Mac OS X 10.5 Help
About naming files for sharing
When you create a file-sharing or download page to share files on your iDisk, the files are available to anyone on the Internet regardless of the type of computer they use.
To offer your files to the widest possible audience, use filenames that are compatible with computers that don't offer the same file-naming flexibility as your Macintosh.
Consider the following when naming files you want to share:
Special characters in filenames can cause problems on some computers. Use only uppercase letters (A-Z), lowercase letters (a-z), numbers (0-9), and the underscore (_) in your filenames.
Use a period (.) only to separate a filename extension from the rest of the name. Do not begin a filename with a period.
Some computers rely on filename extensions (for example, the ".doc" in the filename "letter.doc" or ".jpg" in "picture.jpg") to decide which application should open a file. If you don't include extensions in your filenames, someone downloading a file might not know how to open it.
Some computers use short filenames. To make sure anyone can copy shared files, use 8 or fewer characters to name them (12 characters total if you include an extension).
If you include extensions in your filenames, when someone using a different type of computer tries to download a file from your file-sharing page, their browser may open the file in a browser window instead of copying the file to their disk. In this case, they should be able to use the browser's Save or Save As command to save a copy of the file.