RFC 1740 (rfc1740) - Page 2 of 16

MIME Encapsulation of Macintosh Files - MacMIME

RFC 1740                  MIME-based Mac files             December 1994


   The two styles of use are [APPL90]:

   AppleSingle:   Apple's standard format for encoding Macintosh files
                  as one byte stream.
   AppleDouble:   Similar to AppleSingle except that the Data fork is
                  separated from the Macintosh-specific parts by the
                  AppleDouble encoding.

   AppleDouble is the preferred format for a Macintosh file that is to
   be included in an Internet mail message, because it provides
   recipients with Macintosh computers the entire document, including
   Icons and other Macintosh specific information, while other users
   easily can extract the Data fork (the actual data) as it is separated
   from the AppleDouble encoding.

2.  MIME format for Apple/Macintosh-specific file information

   2a.  APPLICATION/APPLEFILE

      MIME type-name:            APPLICATION
      MIME subtype name:         APPLEFILE
      Required parameters:       none
      Optional parameters:       NAME, which must be a "value" as
                                 defined in RFC-1521 [BORE93].
      Encoding considerations:   The presence of binary data will
                                 typically require use of
                                 Content-Transfer-Encoding: BASE64
      Security considerations:   See separate section in the document
      Published specification:   Apple-single & Apple-double [APPL90]
      Rationale:                 Permits MIME-based transmission of
                                 data with Apple/Macintosh specific
                                 information, while allowing general
                                 access to non-specific user data.

   2b.  MULTIPART/APPLEDOUBLE

      MIME type-name:            MULTIPART
      MIME subtype name:         APPLEDOUBLE
      Required parameters:       none
      Optional parameters:       NAME, which must be a "value" as
                                 defined in RFC-1521 [BORE93].
      Encoding considerations:   none
      Security considerations:   See separate section in the document
      Published specification:   Apple-single & Apple-double [APPL90]
      Rationale:                 Permits MIME-based transmission of
                                 data with Apple/Macintosh specific
                                 information, while allowing general
                                 access to non-specific user data.



Faltstrom, Crocker & Fair