Encoding is a process that transforms files so they can be safely transferred across the Internet. Most Macintosh files cannot be transferred across the Internet without first being encoded. A Macintosh file is made up of two parts, or forks - a data fork and a resource fork. Each fork is made up of 8 bits, making the average Macintosh file 16 bits. On Windows-based and other computers, files have only one part - a data fork, creating 8-bit files.
Below are the most common forms of file encoding:
UU encoding takes only the 8-bit data fork and converts it into a 7-bit file. This format is normally used for Windows files because it only recognizes the file's data fork. It can be used for Mac files that do not store crucial information in their resource fork (i.e., '.jpg' files, text files without formatting), however most Mac files store crucial information in the resource fork, such as applications, some word processing documents, and control panels. This method of encoding typically produces the largest file of any of these encoding methods. Files that have been UU-encoded typically have a '.uu' extension in the name.
MIME (Multipurpose Internet Mail Extensions) is not a method of encoding, but rather a map. It maps a particular method of encoding to an application that can decode that file. You may be most familiar with this as your Netscape Navigator or Internet Explorer helper applications. If you choose to change or add a helper application, you must specify the MIME type. As part of the encoded file, the MIME type maps to, or uses, a particular application to decode, or read, a file. For example, Expander is the typical application mapped to decode files whose MIME type is application/mac-binhex40. Microsoft Word is the application that is mapped to decode, or read, files whose MIME type is application/msword.
Base64 encoding takes an 8-bit file and converts it into a 7-bit file. You can use this format to transfer files through any method. This method of encoding typically produces the smallest file of any of these encoding methods. This method is relatively new and not all programs that use it do so in the same way. For instance, some programs may include both the data and resource forks, others may not. There are also some programs that do not support this method at all. While it seems that this method may become a standard, currently you may want to check the results when using it.
BinHex encoding takes the 8-bit resource and data forks of a Macintosh file and converts them into a single 7-bit file. This is useful for transferring files in any method, including via email. Files that have been BinHex encoded typically have an '.hqx' extension in the name.
MacBinary encoding takes the 8-bit resource and data forks of a Macintosh file and converts them into a single 8-bit file. This method should normally be used for transferring files to and from Macintosh computers. Files that have been MacBinary-encoded typically have a '.bin' extension in the name.
AppleDouble encoding takes the 8-bit resource and data forks of a Macintosh file and converts them into a single 8-bit file, then uses Base64 encoding to convert that file to a 7-bit file.
StuffIt products support these encoding formats and more. |
