On Sun, 11 Jul 2004 20:15:21 -0400, Ph. D. <phild@...> wrote:

> Yes, I know. I was trying to simplify.

Sorry!

> An application only has to call an internal Windows routine specifying
> the endpoints, then Windows calculates which points on the screen need
> to change color to render the line segment.

That is, if one is running Windows, which most people are. :)

> I was trying to emphasize that a pattern of points on the screen means
> nothing to a computer, only to a human who interprets it.

The prime reason for replying is that what a computer creates is really in
a sense a very successful illusion; decades of work has been devoted to
enhance the illusion toward making it appear what humans want it to be.
One could even hold a similar point of view about photography (and
painting?) -- that images are usually-flat patterns of differing amounts
and (in many cases) colors of pigments or dyes.
It's their arrangement, patterns and such details that give meaning.

It's a philosophical point; however, the underlying structure of computer
data is even more abstract than images on paper or canvas.

> In the same way, the computer cannot tell what a sequence of bytes in
> memory represents. It could be machine code or encoded text or a
> floating point number or something else. It's only a matter of
> interpretation.

Assuming that a computer is working right, a given sequence of bytes is
put into memory by a program exactly in a place in memory where that
program will place an interpretation of those bytes. Mojibake, if I recall
the term right, is a minor instance of misinterpretation.
Binary data, (or bytes, or bits if you like) has no more intrinsic
identity than the ink used to print a page of text.

[Actually, to some degree, it is possible for analytical programs to
examine a file of bytes and come to sometimes-useful conclusions about its
nature. It seems commonplace for the first few bytes of data in a file to
represent the nature of its content. For instance, the string "ÿØÿà" (you
need Latin-1) seems to appear as the first four bytes of probably all JPEG
images. DOS/Windows executable files begin with "MZ", very likely the
initials of an early enterprising programmer. However, all this does not
contradict Ph. D.'s essential point.]

--
Nota Bene /*|*\ Waltham, Mass.
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