[Ffmpeg-devel] [PATCH] Print KB for 1024 bytes

Trent Piepho xyzzy
Thu Feb 15 23:17:17 CET 2007


On Thu, 15 Feb 2007, Panagiotis Issaris wrote:
> M??ns Rullg??rd schreef:
> > Panagiotis Issaris said:
> >[...]
> >>>>>>>> Rejected.  The standard abbreviation for kilo is a lowercase k.
> >>>>>> For kilo-1000 or kilo-1024? Currently, in the *same* message, k in
> >>>>>> kB means 1024 and k in kbits/sec means 1000. They cant both be
> >>>>>> right!
> >>> They ARE both right.  That is the historical use of kilo when talking
> >>> about bytes and bitstreams.  When specifying the size of RAM chips,
> >>> kilo of course means 1024.  It's all in the context.
> >> I do not think that the meaning of units should be context dependent.
> >
> > They are.  Just accept it.
> Units such as "s", "m", "g" and prefixes such as "M", "G", ... are _not_
> context dependent. Why should "k" be? And AFAIK "k" is _only_ context
> dependent in IT|computer science field, which makes it even more painful.

k = 2^10 when referring to sizes, and k = 10^3 when referring to rates

It is the same for M and G:
M = 2^20 when referring to sizes, and M = 10^6 when referring to rates
G = 2^30 when referring to sizes, and G = 10^9 when referring to rates
T = 2^40 when referring to sizes, and T = 10^12 when referring to rates

It is only recently that using powers of 10 for sizes has been foisted upon
us by marketroids.  A 360 kilobyte floppy disk was 360 * 1024 bytes.  A
1.44 megabyte floppy was 1.44 * 1000 * 1024 bytes (see they start small,
not going to powers of ten all at once).  Then hard drive makers decided a
gigabyte would be 1000 * 1000 * 1000 bytes, and tape drive makes got really
cheeky and decided a gigabyte would be 500 * 1000 * 1000 bytes.  A gigabyte
just ain't what is used to be.

Maybe in 50 years, I'll be telling the kids that I remember when you could
buy a cup of coffee for $3.50 and a hundred terrabytes was enough for ten
libraries of congress.




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