Re: Abbr. for kilobyte?

["David L. Bergart" <bodafu -at- CCVAX -dot- SINICA -dot- EDU -dot- TW>]

Keith Ivey <kcivey -at- cpcug -dot- org>:

  >The SI system, of course, uses "k" for 1,000, so there is an
  >argument that "K" should be used for 1,024--but this leaves open the
  >question of how to distinguish between "M" meaning 1,000,000 and "M"
  >meaning 1,048,576.

Vicki Richman <vicric -at- PANIX -dot- COM>:

  >Of course, megabytes and megabits are MB and Mb. But
  >hard-drive vendors may use your cited ambiguity to make
  >their products seem larger. They advertise, say, 105 M bytes
  >for a drive with 100 MB.


Why do you assume that any reference to a number of bits or bytes must be a
binary number? Binary numbers are used when referring to RAM size because
addresses in RAM are generated by a binary process -- setting the voltage on
each of a series of wires either on or off -- and as a consequence there is a
power-of-two number of memory locations in a RAM chip.  Disk drives, however,
have a completely different addressing scheme.  The standard 5 1/4 "  floppy
disk, for example, has *nine* sectors of data on each of *40* tracks.  Neither
is a power-of-two, and the total number of bytes on any disk will be a
power-of-two only by coincidence.

It is quite common and arguably correct to specifiy *disk sizes* such that
1,000,000 bytes = 1 megabyte.  Where those @#$%^& drive vendors mislead you
is in specifiying the unformated size rather than the amount of disk space
that is free for your data after formatting the disk.  Formatting is akin to
the page numbers and running headers in a book -- it is prewritten information
that the computer uses to determine where it on the disk, but it takes up some
space.

Let us now contemplate that in the printing industry M = 1000.

David


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