raw)
In-Reply-To: <CAHp75Vdc9=uotvaf4pQfRoViyWuEXhXjZH7GVWEG79AquPVi5A@mail.gmail.com>

On Sat, 2016-01-23 at 19:18 +0200, Andy Shevchenko wrote:
> On Sat, Jan 23, 2016 at 6:44 PM, James Bottomley
> <James.Bottomley@hansenpartnership.com> wrote:
> > Not an attack on you patch per-se, but I really hate the IEC
> > convention
> > that was essentially a ploy by disk manufacturers to inflate their
> > disk
> > sizes by 10% simply by relabelling them.
> 
> >  Everyone was happy when a GB was 2^30,
> 
> No, not everyone. It was a misspelling done by some first storage
> producer.

No, it was the adopted convention in computer science to use units in
2^10 since all sizes were usually binary.  It actually began with
memory sizes.  So a GB never meant 10^9 bytes before 2007 because the
classical unit users had no idea what a byte was.  The first bytes were
counted in powers of 2.

>  Try to look at the problem from physics point of view. Units
> are essential part of a value. There is an agreement how to use
> multipliers and their code names. 1000 x Unit means kiloUnit. As per
> agreement.

It's not about physics (and certainly astronomers, who often take pi to
be 1 would be happy with 2^10 = 10^3) it's about politics: disk
manufacturers wanted a way to report bigger sizes, so they made a huge
fuss about the "inconsistency" of computer science using units in
increments of 2^10 and forced through this IEC standard.

> > now everyone's simply confused whenever they see GB.  We had
> > to pander to this in block devices because people got annoyed when 
> > we reported a size that was different from the label but are you 
> > sure we have to extend the madness to memory?
> 
> I actually don't know who is from us is being more conservative. I
> could call a madness to mess things from ancient (classical
> mathematics and physics) with something which has less than hundred
> years in development.

In engineering terms, counting in powers of 2 makes a lot of sense for
quantites using binary address busses and the IEC even recognised that
by inventing a new unit for it.  Having GB mean 2^30 up to 2007 and
10^9 after it is confusing for everyone born before about 1990.

James

WARNING: multiple messages have this Message-ID (diff)
From: James Bottomley <James.Bottomley-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
To: Andy Shevchenko
	<andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Andy Shevchenko
	<andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
	Matt Fleming
	<matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>,
	Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
	Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"H . Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
	linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Rasmus Villemoes
	<linux-qQsb+v5E8BnlAoU/VqSP6n9LOBIZ5rWg@public.gmane.org>,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	"linux-kernel @ vger . kernel . org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Robert Elliott <elliott-ZPxbGqLxI0U@public.gmane.org>
Subject: Re: [PATCH v3 3/4] x86/efi: print size in binary units in efi_print_memmap
Date: Sat, 23 Jan 2016 10:12:55 -0800	[thread overview]
Message-ID: <1453572775.2470.56.camel@HansenPartnership.com> (raw)
In-Reply-To: <CAHp75Vdc9=uotvaf4pQfRoViyWuEXhXjZH7GVWEG79AquPVi5A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Sat, 2016-01-23 at 19:18 +0200, Andy Shevchenko wrote:
> On Sat, Jan 23, 2016 at 6:44 PM, James Bottomley
> <James.Bottomley-JuX6DAaQMKPCXq6kfMZ53/egYHeGw8Jk@public.gmane.org> wrote:
> > Not an attack on you patch per-se, but I really hate the IEC
> > convention
> > that was essentially a ploy by disk manufacturers to inflate their
> > disk
> > sizes by 10% simply by relabelling them.
> 
> >  Everyone was happy when a GB was 2^30,
> 
> No, not everyone. It was a misspelling done by some first storage
> producer.

No, it was the adopted convention in computer science to use units in
2^10 since all sizes were usually binary.  It actually began with
memory sizes.  So a GB never meant 10^9 bytes before 2007 because the
classical unit users had no idea what a byte was.  The first bytes were
counted in powers of 2.

>  Try to look at the problem from physics point of view. Units
> are essential part of a value. There is an agreement how to use
> multipliers and their code names. 1000 x Unit means kiloUnit. As per
> agreement.

