Bit rate units on mirror page.

Jörg W Mittag Joerg.Mittag at Web.De
Fri Jan 23 15:07:45 PST 2004


Paul Campbell wrote:
> Just being picky but.....
> 
> Capital K is generally used to mean 1024, and small k for 1000 in bit rates.  
> 
> 1 Kbit/s = 1024 bits per second = 1024 bits^-1
> 1 kbit/s = 1000 bits per second = 1000 bits^-1

If you want to be *real* picky:

The International Units System specifies that kilo (k) is 10^3, Mega (M) is
10^6 and so on. However, this system is only mandatory for units which are
part of the SI system, and neither Bit nor Byte are part of that system.
(Plus it is only mandatory in special circumstances like e.g. commercial
advertising.)

The NIST and the IEC have invented the terms Kibi (Ki), Mebi (Mi), Gibi (Gi)
and so on for 2^10, 2^20, 2^30 and so forth. (Kibi, Mebi etc. means
Kilobinary, Megabinary, ...). However, *this* system is only mandatory
within the USA. (Plus ... the same as above).

The prefix "K" (capital letter K) is specified in neither of the two
standards.

And if you want to be real real real *real* _REAL_ picky, then you should
also mention that the size of one Byte depends on the platform used and may
vary from about 6 to 12 Bits and there are even platforms which don't have
Bytes at all.

And the very last problem is that no official abbreviations for Bit and Byte
exist. Byte is usually abbreviated "B" but Bit uses both "B" and "b".

For me, I have come to the conclusion to never abbreviate Bit or Byte (it
saves you only three letters maximum but calls for misinterpretation) and
always use IEC prefixes for 2^10 and avoid SI prefixes at all in an IT or
computer context. (Instead one can use scientific notation like 2*10^9 for
"two Giga" and 2*2^30 for "two Gibi".)

So, my DSL connection has a bandwith of 128000 Bit/s / 768000 Bit/s (note
how I avoid using "k" here, because it could be confused with Kibi) and my
"120" harddisk has a capacity of 115,04 GiByte (assuming Bytes of 8 Bits).

In view of the fact that the mirrors page deals with communication issues
and in the communications world multiplicators of 10^3 are traditionally
used it would probably be best to standardize the format to KBit/s and
MBit/s, meaning 10^3 and 10^6 respectively (the same applies for TBit/s, of
course, in case somebody is volunteering to donate such a mirror (-;).

But that's just MHO and it is a very minor problem, actually, compared to
the current Glibc and headers discussions or the CMS transition. (-;

jwm
-- 
rpm-4.1% ./configure
checking the coffee machine... empty - operator may not work as
    expected



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