How to Decipher Mac Filenames
Filenames in Mac OS X can be up to 255 characters long, and you can use any characters you like except the colon (:). Windows doesn’t allow any of the following special characters in filenames:
: \ / | * < ? " >
If you’re planning to move files back and forth between your PC and Mac, it’s a good idea to follow the more restrictive Windows naming rules so that filenames don’t get mangled.
In the Windows world, filenames have extensions — a period (.) and a few letters that are added to the end of a filename, for example, Chapter5.doc. The file extension tells the operating system what type of file it is so that the OS knows which program should open it. OS X uses file extensions in the same way, but it also has a separate way to know the file type and creator, using special four-letter codes for each that are stored with the file’s directory entry.
A file is stored in a folder, which may be in another folder, which may be in another folder, and so on. Operating systems keep track of all that hierarchy using a pathname. The pathname lists all the folders you have to visit in turn to find your file. The names are separated by a special character. In Windows, this character is the backslash (\). For Macs — and in UNIX, in Linux, and on the Internet — the forward slash (/), sometimes called the front slash, is used.