It's not about physics (and certainly astronomers, who often take pi to
be 1 would be happy with 2^10 = 10^3) it's about politics: disk
manufacturers wanted a way to report bigger sizes, so they made a huge
fuss about the "inconsistency" of computer science using units in
increments of 2^10 and forced through this IEC standard.

> > now everyone's simply confused whenever they see GB.  We had
> > to pander to this in block devices because people got annoyed when 
> > we reported a size that was different from the label but are you 
> > sure we have to extend the madness to memory?
> 
> I actually don't know who is from us is being more conservative. I
> could call a madness to mess things from ancient (classical
> mathematics and physics) with something which has less than hundred
> years in development.

In engineering terms, counting in powers of 2 makes a lot of sense for
quantites using binary address busses and the IEC even recognised that
by inventing a new unit for it.  Having GB mean 2^30 up to 2007 and
10^9 after it is confusing for everyone born before about 1990.

James

  parent reply	other threads:[~2016-01-23 18:13 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-23 14:55 [PATCH v3 0/4] x86/efi: use binary units when printing Andy Shevchenko
2016-01-23 14:55 ` [PATCH v3 1/4] lib/string_helpers: export string_units_{2,10} for others Andy Shevchenko
2016-01-23 16:14   ` James Bottomley
2016-01-23 16:14     ` James Bottomley
2016-01-23 16:58     ` Andy Shevchenko
2016-01-23 16:58       ` Andy Shevchenko
2016-01-23 14:55 ` [PATCH v3 2/4] lib/string_helpers: fix indentation in few places Andy Shevchenko
2016-01-23 14:55 ` [PATCH v3 3/4] x86/efi: print size in binary units in efi_print_memmap Andy Shevchenko
2016-01-23 16:44   ` James Bottomley
2016-01-23 16:44     ` James Bottomley
2016-01-23 17:18     ` Andy Shevchenko
2016-01-23 17:18       ` Andy Shevchenko
2016-01-23 18:03       ` James Bottomley
2016-01-23 18:03         ` James Bottomley
2016-01-25  8:31         ` Andy Shevchenko
2016-01-25  8:31           ` Andy Shevchenko
2016-01-25 15:25           ` James Bottomley
2016-01-25 15:25             ` James Bottomley
2016-01-23 18:12       ` James Bottomley [this message]
2016-01-23 18:12         ` James Bottomley
2016-01-23 20:29         ` One Thousand Gnomes
2016-01-23 20:43           ` H. Peter Anvin
2016-01-23 20:43             ` H. Peter Anvin
2016-01-25 18:02     ` Elliott, Robert (Persistent Memory)
2016-01-25 18:02       ` Elliott, Robert (Persistent Memory)
2016-01-25 18:56       ` James Bottomley
2016-01-25 18:56         ` James Bottomley
2016-01-25 19:28         ` Andy Shevchenko
2016-01-25 19:28           ` Andy Shevchenko
2016-01-25 19:45           ` James Bottomley
2016-01-25 19:45             ` James Bottomley
2016-01-25 20:01             ` Andy Shevchenko
2016-01-25 20:01               ` Andy Shevchenko
2016-01-25 20:18               ` James Bottomley
2016-01-25 20:18                 ` James Bottomley
2016-01-25 20:37               ` Elliott, Robert (Persistent Memory)
2016-01-25 20:37                 ` Elliott, Robert (Persistent Memory)
2016-01-26 11:50                 ` Matt Fleming
2016-01-26 11:59                   ` Andy Shevchenko
2016-01-26 11:59                     ` Andy Shevchenko
2016-01-28  9:29                     ` Matt Fleming
2016-01-28  9:29                       ` Matt Fleming
2016-01-28 11:15                       ` Andy Shevchenko
2016-01-28 11:15                         ` Andy Shevchenko
2016-01-25 20:44               ` James Bottomley
2016-01-25 20:44                 ` James Bottomley
2016-01-23 14:55 ` [PATCH v3 4/4] x86/efi: Use proper units in efi_find_mirror() Andy Shevchenko
2016-01-23 14:55   ` Andy Shevchenko
2016-01-23 16:34 ` [PATCH v3 0/4] x86/efi: use binary units when printing James Bottomley
2016-01-23 16:34   ` James Bottomley
2016-01-23 17:20   ` Andy Shevchenko
2016-01-23 17:20     ` Andy Shevchenko

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