Re: Bad Metric ... 1k = 1024 or 1000?

[dempson@actrix.gen.nz (David Empson)]

Rubywand <rubywand@swbell.net> wrote:

>      Agree. 1k bytes, Ohms, Volts, eggs, ... is, precisely speaking, 1000 of
> them. That we expect "1k bytes" to be 1024 bytes is beside the point. The
> accepted interpretation of "1k bytes" is that it is a term of convenience
> which incorporates a roundoff.
> 
>      Similarly, the normal interpretation of 140k as the capacity figure for
> a 5.25" 16-sector Apple II diskette side is that it is a nearest 10,000
> roundoff designator. A similar sort of understanding exists for "4MB RAM".

But it isn't always a "nearest 10000" roundoff.  An "800K" disk holds
819200 bytes.  If the disk capacity was rounded to the nearest 10K, then
we would call it an 820K disk.  I've never seen it described this way.

Almost everyone in the computer industry uses the definitions of K =
2^10, M = 2^20, G = 2^30 and T = 2^40, except hard drive manufacturers,
who use the normal metric definitions.

For example, RAM is always described in manufacturers' data sheets using
the binary K/M, unless they describe it as an exact number of bits or
bytes (e.g. "131072 bits"), which gets unwieldy when you are talking
about something like a 64M RAM.

>      Notwithstanding the above, those who argue that, for memory, disk, file,
> ... size, "1k" is a standard unit = 1024 can find some support in the way
> file size is reported by popular operating systems. For example, GS System
> and Windows 95 both use 1k = 1024.

So does the Mac.  Not sure about Unix (I don't recall seeing any
abbreviations - it displays file sizes in directory listsing as an exact
number of bytes).

Does anyone know of any operating system on any platform which uses K, M
or G abbreviations, and which defines them as being 1000, 1000000 and
1000000000 instead of 1024, 1048576 and 1073741824?

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand