Encoding and Decoding: Overview and List of Third-Party Vendors

ID: q179323

The information in this article applies to:
  • Apple Macintosh System Software, versions 7.0, 7.0.1, 7.1, 7.5, 7.5.1, 7.5.2, 7.5.3, 7.5.5, 7.6, 7.6.1, 8.0
  • Microsoft Windows 95

SUMMARY

This article includes the following information:

  • A brief history of file encoding


  • A list of encoding guidelines


  • A list of third-party manufacturers of encoding and decoding utilities


A BRIEF HISTORY OF ENCODING

Uuencoding

This was historically the first method invented. The encoding was quite simple and caused frequent problems. In particular, the first implementation used the space character for encoding. But, some mail gateways stripped spaces at the end of a line; so, what the recipient got was invalid. Later, a special case was introduced to avoid this problem.

Xxencoding

This rarely used method appeared after the initial problems with uuencoding, but before they were fixed. It avoids using the space character by using a different character set for encoding.

Base64

This method was introduced for Multipurpose Internet Mail Extensions (MIME) standard, avoiding some rarely encountered problems with the other two methods (which used some characters not available on some computers). Together, with other benefits of MIME, this is the most secure method.

BinHex

A method conceived for transferring files among Macintosh systems. Files on a Macintosh consist of two parts, the "data fork" and the "resource fork." This encoding first adds a third header part, and composes the three parts into a single data stream, which is then slightly compressed and encoded.

ENCODING GUIDELINES

When you work with file encoding, follow these guidelines:
  • Avoid Xxencoding, which is obsolete.


  • You must use BinHex for Macintosh systems. It should not be used on other systems, because decoders are not widespread elsewhere.


  • If your mail software is MIME-compliant and offers to "attach" files encoded in Base64, use this method of encoding, as it is the preferred method for MIME messages. Otherwise, use uuencoding, which is still the most common encoding method.

    Notes:

    • MIME-compliance is something only the mail software can handle. For example if you encode data to Base64 using UUDeview and then include the encoded data in your message, the resulting message will not be MIME-compliant.


    • If your mail software does not allow "attachments" on its own and you have to use an external encoder, always use uuencoding.


    • Software is becoming more and more MIME-compliant which means that the uuencoding method will be replaced by Base64. However, as long as there is the possibility that the recipient uses older software, uuencoding is the safest method.




  • Compression is also an important issue. When possible, you should send a file compressed into a ZIP file or some similar format.


THIRD-PARTY ENCODING AND DECODING UTILITIES

The following third-party utilities can reintegrate a text-encoded file into its binary format:


MORE INFORMATION

The third-party contact information included in this article is provided to help you find the technical support you need. This contact information is subject to change without notice. Microsoft in no way guarantees the accuracy of this third-party contact information.

The third-party products discussed here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.

Additional query words: bin-hex hexadecimal

Keywords : kb3rdparty
Version : MACINTOSH:7.0,7.0.1,7.1,7.5,7.5.1,7.5.2,7.5.3,7.5.5,7.6,7.6.1,8.0; WINDOWS:95
Platform : MACINTOSH WINDOWS
Issue type : kbinfo


Last Reviewed: January 20, 2000
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