🚀 go-pugleaf

In article <2oce21$cm8@vixen.cso.uiuc.edu> th9708@meibm8.cen.uiuc.edu (Todd Lee Henderson) writes:
>grante@hydro.rosemount.com (Grant Edwards) writes:
>>Wrong.  For disk capacity K is 2^10 and M is 2^20.  For communications
>>the normal base 10 numbers are used: K = 10^3, M = 10^6.
>
>Wrong group for this discussion, but why in the hell did the first CS
>folks redefine kilo and mega?  They are the ones at fault here it would
>seem.  If you were to ask most people that have a knowledge of SI units
>what a kilobyte or megabyte you would probably get 1000 bytes and 10^6
>bytes.  I used to believe this, and I still wonder why it's not so???
>
>Thanks to anyone that can answer this mystery of nature!

When I first bought a computer, it was a Commodore PET 2001. It had 8 kB
of ram (plus 1 kB for the screen). These were k's of 1024 bytes. Memory
chips are just made in capacities of powers of 2. When specifying the
size of a program for the PET, we used k=1024 because everyone (well...)
was used to this abbreviation. Furthermore, memory addresses were often
expressed in the hex number system. Most debuggers (monitors) used hex
notation for machine code numbers.

When I bought a floppy disk drive for my PET, it used 1 kB sectors, was
single sided and used 40 tracks, i.e. 200 kB per disk (side). Yes, again
k=1024. And again it was quite easy to match disk (free) sizes and
program sizes.

Of course, when a computer apprentice asked what a k in computer language
is an I answered that it's 1024, most people found it a little strange,
as everyone had learned in physics class at school that 1k=1000 (when
didn't talk about M those days ;-) . Everyone I knew then, quickly
adapted to the k=1024 as they all found out that it was most easyist to
do calculations with.

When the PC era arrived, I, and the people I knew, also used k=1024 for
memory sizes. Noone complained about 32 kB ROM, 640 kB RAM, 360 kB floppy
disk drives, etc, being wrong for the specific devices. The good old PC-XT
hard disk, 17 sectors per track, 4 heads and 306 cylinders, was called a
10 MB disk although its 10653696 bytes might be reason to call it an 11 MB
disk. But later on, when bigger hard disks arrived, some manufacturers
found out that it's better (marketing wise) to use M=1000000. I don't
think that they were purists who were closely attached to the SI system.

I think that for some calculations, it's best to use M=1000000, and for
others, it's easyier to use M=1048576. I don't mind which M you use, as
long as it's not used to fool people.

Adrie Koolen (adrie@ica.philips.nl)
Philips Consumer Electronics, Eindhoven, the Netherlands

PS. I've never seen kB where k=1000, but perhaps I didn't look that well...