File-formats and extensions
Every file on your computer must have a name, sometimes you gave that name,
sometimes the system did. That name is unique, otherwise you yourself and the
computer couldn't find anything on the system anymore. So you can't have two
different files with the same filename. At least the filename can't occur twice
in the same directory, technically you could use the same name in another
directory, but it's obvious that this may lead to misunderstandings. So it's a
lot easier and safer to give each file a different name.
For a better understanding, it's very useful to have some basic knowledge about
how your system works with files.
File-formats and extensions
Every filename consists of the name itself, and a so-called "extension". That's
the three (or sometimes more or less) letter-code after the filename. Filename
and extension are separated by a point, which belongs to the extension. The
computer uses the extensions to know what kind of file it is and what to do with
it. This is known as the "file-format".
Example: in the filename "MyLetter.doc", the filename is "MyLetter" and ".doc"
is the extension. The file (or the "document") is in the ".doc"-format.
Remark: if in Windows Explorer, those file-extensions don't show up on your
computer, this simply means that your configuration is set to hide them (the
default setting). To change it to show the extensions (and some other things),
in Windows Explorer, go to the Options in the menu "Extra", and on the view-tab
uncheck the option to hide file-extensions. You may also want to check/uncheck
some other options there, resulting in a much more advanced and wider file
viewing. You can do this without risk, for in case you don't want to keep the
changes, you always can set them back to default by clicking the
standard/default button.
As the filename "MyLetter" literally means nothing to the computer, it's thanks
to the extension ".doc", the system will know it's a text-document written in Ms
Word and next time you open the file, it will remember to start Ms Word (or
another suitable word-processing program). Without the extension, the system
won't know what to do with the file.
Another example: if you save a picture on your computer, lets say
"mypicture.bmp", then by the extension ".bmp" the computer knows it's a picture
and it's to be opened and viewed with an image-viewer program. The file (or
"document") is in the ".bmp"-format.
Remark: out of the above follows that you must have a bundle of suitable
programs on your computer to open an view the different kinds of files with
their different extensions. Most of the time, this won't give much problems,
'cause most programs you need to open and view the most commonly used
file-formats are already build-in into your operating system.
But remember, when you've got a file and you can't open it, then probably you
don't have the right program to view it installed on your system. If you got
that file from someone other, then ask with which program the file was created.
In the early days file-naming conventions were a lot stricter, a file-name then
could only consist of maximum 8 characters, followed by the point and the
extension, while a directory (folder) name could consist only out of 11
characters; spaces and some other characters were never admitted.
Example : in the filename "myletter.doc", the name "myletter" could only contain
8 characters, no more.
Since the introduction of windows 9.x those conventions are far more relaxed,
and now you can use long file- and folder-names, including spaces (although some
characters (such as the slashes, the asterix and other) are still forbidden,
but windows will warn you about that). So normally you shouldn't encounter much
problems when using long filenames, but... as there're lots of programs on the
market, many of them do still have difficulties with some file-names; especially
when there are spaces in the file-name...
Repeat ;-) especially when there are spaces in the file-name...! A well-known
problem is that a program refuses to open a file from within windows-explorer
because the file-name, and/or the folder-name contains a space; remove the
space(s) in the file-name and everything goes fine...
So if you want to stay on the safe side, do not use spaces in a file- or
folder-name, you can safely use the underscore (_) or hyphen (-) character
instead, or you can switch between uppercase and under case characters (see the
examples below).
e.g.: use the file-name (without the quotes) "Letter-to-Alice.doc" or
"letter_to_alice.doc" or LetterToAlice.doc" instead of "Letter to Alice.doc"
All info provided on an "as is"-basis, without any warranty and/or further
responsibility whatsoever.
All texts are free for personal non-commercial use. Copyright by the NightOwl
(2008).