GNU bug report logs - #17505
Interface inconsistency, use of intelligent defaults.

Previous Next

Full log

View this message in rfc822 format

From: Linda Walsh <coreutils <at> tlinx.org>
To: Christian Groessler <chris <at> groessler.org>
Cc: 17505 <at> debbugs.gnu.org, Pádraig Brady <P <at> draigBrady.com>
Subject: bug#17505: Pádraig: does this solve your consistency	concern? (was bug#17505: dd statistics output)
Date: Mon, 28 Jul 2014 17:17:23 -0700

Christian Groessler wrote:
> On 07/27/14 19:11, Linda Walsh wrote:
>> It is more common to specify transfer sizes in SI and mean IEC if you
>> are in the US where the digital computer was created.
>>
>> People in the US have not adopted SI units and many wouldn't know
>> a meter from a molehill, so SI units aren't the first thing that
>> they are likely to be meaning.  Computer scientists and the industry 
>> here,
>> grew up with using IEC prefixes where multiples of 8 are already in
>> use.  I.e. if you are talking *bytes*, you are using base 2.
> 
> 
> I didn't grow up in the US, and grew up with the metric system, but when 
> I'm
> talking about memory sizes I always mean IEC (2^10) and never SI (10^3).
> The only pitfall here are hard disk sizes where I have to remember that 
> "they"
> mean SI.
----
	I was trying to come up with some reason for Padraig's belief
that people usually meant SI when using IEC prefixes for computer
sizes like units bytes (2^3bits) or sectors (2^12 bits)... now what
power of 10 is that?  I've never heard of anyone supporting Padraig
position -- so I assumed it must be some foreign country where the
metric system and metric prefixes are meant to apply to non-unary
and non-base-10 quantities.  Pádraig: where did you get your impression?

	When it comes to disk space -- computers always give it in
IEC -- except where they've bought the line that mixed base-2 and power-of-10
prefixes is a good thing, then they try to get others to buy into such.

But reality is that one can't express disk space as a power of 10 as there
is no multiple of 10 that lines up with a 512-byte multiple.  I.e. the system is
designed to be inaccurate and confuse the issue to make it harder for
consumers to do comparisons.


> I don't get the reason for the dynamic switch at all. Can somebody 
> enlighten me?
----
	I think it was thrown in as a red herring, as I can't think
of any useful case for it.  Having the output vary units randomly, not
at the bequest of the user, doesn't seem especially useful.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.