Saturday, February 5, 2011

Meaning of Extension

 :

Amount or degree or range to which something extends; "the wire has an extension of 50 feet"
Synonyms: lengthiness, prolongation

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History of a file extension

A precise outline of the nature and function of file extensions is surprisingly difficult to define, due to over 40 years of developments in computer hardware and software, and the competing influences of Mac, Windows/Dos, and Unix-like operating systems, each with their own file systems and metadata formats.

The earliest implementation of file extensions was by Digital Equipment Corporation, during the early 1960s, which then broke a file name into the base name and the file extension. Eventually this convention was adopted by Microsoft DOS operating systems and then by Windows. As a matter of interest, expressing the base name and file extension as a single name, separated by a full stop, was only a convention for showing both pieces of information together.
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How should one choose filename extensions?

> Apple is making the right move here (however even they don't use it
> correctly).  The concept of file type extensions have been used by many
> platforms for a long time.  Many people think that this is an adoption of
> some Windows(r) idea.  I don't believe that this is to strictly
> be-like-Windows.  File extensions are used all over the WWW.  Because of
> this, the Mac platform was extension-stupid for a long time.  Sure, they
> had the File Exchange control panel in later systems which helped to solve
> this problem, but it still wasn't where it needed to be.  Mac OS X
> embraces file extensions because they are widely used on the internet.

True. I wasn't saying the whole idea was stupid- just that making them the
"norm" is stupid :)

>
> I believe that file extensions should not be used for EVERY document ever
> produced.  I can understand why we use them on HTML, GIF, JPG, etc.
> however I don't think that the Finance 2001 example is valid.  If we
> understand why extensions are used, it should help to give us guidelines
> for when to use them, and when to use the Mac-like Type/Creator
> combination.
Right.
>
> 1. File extensions help to identify the file type to Mac-dumb operating
> systems.
>
> What I mean is that HTTP servers probably aren't going to become Mac-Savvy
> anytime soon.  That would be quite a movement in the industry.  So, we
> accept this, and make sure that documents likely to end up being
> transported by such systems are using extensions to provide type
> information.  Here we can see that HTML, XML, GIF, JPG, MOV, etc. are used
> effectively.  However, since it is not likely that the Web browsers will
> ever include translators for "Finance 2001" application, it isn't
> necessary to "hint" this information to these kinds of systems.

Browsers don't actually use the file extension to determine the viewer.
They use the MIME type given them by the web server; therefore, it would
be only a few hours' work to edit Apache to determine the mime-type from
the MacOS Type code rather than the extension.

>
> 2.  File extensions help to classify "standard" document types for
> internet and cross-platform use.
>
> Here we can adopt this concept: "If the document has 'viewers' or
> 'editors' across platform boundaries, we should 'type' this document with
> an extension."  If the Finance 2001 application has a Windows and Linux
> version, it might be appropriate for them to use file extensions so that
> when users transport their documents, they appear and interpret correctly.
>  This is also true of all internet-standard document types such as the
> (numerously mentioned) HTML, GIF, etc.  It is proper to embrace the
> internet-standard convention for typing.
>

True enough. It seems to me that what determines whether a file should
have an extension is whether all of the data is in the data fork or not,
and whether the actual user-content of the data is visible in the data
fork. For example: If one opens an Appleworks document in a text editor,
one can read at least parts of the item and know what it is. If one opens
a JPG in a text editor, oh well!
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Advantages of zipping the files:

The process of "zipping" a file refers to putting it into an archive format such as "ZIP." This compresses the file, making it smaller. You can compress several files into a single ZIP archive, making them easier to store and transfer over email as the files are smaller, and they can be moved by just moving that one ZIP file. If you need to move many files, or very large ones, then zipping them may be the best way to go.



Read more: The Advantages of Zipping Files | eHow.com http://www.ehow.com/about_5459328_advantages-zipping-files.

Another advantage to zipping files is that you can more easily transfer them. A file zipped in an archive will be smaller than the original version. It will also be just one file, as you can zip many files into it. This makes emailing the zipped file as an attachment to someone else over the Internet a lot easier, especially because some email websites have a limitation for how large a file you can send through them. That means that you can email a file to someone in zipped format where you wouldn't have been able to send it to them at all otherwise.
Transfe


Read more: The Advantages of Zipping Files | eHow.com http://www.ehow.com/about_5459328_advantages-zipping-files.
Another advantage to zipping files is that you can more easily transfer them. A file zipped in an archive will be smaller than the original version. It will also be just one file, as you can zip many files into it. This makes emailing the zipped file as an attachment to someone else over the Internet a lot easier, especially because some email websites have a limitation for how large a file you can send through them. That means that you can email a file to someone in zipped format where you wouldn't have been able to send it to them at all otherwise.
Transfe


Read more: The Advantages of Zipping Files | eHow.com http://www.ehow.com/about_5459328_advantages-zipping-files.






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