Information Technology Reference
In-Depth Information
Fig. 4.7
GOME data - processed to show ozone data with particular projection
We can also have two files of the same format, say a sound file such as MP3, the
first of which (“music.mpg”) is indeed something that can be used to play music,
but a second, also an MP3 file (“config.mpg”), which contains numbers which are
configuration parameters for setting up some software. If we click on the first on a
home computer then it will play some music because the “.mpg” causes the com-
puter try to use a music application. Clicking on the second will cause the computer
to try to use that same application but it may produce only a brief grating sound, or
perhaps nothing audible at all.
The important points are that we currently rely on many clues, such as having
a file ending “.txt” or “.mpg” which many computers use to choose an applica-
tion for displaying or playing the file. On the other hand, even now these clues are
insufficient, as with “table.txt” (Fig.
4.8
).
Of course computers are not intelligent - in fact they have been instructed which
applications to use for which file extensions, for example Notepad for files with
X
Y
Z
1.3,
2.7,
4.2
2.4,
5.3,
2.5
7.4,
2.3,
6.7
Fig. 4.8
Text file “table.txt”
